Tropical Storm Josephine

Josephine Remnants Track 1700 Hours August 16 2020
Josephine Remnants Track 1700 Hours August 16 2020

Tropical Storm Josephine Wind Speed FieldTropical Storm Josephine  – NWS National Hurricane Center Miami FL 500 PM AST Sun Aug 16, 2020 (see new video below)

The low-level swirl seen in visible satellite imagery has become less defined this afternoon, and ASCAT surface wind data that arrived shortly after the release of the previous advisory indicated that Josephine had degenerated into a trough of low pressure. As a result, this will be the final NHC advisory on this system. The ASCAT revealed a small area of 30-kt winds along the northeast side of the trough axis, and that will be the initial wind speed for this advisory.

The remnants are forecast to continue encountering a hostile upper-level wind environment over the next couple of days and re-generation of the system is not expected during that time. The strong upper-level winds are forecast to decrease later in the week, but it appears that there will not be much left of the system to take advantage of those conditions. The remnants are moving west-northwestward at 10 kt, and should turn northwestward and northward over the next couple of days as a low- to mid-level trough moves near the southeastern U.S. coast.

This is the last NHC advisory on this system.

FORECAST POSITIONS AND MAX WINDS

INIT  16/2100Z 20.9N  65.8W   30 KT  35 MPH - Depression (ENE San Juan, Puerto Rico)
 12H  17/0600Z...DISSIPATED

NWS National Hurricane Center Miami FL 1100 AM AST Sun Aug 16, 2020

Strong vertical wind shear has continued to take a toll on Josephine, with the exposed center continuing to race well ahead of the primary convective mass. A new burst of convection has developed a little closer to the center within the past couple of hours, but with the continued loss of organization the initial wind speed has been lowered to 30 kt. With strong shear forecast to prevail over the cyclone during the next few days, continued weakening is expected and Josephine will likely become a remnant low within 24 hours or dissipate by opening into a trough of low pressure. Although the shear could lessen somewhat in a few days, it appears that there will not be much left of the system to take advantage of those conditions. As a result, the new NHC forecast calls for the dissipation of the remnant low by 96 hours.

Josephine jogged a bit westward overnight, but the longer term motion is 285/11 kt. The system is forecast to turn northwestward over the next 24-36 hours as the ridge over the western Atlantic weakens due to an approaching trough of low pressure. As the low- to mid-level trough moves offshore of the southeastern United States, this should cause Josephine or it remnants to turn northward on Tuesday. The updated track forecast is a little to the left of the previous advisory, primarily to more southward and westward initial position, however, it still lies near the middle of the track guidance envelope.

FORECAST POSITIONS AND MAX WINDS

INIT  16/1500Z 20.4N  65.0W   30 KT  35 MPH - Depression (ENE San Juan, Puerto Rico)
 12H  17/0000Z 21.3N  66.4W   25 KT  30 MPH - Depression (WNW San Juan, Puerto Rico)
 24H  17/1200Z 22.5N  67.9W   25 KT  30 MPH - Low (WSW St. Georges, Bermuda)
 36H  18/0000Z 23.9N  69.0W   25 KT  30 MPH - Low (WSW St. Georges, Bermuda)
 48H  18/1200Z 25.5N  69.4W   20 KT  25 MPH - Low (WSW St. Georges, Bermuda)
 60H  19/0000Z 26.8N  69.0W   20 KT  25 MPH - Low (WSW St. Georges, Bermuda)
 72H  19/1200Z 28.2N  68.3W   20 KT  25 MPH - Low (WSW St. Georges, Bermuda)
 96H  20/1200Z...DISSIPATED

NWS National Hurricane Center Miami FL 1100 PM AST Sat Aug 15, 2020 

An Air Force Reserve reconnaissance aircraft investigating Josephine this evening manages to find a barely close low-level circulation center that was displaced about 90 nmi to the west of the edge of the southernmost burst of deep convection. Maximum flight-level and surface were likely missed since the aircraft did not fly through the strongest convection. Thus, the intensity is being maintained at 40 kt based on continuity and a blend of subjective and objective satellite classifications.

