Tropical Storm Humberto

Hurricane Humberto Track 1100 Hours September 17 2019
Hurricane Humberto Track 1100 Hours September 17 2019

Hurricane Humberto Satellite 0500 Hours September 17 2019Tropical Storm Humberto – NWS National Hurricane Center Miami FL 1100 AM EDT Tue Sep 17, 2019

An Air Force Reserve reconnaissance aircraft that investigated Humberto (see Tuesday video below) earlier this morning found 700-mb flight-level winds of 96 kt and 82-kt surface winds on a dropsonde in the southwestern quadrant, and 81-kt SFMR surface winds in the northwestern quadrant. More importantly, the wind data indicate that Humberto’s wind field has expanded significantly and is becoming asymmetric with the largest wind radii now located in the southern semicircle. The aircraft also measured a central pressure of 961 mb, down 18 mb since this time yesterday. The central pressure typically corresponds to an intensity of around 100 kt, but the expansion of the wind field has resulted in little increase in the eyewall wind field for now. Based on these data, the initial intensity has been increased to 85 kt.

Humberto has maintained an east-northeastward motion of 075/07 kt. The hurricane is forecast to remain embedded within the mid-latitude westerlies though the forecast period. A deep-layer trough is forecast to dig southward to the west of Humberto in the 24-48 hour period, causing the hurricane to gradually gain latitude and pass just to the northwest of Bermuda in around 36 hours. The models are in excellent agreement on this developing track scenario and are tightly clustered around the previous advisory track. However, the recent expansion of the wind field and the expected additional increase in the wind on the southeast side of Humberto’s circulation will result in the island being in near-hurricane-force conditions. By 72 hours and beyond, Humberto will accelerate northeastward over the cold waters of the north Atlantic and interact with a strong frontal system, resulting in the transition into a large extratropical low. The official track forecast is similar to the previous advisory track through 48 hours, and then is a little faster in the 72-120 hour period, close to a blend of the various consensus models.

Due to the expansion of Humberto’s wind field and large 35-40-n mi wide eye, only modest strengthening is expected during the next 36 hours or so. Although not explicitly shown, Humberto could still become a major hurricane between 24-36 hours when the cyclone will be located over the warmest water of about 29C. Thereafter, gradual wakening is forecast due to cooler waters and strong southwesterly vertical wind shear in excess of 40 kt. However, the typical rate of weakening due to such hostile shear conditions will be tempered owing to the increasing baroclinic forcing in the right-rear entrance region of a polar jet maximum. The new intensity forecast is nearly identical to the previous advisory, and follows a blend of the consensus models HCCA and FSSE.

Key Messages:

  • 1. Tropical-storm-force winds are expected to reach Bermuda by Wednesday afternoon, with hurricane conditions possible Wednesday night and Thursday morning. Residents there should follow advice given by local officials.
  • 2. Large swells will increase along the coast of Bermuda by Wednesday. Dangerous breaking waves, especially along south-facing beaches, could cause coastal flooding Wednesday night and Thursday.
  • 3. Swells will continue to affect the northwestern Bahamas and the southeastern coast of the United States from east-central Florida to North Carolina during the next couple of days, creating life- threatening surf and rip current conditions.
FORECAST POSITIONS AND MAX WINDS

 12H  18/0000Z 31.1N  72.0W   90 KT 105 MPH - Category 2 (ESE Savannah, GA)
 24H  18/1200Z 31.8N  69.4W   95 KT 110 MPH - Category 2 (WSW St George's, Bermuda)
 36H  19/0000Z 33.1N  66.1W   95 KT 110 MPH - Category 2 (WNW St George's, Bermuda)
 48H  19/1200Z 35.3N  62.6W   90 KT 105 MPH - Category 2 (ENE St George's, Bermuda)
 72H  20/1200Z 39.6N  58.4W   70 KT  80 MPH - Category 1 (ESE New York City, NY)
 96H  21/1200Z 43.0N  52.2W   60 KT  70 MPH - Tropical Storm (ESE Sherbrooke, Nova Scotia)
120H  22/1200Z 44.5N  40.0W   50 KT  60 MPH - Tropical Storm (ESE St. John's, Newfoundland)

NWS National Hurricane Center Miami FL 500 AM EDT Tue Sep 17, 2019

The Hurricane Humberto cloud pattern continues to be rather impressive, but the eye is ragged looking and less defined than a few hours ago. Dvorak estimates from TAFB and SAB have not changed significantly and support an initial intensity of 80 kt. Another reconnaissance plane will check the hurricane’s structure in the morning.

Humberto is expected to continue to move over warm waters for the next few days, and intensity guidance, as well as global models, strengthen the hurricane a little more. On this basis, the NHC forecast calls for the system to become a major hurricane in about 24 to 36 hours. After that time, upper-level winds are expected to be hostile, resulting in weakening. By day 5, if not sooner, the cyclone should become embedded within a frontal zone and begin to acquire extratropical characteristics at that time.

Satellite fixes indicate that the initial motion continues toward the east-northeast or 075 degrees at 7 kt. Humberto is well embedded within the mid-latitude westerlies, and this general motion with a turn to the northeast and an increase in forward speed is forecast for the next 5 days. Track models are in good agreement with this solution, and the NHC forecast remains in the middle of the guidance envelope. It is also very similar to the previous official forecast. It is still too early to give a good estimate as to how close the core of the hurricane will come to Bermuda. Interests should not focus on the exact forecast track; only a slight deviation to the right could bring the center near or over the island.

Large swells from Humberto will affect Bermuda by Wednesday and will be affecting portions of the northwestern Bahamas and southeastern United States coast during the next couple of days. These swells are expected to produce dangerous surf conditions and life-threatening rip currents.

FORECAST POSITIONS AND MAX WINDS

INIT  17/0900Z 30.6N  74.3W   80 KT  90 MPH - Catgory 1 (ENE Jacksonville Beach, FL)
 12H  17/1800Z 31.0N  73.0W   90 KT 105 MPH - Category 2 (ESE Brunswick, GA)
 24H  18/0600Z 31.6N  70.7W   95 KT 110 MPH - Category 2 (WSW St George's, Bermuda)
 36H  18/1800Z 32.5N  68.0W  100 KT 115 MPH - Category 3 (WSW St George's, Bermuda)
 48H  19/0600Z 34.0N  64.5W   90 KT 105 MPH - Category 2 (ENE St George's, Bermuda)
 72H  20/0600Z 38.0N  60.0W   70 KT  80 MPH - Catgory 1 (ESE Ocean City, MD)
 96H  21/0600Z 42.0N  55.0W   65 KT  75 MPH - Catgory 1 (ESE Shelburne, Nova Scotia)
120H  22/0600Z 44.0N  45.0W   55 KT  65 MPH - Tropical Storm (ESE Biscay Bay, Newfoundland)

NWS National Hurricane Center Miami FL 500 PM EDT Mon Sep 16, 2019

A NOAA Hurricane Hunter aircraft investigating Humberto this afternoon found peak 850-mb flight-level winds of 78 kt in the western quadrant, along with SFMR surface winds of 71-72 kt, which is an increase in the winds in this part of storm since the earlier Air Force Reserve reconnaissance flight. The NOAA aircraft also measured a central pressure of 972 mb, down 4 mb from the previous flight. A combination of subjective and objective satellite intensity estimates of 90 kt and the aircraft data support an initial intensity of 80 kt.

