Tropical Storm Paulette

Tropical Storm Paulette Track 1500 Hours Sepember 22 2020
Tropical Storm Paulette Track 1500 Hours Sepember 22 2020

Tropical Storm Paulette Wind Speed FieldREVIVED Tropical Storm Paulette – NWS National Hurricane Center Miami FL 900 PM GMT Tue Sep 22, 2020 (see Tuesday video below)

Although Paulette lacks the typical definition for deep convection, there remains some convection with cloud tops to -20 deg C encircling an eye-like feature noted in the lower cloud layer. Given the low tropopause level across that portion of the Atlantic basin causing the relatively low cloud tops, Paulette is being maintained as a tropical cyclone for at least this cycle. Vertical wind shear near 30 kt along with sea-surface temperatures of 23-22 deg C are expected to result in a gradual weakening and spin down of Paulette’s circulation throughout the forecast period. As a result, the small cyclone should become a remnant low on Wednesday and dissipate by Friday or Saturday when the shallow system will be moving westward into westerly mid-level shear.

Paulette is moving eastward or 080/10 kt. This general motion is forecast to continue through Wednesday as Paulette remains embedded within deep-layer westerly flow on the east side of mid- to upper-level trough. As Paulette weakens and becomes more vertically shallow, the post-tropical cyclone is expected to slow down in the 36-48 time period and turn southward. Thereafter, Paulette should be steered westward by low-level easterly flow on the south side of the Bermuda-Azores High. The new NHC track forecast is similar to the previous advisory track, and essentially lies down the middle of the NHC track guidance models.

FORECAST POSITIONS AND MAX WINDS

INIT  22/2100Z 34.8N  21.2W   35 KT  40 MPH - Tropical Storm (ENE Funchal, Madeira)
 12H  23/0600Z 35.0N  19.4W   30 KT  35 MPH - Low (ENE Funchal, Madeira)
 24H  23/1800Z 35.4N  17.5W   30 KT  35 MPH - Low (ENE Funchal, Madeira)
 36H  24/0600Z 35.3N  16.4W   25 KT  30 MPH - Low (ENE Funchal, Madeira)
 48H  24/1800Z 34.7N  16.7W   25 KT  30 MPH - Low (ENE Camacha, Portugal)
 60H  25/0600Z 33.6N  19.0W   25 KT  30 MPH - Low (ENE Funchal, Madeira)
 72H  25/1800Z 32.8N  22.4W   25 KT  30 MPH - Low (ENE Funchal, Madeira)
 96H  26/1800Z...DISSIPATED

NWS National Hurricane Center Miami FL 300 PM GMT Tue Sep 22, 2020

The last of the deep convection near the center of Paulette dissipated early this morning, and the circulation now consists of low-topped shower activity with the cloud tops warmer than -30 degrees C. The nearest shower activity that could qualify as deep convection is nearly 100 n mi from the cyclone’s center and appears to be associated with a frontal boundary. A pair of recent ASCAT overpasses sampled peak winds of 33 kt, and therefore the initial advisory intensity is being lowered to 35 kt. Moderate-to-strong vertical wind shear and cool sea surface temperatures are expected to continue to weaken Paulette, and the cyclone is forecast to become a remnant low within 36 h. If the deep convection does not return to Paulette soon, then the cyclone could be declared a remnant low by as early as this evening.

Paulette is moving eastward at 12 kt, and this general motion is expected to continue through Wednesday as the cyclone remains embedded in the flow around a mid-latitude trough to its north. The trough is expected to lift out of the region in about 36 h, and a ridge is forecast to build in its place in a couple of days. This evolution should cause Paulette, or its remnants, to slow down and make a 180 degree right turn over the course of a couple of days. By late week, whatever is left of the cyclone should be moving west-southwestward. An alternate scenario depicted by a couple of the models is that Paulette never escapes the flow around the trough and continues to move east-northeast until it dissipates. The latest NHC track forecast is in good agreement with the previous one, but is somewhat uncertain after 36 h due to the diverging model solutions.

FORECAST POSITIONS AND MAX WINDS

INIT  22/1500Z 35.0N  22.3W   35 KT  40 MPH - Tropical Storm (ENE Funchal, Madeira)
 12H  23/0000Z 35.2N  20.3W   35 KT  40 MPH - Tropical Storm (ENE Funchal, Madeira)
 24H  23/1200Z 35.6N  18.1W   30 KT  35 MPH - Depression (ENE Funchal, Madeira)
 36H  24/0000Z 35.9N  16.5W   30 KT  35 MPH - Low (ENE Funchal, Madeira)
 48H  24/1200Z 35.6N  15.9W   25 KT  30 MPH - Low (ENE Funchal, Madeira)
 60H  25/0000Z 34.9N  15.8W   25 KT  30 MPH - Low (ENE Camacha, Portugal)
 72H  25/1200Z 33.9N  18.8W   25 KT  30 MPH - Low (WNW Funchal, Madeira)
 96H  26/1200Z...DISSIPATED

NWS National Hurricane Center Miami FL 300 AM GMT Tue Sep 22, 2020

Deep convection associated with the post-tropical remnants of Paulette that moved southward to the southwest of the Azores over the past few days has become better organized over the past 6-12 hours. An ASCAT over pass from a few hours ago indicate that increase in convective organization has result in strengthening and the system is being classified as a tropical cyclone once again. The ASCAT revealed peak winds of just over 45 kt, and given that instruments typical undersampling, the initial intensity is set at 50 kt. The scatterometer data also indicated a small radius of maximum winds of about 30 n mi, therefore the system is being classified as a tropical cyclone rather than subtropical.

Paulette is moving east-northeastward or 075/14 kt. The tropical storm should continue moving east-northeastward ahead of a mid-latitude trough dropping southeastward over the northeastern Atlantic, and the global models are in reasonably good agreement through 24-36 hours. After that time, there is significant bifurcation in the track guidance with the GFS, HWRF, and HMON all taking a stronger Paulette faster east-northeastward over the eastern Atlantic, while the UKMET and ECMWF show a weaker cyclone slowing down and turning west-southwestward in the low-level steering flow late in the forecast period. The NHC track forecast shows Paulette slowing down and turning southward, and then southwestward between 48-96 h, but it’s not nearly as far west as the UKMET and ECMWF models. Given the large spread in the track guidance at that time period, the NHC forecast is near the HFIP corrected consensus.

Paulette is already over marginal SSTs and cooler waters lie ahead along the forecast track. This, along with moderate vertical wind shear should result in gradual weakening beginning on Tuesday. The NHC intensity forecast calls for Paulette to weaken to a tropical depression in 48-60 h, and become a remnant low shortly thereafter.

FORECAST POSITIONS AND MAX WINDS

INIT  22/0300Z 33.9N  25.3W   50 KT  60 MPH - Tropical Storm (ESE Ponta Delgada, Azores)
 12H  22/1200Z 34.4N  22.8W   50 KT  60 MPH - Tropical Storm (ESE Ponta Delgada, Azores)
 24H  23/0000Z 34.7N  20.4W   45 KT  50 MPH - Tropical Storm (WNW Funchal, Madeira)
 36H  23/1200Z 35.1N  18.2W   40 KT  45 MPH - Tropical Storm (WNW Funchal, Madeira)
 48H  24/0000Z 35.3N  16.8W   35 KT  40 MPH - Tropical Storm (ENE Funchal, Madeira)
 60H  24/1200Z 34.7N  16.3W   30 KT  35 MPH - Low (ENE Funchal, Madeira)
 72H  25/0000Z 34.0N  16.3W   25 KT  30 MPH - Low (ENE Camacha, Portugal)
 96H  26/0000Z 33.1N  18.4W   25 KT  30 MPH - Low (ENE Funchal, Madeira)
120H  27/0000Z...DISSIPATED

NWS National Hurricane Center Miami FL 1100 AM AST Wed Sep 16, 2020 

Conventional GOES-16 visible and enhanced BD-curve satellite imagery show that Paulette has merged with the large baroclinic zone extending over the north-central Atlantic. Deep convection just to the north of the surface center that was noted on earlier microwave images has dissipated. Therefore, the system is now classified as extratropical cyclone and this is the last NHC advisory. The initial intensity is conservatively lowered to 75 kt based on 1221 UTC scatterometer data, earlier Dvorak intensity estimates and a SATCON analysis of 64 kt. The NHC intensity forecast is based on a blend of the global models and is just above the HCCA multi-model consensus. Although not specified in the NHC forecast, there is some chance that Paulette could reacquire tropical or subtropical characteristics later this week or over the weekend when it turns southward back over warmer oceanic temperatures. This possibility will be monitored for inclusion in future Tropical Weather Outlooks, if necessary.

The post-tropical cyclone’s initial motion is east-northeastward, or 060/30 kt. The low is expected to continue quickly in this general motion through Thursday morning within the deep-layer mid-latitude flow. By mid-period, Post-Tropical Paulette is expected to slow down and turn southeastward to southward as it moves on the west side of mid- to upper-level low to the east of the cyclone. The new track forecast is based primarily on the HCCA and TVCA consensus aids.

Paulette is producing a large area of high seas. The maximum seas estimated by the Ocean Prediction Center near the core of the hurricane are up to 50 feet. Swells from Post-Tropical Cyclone Paulette have spread far away from the center and continue to affect Atlantic Canada, Bermuda, and portions of the U.S. east coast.

This is the last NHC advisory on Paulette – or not as NWS changes last advisory.

FORECAST POSITIONS AND MAX WINDS

INIT  16/1500Z 43.3N  45.2W   75 KT  85 MPH - Post Tropical (ESE St. John's, Canada)
 12H  17/0000Z 45.0N  39.9W   60 KT  70 MPH - Post Tropical (ESE St. John's, Canada)
 24H  17/1200Z 46.2N  35.3W   50 KT  60 MPH - Post Tropical (ESE St. John's, Canada)
 36H  18/0000Z 45.1N  33.1W   40 KT  45 MPH - Post Tropical (ESE St. John's, Canada)
 48H  18/1200Z 42.5N  32.5W   35 KT  40 MPH - Post Tropical (WNW Vila do Corvo, Azores)
 60H  19/0000Z 39.5N  32.5W   35 KT  40 MPH - Post Tropical (WNW Vila do Corvo, Azores)
 72H  19/1200Z 37.0N  32.7W   35 KT  40 MPH - Post Tropical (WSW Vila do Corvo, Azores)
 96H  20/1200Z 35.0N  32.9W   35 KT  40 MPH - Post Tropical (WSW Ponta Delgada, Azores)
120H  21/1200Z 34.0N  32.4W   35 KT  40 MPH - Post Tropical (WSW Ponta Delgada, Azores)

NWS National Hurricane Center Miami FL 1100 PM AST Tue Sep 15, 2020 

Paulette is gradually losing tropical characteristics. Geostationary satellite and microwave data indicate that the low-level center is located near the southern edge of the main area of deep convection and that the hurricane is starting to get tangled up with a nearby baroclinic zone. A recent ASCAT-B overpass showed maximum winds in the 75-80 kt range in the southwestern quadrant. It is quite impressive to see such high values from that instrument given that ASCAT usually can’t resolve the maximum winds in hurricanes. The initial intensity is therefore held at 85 kt.

Since Paulette is forecast to move over much cooler waters and into an environment of strong wind shear and dry air, weakening is expected. Paulette is forecast to become an extratropical cyclone in about 24 hours when it will likely merge with the nearby front and move over SSTs of about 20 C. There is some chance that Paulette could regain tropical or subtropical characteristics toward the end of the forecast period when it is expected to move back over warmer waters. The NHC intensity forecast is largely an update of the previous one, which is a blend of the intensity consensus models and the GFS.

The hurricane continues to race east-northeastward at about 24 kt. A continued fast east-northeastward motion within the mid-latitude westerlies is expected for another day or so. After that, Post-tropical Paulette is expected to slow down and turn southeastward and then southward as it moves on the west side of a deep-layer low pressure system. The new track forecast is similar to the previous one and lies between the HCCA and TVCA consensus models.

Paulette is producing a large area of high seas. The maximum seas estimated by the Ocean Prediction Center near the core of the hurricane are 52 feet. Swells from the hurricane have spread far away from the center and continue to affect Atlantic Canada, Bermuda, and portions of the U.S. east coast.

FORECAST POSITIONS AND MAX WINDS

INIT  16/0300Z 40.7N  52.4W   85 KT 100 MPH - Category 2 (ESE St. Georges, Bermuda)
 12H  16/1200Z 42.6N  47.4W   80 KT  90 MPH - Category 1 (ESE St. Georges, Bermuda)
 24H  17/0000Z 44.7N  40.8W   70 KT  80 MPH - Extra Tropical (ESE St. John's, Canada)
 36H  17/1200Z 45.7N  36.1W   55 KT  65 MPH - Extra Tropical (ESE St. John's, Canada)
 48H  18/0000Z 44.8N  34.2W   50 KT  60 MPH - Extra Tropical (ESE St. John's, Canada)
 60H  18/1200Z 42.4N  33.7W   45 KT  50 MPH - Extra Tropical (WSW Vigo, Spain)
 72H  19/0000Z 40.1N  33.7W   40 KT  45 MPH - Extra Tropical (WNW Vila do Corvo, Azores)
 96H  20/0000Z 36.8N  34.0W   35 KT  40 MPH - Extra Tropical (WSW Vila do Corvo, Azores)
120H  21/0000Z 34.4N  34.2W   35 KT  40 MPH - Extra Tropical (WSW Vila do Corvo, Azores)

NWS National Hurricane Center Miami FL 500 PM AST Tue Sep 15, 2020 

Another fortuitous AMSR2 microwave pass over the cyclone showed the outer concentric ring open over the south semicircle and a more noticeable vertical tilt. Furthermore, the cloud tops associated with the deep convection in the north quadrant have warmed during the past several hours. Consequently, the initial intensity is lowered to 85 kt and is in best agreement with the subjective and objective satellite intensity estimates.

Paulette continues to lose its tropical characteristics as it mingles with the rapidly approaching baroclinic zone from the northwest. In fact, earlier successive METOP A and B scatterometer passes on Paulette revealed that the northwest quadrant 34-kt wind radii had nearly doubled in size due to the aforementioned invading frontal zone moving out of the Canadian Maritimes. The sea surface temperatures quickly decrease to less than 20C within 24 hours as Paulette accelerates east-northeastward. As a result, the cyclone should weaken rather quickly and complete its extratropical transition on Thursday, as indicated in the global models and the statistical-dynamical guidance.