The initial motion is west-northwestward or an uncertain 300/13 kt. Due to Josephine’s severely sheared state, the system could open up into a sharp tropical wave at any time during the next 36 hours, which complicates determining a forecast track. For now, it will be assumed that there will be some identifiable low-level vorticity feature that will serve as a proxy center for Josephine or its remnants, which are forecast to continue to move west-northwestward along the southwestern periphery of a deep-layer subtropical ridge. Thereafter, the cyclone is expected to recurve to the north and north-northeast through a break in the ridge that is forecast to develop southwest of Bermuda in 48 hours or so, with at least the remnants passing near Bermuda in about 120 hours. The NHC official forecast track lies close to the previous advisory track and the tightly-clustered simple- and corrected-consensus models.

Josephine is expected to remain in an environment of moderate to strong westerly shear for at least the next 48-60 h, followed by sharply decreasing shear conditions thereafter. For the next two days or so, however, Josephine is forecast to weaken owing to the strong shear conditions and surrounding dry mid-level air, with the possibility of the tropical storm degenerating into an open wave at any time. If the remnant vorticity can manage to remain intact through a deep enough layer of the troposphere, then some regeneration could occur in the 72-120 hour time when the vertical shear/mid-level moisture are forecast to decrease/increase significantly. However, it still remains unclear at this time whether there will be enough remnant circulation to take advantage of those more favorable conditions.

KEY MESSAGES:

  • 1. Josephine is passing far enough to the northeast of the Leeward Islands to prevent major impacts. However, interests there should continue to monitor its progress until the storm has passed north of that area.
  • 2. Locally heavy rainfall is possible in the northern Leeward Islands, the Virgin Islands, and Puerto Rico as Josephine passes by to the northeast. Isolated minor flooding is possible in Puerto Rico through Monday.
FORECAST POSITIONS AND MAX WINDS

INIT  16/0300Z 20.1N  62.6W   40 KT  45 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 12H  16/1200Z 21.0N  64.3W   35 KT  40 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 24H  17/0000Z 22.3N  66.3W   35 KT  40 MPH - Tropical Storm (WNW San Juan, Puerto Rico)
 36H  17/1200Z 23.7N  67.9W   30 KT  35 MPH - Depression (ESE St. John's, Antigua)
 48H  18/0000Z 25.1N  68.8W   30 KT  35 MPH - Depression (ESE St. John's, Antigua)
 60H  18/1200Z 27.1N  68.8W   25 KT  30 MPH - Low (WSW St. Georges, Bermuda)
 72H  19/0000Z 29.0N  68.0W   25 KT  30 MPH - Low (WSW St. Georges, Bermuda)
 96H  20/0000Z 30.6N  67.0W   25 KT  30 MPH - Low (WSW St. Georges, Bermuda)
120H  21/0000Z 32.8N  64.1W   25 KT  30 MPH - Low (ENE St. Georges, Bermuda)

NWS National Hurricane Center Miami FL 1100 AM AST Sat Aug 15, 2020

Josephine has a sheared cloud pattern in satellite imagery this morning, with the low-level center located near the western edge of the main convective area. An Air Force Reserve Hurricane Hunter aircraft investigating the storm reported flight-level winds as high as 47 kt at 925 mb, along with surface wind estimates from the Stepped Frequency Microwave Radiometer of 35-40 kt. Based on these data, the initial intensity remains 40 kt. The aircraft also reported that, while the area of westerly winds south of the center was small, the circulation is still closed and that the central pressure was near 1008 mb.

The storm has moved a little to the left since the last advisory, with the motion now west-northwestward or 290/14 kt. Other than that, there is little change in the forecast track or the forecast track philosophy. During the next 2-3 days, Josephine or its remnants are likely to continue to move west-northwestward to the south and southwest of a subtropical high pressure area. After that, the system is forecast to re-curve to the north and north-northeast through a break in the western portion of the high. The new NHC forecast lies to the the center of the tightly- clustered guidance and near the various consensus models. Josephine is expected to remain in an environment of moderate to strong westerly shear for at least the next 48-60 h. This should cause the system to weaken, with the new intensity forecast now calling for Josephine to weaken to a depression between 36-48 h and degenerate to a remnant low by 72 h. Several global models forecast the cyclone to degenerate to a tropical wave before 72 h, and this remains a viable alternative forecast scenario, especially considering how small the closed circulation is.