The initial motion estimate remains east-northeastward or 070/06 kt. Humberto made a wobble to the north during the past few hours, but has now wobbled toward the east, which is an indication that the hurricane’s inner core is continuing to consolidate and contract. That being said, the latest model guidance is in even better agreement with and more convergent about the previous forecast track.Hurricane Humberto Tropical Force Wind Speed Probability September 16 2019

Thus no significant changed were required through 72 hours. Thereafter, the models are also now in better agreement that Humberto will not slow down as much as previously expected, and the hurricane is forecast to gradually lift out and accelerate to the northeast on days 4 and 5 when Humberto is well to the northeast of Bermuda. No significant track changes were made to the previous advisory track through 48 hours, with the track having been nudged southward slightly on days 3-5 in agreement with the consensus models TVCN, NOAA-HCCA, and FSSE.

Humberto has continued to strengthen at a rate of 20 kt per 24 hours, and I see no physical reasons why this trend should not continue for another 24-36 hours. By 48 hours and beyond, the hurricane will be entering the right-rear quadrant of a strong upper-level jet maximum that could briefly impart some additional baroclinic forcing on the cyclone, helping it to maintain its intensity or at least slow down the weakening process. By day 3 and beyond, however, the wind shear becomes prohibitively hostile at more than 50 kt, which should cause the central deep convection to erode, resulting in significant weakening. On day 5, extratropical transition over the colder north Atlantic waters is forecast to begin as Humberto interacts and possibly merges with a strong cold front.

Large swells from Humberto will affect Bermuda by late Tuesday, and affect portions of the northwestern Bahamas and southeastern United States coast during the next couple of days. These swells are expected to produce dangerous surf conditions and life-threatening rip currents.

FORECAST POSITIONS AND MAX WINDS

INIT  16/2100Z 30.2N  75.9W   80 KT  90 MPH - Category 1 (ESE Jacksonville Beach, FL)
 12H  17/0600Z 30.4N  74.9W   90 KT 105 MPH - Category 2 (ESE Jacksonville Beach, FL)
 24H  17/1800Z 30.8N  73.3W   95 KT 110 MPH - Category 2 (ESE Brunswick, GA)
 36H  18/0600Z 31.2N  71.3W  100 KT 115 MPH - Category 3 (ESE Brunswick, GA)
 48H  18/1800Z 32.0N  68.7W   95 KT 110 MPH - Category 2 (WSW St George's, Bermuda)
 72H  19/1800Z 36.0N  61.3W   85 KT 100 MPH - Category 2 (ENE St George's, Bermuda)
 96H  20/1800Z 40.1N  59.0W   70 KT  80 MPH - Category 1 (ENE New York City, NY)
120H  21/1800Z 41.7N  54.0W   60 KT  70 MPH - Tropical Storm (Biscay Bay, Newfoundland)

NWS National Hurricane Center Miami FL 1100 AM EDT Mon Sep 16, 2019

An Air Force Reserve reconnaissance aircraft investigating Humberto this morning found peak 850-mb flight-level winds of 88 kt in the southeastern and northeastern quadrants, along with SFMR surface winds of 72-73 kt in the northeastern quadrant and a minimum pressure of 978 mb. These data support an intensity of 75 kt.

The initial motion estimate is east-northeastward or 070/06 kt. Humberto is now solidly located north of the Bermuda-Azores ridge axis, and a continued east-northeastward motion is expected for the 48 hours or so. Thereafter, a large deep-layer trough is forecast to dig southward out of Atlantic Canada and the Canadian Maritimes to the west of Humberto, forcing the hurricane to gradually lift out to the northeast. The exact timing that the trough begins to affect Humberto’s motion will be critical in determining how close the hurricane will come to Bermuda. The latest model guidance is in better agreement and more tightly packed than previous runs, suggesting that the poleward turn will occur at least 100 n mi west of the island. By days 4 and 5, however, the model guidance becomes strongly divergent with a large spread of about 1000 n mi on day 5, resulting in lower-than-normal confidence in the track forecast on those days.

Humberto has been strengthening at a rate of 20 kt per 24 hours since this time yesterday, and that trend is expected to continue for the next day or so given the warm water beneath the hurricane and a continued favorable upper-level outflow pattern. The hurricane is expected to peak as a major hurricane in 36-48 hours when the cyclone will be located over SSTs of about 29 deg C and moving into the right-rear quadrant of a strong upper-level jet maximum. Thereafter, strong southwesterly vertical wind shear is expected to gradually diminish convection around the center despite the impressive baroclinic/dynamically driven pressure falls, which will mainly act to spread out the surface wind field rather than intensify the cyclone. Humberto is forecast to interact with an approaching cold front on day 5, resulting in extratropical transition over the colder Atlantic waters north of the Gulf Stream. The official intensity forecast is just an update of the previous advisory and now shows Humberto reaching major hurricane status, similar to the HCCA, FSSE, and HWRF models. Since Humberto’s wind field is expected to expand significantly by day 2, a Tropical Storm Watch for Bermuda will likely be required on the 500 pm EDT advisory.

Large swells from Humberto will affect portions of the northwestern The Bahamas and the southeastern United States coast during the next few days. These swells are expected to produce dangerous surf conditions and life-threatening rip currents.