Paulette is moving east-northeastward, or 060/26 kt, and this motion should continue with a further increase in forward speed through Thursday. Toward the end of the week, the cyclone will likely turn south-southeastward to southward as it moves within the western peripheral flow of a mid- to upper tropospheric cut off low to the east of the cyclone. The NHC track forecast is basically an update of the previous advisory and is based on the various consensus guidance.

The initial wind radii and subsequent forecast wind radii were adjusted based on METOP A/B ASCAT 1110 UTC and 1424 UTC scatterometer passes.

FORECAST POSITIONS AND MAX WINDS

INIT  15/2100Z 39.5N  55.0W   85 KT 100 MPH - Category 2 (ESE St. Georges, Bermuda)
 12H  16/0600Z 41.4N  50.1W   80 KT  90 MPH - Category 1 (ESE St. Georges, Bermuda)
 24H  16/1800Z 44.0N  42.9W   70 KT  80 MPH - Category 1 (ESE St. Georges, Bermuda)
 36H  17/0600Z 45.8N  36.8W   55 KT  65 MPH - Extra Tropical (ESE St. Georges, Bermuda)
 48H  17/1800Z 45.8N  33.7W   50 KT  60 MPH - Extra Tropical (ESE St. John's, Canada)
 60H  18/0600Z 43.9N  32.8W   45 KT  50 MPH - Extra Tropical (ESE St. John's, Canada)
 72H  18/1800Z 41.2N  32.8W   40 KT  45 MPH - Extra Tropical (ESE St. John's, Canada)
 96H  19/1800Z 38.0N  32.5W   35 KT  40 MPH - Extra Tropical (WSW Bordeaux, France)
120H  20/1800Z 34.5N  32.3W   35 KT  40 MPH - Extra Tropical (WNW Vila Do Corvo, Portugal)

NWS National Hurricane Center Miami FL 1100 AM AST Tue Sep 15, 2020 

A 0533 UTC AMSR2 overpass on Paulette already reveals structural changes associated with the approaching mid-latitude baroclinic zone. The microwave image and GOES-16 mid- to upper-level water vapor imagery show drier more stable air beginning to intrude into the western portion of the cyclone. Additionally, Paulette’s rain shield is more confined to the northern half of the system, while drying out in the southern semi-circle. Only fragments of the eyewall remain in that particular area. The initial intensity is held at 90 kt for this advisory and is supported by the subjective satellite intensity estimate T-numbers from TAFB and SAB. Although Paulette is beginning to lose some of its tropical characteristics, the cyclone still has a small window of opportunity to strengthen while it continues moving over warm sea surface temperatures during the next 12-18 hrs. Afterward, the water temperature drop drastically to less than 20C while Paulette becomes more involved with the aforementioned baroclinic system. As a result, the cyclone should weaken rather rapidly and complete its extratropical transition on Thursday, and this is based on an agreement of the large-scale models and the statistical-dynamical guidance.

The aforementioned microwave pass indicated that the center of circulation was a bit west-southwest of the previous position and therefore the initial estimated motion is believed to be northeastward, or 055/25 kt. Paulette is forecast to accelerate further and turn east-northeastward later tonight and continuing through Wednesday night, then slow down a bit on Thursday. Toward the end of the week, the cyclone will likely turn east- southeastward to south-southeastward as it moves within the western peripheral flow of a mid- to upper tropospheric cut off low to the east of the cyclone. The NHC track forecast is just a little faster than the previous one through 60 hours and lies closer to the HFIP Corrected Consensus Approach model and is also similar to the GFEX ECMWF/FV3 simple consensus.

FORECAST POSITIONS AND MAX WINDS

INIT  15/1500Z 38.3N  57.9W   90 KT 105 MPH - Category 2 (ESE St. Georges, Bermuda)
 12H  16/0000Z 40.1N  53.6W   95 KT 110 MPH - Category 2 (ESE St. Georges, Bermuda)
 24H  16/1200Z 42.7N  46.8W   85 KT 100 MPH - Category 2 (ESE St. Georges, Bermuda)
 36H  17/0000Z 45.0N  40.1W   70 KT  80 MPH - Category 1 (ESE St. Georges, Bermuda)
 48H  17/1200Z 46.2N  35.7W   55 KT  65 MPH - Extra Tropical (ESE St. Georges, Bermuda)
 60H  18/0000Z 45.6N  33.9W   45 KT  50 MPH - Extra Tropical (ESE St. John's, Canada)
 72H  18/1200Z 43.9N  33.3W   40 KT  45 MPH - Extra Tropical (ESE St. John's, Canada)
 96H  19/1200Z 39.9N  32.2W   35 KT  40 MPH - Extra Tropical (WSW Bordeaux, France)
120H  20/1200Z 37.0N  31.5W   35 KT  40 MPH - Extra Tropical (WNW Vila Do Corvo, Portugal)

NWS National Hurricane Center Miami FL 1100 PM AST Mon Sep 14, 2020 

Paulette’s cloud pattern has degraded during the past few hours, and recent microwave imagery suggests that the eyewall of the hurricane was at least for a time open to the south. A larger mostly closed ring of convection was also present, indicating that Paulette may be going through an eyewall replacement cycle. Satellite-based current intensity estimates range from 65 to 102 kt, but have generally decreased since the last advisory. The intensity estimate remains 90 kt at this time, but there is a high degree of uncertainty in this assessment.

Assuming Paulette can maintain a well-defined inner core, either through the completion of an eyewall replacement cycle or redevelopment of convection in the southern eyewall, it should have an opportunity to strengthen during the next 24 h. The intensity guidance is not quite as bullish anymore, so the intensity forecast has been lowered slightly, but it is still above the intensity consensus through 36 h. Paulette could begin to lose tropical characteristics around that time and rapid weakening is expected as a result. The NHC forecast conservatively shows Paulette becoming fully post-tropical in 72 h, but there are indications from the GFS simulated satellite imagery that it could complete its transition sooner.

Paulette has turned northeastward and is accelerating, as predicted, with an initial motion estimate of 35/15 kt. The system will likely race generally east-northeastward for the next few days. A slower motion and eventual turn southeastward or even southward is expected near the end of the week when the cyclone encounters a large cut-off low over the eastern Atlantic, however it should be post-tropical by that time. The track guidance remains in excellent overall agreement overall, and NHC forecast is based heavily on TVCN and HCCA.

FORECAST POSITIONS AND MAX WINDS

INIT  15/0300Z 35.7N  62.3W   90 KT 105 MPH - Category 2 (ESE St. Georges, Bermuda)
 12H  15/1200Z 37.4N  59.6W  100 KT 115 MPH - Category 3 (ENE St. Georges, Bermuda)
 24H  16/0000Z 39.8N  54.4W  105 KT 120 MPH - Category 3 (ENE St. Georges, Bermuda)
 36H  16/1200Z 42.3N  48.2W   95 KT 110 MPH - Category 2 (ENE St. Georges, Bermuda)
 48H  17/0000Z 44.6N  41.9W   75 KT  85 MPH - Category 1 (ESE St. John's, Canada)
 60H  17/1200Z 46.0N  37.3W   60 KT  70 MPH - Tropical Storm (ESE St. John's, Canada)
 72H  18/0000Z 45.8N  35.6W   45 KT  50 MPH - Low (ESE St. John's, Canada)
 96H  19/0000Z 43.0N  33.5W   35 KT  40 MPH - Low (WSW Bordeaux, France)
120H  20/0000Z 39.0N  32.0W   35 KT  40 MPH - Low (WNW Vila Do Corvo, Portugal)

The wind radii analysis and forecast were updated based on data from an ASCAT-A overpass at 0050 UTC.

NWS National Hurricane Center Miami FL 500 PM AST Mon Sep 14, 2020 

Overall, Paulette’s satellite presentation has improved during the past several hours. In fact, a 1743 UTC AMSR2 microwave pass showed a developing concentric eyewall cloud pattern with a fully enclosed eyewall and a larger outer convective ring that was nearly closed off. A blend of the UW-CIMSS objective T-number of 94 kt and the Dvorak satellite intensity estimates from TAFB and SAB yields an initial intensity of 90 kt for this advisory.

Additional strengthening is expected as Paulette moves away from Bermuda and accelerates northeastward over the North Atlantic. Paulette should be at or near major hurricane strength within the next 12-24 hours. On Wednesday, weakening is expected to begin as the cyclone traverses a sharp gradient of decreasing (less than 23C) oceanic temperatures. Around the same time, the deterministic models are indicating that the cyclone will begin to interact with a baroclinic boundary associated with major shortwave trough. Paulette should begin to lose its tropical characteristics at that time and complete an extratropical cyclone transition in 3 days. The ECMWF and FV3 SHIPS intensity models show the transition completed in 48 hours, which is also a possibility.

The initial motion is estimated to be north-northeastward, or 030/13 kt. Paulette will begin accelerating northeastward by Tuesday morning, and then turn east-northeastward with a further increase in forward speed by Tuesday night. A slower southeastward motion is forecast on Friday in response to a larger mid- to upper tropospheric cut-off low approaching the eastern Atlantic. The NHC forecast is basically an update of the previous advisory and is very close to the HFIP Corrected Consensus Approach model and lies down the middle of the tightly clustered various interpolated deterministic aids.

The initial wind radii and subsequent forecast wind radii were adjusted based on METOP A/B ASCAT 1232 UTC scatterometer passes.

FORECAST POSITIONS AND MAX WINDS

INIT  14/2100Z 34.5N  63.8W   90 KT 105 MPH - Category 2 (ESE St. Georges, Bermuda)
 12H  15/0600Z 36.1N  61.9W  100 KT 115 MPH - Category 3 (ENE St. Georges, Bermuda)
 24H  15/1800Z 38.4N  57.2W  110 KT 125 MPH - Category 3 (ENE St. Georges, Bermuda)
 36H  16/0600Z 40.8N  51.3W  110 KT 125 MPH - Category 3 (ENE St. Georges, Bermuda)
 48H  16/1800Z 43.3N  44.9W   90 KT 105 MPH - Category 2 (ENE St. Georges, Bermuda)
 60H  17/0600Z 45.4N  39.4W   65 KT  75 MPH - Category 1 (ESE St. John's, Canada)
 72H  17/1800Z 46.6N  35.8W   50 KT  60 MPH - Post Tropical (ESE St. John's, Canada)
 96H  18/1800Z 44.3N  32.6W   40 KT  45 MPH - Post Tropical (WSW Bordeaux, France)
120H  19/1800Z 39.1N  31.3W   35 KT  40 MPH - Post Tropical (WNW Vila Do Corvo, Portugal)

NWS National Hurricane Center Miami FL 1100 AM AST Mon Sep 14, 2020

The 53rd Air Force Reserve hurricane hunter aircraft observed a peak 700 mb flight-level wind of 93 kt and a SFMR wind of 80 kt 25 miles to the northeast of the center of the 35 mile wide eye. The central pressure, also reported by the aircraft, has fallen to 970 mb. Based on these data, the initial intensity is increased to 85 kt for this advisory. Additional strengthening is expected as Paulette moves away from Bermuda and accelerates northeastward over the North Atlantic. Paulette should be at or near major hurricane strength within the next 24 hours. At the 48 hour forecast period, weakening will commence as the cyclone becomes involved with a mid-latitude shortwave trough approaching from the Canadian Maritimes. Paulette should begin losing its tropical characteristics toward the end of the week. The peak intensity is increased a little at the 24 hour period to agree with the HCCA and IVCN intensity multi-models and follows these aids through the remaining portion of the forecast period. The initial motion estimate is 355/12 kt. Paulette will begin accelerating northeastward by Tuesday morning then turn east-northeastward with a further increased in forward motion early Wednesday morning. A slower eastward to southeastward motion is forecast on Friday in response to a larger mid- to upper tropospheric cut-off low approaching the eastern Atlantic. The NHC forecast is a little faster than the previous one beyond the 36 hour period and basically lies down the middle of the tightly clustered deterministic and regional model guidance.

Key Messages:

  • 1. The eye of Paulette will gradually move away from Bermuda today, however, hurricane and tropical storm conditions, storm surge, and very heavy rainfall will likely continue into this afternoon.
  • 2. Swells produced by Paulette are affecting portions of the Leeward Islands, the Greater Antilles, the Bahamas, Bermuda, and the east coast of the United States. These swells could cause life-threatening surf and rip current conditions.
FORECAST POSITIONS AND MAX WINDS

INIT  14/1500Z 33.4N  64.7W   85 KT 100 MPH - Category 2 (ESE St. Georges, Bermuda)
 12H  15/0000Z 35.1N  63.6W   95 KT 110 MPH - Category 2 (ESE St. Georges, Bermuda)
 24H  15/1200Z 37.5N  59.8W  110 KT 125 MPH - Category 3 (ENE St. Georges, Bermuda)
 36H  16/0000Z 40.1N  54.2W  110 KT 125 MPH - Category 3 (ENE St. Georges, Bermuda)
 48H  16/1200Z 42.9N  47.6W   90 KT 105 MPH - Category 2 (ENE St. Georges, Bermuda)
 60H  17/0000Z 45.5N  41.1W   75 KT  85 MPH - Category 1 (ESE St. John's, Canada)
 72H  17/1200Z 47.1N  36.8W   65 KT  75 MPH - Category 1 (ESE St. John's, Canada)
 96H  18/1200Z 45.5N  33.2W   50 KT  60 MPH - Tropical Storm (WSW Bordeaux, France)
120H  19/1200Z 40.1N  32.1W   45 KT  50 MPH - Low (WNW Vila Do Corvo, Portugal)

NWS National Hurricane Center Miami FL 1100 PM AST Sun Sep 13, 2020 

The eye of Paulette is steadily nearing Bermuda. Although it has appeared slightly ragged at times in IR imagery, radar imagery from Bermuda and the NOAA P3 show that the eye and eyewall of Paulette are very well defined in all quadrants but the southwest. The NOAA hurricane hunter plane measured peak flight-level winds of 89 kt (which adjust to 80 kt at the surface) and SFMR winds of 70 kt. Taking an average of those supports the initial intensity of 75 kt. The minimum pressure measured by the NOAA aircraft in its last pass through the eye was 976 mb.