FORECAST POSITIONS AND MAX WINDS

INIT  16/1500Z 29.9N  76.5W   75 KT  85 MPH - Category 1 (ESE St. Augustine, FL)
 12H  17/0000Z 30.1N  75.6W   85 KT 100 MPH - Category 2 (ESE St. Augustine, FL)
 24H  17/1200Z 30.4N  74.4W   95 KT 110 MPH - Category 2 (ESE Jacksonville Beach, FL)
 36H  18/0000Z 30.7N  72.7W  100 KT 115 MPH - Category 3 (ESE Jacksonville Beach, FL)
 48H  18/1200Z 31.3N  70.5W   95 KT 110 MPH - Category 2 (ESE St George's, Bermuda)
 72H  19/1200Z 33.7N  65.0W   85 KT 100 MPH - Category 2 (WNW  St George's, Bermuda )
 96H  20/1200Z 37.9N  60.9W   70 KT  80 MPH - Category 1 (WNW Ocean City, MD)
120H  21/1200Z 40.8N  56.8W   60 KT  70 MPH - Tropical Storm (Biscay Bay, Newfoundland)

NWS National Hurricane Center Miami FL 1100 PM EDT Sun Sep 15, 2019

Hurricane Hunter aircraft investigating Humberto indicates that the system’s intensity is now 65 kt. This is also supported by Dvorak classifications from TAFB and SAB, and it makes the cyclone the third hurricane of the 2019 Atlantic season. Humberto’s cloud pattern has continued to gradually become better organized, with increasing coverage and intensity of deep convection, and pronounced upper-level outflow over the eastern semicircle of the circulation.

The hurricane is expected to traverse warm Gulf Stream waters for the next several days, but the dynamical models forecast a significant increase in southwesterly vertical shear through 72 hours. In spite of the latter unfavorable factor, numerical guidance generally shows intensification. This is likely at least partially due to some baroclinic forcing caused by a strong mid-latitude trough to the north and northeast of Humberto. The official forecast is a blend of the latest simple and corrected consensus models and is very similar to the previous one.

Humberto continues to move very slowly and the latest aircraft and satellite center fixes indicate that the motion is now northeastward or 040/3 kt. The hurricane has just rounded the western periphery of a subtropical anticyclone and steering currents are likely to remain weak for the next couple of days. An east-northeastward track with a very gradual increase in forward speed is expected for much of the period while Humberto moves between the subtropical high and stronger westerlies associated with the trough to the north. The new NHC track forecast is a little slower than the previous one in 4-5 days, but not as slow as the latest ECMWF and GFS global model runs.

Large swells from Humberto will affect portions of the northwestern The Bahamas and the southeastern United States coast during the next few days. These swells are expected to produce dangerous surf conditions and life-threatening rip currents. See products issued by your local weather office for additional information.

FORECAST POSITIONS AND MAX WINDS

INIT  16/0300Z 29.4N  77.6W   65 KT  75 MPH - Category 1 (ESE St. Augustine, FL)
 12H  16/1200Z 29.8N  77.1W   70 KT  80 MPH - Category 1 (ESE Palm Coast FL)
 24H  17/0000Z 30.1N  76.0W   75 KT  85 MPH - Category 1 (ESE Jacksonville Beach, FL)
 36H  17/1200Z 30.5N  74.7W   80 KT  90 MPH - Category 1 (ESE Jacksonville Beach, FL)
 48H  18/0000Z 30.8N  73.0W   85 KT 100 MPH - Category 2 (ESE Brunswick, GA)
 72H  19/0000Z 31.8N  68.3W   95 KT 110 MPH - Category 2 (ESE St George's, Bermuda)
 96H  20/0000Z 35.0N  63.3W   80 KT  90 MPH - Category 1 (ESE Virginia Beach, VA)
120H  21/0000Z 39.0N  60.0W   60 KT  70 MPH 0 Tropical Storm (ESE New York City, NY)

NWS National Hurricane Center Miami FL 500 PM EDT Sun Sep 15, 2019

Humberto’s convective structure continues to improve in satellite imagery and reflectivity data from the Melbourne NOAA Doppler weather radar, including intermittent appearances of a closed eye. An Air Force Reserve reconnaissance aircraft investigating Humberto this afternoon found SFMR winds of 58-59 kt in the northeastern quadrant outside of the heaviest rain areas, and that the pressure had fallen 4 mb during the past 2 hours, now down to 989 mb. Based on these data, the intensity has been increased to 60 kt.

The initial motion estimate is now 360/05 kt. There are no significant changes to the previous forecast track or reasoning. Humberto is likely located on or near an east-west oriented ridge axis, and a sharp turn toward the northeast is likely during the next 6-12 hours. The latest NHC model guidance remains highly convergent on the previous forecast track and continues to show the cyclone gradually being accelerated toward the northeast and east-northeast during the 24-120 hour period. The large deep-layer trough and associated cold front that will be digging southward out of eastern Canada and the northeastern United States is forecast by the ECMWF model to develop a cutoff low over the northwestern Atlantic that results in some binary interaction with Humberto on day 5. However, this is a new development and is considered to be an outlier scenario at this time. The new forecast track is similar to the previous advisory and lies close to the TVCN and HCCA consensus track models.

Likewise, there is no significant change to the previous intensity forecast. All of the available model guidance continues to support steady strengthening for the 3 days. In 48-72 hours, Humberto is forecast to be moving into the right-rear quadrant of a strong, anticyclonically curved 300-200 mb jet maximum. The associated strong baroclinic/dynamical forcing is expected to produce strong pressure falls and strengthening despite the hostile vertical wind shear conditions of at least 30 kt. On days 4 and 5, the combination of slightly cooler waters, drier and more stable air, and much stronger vertical shear of 40-50 kt should cause steady weakening despite the favorable jetstream dynamics. The previous NHC intensity forecast remains unchanged and continues to show Humberto reaching its peak intensity in 72 hours, coincident with the warmest sea-surface temperatures and strongest jetstream dynamical forcing.

Large swells from Humberto will affect portions of the northwestern The Bahamas and the southeastern United States coast during the next few days. These swells are expected to produce dangerous surf conditions and life-threatening rip currents.

FORECAST POSITIONS AND MAX WINDS

INIT  15/2100Z 29.3N  78.0W   60 KT  70 MPH - Tropical Storm (ENE Daytona Beach, FL)
 12H  16/0600Z 29.8N  77.6W   65 KT  75 MPH - Categort 1 (ESE St. Augustine, FL)
 24H  16/1800Z 30.1N  76.7W   70 KT  80 MPH - Categort 1 (ESE Jacksonville Beach, FL)
 36H  17/0600Z 30.4N  75.4W   80 KT  90 MPH - Categort 1 (ESE Daytona Beach, FL)
 48H  17/1800Z 30.7N  73.6W   85 KT 100 MPH - Categort 2 (ESE Brunswick, GA)
 72H  18/1800Z 31.7N  68.9W   95 KT 110 MPH - Categort 2 (ESE St George's, Bermuda)
 96H  19/1800Z 35.0N  62.0W   85 KT 100 MPH - Categort 2 (ENE St George's, Bermuda)
120H  20/1800Z 39.6N  56.1W   60 KT  70 MPH - Tropical Storm (ESE New York City, NY)

NWS National Hurricane Center Miami FL 1100 AM EDT Sun Sep 15, 2019

Visible and passive microwave satellite imagery indicate that Humberto’s inner-core region has improved markedly since early this morning, including the development of a small but ragged mid-level eye. In addition, significant dry air entrainment that has been plaguing the cyclone since its formation appears to have abated based on the recent development of deep convection in the dry slot located in the southern semicircle of Humberto’s circulation. The anticyclonic outflow has also been increasing in all quadrants, along with a hint of the cloud-filled eye in recent visible imagery. Buoy 41010 located just west of the center recently reported a pressure of 1001.8 mb and 41-kt winds at 4-meters elevation.  AN Air Force Reserve reconnaissance aircraft will reconnoiter Humberto this afternoon, providing more detailed information on the cyclone’s intensity.Tropical Storm Humberto Tropical Storm Force Wind Probability September 15 2019

The initial motion estimate is 350/06 kt, based mainly on microwave satellite fix positions. NHC model guidance remains in excellent agreement on Humberto moving slowly northward through a break in the subtropical ridge today and tonight, then making a sharp turn toward the northeast on Monday when the cyclone passes north of the narrow east-west oriented ridge axis. On days 2-5, the tropical cyclone is forecast to gradually accelerate toward the northeast and east-northeast under the influence of increasing westerlies ahead of a deepening mid-latitude trough forecast to dig southeastward out of Canada and into the extreme northwestern Atlantic Ocean. The new the official forecast track is very similar to the previous advisory track, and lies close to a blend of the tightly packed consensus track models.

Humberto now appears to be well on its way to becoming a hurricane fairly soon based on the newly formed central dense overcast and mid-level eye feature. Although the large-scale shear is fairly large in the SHIPS intensity models, the shear directly over the center of Humberto is forecast to remain low for the next 48 hours or so, which should allow for steady strengthening. By 72 hours, the cyclone is forecast to be situated in the right-rear quadrant of a strong, anticyclonically curved jet maximum. The associated upper-level divergence is expected to induce strong pressure falls and strengthening despite the vertical shear increasing to more than 30 kt. By 96 hours and beyond, slightly cooler waters, much drier air, and very hostile shear conditions of more than 40 kt should cause steady weakening. The new NHC intensity forecast follows the trend of the previous advisory but now shows Humberto reaching peak intensity in 72 hours, coincident with the warmest water temperatures of about 29C and greatest jetstream dynamical forcing.

Large swells from Humberto will affect portions of the northwestern The Bahamas and the southeastern United States coast during the next few days. These swells are expected to produce dangerous surf conditions and life-threatening rip currents. See products issued by your local weather office for additional information.

FORECAST POSITIONS AND MAX WINDS

INIT  15/1500Z 28.9N  77.9W   55 KT  65 MPH - Tropical Storm (ESE New Smyrna Beach, FL)
 12H  16/0000Z 29.5N  77.7W   65 KT  75 MPH - Category 1 (ESE Palm Coast, FL)
 24H  16/1200Z 30.0N  77.1W   70 KT  80 MPH - Category 1 (ESE St. Augustine, FL)
 36H  17/0000Z 30.3N  75.9W   80 KT  90 MPH - Category 1 (ESE Jacksonville Beach, FL)
 48H  17/1200Z 30.7N  74.4W   85 KT 100 MPH - Category 2 (ESE Brunswick, GA)
 72H  18/1200Z 31.6N  69.6W   95 KT 110 MPH - Category 2 (ESE St George's, Bermuda)
 96H  19/1200Z 34.5N  62.8W   85 KT 100 MPH - Category 2 (ENE St George's, Bermuda)
120H  20/1200Z 39.0N  57.0W   65 KT  75 MPH - Category 1 (ESE New York City, NY)

NWS National Hurricane Center Miami FL 1100 PM EDT Sat Sep 14, 2019

Humberto is gradually strengthening. Both the NOAA and Air Force Hurricane Hunters have been investigating the storm this evening and they have found that the cyclone is a little stronger. Based on that data, the initial wind speed is nudged upward to 50 kt and the minimum pressure is around 1000 mb. Satellite images also show that the storm’s structure is improving with an inner core trying to form and banding features becoming better defined to the north of the center. Doppler radar data from the NOAA P-3 aircraft indicate that the cyclone has become less titled in the vertical, suggesting that the shear has lessened over the system. However, there is still some signs of dry air being wrapped into the southern side of the circulation.

Satellite and aircraft fixes indicate that the storm is moving north-northwestward at about 5 kt, steered by a mid-level ridge to its north-northeast over the western Atlantic. Humberto is expected to slow down and turn northward on Sunday well off the coast of east-central Florida as it moves into a developing weakness in the ridge. After that time, a turn to the northeast and then the east-northeast with a gradual increase in forward speed is predicted as Humberto moves along with the flow near the base of a large scale trough. The track models are in relatively good agreement, and only small changes were made to the previous forecast.

The tropical storm is likely to continue strengthening during the next 3 to 4 days as it remains in relatively low wind shear conditions and over the warm Gulf Stream waters. Beyond that time, an increase in wind shear associated with an approaching shortwave trough will likely cause some weakening. The NHC intensity forecast is slightly higher than the previous one and shows Humberto becoming a hurricane in about 24 hours with additional strengthening thereafter. This forecast is in best agreement with the intensity consensus models HCCA, IVDR, and IVCN. The global models suggest that as Humberto gains latitude and intensifies, its wind field will gradually expand, and that is reflected in the NHC wind radii forecast.

FORECAST POSITIONS AND MAX WINDS

INIT  15/0300Z 27.6N  77.3W   50 KT  60 MPH - Tropical Storm (ENE Coopers Town, Bahamas)
 12H  15/1200Z 28.5N  77.8W   60 KT  70 MPH - Tropical Storm (ESE Titusville, FL)
 24H  16/0000Z 29.3N  77.8W   65 KT  75 MPH - Category 1 (ENE Daytona Beach, FL)
 36H  16/1200Z 29.9N  77.1W   70 KT  80 MPH - Category 1 (ESE St. Augustine, FL)
 48H  17/0000Z 30.4N  75.8W   75 KT  85 MPH - Category 1 (ESE Jacksonville Beach, FL)
 72H  18/0000Z 31.2N  72.0W   90 KT 105 MPH - Category 2 (ENE Brunswick, GA)
 96H  19/0000Z 33.0N  65.6W   95 KT 110 MPH - Category 2 (WNW St George's, Bermuda)
120H  20/0000Z 36.9N  58.9W   75 KT  85 MPH - Category 1 (ENE St George's, Bermuda)

NWS National Hurricane Center Miami FL 500 PM EDT Sat Sep 14, 2019

An Air Force Hurricane Hunter plane extensively investigated Tropical Storm Humberto during the past several hours. Data from the plane indicated that the circulation was much better defined than yesterday and the winds increased to 45 kt. Since the plane left, satellite images revealed that the cloud pattern has continued to become better organized, and the low-level center is now under the convection. However, the Dvorak numbers still support keeping the same intensity of 45 kt at this time.