The track, intensity, and wind radii forecasts for Paulette are very similar to the last advisory. Given its improved structure over the past day or so and its favorable upper-air environment, some additional strengthening appears likely as Paulette approaches Bermuda during the next few hours. Further intensification is possible after the hurricane accelerates northeastward away from Bermuda and Paulette is expected to be at or near major hurricane strength on Tuesday. By the end of the forecast period, weakening is expected as Paulette interacts with a mid-latitude trough and begins to lose its tropical characteristics. The NHC intensity forecast is generally just above the intensity consensus but is within the tightly clustered guidance envelope at all times.

Confidence in the track forecast is quite high and the models are in excellent agreement on Paulette’s future for the next few days. The hurricane will approach Bermuda and turn northward tomorrow, then accelerate northeastward through the middle of the week. A slower eastward or even southeastward motion is possible by Friday when a large cut-off mid- to upper-level low over the eastern Atlantic is forecast to begin influencing Paulette’s track.

Key Messages:

  • 1. The eye of Paulette will approach Bermuda early Monday and hurricane conditions are expected to begin on the island within the next few hours. A prolonged period of strong winds, storm surge, and very heavy rainfall will likely continue into Monday afternoon.
  • 2. Swells produced by Paulette are affecting portions of the Leeward Islands, the Greater Antilles, the Bahamas, Bermuda, and the east coast of the United States. These swells could cause life-threatening surf and rip current conditions.
FORECAST POSITIONS AND MAX WINDS

INIT  14/0300Z 31.4N  64.0W   75 KT  85 MPH - Category 1 (ESE St. Georges, Bermuda)
 12H  14/1200Z 32.8N  64.7W   85 KT 100 MPH - Category 2 (ESE St. Georges, Bermuda)
 24H  15/0000Z 34.9N  63.6W   95 KT 110 MPH - Category 2 (ENE St. Georges, Bermuda)
 36H  15/1200Z 37.1N  60.1W  100 KT 115 MPH - Catagory 3 (ENE St. Georges, Bermuda)
 48H  16/0000Z 39.3N  55.2W   95 KT 110 MPH - Category 2 (ENE St. Georges, Bermuda)
 60H  16/1200Z 41.6N  49.6W   85 KT 100 MPH - Category 2 (ENE St. Georges, Bermuda)
 72H  17/0000Z 43.8N  44.0W   75 KT  85 MPH - Category 1 (ESE St. John's, Canada)
 96H  18/0000Z 46.0N  37.5W   55 KT  65 MPH - Tropical Storm (ESE St. John's, Canada)
120H  19/0000Z 43.5N  34.0W   45 KT  50 MPH - Post Tropical (WSW Bordeaux, France)

NWS National Hurricane Center Miami FL 500 PM AST Sun Sep 13, 2020 

Paulette has recovered from the dry air intrusion that was eroding the eastern eyewall this morning. A ring of deep convection with cloud tops ranging from about -50 to -65 C now completely surrounds a partially cleared eye. An Air Force Hurricane Hunter aircraft investigating the hurricane earlier this afternoon measured peak flight-level winds of 84 kt, which reduces to about 67 kt at the surface. However, since that time there has been steady improvement in the satellite presentation, and the latest Dvorak satellite T-numbers from TAFB and SAB are now at 4.5, supporting increasing the initial intensity to 75 kt for this advisory.

Paulette is expected to remain in a low-shear environment over warm SSTs for the next 24-36 h, so gradual strengthening is likely during that time. Around 48 h from now, vertical wind shear is forecast to rapidly increase ahead of an approaching mid- upper level trough. This should cause the cyclone to begin weakening. By 72 h, Paulette is expected to be over waters less that 26 degrees C and should remain over cooler waters for the remainder of the forecast period. Around that same time, global models are indicating that the cyclone will begin to interact with a frontal boundary associated with the aforementioned trough. This should induce a gradual transition of Paulette to an extratropical cyclone, and that transition should be completed by 120 h, if not sooner. The latest NHC intensity forecast is little changed from the previous one and shows Paulette continuing to strengthen as it passes near or over Bermuda early Monday. The forecast also shows Paulette becoming a major hurricane by Monday night, after the cyclone has moved away from Bermuda. This intensity forecast is in good agreement with the HFIP corrected consensus, HCCA.

Paulette is moving northwestward at 11 kt, to the southwest of a mid-level ridge. There is no change to the forecast track reasoning. This northwest motion should continue until just after the cyclone passes Bermuda Monday morning. Later on Monday, the hurricane should turn north, then northeastward, as it rounds the periphery of the ridge. After turning northeastward, the cyclone is expected to accelerate as it gets picked up in the mid-latitude flow ahead of the approaching trough. Later on in the forecast period a slower eastward motion is indicated once the trough bypasses the cyclone. The latest NHC forecast was nudged only slightly to the left of the previous one, and is in agreement with tightly clustered global and regional track guidance. Tropical storm conditions should reach Bermuda in the next couple of hours, with hurricane force winds arriving there overnight.

Key Messages:

  • 1. Paulette is expected to approach Bermuda as a hurricane today and will be near the island tonight and Monday. A prolonged period of strong winds, storm surge, and heavy rainfall is expected on Bermuda beginning this evening, and a hurricane warning is in effect for the island. Preparations to protect life and property should be rushed to completion.
  • 2. Swells produced by Paulette are affecting portions of the Leeward Islands, the Greater Antilles, the Bahamas, Bermuda, and the east coast of the United States. These swells could cause life-threatening surf and rip current conditions.
FORECAST POSITIONS AND MAX WINDS

INIT  13/2100Z 30.6N  63.1W   75 KT  85 MPH - Category 1 (ESE St. Georges, Bermuda)
 12H  14/0600Z 31.8N  64.5W   85 KT 100 MPH - Category 2 (ESE St. Georges, Bermuda)
 24H  14/1800Z 33.9N  64.8W   95 KT 110 MPH - Category 2 (ENE St. Georges, Bermuda)
 36H  15/0600Z 36.1N  62.4W  100 KT 115 MPH - Category 3 (ENE St. Georges, Bermuda)
 48H  15/1800Z 38.1N  57.8W  100 KT 115 MPH - Category 3 (ENE St. Georges, Bermuda)
 60H  16/0600Z 40.3N  52.6W   95 KT 110 MPH - Category 2 (ENE New York City, NY)
 72H  16/1800Z 42.4N  47.4W   80 KT  90 MPH - Category 2 (ESE St. John's, Canada)
 96H  17/1800Z 45.5N  38.7W   60 KT  70 MPH - Tropical Storm (ESE St. John's, Canada)
120H  18/1800Z 44.4N  34.1W   45 KT  50 MPH - Post Tropical (WSW Bordeaux, France)

NWS National Hurricane Center Miami FL 1100 AM AST Sun Sep 13, 2020 

An Air Force Hurricane Hunter aircraft investigating Paulette this morning found peak 700-mb flight-level winds of 92 kt, which reduces to around 75 kt at the surface. However, around that same time the peak winds measured by the SFMR instrument on board the aircraft were only 58 kt. It is possible that the stronger winds suggested by the flight-level values were not reaching the surface at that location. Later on in the flight, the SFMR measured 64-kt winds in the northwestern quadrant. Since there has been no notable change to the structure of the hurricane since the aircraft was in the system a few hours ago, the initial intensity is being held at 70 kt and is a compromise of those two different peak values measured by the aircraft.

Infrared satellite imagery has been showing some dry air intrusion over the eastern portion of the circulation, causing a break in the eyewall there over the past few hours. There is currently deep convection firing around the remainder of the eyewall, and therefore it is anticipated the dry air will be worked out of the system soon. Very low wind shear and warm waters will support strengthening over the next couple of days, and Paulette is expected to be a dangerous hurricane as it nears Bermuda Monday morning.

The window for strengthening should continue for another 12-24 h after the cyclone passes Bermuda, and Paulette could become a major hurricane during that time. After 48 h, vertical wind shear is forecast to rapidly increase. After 72 h, Paulette is expected to cross the 26 degree C SST isotherm, and by 120 h those SSTs will be near 22 degrees C. The NHC forecast shows a weakening trend beginning after 48 h due to the negative environmental factors. By 120 h, the global models suggest that Paulette will have completed a transition to an extratropical cyclone. The only change to the NHC intensity forecast from the previous advisory was a slight upward adjustment over the first few days due to the increase in strength found by the aircraft this morning. This forecast is in between the LGEM and HFIP corrected consensus, HCCA. Paulette is now moving northwestward at 12 kt, to the southwest of a mid-level ridge.

This motion should continue until just after the cyclone passes Bermuda. Later on Monday, the hurricane should turn north, then on Monday night northeastward, as it rounds the periphery of the ridge. After turning northeastward, the cyclone is expected to accelerate as it gets picked up in the mid-latitude flow ahead of an approaching mid- to upper-level trough. Later on in the forecast period, a slower eastward motion is indicated once the aforementioned trough bypasses the cyclone. The latest NHC forecast track is little changed from the previous one through 48 h and lies in the middle of the latest global and regional track model guidance. Beyond 48 h, the NHC forecast is a little faster than the previous one, and lies near the tightly clustered consensus track guidance. On the forecast track, tropical storm conditions should reach Bermuda by this evening, with hurricane force winds arriving there overnight.

Key Messages:

  • 1. Paulette is expected to approach Bermuda as a hurricane today and will be near the island tonight and Monday. A prolonged period of strong winds, storm surge, and heavy rainfall is expected on Bermuda beginning this evening, and a hurricane warning is in effect for the island. Preparations to protect life and property should be rushed to completion.
  • 2. Swells produced by Paulette are affecting portions of the Leeward Islands, the Greater Antilles, the Bahamas, Bermuda, and the east coast of the United States. These swells could cause life-threatening surf and rip current conditions.
FORECAST POSITIONS AND MAX WINDS

INIT  13/1500Z 29.9N  61.9W   70 KT  80 MPH - Category 1 (ESE St. Georges, Bermuda)
 12H  14/0000Z 30.9N  63.6W   80 KT  90 MPH - Category 1 (ESE St. Georges, Bermuda)
 24H  14/1200Z 32.8N  64.8W   90 KT 105 MPH - Category 2 (ENE St. Georges, Bermuda)
 36H  15/0000Z 35.0N  63.5W   95 KT 110 MPH - Category 2 (ENE St. Georges, Bermuda)
 48H  15/1200Z 37.0N  60.0W  100 KT 115 MPH - Category 3 (ENE St. Georges, Bermuda)
 60H  16/0000Z 39.1N  55.1W   95 KT 110 MPH - Category 2 (ESE Ocean City, MD)
 72H  16/1200Z 41.4N  49.1W   85 KT 100 MPH - Category 2 (ENE New York City, NY)
 96H  17/1200Z 43.9N  42.0W   65 KT  75 MPH - Category 1 (ESE St. John's, Canada)
120H  18/1200Z 44.0N  36.6W   50 KT  60 MPH - Low (ESE St. John's, Canada)

NWS National Hurricane Center Miami FL 1100 PM AST Sat Sep 12, 2020

An Air Force Reserve Hurricane Hunter aircraft made multiple passes through the center of Paulette earlier this evening. The plane reported max 850-mb flight-level winds of 78 kt and believable SFMR winds of 58 kt. A dropsonde in the southeast quadrant measured adjusted mean boundary layer winds of just over 60 kt while multiple center drops revealed that the minimum pressure is now down to 981 mb. Taken together, these observations support an intensity of 65 kt, making Paulette the 6th hurricane of the 2020 Atlantic season.

The plane found the Paulette has turned west-northwestward and is nearly exactly on the previous forecast track. With no major changes in the track guidance either, there is no reason to make any changes of note to the previous NHC track forecast at this time. A mid-level ridge building to the north of Paulette should keep the hurricane moving generally west-northwestward for the next day or so. The ridge and a mid-level trough to the west should then slide eastward by early Monday, causing Paulette to slow and turn northward, moving very near or over Bermuda Monday morning. Paulette is then forecast to turn northeastward and accelerate in that direction by Tuesday. The NHC forecast remains in the middle of the tightly clustered guidance suite at all forecast hours.

Paulette appears to be getting more vertically aligned as the shear that has affected the cyclone for the past several days slowly decreases. Further intensification appears likely through early Monday given the warm SSTs below Paulette and favorable upper-air environment that is expected to develop around the cyclone. Dry air in the surrounding environment could be a limiting factor, but all of the intensity guidance continues to indicate that Paulette will be a dangerous hurricane when it approaches Bermuda late Sunday and early Monday. Further intensification will then be possible for another day or so after the hurricane begins to move away from Bermuda and it could be near major hurricane strength by the middle of next week. The NHC intensity forecast is near the middle of the latest intensity guidance throughout the forecast period.

Key Messages:

  • 1. Paulette is expected to approach Bermuda as a hurricane on Sunday and will be near the island Sunday night and Monday. A prolonged period of strong winds, storm surge, and heavy rainfall is expected on Bermuda beginning Sunday evening, and a hurricane warning is in effect for the island. Preparations to protect life and property should be rushed to completion.
  • 2. Swells produced by Paulette are affecting portions of the Leeward Islands, the Greater Antilles, the Bahamas, Bermuda, and the east coast of the United States. These swells could cause life-threatening surf and rip current conditions.
FORECAST POSITIONS AND MAX WINDS

INIT  13/0300Z 28.9N  59.7W   65 KT  75 MPH - Category 1 (ESE St. Georges, Bermuda)
 12H  13/1200Z 29.7N  61.6W   70 KT  80 MPH - Category 1 (ESE St. Georges, Bermuda)
 24H  14/0000Z 31.0N  63.8W   80 KT  90 MPH - Category 1 (ESE St. Georges, Bermuda)
 36H  14/1200Z 32.6N  65.0W   85 KT 100 MPH - Category 2 (ESE St. Georges, Bermuda)
 48H  15/0000Z 34.5N  64.0W   90 KT 105 MPH - Category 2 (ESE St. Georges, Bermuda)
 60H  15/1200Z 36.2N  61.0W   95 KT 110 MPH - Category 2 (ESE St. Georges, Bermuda)
 72H  16/0000Z 37.7N  57.5W   95 KT 110 MPH - Category 2 (ESE Ocean City, MD)
 96H  17/0000Z 41.0N  49.0W   85 KT 100 MPH - Category 2 (ENE New York City, NY)
120H  18/0000Z 43.5N  42.0W   70 KT  80 MPH - Category 1 (ESE St. John's, Canada)

NWS National Hurricane Center Miami FL 500 PM AST Sat Sep 12, 2020 

Convective cloud tops have cooled again as deep convection has redeveloped since this morning, with an eye-like feature noted in visible satellite imagery. Since the storm is still being affected by 20-25 kt of southerly shear, it is assumed that the low-level center is still displaced to the south of this feature a bit. But it won’t be surprising if the low- and mid-level centers become collocated soon as the shear drops significantly during the next 6-12 hours. The initial intensity remains 60 kt, and we should get a much better handle on Paulette’s maximum winds and structure once the first Air Force Hurricane Hunter aircraft reaches the storm this evening.