Now that the shear appears to be decreasing and Humberto will be moving over warm waters, the NHC forecast continues to call for strengthening. Humberto is anticipated to become a hurricane in about 36 hours over the western Atlantic well east of the Florida east coast, and well away from the Bahamas.

The intensity forecast continues to be consistent with the solutions of the consensus model and the corrected consensus HCCA. In addition, all global models intensify Humberto and show an increase in the size of the storm.

Satellite and reconnaissance fixes indicate that Humberto has begun to move very slowly toward the north-northwest or 330 degrees at 6 kt. The ridge over the western Atlantic that has been trapping Humberto is already weakening, and this should result in a slow-motion toward the north-northwest and then north during the next day or so.

After that time, the cyclone will encounter the mid-latitude westerlies, and Humberto, by then a hurricane, is forecast to sharply recurve northeastward away from the United States with no significant increase in forward speed. Only by the end of the forecast period, Humberto should begin to accelerate. The NHC forecast is very consistent with the track guidance which once again clearly depict the slow motion of the system, and then a sharp right turn in 2 or 3 days.

FORECAST POSITIONS AND MAX WINDS

INIT  14/2100Z 27.4N  77.3W   45 KT  50 MPH - Tropical Storm (WNW Coopers Town, Bahamas)
 12H  15/0600Z 28.2N  77.9W   55 KT  65 MPH - Tropical Storm (ENE Palm Bay, FL)
 24H  15/1800Z 29.3N  78.3W   60 KT  70 MPH - Tropical Storm (ESE Daytona Beach, FL)
 36H  16/0600Z 29.9N  77.9W   65 KT  75 MPH - Category 1 (ESE St. Augustine, FL)
 48H  16/1800Z 30.5N  76.7W   75 KT  85 MPH - Category 1 (ENE Jacksonville, FL)
 72H  17/1800Z 31.2N  73.5W   85 KT 100 MPH - Category 2 (ESE Brunswick, GA)
 96H  18/1800Z 32.5N  67.5W   90 KT 105 MPH - Category 2 (WNW St George's, Bermuda)
120H  19/1800Z 36.0N  61.0W   80 KT  90 MPH - Category 1 (ENE St George's, Bermuda)

NWS National Hurricane Center Miami FL 1100 AM EDT Sat Sep 14, 2019

The center of Humberto is better defined today, but due to shear, it is still located south of the main area of deep convection. Satellite images indicate that a cyclonically-curved convective band is also developing southeast of the center. Recent reports from an Air Force reconnaissance plane indicate that the winds have increased, and the maximum intensity has been adjusted upward to 45 kt. These strong winds are confined to the north and east of the center of the cyclone.

The current unfavorable shear over Humberto is forecast to weaken, and since the cyclone is expected to move over warm waters, the NHC forecast calls for strengthening. Humberto is anticipated to become a hurricane in about 36 hours over the western Atlantic well east of the Florida east coast and well away from the Bahamas. The intensity forecast is consistent with the solutions of the consensus model and the corrected consensus HCCA. In addition, all global models intensify Humberto and show an increase in the size of the storm.

Satellite and reconnaissance fixes indicate that Humberto has barely moved during the past few hours. Humberto is being trapped by a ridge to the north, but this feature is forecast to weaken. The expected flow pattern should steer the cyclone very slowly toward the northwest and north during the next 24 to 36 hours. After that time, the cyclone will encounter the mid-latitude westerlies, and most likely, Humberto will sharply recurve northeastward away from the United States with no significant increase in forward speed. Only by the end of the forecast period, Humberto should begin to accelerate. The NHC forecast is very consistent with the track guidance which clearly depicts the slow motion of the system and the sharp turn to the right in 2 or 3 days.

Key Messages:

  • 1. Humberto will likely bring tropical-storm-force winds and heavy rainfall to portions of the northwestern Bahamas today. Significant storm surge is not expected in the northwestern Bahamas from this system. Residents, there should follow any advice given by local officials.
FORECAST POSITIONS AND MAX WINDS

INIT  14/1500Z 26.6N  76.7W   45 KT  50 MPH - Tropical Storm (ENE Elbow Cay, Bahamas)
 12H  15/0000Z 27.6N  77.6W   55 KT  65 MPH - Tropical Storm (WNW Coopers Town, Bahamas)
 24H  15/1200Z 28.7N  78.1W   60 KT  70 MPH - Tropical Storm (ESE Titusville, FL)
 36H  16/0000Z 29.5N  78.0W   65 KT  75 MPH - Category 1 (ESE Palm Coast, FL)
 48H  16/1200Z 30.0N  77.0W   70 KT  80 MPH - Category 1 (ESE St. Augustine, FL)
 72H  17/1200Z 30.5N  74.5W   80 KT  90 MPH - Category 1 (ESE Jacksonvill4e, FL)
 96H  18/1200Z 31.5N  70.0W   85 KT 100 MPH - Category 2 (WSW St George's, Bermuda)
120H  19/1200Z 34.5N  63.0W   90 KT 105 MPH - Category 2 (ENE St George's, Bermuda)

NWS National Hurricane Center Miami FL 1100 PM EDT Fri Sep 13, 2019

Corrected to change depression to storm in the second paragraph Deep convection has been gradually increasing this evening, and it is currently most organized in a curved band to the east of the estimated center. In addition, data from the NOAA Hurricane Hunters indicate that the depression has strengthened. The maximum flight-level wind at 700 mb was 41 kt and reliable SFMR values were 35 kt. Based on that data, the initial intensity is increased to 35 kt, making the cyclone Tropical Storm Humberto. The data from the aircraft indicate that the cyclone is titled to the northeast with height, likely due to southwesterly wind shear.

Humberto has been moving erratically during the past 12 to 18 hours as the cyclone has been trying to organize, but my best guess at the initial motion is 320/5. During the next few days, a ridge to the north of the system over the eastern United States and the western Atlantic is expected to slide southeastward, with a weakness in the ridge developing due to a mid- to upper-level trough over the northeastern U.S. This change in the steering pattern should cause the storm to slow down and turn northward off the east coast of Florida in 36 to 48 hours.