The motion remains northwestward (305/13 kt) due to a break in the subtropical ridge to the north-northeast of Paulette. A mid-tropospheric high currently centered near the U.S. Mid-Atlantic coast is expected to slide eastward to the north of Paulette during the next 24 hours, which should cause the cyclone to turn west-northwestward tonight. Once the high becomes established over the central Atlantic, Paulette is expected to recurve around its western periphery toward a longwave trough over the northeastern United States Sunday night through Monday night. On days 3 through 5 of the forecast period, Paulette should be accelerating northeastward toward the north Atlantic, embedded in the mid-latitude westerlies. The new NHC track forecast is embedded among the very tightly clustered guidance envelope, and no significant changes were made from the morning forecast.

As stated above, deep-layer shear is expected to be 10 kt or less between 12 and 48 hours. While ocean waters are plenty warm at 28-29 degrees Celsius, the main possible limiting factor for strengthening would be mid-level dry air, with the SHIPS model diagnosing ambient relative humidities of 30-40 percent for the next couple of days. But, if the shear remains low enough, that dry air is unlikely to infiltrate the circulation, and Paulette is therefore expected to intensify during the next 2-3 days. The NHC intensity forecast is close to the SHIPS, HCCA, and HWRF solutions, showing a peak intensity just under the major hurricane threshold in 2-3 days, when Paulette should be starting to move away from Bermuda.

Key Messages:

  • 1. Paulette is expected to approach Bermuda as a hurricane on Sunday and be near the island Sunday night and Monday. A prolonged period of strong winds, storm surge, and heavy rainfall is expected on Bermuda beginning Sunday evening, and a hurricane warning is in effect for the island. Preparations to protect life and property should be rushed to completion.
  • 2. Swells produced by Paulette are affecting portions of the Leeward Islands, the Greater Antilles, the Bahamas, and Bermuda, and are expected to spread westward to the east coast of the United States during the next day or two. These swells could cause life-threatening surf and rip current conditions.
FORECAST POSITIONS AND MAX WINDS

INIT  12/2100Z 28.4N  58.5W   60 KT  70 MPH - Tropical Storm (ESE St. Georges, Bermuda)
 12H  13/0600Z 29.2N  60.4W   65 KT  75 MPH - Category 1 (ESE St. Georges, Bermuda)
 24H  13/1800Z 30.3N  62.8W   75 KT  85 MPH - Category 1 (ESE St. Georges, Bermuda)
 36H  14/0600Z 31.8N  64.6W   85 KT 100 MPH - Category 2 (ESE St. Georges, Bermuda)
 48H  14/1800Z 33.5N  64.9W   90 KT 105 MPH - Category 2 (ENE St. Georges, Bermuda)
 60H  15/0600Z 35.3N  63.2W   95 KT 110 MPH - Category 2 (ENE St. Georges, Bermuda)
 72H  15/1800Z 37.0N  59.8W   95 KT 110 MPH - Category 2 (ENE St. Georges, Bermuda)
 96H  16/1800Z 40.0N  52.0W   85 KT 100 MPH - Category 2 (ENE New York City, NY)
120H  17/1800Z 43.5N  44.0W   70 KT  80 MPH - Category 1 (ESE St. John's, Canada)

NWS National Hurricane Center Miami FL 1100 AM AST Sat Sep 12, 2020 

Paulette’s structure is going through a bit of an evolution as the deep-layer shear backs from southwesterly to southeasterly. Most of the deep convection had waned earlier this morning, but new convection is beginning to develop near the center as the cyclone reconstitutes itself. For now, the initial intensity remains 60 kt. An overnight AMSR microwave pass showed that Paulette has well-defined low-level banding features, and this structure should allow the cyclone to strengthen as vertical shear falls below 10 kt during the next 12-24 hours.

Strengthening is anticipated to continue through day 3, and after that time, gradual weakening is possible due to increasing southwesterly shear. The intensity guidance has been fairly stable for the past few forecast cycles, and no significant changes were required to this new NHC intensity forecast, which lies close to the HCCA model and just a bit above the intensity consensus. Paulette is likely to be strengthening while it makes its closest approach to Bermuda in about 48 hours, and the GFS-based SHIPS and HWRF models each suggest that there is a possibility of it becoming a major hurricane in 72 hours.

Paulette is moving northwestward (310/13 kt), with a break in the subtropical ridge located due north of the storm. The ridge may strengthen briefly over the next day or so, causing Paulette to move west-northwestward for a short time, but it should resume the northwestward motion by late Sunday. After that time, an approaching longwave trough over the northeastern United States will erode the ridge eastward, causing Paulette to recurve sharply toward the north and then northeast between days 2 and 3. The hurricane is then expected to accelerate east-northeastward toward the north Atlantic on days 4 and 5, embedded within the mid-latitude flow. The track guidance is well clustered and has not shown any significant shifts over the past few forecast cycles. Therefore, the new NHC track forecast is similar to the previous one.

Key Messages:

  • 1. Paulette is expected to approach Bermuda as a hurricane on Sunday and be near the island Sunday night and Monday. A prolonged period of strong winds, storm surge, and heavy rainfall is expected on Bermuda beginning late Sunday evening, and a hurricane warning has been issued for the island. Preparations to protect life and property should be rushed to completion.
  • 2. Swells produced by Paulette are affecting portions of the Leeward Islands, the Greater Antilles, the Bahamas, and Bermuda, and are expected to spread westward to the east coast of the United States during the next day or two. These swells could cause life-threatening surf and rip current conditions.
FORECAST POSITIONS AND MAX WINDS

INIT  12/1500Z 27.5N  57.2W   60 KT  70 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 12H  13/0000Z 28.5N  59.1W   65 KT  75 MPH - Category 1 (ESE St. Georges, Bermuda)
 24H  13/1200Z 29.5N  61.4W   75 KT  85 MPH - Category 1 (ESE St. Georges, Bermuda)
 36H  14/0000Z 30.8N  63.6W   80 KT  90 MPH - Category 1 (ESE St. Georges, Bermuda)
 48H  14/1200Z 32.4N  64.8W   85 KT 100 MPH - Category 2 (ESE St. Georges, Bermuda)
 60H  15/0000Z 34.2N  64.2W   90 KT 105 MPH - Category 2 (ENE St. Georges, Bermuda)
 72H  15/1200Z 35.8N  61.5W   95 KT 110 MPH - Category 2 (ENE St. Georges, Bermuda)
 96H  16/1200Z 39.0N  54.5W   90 KT 105 MPH - Category 2 (ENE New York Coty, NY)
120H  17/1200Z 42.0N  47.0W   75 KT  85 MPH - Category 1 (ESE St. John's, Canada)

NWS National Hurricane Center Miami FL 1100 PM AST Fri Sep 11, 2020 

Paulette remains sheared and asymmetric, with all its deep convection north of its low-level center of circulation. Despite the shear, ASCAT-B data that just arrived showed maximum winds near or just over 55 kt. Since that instrument tends to under-sample the maximum winds, the initial intensity is increased to 60 kt.

An upper-level low located to the west of Paulette is responsible for the southerly shear currently affecting the cyclone. Global model forecasts suggest that the shear will continue for another day or so, and only slight strengthening is likely through that period. By Sunday, the upper-level low will move farther southwest and the tropical cyclone will encounter a very favorable upper-air pattern. Paulette will likely strengthen further in response, possibly at a fast rate.

All of the intensity guidance indicates that Paulette will be a hurricane when it nears Bermuda early Monday, and it could approach major hurricane strength early next week. The NHC intensity forecast has not changed since the last advisory. It is worth mentioning that Paulette could experience a period of slow development for the next 24 hours, followed by quick intensification, rather than the more steady strengthening shown by the NHC forecast. It is also important to note that the average NHC intensity errors are around 10-15 kt at 48-72 h, the range at which Paulette will likely be nearest to Bermuda.

Paulette has jogged slightly right of track during the past few hours, but the overall NHC forecast track is not different from the previous advisory. A building mid-level ridge to the north of Paulette will likely steer the tropical storm generally west-northwestward or northwestward for the next 2-3 days. The cyclone is then expected to turn northeastward and accelerate in that direction ahead of a mid-latitude trough. The model spread remains relatively low, especially for the first few days. Confidence is high that Paulette will move near Bermuda early Monday, though it is still too soon to specify exactly how close it will get. The NHC forecast is based heavily on the TVCA and HCCA consensus aids and is not far from any of the global model forecast.

Key Messages:

  • 1. Paulette is expected to approach Bermuda as a hurricane on Sunday and Monday. A prolonged period of strong winds, storm surge, and heavy rainfall on Bermuda beginning Sunday night is becoming more likely. A tropical storm watch is in effect and a hurricane watch could be required for the island early Saturday.
  • 2. Swells produced by Paulette are affecting portions of the Leeward Islands and will continue to spread westward to the Greater Antilles, the Bahamas, Bermuda, and the southeastern United States into the weekend. These swells could cause life-threatening surf and rip current conditions.
FORECAST POSITIONS AND MAX WINDS

INIT  12/0300Z 25.8N  54.8W   60 KT  70 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 12H  12/1200Z 27.1N  56.5W   65 KT  75 MPH - Category 1 (ESE St. Georges, Bermuda)
 24H  13/0000Z 28.5N  58.8W   65 KT  75 MPH - Category 1 (ESE St. Georges, Bermuda)
 36H  13/1200Z 29.6N  61.2W   70 KT  80 MPH - Category 1 (ESE St. Georges, Bermuda)
 48H  14/0000Z 30.7N  63.7W   80 KT  90 MPH - Category 1 (ESE St. Georges, Bermuda)
 60H  14/1200Z 32.1N  65.1W   85 KT 100 MPH - Category 2 (WSW St. Georges, Bermuda)
 72H  15/0000Z 33.8N  65.0W   90 KT 105 MPH - Category 2 (ENE St. Georges, Bermuda)
 96H  16/0000Z 37.0N  60.0W   95 KT 110 MPH - Category 2 (ENE St. Georges, Bermuda)
120H  17/0000Z 40.0N  54.0W   85 KT 100 MPH - Category 2 (ESE New York City, NY)

NWS National Hurricane Center Miami FL 500 PM AST Fri Sep 11, 2020 

Paulette inconveniently fell in a gap between all three ASCAT passes this morning, so we haven’t gotten any better handle on the cyclone’s intensity since last evening’s pass. However, Dvorak classifications have not budged, so maintaining the initial intensity of 55 kt seems sound. In addition, although an AMSR microwave pass from around 17 UTC still showed the system being sheared, it also revealed a ragged mid-level eye feature. Since the shear is expected to abate to less than 10 kt by 48 hours, Paulette is likely to intensify, possibly significantly so, and it is now forecast to become a hurricane on Saturday. The intensification trend is expected to continue through day 4, and Paulette has the potential to be a dangerous hurricane when it makes its closest approach to Bermuda on Monday. Paulette’s forecast peak intensity (on day 4) has been nudged up slightly, lying near the SHIPS and HCCA guidance, but still a little below the latest HWRF simulation.

Paulette has picked up some speed and is now moving toward the northwest (310 degrees) at 11 kt. The track forecast reasoning has not changed since this morning. Paulette should maintain a motion toward the northwest or west-northwest during the next 2 to 3 days to the south of a weakening subtropical ridge. By day 3, a longwave trough is forecast to move across the northeastern United States, eroding the ridge eastward, and causing Paulette to recurve sharply toward the north and northeast in the vicinity of Bermuda on Monday. After that time, Paulette is forecast to become embedded in the mid-latitude flow and accelerate northeastward toward the north Atlantic. The spread in the track guidance has continued to tighten up, which increases the confidence in the official track forecast. The updated forecast has been shifted slightly westward around the time that Paulette will be near Bermuda, and it is embedded among the usually-reliable GFS, ECMWF, and HCCA model solutions.

Key Messages:

  • 1. Paulette is expected to approach Bermuda as a hurricane during the next couple of days and make its closest approach to the island on Monday. A prolonged period of strong winds, storm surge, and heavy rainfall on Bermuda beginning Sunday night is becoming more likely, and a hurricane watch could be required for the island tonight or early Saturday.
  • 2. Swells produced by Paulette are affecting portions of the Leeward Islands and will continue to spread westward to the Greater Antilles, the Bahamas, Bermuda, and the southeastern United States into the weekend. These swells could cause life-threatening surf and rip current conditions.
FORECAST POSITIONS AND MAX WINDS

INIT  11/2100Z 24.6N  53.7W   55 KT  65 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 12H  12/0600Z 25.9N  55.3W   60 KT  70 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 24H  12/1800Z 27.5N  57.5W   65 KT  75 MPH - Category 1 (ESE St. Georges, Bermuda)
 36H  13/0600Z 28.7N  59.8W   70 KT  80 MPH - Category 1 (ESE St. Georges, Bermuda)
 48H  13/1800Z 29.8N  62.3W   80 KT  90 MPH - Category 1 (ESE St. Georges, Bermuda)
 60H  14/0600Z 31.1N  64.5W   85 KT 100 MPH - Category 2 (ESE St. Georges, Bermuda)
 72H  14/1800Z 32.6N  65.3W   90 KT 105 MPH - Category 2 (WSW St. Georges, Bermuda)
 96H  15/1800Z 36.0N  62.0W   95 KT 110 MPH - Category 2 (ESE St. Georges, Bermuda)
120H  16/1800Z 39.0N  56.0W   85 KT 100 MPH - Category 2 (ESE Atlantic City, NJ)

NWS National Hurricane Center Miami FL 1100 AM AST Fri Sep 11, 2020 

Despite what is being analyzed as roughly 40 kt of deep-layer southwesterly shear, Paulette’s center is embedded beneath the cirrus canopy of a strong convective burst to the north. Recent microwave images do confirm, however, that the center remains displaced from the convection. We have not yet received new scatterometer data over Paulette, and since the structure has not degraded from overnight, the initial intensity remains 55 kt. This is in best agreement with the Dvorak estimate from TAFB.

Paulette appears to have turned toward the northwest (305/9 kt) based on center fixes over the past 12 hours. A weakness in the subtropical ridge is beginning to develop to the north of Paulette, which should allow the cyclone to maintain a motion toward the northwest or west-northwest during the next 3 days. After that time, a longwave trough forecast to move across the northeastern United States is expected to erode the ridge eastward, causing Paulette to recurve sharply toward the north and northeast in the vicinity of Bermuda on days 4 and 5. Except for some minor speed differences, the track models agree on this general trajectory and have less east-to-west spread during the recurvature phase than they did yesterday. The GFS, ECMWF, HCCA, and Florida State Superensemble aids all lie along the western side of the guidance envelope at the time of recurvature, and as a result the new NHC track has been nudged a little west of the previous prediction during that period in deference to those normally reliable models.

The shear affecting Paulette is forecast to abate over the next 48 hours while the storm also moves over warmer ocean waters and into a more unstable environment. Given the cyclone’s hardiness in the face of the ongoing shear, Paulette is unlikely to have problems responding to the improving environment. Paulette is now forecast to become a hurricane in 36 hours, which is supported by the latest dynamical hurricane models, the superensemble aids, and the IVCN intensity consensus. Continued strengthening is anticipated after 36 hours, with Paulette likely to reach a peak intensity in 4-5 days.

Key Messages:

  • 1. Paulette is expected to approach Bermuda as a hurricane this weekend and make its closest approach to the island on Monday. While the exact details of Paulette’s track and intensity near the island are not yet known, the risk of strong winds, storm surge, and heavy rainfall on Bermuda continues to increase.
  • 2. Swells produced by Paulette are affecting portions of the Leeward Islands and will continue to spread westward to the Greater Antilles, the Bahamas, Bermuda, and the southeastern United States into the weekend. These swells could cause life-threatening surf and rip current conditions.
FORECAST POSITIONS AND MAX WINDS

INIT  11/1500Z 23.6N  52.2W   55 KT  65 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 12H  12/0000Z 24.6N  53.7W   55 KT  65 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 24H  12/1200Z 26.1N  55.5W   60 KT  70 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 36H  13/0000Z 27.6N  57.5W   65 KT  75 MPH - Category 1 (ESE St. Georges, Bermuda)
 48H  13/1200Z 28.9N  59.9W   75 KT  85 MPH - Category 1 (ESE St. Georges, Bermuda)
 60H  14/0000Z 30.2N  62.5W   80 KT  90 MPH - Category 1 (ESE St. Georges, Bermuda)
 72H  14/1200Z 31.6N  64.3W   85 KT 100 MPH - Category 2 (ESE St. Georges, Bermuda)
 96H  15/1200Z 34.5N  63.5W   90 KT 105 MPH - Category 2 (ENE St. Georges, Bermuda)
120H  16/1200Z 37.0N  58.0W   90 KT 105 MPH - Category 2 (ENE St. Georges, Bermuda)

NWS National Hurricane Center Miami FL 1100 PM AST Thu Sep 10, 2020

Paulette has been fighting off intense vertical wind shear, which is analyzed by UW-CIMSS to be on the order of 35-40 kt out of the southwest. Deep convection with cold cloud tops of -70 to -80 degrees C have persisted near and to the northeast of the center throughout the evening. A late arriving ASCAT overpass revealed that Paulette is stronger than previously analyzed, with believable wind vectors of 50-55 kt in the northeastern quadrant. There were some values even higher than these. However, the ASCAT ambiguities and satellite imagery suggest most of those are either rain contaminated or too close to the edge of the ASCAT pass to be trustworthy. Nonetheless, the other values indicate that the initial intensity is now at least 55 kt.

The SHIPS guidance suggests that the current shear over Paulette will begin to gradually decrease tomorrow and continue to decrease into the weekend. By late Saturday the guidance indicates the shear could fall to 10 kt or less. By that time, the cyclone is forecast to be traversing over waters with SSTs near 29 C. The only negative environmental factor could be some dry air in the vicinity of the system. However that same dry air has not seemed to have that much of an effect on Paulette as of late. With shear expected to remain fairly strong the next 24 h, no strengthening is anticipated during that time. After 24 h, Paulette should gradually intensify into early next week. The NHC intensity forecast for this advisory has been increased across the board. In the near term this change is due to the adjusted initial intensity. Beyond 24 h, the latest NHC forecast is close to a blend of the multi-model consensus values, including the HFIP corrected consensus and the Florida State Superensemble.

Paulette is now moving northwest, or 305/09 kt. There is no change to the forecast track reasoning from the previous advisory. The forecast models are in good agreement between a generally northwest to west-northwestward motion over the next 3-4 days as the cyclone is steered around a subtropical ridge to its north. Around day 4, about the same time the system would be making its closest approach to Bermuda, a turn to the northeast is expected as the system rounds the western periphery of the ridge. The latest NHC track forecast is little changed from the previous one, and is near the tracks of the various consensus aids. It should be noted that there is sufficient spread in the track guidance such that it is too soon to know what types of impacts Paulette could have on Bermuda early next week.

Key Messages:

  • 1. Paulette is expected to approach Bermuda as a hurricane this weekend and make its closest approach to the island on Monday and Tuesday. While the exact details of Paulette’s track and intensity near the island are not yet known, the risk of strong winds, storm surge, and heavy rainfall on Bermuda continues to increase.
  • 2. Swells produced by Paulette are expected to affect portions of the Leeward Islands, the Greater Antilles, the Bahamas, Bermuda, and the southeastern United States into the weekend. These swells could cause life-threatening surf and rip current conditions.
FORECAST POSITIONS AND MAX WINDS

INIT  11/0300Z 22.7N  50.9W   55 KT  65 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 12H  11/1200Z 23.4N  52.4W   55 KT  65 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 24H  12/0000Z 24.6N  54.1W   55 KT  65 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 36H  12/1200Z 26.1N  55.8W   60 KT  70 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 48H  13/0000Z 27.6N  57.6W   65 KT  75 MPH - Caregory 1 (ESE St. Georges, Bermuda)
 60H  13/1200Z 28.9N  59.9W   70 KT  80 MPH - Caregory 1 (ESE St. Georges, Bermuda)
 72H  14/0000Z 30.0N  62.3W   80 KT  90 MPH - Caregory 1 (ESE St. Georges, Bermuda)
 96H  15/0000Z 32.6N  65.0W   85 KT 100 MPH - Caregory 2 (WNW St. Georges, Bermuda)
120H  16/0000Z 35.0N  62.5W   90 KT 105 MPH - Caregory 2 (ENE St. Georges, Bermuda)

NWS National Hurricane Center Miami FL 500 PM AST Thu Sep 10, 2020 

Continuous bursts of deep convection have been ongoing to the north and northeast of Paulette’s center of circulation, with the cyclone being affected by nearly 40 kt of deep-layer southwesterly shear. The highest intensity estimates are Dvorak classifications of T3.0/45 kt from TAFB and SAB, and that value remains the initial intensity. The shear should reach its peak magnitude this evening, which is likely to cause Paulette to weaken slightly during the next 24 hours.

However, gradual re-strengthening is forecast to begin in about 36 hours, and the rate of intensification is expected to increase in 2 to 3 days when the shear could fall to 10 kt or less, along with a more unstable atmosphere and warmer sea surface temperatures. Paulette is now forecast to become a hurricane by day 3 and continue to intensify through the end of the forecast period. As was advertised in the previous forecast package, the new NHC forecast intensities have been bumped up on days 3 through 5 and now lie near or just below the IVCN intensity consensus and the HCCA corrected consensus aid.

Paulette’s heading over the past 6-12 hours has been toward the west-northwest, or 300/8 kt. The cyclone’s trajectory is expected to oscillate between northwest and west-northwest for the next 4 days, being dictated by the strength of the subtropical ridge to the north and the depth of the steering flow depending on Paulette’s intensity. The updated NHC track forecast during this period has been nudged a bit to the north, mostly to account for an adjustment of the initial position. The model guidance all agree that Paulette should turn northward around the western side of a central Atlantic high pressure area by day 5, with the expected hurricane likely to make a tight recurvature near Bermuda. There remains some uncertainty on exactly where that turn will occur, but for now the NHC forecast lies between the tighter-turning ECMWF and HCCA models and the more gradually-turning GFS and HWRF models.

Key Messages:

  • 1. Paulette is expected to approach Bermuda as a hurricane this weekend and make its closest approach to the island on Monday and Tuesday. While the exact details of Paulette’s track and intensity near the island are not yet known, the risk of strong winds, storm surge, and heavy rainfall on Bermuda continues to increase.
  • 2. Swells produced by Paulette are expected to affect portions of the Leeward Islands, the Greater Antilles, the Bahamas, Bermuda, and the southeastern United States into the weekend. These swells could cause life-threatening surf and rip current conditions.
FORECAST POSITIONS AND MAX WINDS

INIT  10/2100Z 22.1N  50.1W   45 KT  50 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 12H  11/0600Z 22.5N  51.5W   40 KT  45 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 24H  11/1800Z 23.6N  53.4W   40 KT  45 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 36H  12/0600Z 25.0N  55.1W   45 KT  50 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 48H  12/1800Z 26.6N  56.8W   45 KT  50 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 60H  13/0600Z 28.0N  58.9W   55 KT  65 MPH - Tropical Storm (ESE St. Georges, Bermuda)
 72H  13/1800Z 29.2N  61.4W   65 KT  75 MPH - Category 1 (ESE St. Georges, Bermuda)
 96H  14/1800Z 31.5N  65.5W   75 KT  85 MPH - Category 1 (WSW St. Georges, Bermuda)
120H  15/1800Z 34.5N  64.0W   80 KT  90 MPH - Category 1 (ENE St. Georges, Bermuda)

NWS National Hurricane Center Miami FL 1100 AM AST Thu Sep 10, 2020 

The highest winds in a recent scatterometer pass have decreased a little since last evening, and they remain embedded within deep convection which is displaced to the north of the center of circulation. Paulette’s intensity is estimated to have decreased to 45 kt based on this ASCAT pass and Dvorak CI numbers of 3.0/45 kt from both TAFB and SAB.

The sheared convection has been tugging Paulette’s center northward at times, causing wobbles in the estimated longer-term west-northwestward motion of 295/9 kt. For the next 4 days or so, fluctuations in the strength of the subtropical ridge to the north of Paulette will cause the cyclone’s trajectory to vary between west-northwest and northwest, with a peak in forward speed around day 3. At the end of the forecast period, a mid-latitude trough is expected to move across the northeastern United States, with a mid-tropospheric high becoming established over the central Atlantic. This should allow Paulette to begin to recurve over the western Atlantic, turning northward by day 5. The only notable change in the track guidance on this cycle was a slight westward shift among some of the models on days 4 and 5, and the NHC track forecast follows suit, lying close to the HFIP Corrected Consensus (HCCA) aid.

Southwesterly shear has increased over the cyclone as expected, with the latest UW-CIMSS analysis now between 35 and 40 kt. SHIPS diagnoses suggest that the shear over Paulette should peak in about 12 hours, thus a little more weakening is anticipated over the next day or so. The shear is then forecast to gradually abate, and both the GFS and ECMWF versions of the SHIPS guidance show the shear magnitudes decreasing to 10 kt or less in 3-4 days. This more favorable environment, combined with a more unstable air mass and sea surface temperatures exceeding 29 degrees Celsius, are expected to allow Paulette to restrengthen and become a hurricane as it moves in the vicinity of Bermuda. The new NHC intensity forecast has been raised a bit between days 2 and 4 compared to the previous prediction, although it still lies below the intensity consensus, IVCN, and the HCCA solutions. Therefore, additional upward adjustments to the forecast intensity may be required later today.

FORECAST POSITIONS AND MAX WINDS

INIT  10/1500Z 21.5N  49.1W   45 KT  50 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 12H  11/0000Z 21.8N  50.7W   45 KT  50 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 24H  11/1200Z 22.6N  52.6W   40 KT  45 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 36H  12/0000Z 23.8N  54.4W   40 KT  45 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 48H  12/1200Z 25.4N  56.3W   45 KT  50 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 60H  13/0000Z 26.9N  58.4W   50 KT  60 MPH - Tropical Storm (ESE St. Georges, Bermuda)
 72H  13/1200Z 28.0N  61.0W   60 KT  70 MPH - Tropical Storm (ESE St. Georges, Bermuda)
 96H  14/1200Z 30.0N  65.0W   70 KT  80 MPH - Category 1 (WNW St. Georges, Bermuda)
120H  15/1200Z 32.5N  65.0W   75 KT  85 MPH - Category 1 (WNW St. Georges, Bermuda)

NWS National Hurricane Center Miami FL 1100 PM AST Wed Sep 09, 2020 

Paulette remains a sheared tropical cyclone with the low-level center southwest of a large area of deep convection. Recent scatterometer data showed peak winds of 45-50 kt, so 50 kt is used as the initial wind speed, which happens to be quite similar to a blend of the latest TAFB/SAB Dvorak estimates. Paulette should begin to weaken tomorrow and continue on a downward trend for 2-3 days as strong shear impacts the cyclone. No change has been made to the forecast through Saturday. Thereafter, the storm is likely to move into a lower-shear environment on the northeastern side of a mid/upper-level low, with SSTs rising to about 29C. There is better agreement among the models tonight that Paulette will survive the shear and be able to take advantage of that favorable environment. In fact, almost all of the most reliable guidance, save LGEM/SHIPS, show the storm becoming a hurricane by 120 hours, and the global models are trending in that direction. The new NHC forecast is raised from the previous one, near the model consensus, but isn’t quite as high as the regional hurricane models.

The storm is moving at about the same motion as before (295/9 kt). Paulette should turn westward tomorrow as it weakens and encounters stronger low/mid-level ridging. A weakness in the ridge develops by the weekend due to the aforementioned mid/upper-level low, which should cause the tropical cyclone to turn and move faster toward the northwest. The new NHC track forecast is very similar to the previous one, lying on the western side of the guidance after placing heavier weight on the global models and corrected-consensus aids than on the regional hurricane guidance.