The models show the trough over the northeastern U.S. amplifying early next week, which should cause Humberto to turn northeastward and then eastward away from the U.S. The NHC track forecast has been nudged south and east of the previous one to be in better agreement with the latest consensus models. Since there is increasing confidence that the storm will remain well offshore of the coast of Florida, the Tropical Storm Watch for that area has been discontinued. The storm is still feeling some effects of southwesterly shear and drier air, which is causing its lopsided appearance in satellite images and strong tilt in the aircraft data. The atmospheric conditions are expected to gradually become more conducive for strengthening while Humberto moves over the warm Gulf Stream waters. These environmental parameters support intensification, and the cyclone is expected to become a hurricane in 2 to 3 days. The NHC intensity forecast is largely an update of the previous one and in line with the HCCA and IVCN guidance.

Key Messages:

  • 1. Humberto will likely bring tropical-storm-force winds and heavy rainfall to portions of the northwestern Bahamas on Saturday. Significant storm surge is not expected in the northwest Bahamas from this system. Residents, there should follow any advice given by local officials.
  • 2. Heavy rainfall and scattered flash flooding is possible this weekend in coastal sections of eastern Florida, Georgia, and South Carolina. The chance of heavy rainfall affecting coastal North Carolina early next week continues to diminish.
FORECAST POSITIONS AND MAX WINDS

INIT  14/0300Z 25.6N  75.2W   35 KT  40 MPH - Tropical Storm (ENE Spanish Wells, Bahamas)
 12H  14/1200Z 26.5N  76.5W   35 KT  40 MPH - Tropical Storm (ESE Marsh Harbour, Bahamas)
 24H  15/0000Z 27.6N  77.6W   40 KT  45 MPH - Tropical Storm (WNW Coopers Town, Bahamas)
 36H  15/1200Z 28.8N  78.2W   50 KT  60 MPH - Tropical Storm (ESE New Smyrna Beach, FL)
 48H  16/0000Z 29.8N  78.1W   60 KT  70 MPH - Tropical Storm (ESE St. Augustine, FL)
 72H  17/0000Z 31.0N  75.5W   70 KT  80 MPH - Category 1 (ESE Brunswick, GA)
 96H  18/0000Z 31.3N  72.0W   75 KT  85 MPH - Category 1 (WSW St George's, Bermuda)
120H  19/0000Z 32.3N  67.2W   75 KT  85 MPH - Category 1 (WSW St George's, Bermuda)

NWS National Hurricane Center Miami FL 500 PM EDT Fri Sep 13, 2019

An Air Force plane extensively investigated the disturbance near The Bahamas during the past several hours, and in the last portion of the mission, the crew was able to locate a center of circulation, although weak, near the convection. The center was a little bit to the east of the previous estimates. Satellite images also indicate that the cloud pattern has become a little better organized and Dvorak estimates are T2.0 and 1.5 from TAFB and SAB, respectively. On this basis, the disturbance has been classified as a tropical depression with 25 kt winds.

Conditions are not ideal for strengthening since the depression is still embedded within a moderate shear environment, but this parameter is not expected to be strong enough to halt additional development. The NHC forecast still calls for this system to become a tropical storm on Saturday with gradual intensification thereafter. Global models insist on further development, and the reliable guidance suggests that the cyclone could even reach hurricane intensity in about 3 days, and so does the NHC forecast. By then, the system is expected to be over the Atlantic waters well southeast of the coast of the Carolinas.

Due to the reformation of the apparent center, the initial motion is highly uncertain. The best estimate is toward the northwest or 305 degrees at 7 kt. A weakness in the ridge over the western Atlantic is forecast to develop, and this pattern should steer the system slowly toward the northwest and then northward. In about 3 days, an eastward-moving mid-latitude trough will force the system to recurve away from the coast toward the Atlantic. The track guidance has shifted to the east again, and this shift is larger due to the eastward formation of the center. Consequently, the NHC track forecast was adjusted in that direction, but it remains on the western edge of the guidance envelope.

Key Messages:

  • 1. The depression is forecast to become a tropical storm within the next 24 hours and will likely bring tropical-storm-force winds and heavy rainfall to portions of the northwestern Bahamas later today and Saturday. Significant storm surge is not expected in the northwest Bahamas from this system. Residents, there should follow any advice given by local officials.
  • 2. The system could still bring tropical storm conditions to portions of the Florida east coast. Residents, there should monitor the progress of this system and follow any advice given by local officials.
  • 3. Heavy rainfall and scattered flash flooding is possible this weekend in coastal sections of eastern Florida, Georgia, and South Carolina. The chance of heavy rainfall affecting coastal North Carolina early next week continues to diminish.
FORECAST POSITIONS AND MAX WINDS

INIT  13/2100Z 25.6N  75.0W   25 KT  30 MPH - Tropical Depression (ENE Spanish Wells, Bahamas)
 12H  14/0600Z 26.2N  76.0W   30 KT  35 MPH - Tropical Depression (ESE Little Harbour, Bahamas)
 24H  14/1800Z 27.4N  77.6W   35 KT  40 MPH - Tropical Storm (WNW Coopers Town, Bahamas)
 36H  15/0600Z 28.8N  78.5W   45 KT  50 MPH - Tropical Storm (ESE New Smyrna Beach, FL)
 48H  15/1800Z 30.0N  78.8W   55 KT  65 MPH - Tropical Storm (ESE St. Augustine, FL)
 72H  16/1800Z 31.5N  76.5W   65 KT  75 MPH - Category 1 (ESE Savannah, GA)
 96H  17/1800Z 32.0N  73.0W   70 KT  80 MPH - Category 1 (ENE Charleston, SC)
120H  18/1800Z 32.5N  68.0W   75 KT  85 MPH - Category 1 (WNW St George's, Bermuda)

NWS National Hurricane Center Miami FL 1100 AM EDT Fri Sep 13, 2019

Preliminary data from a reconnaissance plane indicate that the disturbance has not developed a well-defined center yet and continues to be characterized by an elongated SW to NE trough of low pressure. Satellite images, however, suggest that the system could be consolidating a little bit farther to the east within the area of deep convection. The reconnaissance plane will also check this region soon. In this advisory, the initial position is a point near the middle of of the trough, but not quite as far east as the convective area. The initial intensity remains 25 kt. The disturbance is embedded within a moderate shear environment, but this parameter is not expected to be strong enough to halt development.

The NHC forecast still calls for this system to become a tropical cyclone later today or Saturday. Global models develop the system and guidance suggests that the cyclone could even reach hurricane intensity by the end of the forecast period. By then, the system is expected to be over the Atlantic well southeast of the coast of the Carolinas. Due to a lack of a well-defined center, the initial motion is highly uncertain. It appears that there has been little motion during the past few hours. A weakness in the ridge over the western Atlantic is forecast to develop and this pattern should steer the system slowly toward the northwest and then northward. In about 3 days, an eastward-moving mid-latitude trough will force the system to recurve away from the coast toward the Atlantic. The guidance has shifted a little to east this morning and consequently, the NHC track forecast was adjusted in that direction. However, the official forecast is still on the western edge of the guidance envelope. If the disturbance develops a little more to the east, the track forecast will probably be adjusted to the right later today.