FORECAST POSITIONS AND MAX WINDS

INIT  10/0300Z 20.9N  48.1W   50 KT  60 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 12H  10/1200Z 21.3N  49.5W   50 KT  60 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 24H  11/0000Z 21.4N  51.5W   45 KT  50 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 36H  11/1200Z 21.9N  53.2W   40 KT  45 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 48H  12/0000Z 22.8N  54.6W   40 KT  45 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 60H  12/1200Z 24.1N  55.9W   40 KT  45 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 72H  13/0000Z 25.8N  57.3W   45 KT  50 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 96H  14/0000Z 29.0N  62.0W   55 KT  65 MPH - Tropical Storm (ESE St. Georges, Bermuda)
120H  15/0000Z 31.0N  65.0W   65 KT  75 MPH - Category 1 (ESE St. Georges, Bermuda)

NWS National Hurricane Center Miami FL 500 PM AST Wed Sep 09, 2020 

Paulette’s satellite presentation has not changed since this morning, with the center exposed just to the south of the deepest convection. Between this morning’s ASCAT pass and the most recent satellite classifications from TAFB and SAB, which are unchanged at T3.0 and T3.5, respectively, the maximum wind estimate remains 50 kt. Paulette continues to move into an area of stronger southwesterly shear, which is now estimated to be 25-30 kt, and this shear is likely to increase further to 30-35 kt within the next 24 hours. As a result, Paulette is expected to begin weakening by Thursday, and the NHC forecast is embedded among the tightly clustered intensity guidance during the first 2-3 days.

The shear is expected to relax gradually from 48 hours and beyond and turn out of the southeast, which should allow for some restrengthening on days 3 through 5 when shear magnitudes could go as low as 10 kt. The HWRF and COAMPS-TC models in particular take full advantage of this environment and bring Paulette to hurricane intensity by day 4. The updated NHC intensity forecast is not nearly this aggressive, but it does indicate a little more strengthening at the end of the forecast period than has been shown in previous forecasts, lying closest to the statistical-dynamical guidance. Model environmental trends will be monitored, and additional intensity adjustments at the end of the forecast period will be made accordingly in subsequent forecasts.

Paulette remains on a west-northwestward course (295/9 kt), located to the south of low- to mid-level ridging which extends across the central and western Atlantic. The track models suggest that when the cyclone weakens in a day or two, lower-level winds could steer the cyclone westward for a short time. However, a combination of the ridge weakening and Paulette’s expected re-strengthening should cause the cyclone to turn northwestward in 2-3 days and maintain that trajectory through the end of the forecast period. The only significant change from the previous forecast is that the 5-day forecast point has been shifted westward, with the GFS, ECMWF, HWRF, and HCCA models all lying on the left side of the guidance envelope by that time.

FORECAST POSITIONS AND MAX WINDS

INIT  09/2100Z 20.5N  47.4W   50 KT  60 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 12H  10/0600Z 20.9N  48.9W   50 KT  60 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 24H  10/1800Z 21.4N  50.9W   45 KT  50 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 36H  11/0600Z 21.6N  52.7W   40 KT  45 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 48H  11/1800Z 22.3N  54.1W   40 KT  45 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 60H  12/0600Z 23.3N  55.4W   40 KT  45 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 72H  12/1800Z 24.8N  56.6W   45 KT  50 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 96H  13/1800Z 28.0N  60.5W   50 KT  60 MPH - Tropical Storm (ESE St. Georges, Bermuda)
120H  14/1800Z 30.5N  64.5W   55 KT  65 MPH - Tropical Storm (ESE St. Georges, Bermuda)

NWS National Hurricane Center Miami FL 1100 AM AST Wed Sep 09, 2020  

Morning visible satellite images show that Paulette’s center is located beneath a thin veil of cirrus and displaced to the south of the deep convection. Based on a blend of Dvorak estimates from TAFB and SAB, and a recent ASCAT pass which showed an area of 45-50 kt winds northwest of the center, the initial intensity remains 50 kt. A large upper-level trough is located to the northwest of Paulette, and this feature is producing 20-30 kt of south-southwesterly shear over the cyclone. The shear is forecast to increase well over 30 kt during the next day or two as Paulette gets closer to the upper-level disturbance, which should cause the cyclone’s maximum winds to gradually decrease through day 3. The shear is forecast to abate somewhat and back around from the southeast by days 4 and 5, which could allow Paulette to restrengthen a little bit over the subtropical Atlantic at that time. The new NHC intensity forecast is identical to the previous one and is generally close to the IVCN intensity consensus and the HCCA corrected consensus.

Although Paulette has been hopscotching around a bit, likely being influenced by the sheared convection, the 12-hour motion is now toward the west-northwest (290/8 kt). Subtropical ridging to the north of Paulette is forecast to keep the cyclone on a westward or west-northwestward trajectory for the next 48 hours. After that time, the ridge is likely to weaken a bit, which should allow Paulette to move toward the northwest with some increase in forward speed on days 3 though 5. There is a typical amount of spread among the track models for this forecast, and while they all agree on the general future trajectory, there are some speed differences. In particular, the UKMET and HWRF start out much slower than the other models, and the ECWMF is much faster than the rest of the guidance by days 4 and 5. Relying on continuity and the model consensus aids, the updated NHC track forecast has been shifted very little from the previous prediction.

The initial and forecast tropical-storm-force wind radii have been expanded based on the recent scatterometer data.

FORECAST POSITIONS AND MAX WINDS

INIT  09/1500Z 20.0N  46.5W   50 KT  60 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 12H  10/0000Z 20.3N  48.0W   50 KT  60 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 24H  10/1200Z 20.7N  49.9W   45 KT  50 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 36H  11/0000Z 20.9N  51.6W   45 KT  50 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 48H  11/1200Z 21.3N  53.1W   40 KT  45 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 60H  12/0000Z 22.2N  54.3W   40 KT  45 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 72H  12/1200Z 23.5N  55.6W   40 KT  45 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 96H  13/1200Z 27.0N  59.0W   45 KT  50 MPH - Tropical Storm (ENE Scrub Island, Antigua)
120H  14/1200Z 30.0N  62.5W   50 KT  60 MPH - Tropical Storm (ESE St. Georges, Bermuda)

NWS National Hurricane Center Miami FL 1100 PM AST Tue Sep 08, 2020

Microwave and satellite data suggest that vertical shear is weakening Paulette. The center is near the southern side of a large thunderstorm cluster, with the bulk of deep convection in the northeastern quadrant of the cyclone. A recent ASCAT-B pass showed maximum winds of 45-50 kt, a little lower than the other satellite estimates, and 50 kt is chosen as the initial wind speed.

With Paulette already on a weakening trend, it seems that the window for significant strengthening has closed. More likely, a gradual decay of the storm is anticipated due to moderate or strong shear during the next few days. This shear could abate by the end of the forecast period due to Paulette moving around the northeastern side of a large mid-to-upper level low, which is a common position for the re-intensification of a tropical cyclone after encountering the mid-oceanic trough. The new forecast is lowered from the previous one for the first few days and then raised slightly at the longer ranges. This is consistent with a blend of the intensity model consensus, leaning toward the NOAA corrected-consensus guidance at the end.

The storm is moving northwestward at about 8 kt. There has been some convergence of the model guidance during the next few days as Paulette should move west-northwestward tomorrow and westward on Thursday around a mid-level ridge. Thus, little change has been made from the previous forecast during the first 48-72h. Afterwards, the forecast is shifted to the north by 45-60 n mi under the assumption that Paulette stays coherent as a tropical cyclone and takes a turn to the northwest this weekend on the eastern flank of the aforementioned mid-to-upper level low. The new track forecast is northeast of the model consensus and places less emphasis on models, like the 12Z ECMWF, which show Paulette staying weaker and missing the full influence of the low.

FORECAST POSITIONS AND MAX WINDS

INIT  09/0300Z 19.2N  45.0W   50 KT  60 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 12H  09/1200Z 19.8N  46.2W   50 KT  60 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 24H  10/0000Z 20.2N  48.1W   50 KT  60 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 36H  10/1200Z 20.6N  50.0W   45 KT  50 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 48H  11/0000Z 20.8N  51.7W   45 KT  50 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 60H  11/1200Z 21.1N  52.9W   40 KT  45 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 72H  12/0000Z 21.9N  53.8W   40 KT  45 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 96H  13/0000Z 24.4N  55.7W   45 KT  50 MPH - Tropical Storm (ENE Scrub Island, Antigua)
120H  14/0000Z 27.5N  59.0W   55 KT  65 MPH - Tropical Storm (ESE St.Georges, Bermuda)

NWS National Hurricane Center Miami FL 500 PM AST Tue Sep 08, 2020 

Shear has started to take a toll on Paulette’s structure. Convection is again primarily limited to the northeast quadrant with little signs of banding. It is certainly possible that convection will expand again tonight when Paulette is farther removed from the diurnal convective minimum, but for the moment it does not look like further intensification is imminent. Dvorak classifications from TAFB and SAB are still T-3.5/55 kt, and that is the basis for the intensity estimate.

If convection does increase tonight, Paulette will have a brief window for further strengthening before an expected increase in southerly shear on Wednesday. At a minimum, Paulette’s intensity should then level off, and it will probably begin to weaken. Later this week or over the weekend Paulette will have an opportunity to restrengthen, depending on its interaction with an upper-level low expected to be just west of the cyclone. The spread in the guidance at that point is very high ranging from near dissipation to a category 2 hurricane. The NHC intensity forecast is mostly unchanged for now, but Paulette could certainly be much stronger or weaker over the weekend than currently forecast.

There has been no change to the track forecast reasoning, and therefore little change to the track forecast itself. Paulette should gradually turn westward by late Wednesday and then back toward the northwest later this week as a ridge to its north builds and weakens over the next several days. The model spread is high, since there is still quite a bit of uncertainty in exactly how far west Paulette will make it before it turns northwestward. Confidence in the forecast beyond 72 h remains low. The NHC forecast track is based heavily on the HFIP Corrected Consensus (HCCA).

FORECAST POSITIONS AND MAX WINDS

INIT  08/2100Z 18.7N  44.3W   55 KT  65 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 12H  09/0600Z 19.2N  45.4W   60 KT  70 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 24H  09/1800Z 19.9N  47.2W   55 KT  65 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 36H  10/0600Z 20.3N  49.0W   55 KT  65 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 48H  10/1800Z 20.5N  50.6W   50 KT  60 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 60H  11/0600Z 20.7N  52.1W   50 KT  60 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 72H  11/1800Z 21.4N  53.2W   45 KT  50 MPH - Tropical Storm (ENE Scrub Island, Antigua)
 96H  12/1800Z 23.5N  55.5W   45 KT  50 MPH - Tropical Storm (ENE Scrub Island, Antigua)
120H  13/1800Z 26.5N  59.0W   50 KT  60 MPH - Tropical Storm (ENE Scrub Island, Antigua)

NWS National Hurricane Center Miami FL 1100 AM AST Tue Sep 08, 2020

Paulette’s organization has noticeably improved since last night. The tropical storm is still sheared, with its outflow restricted to the southwest, however overnight AMSU imagery indicated that convection was beginning to wrap around the western portion of its circulation. The intensity estimate has been increased to 55 kt based on Dvorak estimates from TAFB and SAB.

Paulette has manged to strengthen despite the shear, and some additional short-term strengthening is certainly possible. It is not out of the question that Paulette could become a hurricane, at least briefly. The global models indicate that the shear will increase on Wednesday, which should cause Paulette’s intensity to level off, and more likely, decrease. The NHC intensity forecast is just above the intensity consensus for the first 3 days, out of respect for Paulette’s recent intensification above most of the guidance. By the weekend, Paulette’s strength will heavily depend on its exact orientation relative to an upper-level low that is expected to be located west or southwest of the tropical storm. Some restrengthening could occur then, but the NHC forecast just shows a steady intensity, near the middle of the guidance suite.

Paulette is forecast to turn generally west-northwestward or westward tonight and Wednesday as a mid-level ridge builds to its north. The guidance then indicates that late this week Paulette will turn northwestward when the ridge weakens. Differences in Paulette’s forward speed on Wednesday and Thursday could result in a very different track late in the period since it affects the point at which the tropical storm will turn northwestward. The NHC forecast is very close to the multi-model consensus throughout the 5-day period, but confidence in the forecast beyond 72 h is lower than normal due to high spread in the track guidance.

FORECAST POSITIONS AND MAX WINDS

INIT  08/1500Z 18.4N  43.3W   55 KT  65 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 12H  09/0000Z 19.0N  44.2W   60 KT  70 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 24H  09/1200Z 19.8N  45.8W   60 KT  70 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 36H  10/0000Z 20.3N  47.8W   60 KT  70 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 48H  10/1200Z 20.6N  49.7W   55 KT  65 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 60H  11/0000Z 20.7N  51.2W   55 KT  65 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 72H  11/1200Z 21.2N  52.6W   50 KT  60 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 96H  12/1200Z 23.1N  55.4W   50 KT  60 MPH - Tropical Storm (ESE Scrub Island, Antigua)
120H  13/1200Z 26.0N  58.5W   50 KT  60 MPH - Tropical Storm (ESE Scrub Island, Antigua)

NWS National Hurricane Center Miami FL 1100 PM AST Mon Sep 07, 2020

Satellite images show that Paulette continues to become better organized, with a more symmetric presentation and very deep convection near or just north of the center. The initial wind speed is increased to 40 kt, a little higher than recent subjective Dvorak estimates, but close to the objective estimates and the UW-CIMSS satellite consensus. Further strengthening is expected during the next day or so while the storm remains in a warm SST and low-to-moderate shear environment.

By midweek, some weakening is forecast due to an increase in shear from an enhanced mid-oceanic upper-level trough. There’s a fair amount of uncertainty on how quickly the tropical cyclone moves across the trough axis, which would then allow Paulette to find an area of lighter shear, plus very warm water, by the end of the forecast period. The intensity forecast is slightly higher in the short-term, and lower in the day-4 period just before the environment is forecast to improve.

Paulette appears to be moving slowly north-northwestward this evening. A mid-level ridge is likely to build over the western and central North Atlantic in a day or two, and this pattern should cause Paulette to move faster toward the northwest tomorrow, and west-northwestward or westward through late week. A turn back toward the west-northwest or northwest is possible over the weekend as the cyclone reaches the western periphery of the ridge. This is not a particularly certain forecast because the track models aren’t in good agreement, perhaps linked to the strength of Paulette, and there is significant spread in the various ensemble guidance. With no clear trends to rely on, and since the new model consensus came in very close to the previous NHC forecast, the new NHC track prediction is basically unchanged from the previous one.

FORECAST POSITIONS AND MAX WINDS

INIT  08/0300Z 17.8N  42.5W   40 KT  45 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 12H  08/1200Z 18.4N  42.9W   45 KT  50 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 24H  09/0000Z 19.2N  44.1W   50 KT  60 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 36H  09/1200Z 19.9N  45.9W   55 KT  65 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 48H  10/0000Z 20.5N  47.9W   55 KT  65 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 60H  10/1200Z 20.9N  49.9W   50 KT  60 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 72H  11/0000Z 21.3N  51.8W   50 KT  60 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 96H  12/0000Z 22.5N  55.0W   45 KT  50 MPH - Tropical Storm (ESE Scrub Island, Antigua)
120H  13/0000Z 25.0N  58.0W   50 KT  60 MPH - Tropical Storm (ESE Scrub Island, Antigua)

NWS National Hurricane Center Miami FL 500 PM AST Mon Sep 07, 2020 

Recent visible imagery shows that Paulette’s circulation has become better defined since this morning. There has also been some evidence of increased banding, however the tropical storm remains sheared, with deep convection occuring primarily in its northeast quadrant. Recent satellite-based intensity estimates range from just below to just above the 35-kt intensity estimate.

The NHC forecast still calls for modest strengthening over the next day or two, and this seems like a good bet given the recent observed improvement of Paulette’s organization and structure. Moderate shear and some surrounding dry air appear to be inhibiting factors for substantial intensification, though the HWRF is a notable outlier that forecasts Paulette to become a hurricane in about 48 h. No major changes to the official intensity forecast were required at this time, and the NHC forecast is between the IVCN and HCCA consensus aids.

Paulette appears to have moved slowly toward the northwest during the past several hours. The guidance spread has increased a little, though the models all have the same general idea. For the next 12 to 24 hours, Paulette will be embedded in an area of weak steering flow, though reformations of the center closer to the convection could result in a northwest to north-northwestward motion. A mid-level ridge is forecast to build over the western and central North Atlantic in a day or two and this should cause Paulette to turn back toward the west. The NHC forecast is slightly north of the previous one and is close to the latest multi-model consensus.

FORECAST POSITIONS AND MAX WINDS

INIT  07/2100Z 17.5N  42.4W   35 KT  40 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 12H  08/0600Z 17.9N  42.7W   40 KT  45 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 24H  08/1800Z 18.8N  43.6W   45 KT  50 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 36H  09/0600Z 19.6N  45.0W   50 KT  60 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 48H  09/1800Z 20.3N  46.8W   50 KT  60 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 60H  10/0600Z 20.8N  48.8W   50 KT  60 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 72H  10/1800Z 21.1N  50.7W   50 KT  60 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 96H  11/1800Z 21.8N  53.8W   50 KT  60 MPH - Tropical Storm (ESE Scrub Island, Antigua)
120H  12/1800Z 24.0N  56.5W   50 KT  60 MPH - Tropical Storm (ESE Scrub Island, Antigua)

NWS National Hurricane Center Miami FL 1100 AM AST Mon Sep 07, 2020 

Visible imagery and recent ASCAT data indicate that the circulation of Paulette is quite elongated from southwest to northeast. However, the ASCAT data indicated that winds up to tropical-storm-force were present, and this was corroborated by a 35 kt Dvorak-based intensity estimate from TAFB. Paulette is the 16th named storm of the 2020 Atlantic hurricane season. It is also the earliest 16th named storm of any Atlantic season by 10 days. The previous record was Philippe, which formed on September 17, 2005.

Although it is elongated, the tropical storm’s structure seems to have improved over the past few hours, with convection increasing in both coverage and organization. Although moderate southerly shear and some dry environmental air appear to be limiting factors, most of the intensity guidance suggests that modest strengthening is likely for the next couple of days. Near the end of the week, the models indicate that Paulette’s winds will plateau or possibly decrease. This appears to be the result of increasing southwesterly shear associated with a upper-level trough that is forecast to deepen over the central Atlantic on Thursday and Friday. The official intensity forecast remains very near the multi-model consensus.

Paulette has moved very little during the past few hours, but a west-northwestward to northwestward motion is expected to resume shortly. Fluctuations in the strength of a mid-level ridge over the western and central Atlantic will likely cause Paulette’s exact speed and heading to fluctuate during the next several says, but the guidance agrees that it should generally head northwestward through the end of the week. It is likely that the stronger Paulette gets, the farther north it will move since the aforementioned upper-level trough will have a greater influence on its track. The NHC track forecast is based on a blend of the previous forecast and the latest multi-model consensus.

FORECAST POSITIONS AND MAX WINDS

INIT  07/1500Z 17.2N  42.2W   35 KT  40 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 12H  08/0000Z 17.4N  42.5W   40 KT  45 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 24H  08/1200Z 17.9N  43.2W   40 KT  45 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 36H  09/0000Z 18.7N  44.4W   45 KT  50 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 48H  09/1200Z 19.6N  46.0W   50 KT  60 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 60H  10/0000Z 20.3N  48.2W   50 KT  60 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 72H  10/1200Z 20.7N  50.0W   50 KT  60 MPH - Tropical Storm (ESE Scrub Island, Antigua)
 96H  11/1200Z 21.0N  53.0W   45 KT  50 MPH - Tropical Storm (ESE Scrub Island, Antigua)
120H  12/1200Z 23.0N  56.5W   45 KT  50 MPH - Tropical Storm (ESE Scrub Island, Antigua)

NWS National Hurricane Center Miami FL 1100 PM AST Sun Sep 06, 2020

The tropical low that the National Hurricane Center has been tracking the past few days west of the Cabo Verde Islands has developed enough convective banding for the system to be classified as a tropical depression. A 06/2345Z ASCAT-B scatterometer pass indicated surface wind speeds of 30-31 kt north of the center, which are supported by a T2.0/30 kt Dvorak satellite intensity estimate from TAFB at 07/0000 UTC.

The initial motion estimate is an uncertain 270/04kt. The center has been jumping around somewhat due to small, brief convective bursts that then dissipate, leaving small swirls rotating around the mean circulation center. However, the latest ASCAT data showed a much better defined overall circulation, especially in the inner core wind field region, so the forward motion should stabilize fairly soon. The depression is expected to remain caught in weak steering flow for the next 5 days, so only a slow westward motion is expected tonight and Monday, followed by a west-northwestward motion by later Monday and Tuesday that will continue through the remainder of the 120-h forecast period. Possible track forecast complications could develop by days 3-5 if binary interaction occurs between the depression and the large low (Invest 93L) currently located southeast of the Cabo Verde Islands, resulting in TD-17 not gaining as much latitude as currently indicated. The NHC forecast track lies down the middle of the simple- and corrected-consensus model guidance envelope.

The depression is only forecast to slowly strengthen for the next 4 days or so due to expected intrusions of dry mid-level air. By day 5, increasing southerly vertical wind shear on the east side of a large upper-level low that is forecast to cut off north of Puerto Rico is expected to induce gradual weakening. However, both the timing of the development of the low and its west-southwestward motion will determine if sufficient shear will prevent further strengthening after 96 h; a slower formation of the low and/or a slower retrograding motion would result in at least less weakening. The NHC intensity forecast closely follows an average of the IVCN and NOAA-HCCA intensity consensus models.

FORECAST POSITIONS AND MAX WINDS

INIT  07/0300Z 17.0N  41.5W   30 KT  35 MPH - Depression (WSW Mindelo, Cape Verde)
 12H  07/1200Z 17.0N  42.1W   30 KT  35 MPH - Depression (WSW Mindelo, Cape Verde)
 24H  08/0000Z 17.2N  42.7W   35 KT  40 MPH - Tropical Storm (WSW Mindelo, Cape Verde)
 36H  08/1200Z 17.5N  43.4W   40 KT  45 MPH - Tropical Storm (WSW Mindelo, Cape Verde)
 48H  09/0000Z 18.0N  44.6W   45 KT  50 MPH - Tropical Storm (ENE St. Johns, AB)
 60H  09/1200Z 18.6N  46.3W   50 KT  60 MPH - Tropical Storm (ENE St. Johns, AB)
 72H  10/0000Z 19.2N  48.2W   55 KT  65 MPH - Tropical Storm (ENE St. Johns, AB)
 96H  11/0000Z 20.4N  51.9W   50 KT  60 MPH - Tropical Storm (ENE St. Johns, AB)

NWS National Hurricane Center Miami FL 800 PM EDT Sun Sep 6, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

  • 1. Thunderstorm activity associated with a well-defined low pressure system located about midway between the west coast of Africa and the northern Leeward Islands continues to get better organized. A tropical depression is expected to form later tonight or on Monday while the low moves westward or west-northwestward across the central tropical Atlantic. * Formation chance through 48 hours…high…near 100 percent. * Formation chance through 5 days…high…near 100 percent.
  • 2. Showers and thunderstorms continue to steadily increase and are showing signs of organization in association with a low pressure system located just west of Senegal. Environmental conditions are conducive for development, and a tropical depression is expected to form within the next day or so while the system moves generally westward over the far eastern tropical Atlantic. Interests in the Cabo Verde Islands should monitor the progress of this system as gusty winds and locally heavy rainfall are likely there Monday night and Tuesday. A Tropical Storm Watch or Warning could be required for the islands by early Monday. * Formation chance through 48 hours…high…90 percent. * Formation chance through 5 days…high…90 percent.
  • 3. A tropical wave located over the central Caribbean Sea south of Jamaica and extending northward across the island is producing limited shower and thunderstorm activity. Upper-level winds are forecast to remain unfavorable for development for the next several days while the system moves westward, and tropical cyclone formation is not expected. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…near 0 percent.
  • 4. A trough of low pressure located just to the southeast of Bermuda is producing disorganized cloudiness and showers. Some slow development of this system is possible during the next several days while it moves west-northwestward. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…low…30 percent.
  • 5. A new tropical wave is forecast to emerge off the west coast of Africa by the middle to latter part of this week. Some gradual development will be possible thereafter while the system moves generally westward. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…20 percent.

NWS National Hurricane Center Miami FL 200 PM EDT Sun Sep 6, 2020 

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

  • 1. An area of low pressure located about midway between the west coast of Africa and the Leeward Islands is gradually becoming better defined. However, the associated showers and thunderstorms are still not well organized. Gradual development of this system is expected, and a tropical depression is likely to form tonight or on Monday while it moves westward or west-northwestward across the central tropical Atlantic. * Formation chance through 48 hours…high…90 percent. * Formation chance through 5 days…high…90 percent.
  • 2. Showers and thunderstorms are showing signs of organization in association with a broad area of low pressure located just off the coast of western Africa. Environmental conditions are conducive for development, and a tropical depression is expected to form within the next couple of days while it moves generally westward over the far eastern tropical Atlantic. Interests in the Cabo Verde Islands should monitor the progress of this system as gusty winds and locally heavy rainfall is likely there Monday night and Tuesday. * Formation chance through 48 hours…high…70 percent. * Formation chance through 5 days…high…90 percent.

3. A tropical wave located over the central Caribbean Sea continues to produce disorganized showers and thunderstorms. Development, if any, of this system should be slow to occur during the next day or two while it moves westward across the central and western Caribbean Sea. After that time, unfavorable upper-level winds should limit its formation chances. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…low…10 percent.

4. A trough of low pressure located just southeast of Bermuda is producing disorganized cloudiness and showers. Some slow development of this system is possible during the next several days while it moves west-northwestward. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…low…30 percent.

NWS National Hurricane Center Miami FL 800 AM EDT Sun Sep 6, 2020 

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

  • 1. An area of low pressure located about midway between the west coast of Africa and the Leeward Islands is gradually becoming better defined. However, the associated showers and thunderstorms remain disorganized. Gradual development of this system is expected, and a tropical depression is likely to form in the next day or so while it moves westward or west-northwestward across the central tropical Atlantic. * Formation chance through 48 hours…high…90 percent. * Formation chance through 5 days…high…90 percent.
  • 2. Showers and thunderstorms are showing signs of organization in association with a tropical wave that is located just off the coast of western Africa. Gradual development of this system is expected, and a tropical depression is likely to form by the middle of the week while it moves generally westward over the far eastern tropical Atlantic. Interests in the Cabo Verde Islands should monitor the progress of this system as gusty winds and locally heavy rainfall is possible there on Monday and Tuesday. * Formation chance through 48 hours…medium…50 percent. * Formation chance through 5 days…high…80 percent.
  • 3. A tropical wave located over the central Caribbean Sea continues to produce disorganized showers and thunderstorms. Development, if any, of this system should be slow to occur during the next day or two while it moves westward across the central and western Caribbean Sea. After that time, unfavorable upper-level winds should limit its formation chances. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…low…10 percent.
  • 4. A trough of low pressure located a couple of hundred miles southeast of Bermuda is producing disorganized cloudiness and showers. Environmental conditions are only marginally conducive for development during the next several days while this system moves west-northwestward. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…low...20 percent.

NWS National Hurricane Center Miami FL 800 PM EDT Sat Sep 5, 2020 

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center has issued the last advisory on Post-Tropical Cyclone Omar, located about 600 miles northeast of Bermuda.

  • 1. A tropical wave and area of low pressure located over the eastern tropical Atlantic continues to produce a large area of disorganized showers and thunderstorms. Gradual development of this system is expected while it moves westward to west-northwestward, and a tropical depression is likely to form late this weekend or early next week when the system reaches the central tropical Atlantic. * Formation chance through 48 hours…high…70 percent. * Formation chance through 5 days…high…90 percent. [Paulette]
  • 2. A tropical wave located over the east-central Caribbean Sea is producing an area of showers and thunderstorms. Some slow development of this system is possible during the next couple of days before upper-level winds become unfavorable for formation. This wave is expected to move westward across the central and western Caribbean Sea during the next few days. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…low…10 percent.
  • 3. Another tropical wave located over western Africa is forecast to move over the eastern tropical Atlantic on Sunday. Gradual development of this system is then expected, and a tropical depression is likely to form by the middle of next week while it moves generally westward over the far eastern tropical Atlantic. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…high…80 percent. [Rene]

NWS National Hurricane Center Miami FL 200 PM EDT Sat Sep 5, 2020 

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical Depression Omar, located about 600 miles northeast of Bermuda.