Key Messages:

  1. 1. The system is expected to become a tropical storm and bring tropical-storm-force winds and heavy rainfall to portions of the northwestern Bahamas later today and Saturday. Significant storm surge is not expected in the northwest Bahamas from this system. Residents there should follow any advice given by local officials.
  2. 2. The system could bring tropical-storm-force winds to portions of the Florida east coast over the weekend. Residents there should monitor the progress of this system and follow any advice given by local officials.
  3. 3. Heavy rainfall and scattered flash flooding is possible this weekend in coastal sections of eastern Florida, Georgia, and South Carolina. Depending on the track of the system, heavy rainfall could reach eastern North Carolina next week.
  4. 4. Note that forecast uncertainty for these disturbances is generally larger than for tropical cyclones, especially beyond 48-72 hours.
FORECAST POSITIONS AND MAX WINDS

INIT  13/1500Z 25.0N  74.5W   25 KT  30 MPH...POTENTIAL TROP CYCLONE (ENE Arthur's Town, Bahamas)
 12H  14/0000Z 25.8N  76.5W   30 KT  35 MPH - Tropical Depression (WSW Spanish Wells, Bahamas)
 24H  14/1200Z 26.6N  78.0W   35 KT  40 MPH - Tropical Storm (WSW August Cay, Bahamas)
 36H  15/0000Z 28.0N  79.4W   40 KT  45 MPH - Tropical Storm (ESE Palm Bay, FL)
 48H  15/1200Z 29.2N  80.0W   50 KT  60 MPH - Tropical Storm (ESE Daytona Beach, FL)
 72H  16/1200Z 31.0N  79.0W   60 KT  70 MPH - Tropical Storm (ESE Brunswick, GA)
 96H  17/1200Z 31.5N  75.0W   65 KT  75 MPH - Category 1 (ESE Charleston, SC)
120H  18/1200Z 32.0N  71.5W   70 KT  80 MPH - Category 1 (WSW St George's, Bermuda)

NWS National Hurricane Center Miami FL 500 AM EDT Fri Sep 13, 2019

Satellite imagery and surface observations indicate that the tropical disturbance is currently comprised of a trough elongated from west-southwest to east-northeast, with a vorticity center near a loosely curved convective band at the eastern end of the trough. While the system has become a little better organized since the last advisory, it does not yet have a well-defined circulation center. The initial intensity remains 25 kt based on satellite intensity estimates and earlier scatterometer data.

The disturbance is now moving a little faster, with the initial motion of 315/5. The system is to the south of a low- to mid-level ridge over the southeastern United States, and it is to the east of a mid- to an upper-level low over the central Gulf of Mexico. The large-scale models forecast the ridge to shift eastward into the Atlantic during the next 24-48 h, with a weakness developing near the southeastern coast of the United States and the east coast of the Florida peninsula. The track guidance indicates that the disturbance will move generally northwestward for 48 h or so, followed by a turn to the north and eventually to the northeast as the system moves through the weakness in the ridge. There is some spread in the guidance, with the GFS model taking a weaker system into the Florida peninsula while the UKMET and ECMWF models show a stronger cyclone farther offshore. Overall, there has been an eastward shift of the guidance since the previous advisory, especially after 72 h. The new forecast track is thus also nudged a little to the east and now calls for the system to spend less time over the Florida peninsula than previously forecast. The new forecast track is to the left of the center of the guidance envelope and the consensus models, and additional adjustments may be necessary once the circulation center becomes better defined.

The disturbance is currently in an environment of moderate southwesterly shear and upper-level divergence caused by the upper-level low and a shortwave trough extending from the low eastward to the southeastern Bahamas. The shear should gradually diminish during the next couple of days, which should allow the disturbance to develop into a tropical cyclone and intensify. The large-scale models forecast the shear to increase after 72 h as a mid-latitude westerly trough moves through the southeastern United States and approaches the system. The new intensity forecast is similar to the previous forecast through 72 h, then it is stronger than the previous forecast due to the forecast track keeping the system more over water.

Key Messages:

  • 1. The system is expected to become a tropical storm and bring tropical-storm-force winds and heavy rainfall to portions of the northwestern Bahamas today and Saturday. Significant storm surge is not expected in the northwest Bahamas from this system. Residents, there should follow any advice given by local officials.
  • 2. The system could bring tropical-storm-force winds to portions of the Florida east coast over the weekend. Residents, there should monitor the progress of this system and follow any advice given by local officials.
  • 3. Heavy rainfall is possible from Potential Tropical Cyclone Nine across portions of eastern Florida into this weekend, which could produce flash flooding. There is greater uncertainty than usual in heavy rainfall prospects farther north across the Carolinas.
  • 4. Note that forecast uncertainty for these disturbances is generally larger than for tropical cyclones, especially beyond 48-72 hours.
FORECAST POSITIONS AND MAX WINDS

INIT  13/0900Z 24.6N  75.2W   25 KT  30 MPH...POTENTIAL TROP CYCLONE
 12H  13/1800Z 25.1N  76.2W   30 KT  35 MPH - Tropical Depression (ESE North Palmetto Point, Bahamas)
 24H  14/0600Z 26.0N  77.8W   35 KT  40 MPH - Tropical Storm (ESE Castaway Cay, Bahamas)
 36H  14/1800Z 27.0N  79.3W   40 KT  45 MPH - Tropical Storm (ESE Jupliter, FL)
 48H  15/0600Z 28.2N  80.4W   45 KT  50 MPH - Tropical Storm (ESE Patrick Air Force Base, FL)
 72H  16/0600Z 30.3N  81.1W   50 KT  60 MPH - Tropical Storm (ESE Atlantic Beach, FL)
 96H  17/0600Z 31.0N  80.5W   50 KT  60 MPH - Tropical Storm (ESE Brunswick, GA)
120H  18/0600Z 32.0N  78.5W   55 KT  65 MPH - Tropical Storm (ESE Hilton Head Island, SC)

NWS National Hurricane Center Miami FL 500 PM EDT Thu Sep 12, 2019

The disturbance in the southeastern Bahamas has not developed a closed circulation yet, but the cloud pattern is gradually becoming better organized. An Air Force plane is currently approaching the disturbance and will give NHC more details on the structure of the system. Advisories are being initiated on this system as a Potential Tropical Cyclone to allow for the issuance of a tropical storm warning for a portion of the northwest Bahamas after consultation with the meteorological service of that country.