  • 1. A tropical wave and area of low pressure located over the eastern tropical Atlantic continues to produce a large area of disorganized showers and thunderstorms. Gradual development of this system is expected while it moves westward to west-northwestward, and a tropical depression is likely to form late this weekend or early next week when the system reaches the central tropical Atlantic. * Formation chance through 48 hours…medium…60 percent. * Formation chance through 5 days…high…90 percent. [Paulette]
  • 2. A tropical wave located over the east-central Caribbean Sea is producing an area of showers and thunderstorms. Some slight development of this system is possible during the next couple of days before upper-level winds become unfavorable for formation. This wave is expected to move westward across the central and western Caribbean Sea during the next few days. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…low…10 percent.
  • 3. Another tropical wave located inland over western Africa is forecast to move offshore on Sunday. Gradual development of this system is then expected, and a tropical depression is likely to form by the middle of next week while it moves generally westward over the far eastern tropical Atlantic. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…high...80 percent. [Rene]

NWS National Hurricane Center Miami FL 800 AM EDT Sat Sep 5, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical Depression Omar, located about 500 miles east-northeast of Bermuda.

  • 1. Shower activity has become less organized in association with a trough of low pressure located about midway between the west coast of Africa and the Windward Islands. Significant development of this system is not expected, as it will likely be hindered by the interaction with a large tropical wave located a few hundred miles to its east. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…low...10 percent.
  • 2. A tropical wave and area of low pressure located over the eastern tropical Atlantic continues to produce a large area of disorganized showers and thunderstorms. Gradual development of this system is expected while it moves westward to west-northwestward, and a tropical depression is likely to form late this weekend or early next week when the system reaches the central tropical Atlantic. * Formation chance through 48 hours…medium…50 percent. * Formation chance through 5 days…high…90 percent. [Paulette]
  • 3. Another tropical wave is forecast to move off the west coast of Africa on Sunday. Gradual development of this system is then expected, and a tropical depression is likely to form by the middle of next week while it moves generally westward over the far eastern tropical Atlantic. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…high…70 percent. [Rene]

NWS National Hurricane Center Miami FL 800 PM EDT Fri Sep 4, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical Depression Omar, located about 475 miles east-northeast of Bermuda.

  • 1. A nearly stationary and poorly-defined area of low pressure is located over the east-central tropical Atlantic about midway between the west coast of Africa and the Windward Islands. This system continues to produce disorganized showers and thunderstorms, and some slow development could occur during the next couple of days before it merges or interacts with the large tropical wave currently located just west of the Cabo Verde Islands. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…low…30 percent.
  • 2. A tropical wave and area of low pressure located just west of the Cabo Verde Islands is producing a large area of disorganized showers and thunderstorms. Gradual development of this system is expected as it moves westward to west-northwestward, and a tropical depression is likely to form late this weekend or early next week when the system reaches the central tropical Atlantic. * Formation chance through 48 hours…medium…40 percent. * Formation chance through 5 days…high…80 percent. [Paulette]
  • 3. Another tropical wave is forecast to move off the west coast of Africa on Sunday. Gradual development of this system is then expected, and a tropical depression could form by the middle of next week while it moves generally westward over the far eastern tropical Atlantic. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…medium...60 percent. [Rene]

NWS National Hurricane Center Miami FL 800 AM EDT Fri Sep 4 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico: The National Hurricane Center is issuing advisories on Tropical Depression Omar, located about 400 miles east-northeast of Bermuda.

  • 1. A non-tropical area of low pressure is located over the north-central Atlantic about 500 miles south-southeast of Cape Race Newfoundland. This low is expected to move north-northeastward near 15 mph, and some slight subtropical or tropical development of this system is possible before it reaches cooler waters tonight. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…low…20 percent.
  • 2. A nearly stationary broad area of low pressure is located over the east-central tropical Atlantic about midway between the west coast of Africa and the Windward Islands. This system continues to produce disorganized showers and thunderstorms, and gradual development is possible after the larger tropical wave located near the Cabo Verde Islands passes to the north of this system on Sunday. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…medium…40 percent. [Rene]
  • 3. A tropical wave located just west of the Cabo Verde Islands is producing a large area of disorganized showers and thunderstorms. Gradual development of this system is expected as it moves westward to west-northwestward, and a tropical depression is likely to form early next week when the system reaches the central tropical Atlantic. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…high…70 percent. [Paulette]
  • 4. Another tropical wave is forecast to move off the west coast of Africa on Sunday. Gradual development of this system is then expected, and a tropical depression could form by the middle of next week while it moves generally westward over the far eastern tropical Atlantic. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…medium…50 percent.

NWS National Hurricane Center Miami FL 800 PM EDT Thu Sep 3 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical Depression Nana, inland near the Guatemala-Mexico border, and on Tropical Depression Omar, located about 400 hundred miles northeast of Bermuda.

  • 1. Shower activity has increased today in association with a non-tropical area of low pressure located over the north-central Atlantic, about 625 miles south of Cape Race Newfoundland. Some slight subtropical or tropical development of this system is possible before it reaches cooler waters later on Friday. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…low…20 percent.[Sally]
  • 2. A broad area of low pressure located over the eastern tropical Atlantic several hundred miles west-southwest of the Cabo Verde Islands is producing a small area of disorganized showers and thunderstorms. Gradual development is possible early next week once the larger tropical wave located off of the coast of Africa passes to the north of the system on Sunday. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…medium…40 percent. [Rene]
  • 3. A tropical wave located off the coast of west Africa is merging with another disturbance located a couple of hundred miles south of the Cabo Verde Islands, resulting in an extensive area of disorganized showers and thunderstorms. Development of this system is expected to be slow during the next couple of days while it moves west- northwestward at about 15 mph. After that, a tropical depression is more likely to form early next week over the central tropical Atlantic where environmental conditions are forecast to be more favorable for development. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…high…70 percent. [Paulette]
  • 4. Another tropical wave is forecast to move off the west coast of Africa over the weekend. An area of low pressure is expected to form from the wave early next week. Gradual development of this low is then expected, and a tropical depression could form while it moves generally westward over the far eastern tropical Atlantic. * Formation chance through 48 hours…low…near 0 percent.

NWS National Hurricane Center Miami FL 200 PM EDT Thu Sep 3, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical Storm Nana, inland near the Guatemala-Mexico border, and on Tropical Depression Omar, located a few hundred miles northeast of Bermuda.

  • 1. A broad area of low pressure located over the eastern tropical Atlantic several hundred miles west-southwest of the Cabo Verde Islands is producing a small area of disorganized showers and thunderstorms. Gradual development is possible early next week as the larger tropical wave located off of the coast of Africa passes to the north of the system on Sunday. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…medium…40 percent. [Rene]
  • 2. A tropical wave located off the coast of west Africa is merging with another disturbance located a couple of hundred miles south of the Cabo Verde Islands, resulting in an extensive area of disorganized showers and thunderstorms. Development of this system is likely to be slow during the next couple of days while it moves west- northwestward at about 15 mph. After that, a tropical depression is more likely to form early next week over the central tropical Atlantic where environmental conditions are forecast to be more favorable for development. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…high…70 percent. [Paulette]
  • 3. Another tropical wave is forecast to move off the west coast of Africa over the weekend. An area of low pressure is expected to form from the wave, and some development of this low will be possible early next week while it moves generally westward over the far eastern tropical Atlantic. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…20 percent. [Sally]

NWS National Hurricane Center Miami FL 800 AM EDT Thu Sep 3, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical Storm Nana, inland over southern Belize, and on Tropical Depression Omar, located a few hundred miles north-northeast of Bermuda.

  • 1. A broad area of low pressure located over the eastern tropical Atlantic several hundred miles west-southwest of the Cabo Verde Islands is producing a small area of disorganized showers and thunderstorms. Gradual development is possible early next week as the larger tropical wave located off of the coast of Africa passes to the north of the system on Sunday. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…medium...40 percent. [Rene]
  • 2. A tropical wave located off the coast of west Africa is merging with another disturbance located a couple of hundred miles south of the Cabo Verde Islands, resulting in an extensive area of disorganized showers and thunderstorms. Development of this system is likely to be slow during the next couple of days while it moves west- northwestward at about 15 mph, and a tropical depression is more likely to form early next week over the central tropical Atlantic where environmental conditions are forecast to be more favorable for development. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…high…70 percent. [Paulette]
  • 3. Another tropical wave is forecast to move off the west coast of Africa over the weekend. An area of low pressure is expected to form from the wave, and some development of this low will be possible early next week while it moves generally westward over the far eastern tropical Atlantic. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…20 percent. [Sally]

NWS National Hurricane Center Miami FL 800 PM EDT Wed Sep 2, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical Depression Omar, located a few hundred miles north of Bermuda, and on Tropical Storm Nana, located about 150 miles east of Belize City, Belize.

  • 1. An area of low pressure located about midway between the Windward Islands and West Africa is producing a small area of showers and thunderstorms. Some development of this system is possible this week as it drifts generally westward over the eastern and central tropical Atlantic Ocean. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…low...30 percent. [Rene]
  • 2. A tropical wave, located just off the coast of West Africa, is producing disorganized shower and thunderstorm activity. The wave is expected to merge with a disturbance centered a couple of hundred miles southeast of the Cabo Verde Islands toward the end of the week. The gradual development of this system is then possible, and a tropical depression could form over the weekend or early next week while it moves westward over the eastern and central tropical Atlantic Ocean. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…medium...60 percent. [Paulette]

NWS National Hurricane Center Miami FL 200 PM EDT Wed Sep 2, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical Storm Omar, located a few hundred miles north-northwest of Bermuda, and on Tropical Storm Nana, located a couple of hundred miles east of Belize City, Belize.

  • 1. An area of low pressure located about midway between the Windward Islands and west Africa is producing a small area of showers and thunderstorms. Some development of this system is possible this week as it drifts generally westward over the eastern and central tropical Atlantic Ocean. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…low…30 percent.  [Rene]
  • 2. A tropical wave, located just off the coast of West Africa, is producing limited shower activity. The wave is expected to merge with a disturbance centered a couple of hundred miles southeast of the Cabo Verde Islands toward the end of the week. The gradual development of this system is then possible, and a tropical depression could form over the weekend while it moves westward over the eastern and central tropical Atlantic Ocean. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…medium…60 percent. [Paulette]

NWS National Hurricane Center Miami FL 800 AM EDT Wed Sep 2 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical Storm Omar, located a few hundred miles northwest of Bermuda, and on Tropical Storm Nana, located a couple hundred miles northeast of the coast of Honduras.

  • 1. Showers and thunderstorms associated with an area of low pressure located about midway between the Windward Islands and west Africa remain disorganized. Some development of this system, however, is possible this week as it meanders over the eastern and central tropical Atlantic Ocean. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…low…30 percent. [Rene]
  • 2. Surface observations and satellite derived data indicate that a tropical wave has emerged off the coast of Africa. The wave is expected to merge with a disturbance centered a couple of hundred miles southeast of the Cabo Verde Islands in the next day or so. Gradual development of this system is then possible, and a tropical depression could form by this weekend while it moves westward over the eastern and central tropical Atlantic Ocean. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…medium...60 percent. [Paulette]

NWS National Hurricane Center Miami FL 800 PM EDT Tue Sep 1, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical Storm Omar, located a couple of hundred miles east of Cape Hatteras, North Carolina, and on Tropical Storm Nana, located about 150 miles southwest of Jamaica.

  • 1. Showers and thunderstorms associated with a small area of low pressure about midway between the Windward Islands and west Africa appear to be slowly becoming better organized. Some additional development of this system is possible this week as the system meanders in the central tropical Atlantic Ocean. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…low…30 percent.
  • 2. A tropical wave is expected to emerge off the coast of Africa on Wednesday and merge with a disturbance centered a couple of hundred miles southeast of the Cabo Verde Islands in the next day or so. Gradual development of this system is then possible, and this system could become a tropical depression by this weekend while it moves slowly westward over the eastern tropical Atlantic Ocean. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…medium…60 percent. [Paulette]

NWS Weather Prediction Center College Park MD 200 PM EDT Tue Sep 1, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical Depression Fifteen, located a couple of hundred miles offshore of North Carolina, and on newly formed Tropical Storm Nana, located about 100 miles south of Jamaica.

  • 1. A small area of low pressure has formed about midway between the Windward Islands and west Africa. Upper-level winds are marginally conducive for some slow development this week as the system meanders in the central tropical Atlantic Ocean. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…low…20 percent. [Omar]
  • 2. A tropical wave is expected to emerge off the coast of Africa in about a day and merge with a disturbance centered about 200 miles southeast of the Cabo Verde Islands in a couple of days. Gradual development of this system is then possible, and this system could become a tropical depression by this weekend while it moves slowly westward over the eastern tropical Atlantic Ocean. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…medium…50 percent.  [Paulette]

NWS National Hurricane Center Miami FL 800 AM EDT Tue Sep 1, 2020

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical Depression Fifteen, located more than 100 miles southeast of Cape Hatteras, North Carolina.

  • 1. A well-organized cluster of showers and thunderstorms associated with a tropical wave continues to move quickly westward across the central Caribbean Sea. Although the disturbance does not yet have a well-defined circulation center, ship observations indicate that tropical-storm-force winds are occurring in the northern portion of wave to the southeast of Jamaica, which will spread near or just south of Jamaica later this morning and into this afternoon. Environmental conditions are expected to become a little more conducive for development, and a tropical depression or a tropical storm is likely to form during the next day or so before the system reaches Central America Wednesday night. Locally heavy rains and gusty winds are possible on Jamaica today, and interests there, as well as in northern Nicaragua, Honduras, Belize, Guatemala, and the Yucatan Peninsula, should monitor the progress of this system. An Air Force Reserve reconnaissance aircraft is currently en route to investigate the disturbance. Potential tropical cyclone or tropical cyclone advisories will likely be issued later today, along with watches and warnings. Additional information on this system can be found in High Seas Forecasts issued by the National Weather Service. * Formation chance through 48 hours…high…80 percent. * Formation chance through 5 days…high…80 percent. [Omar]
  • 2. A tropical wave is expected to emerge off the coast of Africa in a day or so. Gradual development of this system will be possible through the end of the week while it moves slowly westward over the far eastern tropical Atlantic Ocean. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…medium…40 percent. [Paulette]

If this system is named, it will become Tropical Storm Paulette.

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