The system is still under the influence of strong shear caused by an upper-level low in the Gulf of Mexico. As the disturbance moves away from the upper low, conditions are expected to be a little more conducive for development as indicated in the intensity forecast. With the exception of the GFS, which forecasts a vigorous trough crossing Florida into the Gulf of Mexico, the remainder of the global models develop a tropical cyclone near the northwestern The Bahamas and move it as an intensifying system very close to the east coast of Florida. The NHC forecast opted for the solution of these latter models, however, it is emphasized that given the model the discrepancy, both the track and intensity forecasts are highly uncertain, more than usual I would say.

Key Messages:

  • 1. The disturbance is expected to become a tropical storm and bring tropical-storm-force winds to portions of the northwest Bahamas within 36 hours. As a result, advisories have been initiated on Potential Tropical Cyclone Nine. Note that forecast uncertainty for these disturbances is generally larger than for tropical cyclones, especially beyond 48-72 hours.
  • 2. The system is expected to bring tropical-storm-force winds and heavy rainfall to portions of the northwest Bahamas on Friday and Saturday. Significant storm surge is not expected in the northwest The Bahamas from this system. Residents, there should follow any advice given by local officials.
  • 3. The system could bring tropical-storm-force winds and rainfall to portions of the Florida east coast over the weekend. Residents, there should monitor the progress of this system.
FORECAST POSITIONS AND MAX WINDS

INIT  12/2100Z 23.7N  74.8W   25 KT  30 MPH 
-Tropical Depression (Rum Cay, Bahamas)

12H  13/0600Z 24.5N  76.0W   25 KT  30 MPH 
-Tropical Depression (WSW Little San Salvador Island, Bahamas)

24H  13/1800Z 25.5N  77.2W   30 KT  35 MPH 
-Tropical Storm (ESE Sandy Point, Bahamas)

36H  14/0600Z 26.5N  78.9W   40 KT  45 MPH 
-Tropical Storm (WSW Bain Town, Bahamas)

48H  14/1800Z 27.5N  80.2W   45 KT  50 MPH 
-Tropical Storm (ESE South Beach, FL)

72H  15/1800Z 30.0N  82.0W   30 KT  35 MPH 
-Tropical Storm (WSW Middleburg, FL)
 
96H  16/1800Z 31.0N  82.0W   25 KT  30 MPH 
-Tropical Depression (ESE Winokur, GA)

120H  17/1800Z 31.5N  80.0W   30 KT  35 MPH 
-Tropical Storm (WSW Tybee Island, GA)

NWS National Hurricane Center Miami FL 200 PM EDT Thu Sep 12, 2019

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

Satellite-derived winds and surface observations indicate that the disturbance in the Bahamas has not yet developed a closed circulation and that the winds are not strong at this time. However, surface pressures remain low and environmental conditions are favorable for a tropical depression or tropical storm to form within the next day or two as the system moves toward the northwest at 5 to 10 mph through the northwestern Bahamas and toward the Florida Peninsula.

Potential Tropical Cyclone advisories could be needed later today or Friday, and interests in the central and northwestern Bahamas, as well as Florida, should monitor the progress of this disturbance. Regardless of development, this disturbance will bring heavy rainfall and gusty winds to portions of the Bahamas through Friday, including areas of the northwestern Bahamas affected by Hurricane Dorian. An Air Force Reserve reconnaissance aircraft is still scheduled to investigate the system this afternoon.

* Formation chance through 48 hours…high…70 percent. * Formation chance through 5 days…high…80 percent.

NWS National Hurricane Center Miami FL 800 AM EDT Thu Sep 12, 2019

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

Satellite images indicate that the area of disturbed weather over the central and southeastern Bahamas is gradually becoming better organized while surface pressures are falling in the area. Conditions are becoming favorable for a tropical depression or a tropical storm to form within the next day or so as the system moves toward the northwest through the northwestern Bahamas and toward the Florida Peninsula at 5 to 10 mph.

If this development trend continues Potential Tropical Cyclone advisories will likely be initiated later today. This disturbance will bring heavy rainfall and gusty winds across portions of the Bahamas through Friday, especially in portions of the northwestern Bahamas affected by Hurricane Dorian. An Air Force Reserve reconnaissance aircraft is scheduled to investigate the system this afternoon, if necessary.

* Formation chance through 48 hours…high…70 percent. * Formation chance through 5 days…high…80 percent.

NWS National Hurricane Center Miami FL 800 PM EDT Wed Sep 11, 2019

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

Widespread cloudiness and showers extending from the southeastern Bahamas northward over the southwestern Atlantic for a few hundred miles are associated with a sharp trough of low pressure.

Although limited development of this system is anticipated tonight and Thursday, conditions are forecast to become a little more conducive for tropical cyclone formation over the weekend, and a tropical depression is likely to form as the system moves slowly toward the west-northwest across the Florida Straits and southeastern Florida, and into the eastern Gulf of Mexico. This disturbance will likely produce periods of locally heavy rainfall and gusty winds across the Bahamas through Friday, and across Florida during the weekend. An Air Force Reserve reconnaissance aircraft is scheduled to investigate the system Thursday afternoon, if necessary.

* Formation chance through 48 hours…medium…50 percent. * Formation chance through 5 days…high…70 percent.

NWS Weather Prediction Center College Park MD 200 PM EDT Wed Sep 11, 2019

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

1. A large area of showers and thunderstorms was located along a sharp surface trough from near eastern Cuba through the southeastern The Bahamas into the southwestern Atlantic. Conditions are forecast to become more favorable for development late this week, and a tropical depression could form near the northwestern Bahamas or South Florida as early as Friday.

Further development is possible over the eastern The Gulf of Mexico later this weekend. The disturbance will likely produce periods of locally heavy rainfall and gusty winds across The Bahamas through Friday, and across Florida during the weekend.

* Formation chance through 48 hours…medium…40 percent. * Formation chance through 5 days…medium...60 percent.

NWS National Hurricane Center Miami FL 800 AM EDT Wed Sep 11, 2019

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

Widespread cloudiness and showers extending from the southeastern Bahamas northward over the southwestern Atlantic for a few hundred miles are associated with a surface trough of low pressure.

Limited development of this system is anticipated today or tomorrow, however, conditions are forecast to become a little more favorable for development over the weekend, and a tropical depression could form as the disturbance moves slowly toward the west-northwest across the Florida Straits or South Florida and over the eastern Gulf of Mexico. Regardless of development, this disturbance could produce periods of locally heavy rainfall and gusty winds across the Bahamas through Thursday, and across Florida during the weekend.

* Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…medium…60 percent.

If this storm is named, it will be Tropical Storm Humberto.

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