There is a chance that Josephine or its remnants could encounter a less hostile environment after 72 h. However, it is unclear at this time whether there will be enough left of the system to take advantage of that. KEY MESSAGES: 1. Josephine should pass far enough to the northeast of the Leeward Islands today and tonight to prevent major impacts. However, interests there should continue to monitor its progress until the storm has passed north of that area. 2. Locally heavy rainfall is possible in the northern Leeward Islands, the Virgin Islands, and Puerto Rico as Josephine passes by to the northeast. Isolated minor flooding is possible in Puerto Rico through Monday.

NWS National Hurricane Center Miami FL 1100 PM AST Fri Aug 14, 2020 

Josephine continues to produce bursts of deep convection near and to the northeast of its center, however, there is little evidence of any banding features. A fortuitous ASCAT-A overpass has revealed peak winds of 35-40 kt over the northern semicircle of the storm, and the scatterometer ambiguities along with the earlier reconnaissance aircraft data suggest that the circulation is still closed. Based on the scatterometer data, the initial wind speed has been set at 40 kt.

The intensity forecast reasoning remains unchanged from the previous forecast. The moderate to strong southwesterly vertical wind shear that is affecting the cyclone is forecast to increase over the weekend and reach values of around 30 kt on Sunday. This is expected to result in gradual weakening by the latter portion of the weekend, and Josephine is predicted to weaken to a tropical depression in about 48 hours, and become a remnant low in 3-4 days. A plausible alternate scenario that is suggested by some of the global models is for the circulation to open up into a trough of low pressure, resulting in dissipation of the tropical cyclone within the next few days.

The timely ASCAT data was very helpful in determining Josephine’s center location. Based on that and the earlier aircraft fixes, the cyclone continues to move west-northwestward or 300/14 kt. A subtropical ridge to the north of Josephine should steer the cyclone west-northwestward during the next 24-48 hours. After that time, Josephine should turn northwestward, and then northward as a weakness develops in the ridge over the western Atlantic. By late in the period, Josephine or its remnants are expected to turn north-northeastward as it becomes embedded within the mid-latitude westerlies. The latest official forecast is near the middle of the tightly clustered dynamical track models, and is very similar to the previous NHC advisory.

KEY MESSAGES:

  • 1. Josephine should pass far enough to the northeast of the Leeward Islands over the weekend to prevent major impacts. However, interests there should continue to monitor its progress until the storm has passed north of that area.
  • 2. Locally heavy rainfall is possible in the northern Leeward Islands, the Virgin Islands, and Puerto Rico as Josephine passes by to the northeast. Isolated minor flooding is possible in Puerto Rico through Monday.
FORECAST POSITIONS AND MAX WINDS

INIT  15/0300Z 18.3N  57.4W   40 KT  45 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 12H  15/1200Z 19.2N  59.3W   40 KT  45 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 24H  16/0000Z 20.4N  61.6W   40 KT  45 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 36H  16/1200Z 21.7N  63.9W   35 KT  40 MPH - Tropical Storm (ESE St. John's, Antigua)
 48H  17/0000Z 23.2N  65.8W   30 KT  35 MPH - Depression (ESE St. John's, Antigua)
 60H  17/1200Z 24.7N  67.2W   25 KT  30 MPH - Depression (ESE St. John's, Antigua)
 72H  18/0000Z 26.4N  67.7W   25 KT  30 MPH - Depression (ESE St. John's, Antigua)
 96H  19/0000Z 29.5N  67.0W   25 KT  30 MPH - Low (Cockburn Town, Turks Caicos Islands)
120H  20/0000Z 33.0N  64.0W   20 KT  25 MPH - Low (Cockburn Town, Turks Caicos Islands)

NWS National Hurricane Center Miami FL 500 PM AST Fri Aug 14, 2020 

An Air Force Reserve Hurricane Hunter aircraft reported that the circulation of Josephine was still closed, and that the center was a little farther to the north than previously thought – possibly due to reformation close to a strong convective burst. The aircraft reported a minimum pressure of 1004 mb, and the combination of flight-level and SFMR winds support an initial intensity of 35 kt. Satellite imagery indicates that Josephine is encountering increasing westerly shear, with cirrus clouds west of the storm blowing into the cyclone.

Aside from the nudge to the north, the initial motion is generally west-northwestward or 300/14 kt. There is again no change to the track forecast philosophy. Josephine should continue a west- northwestward motion as it approaches a weakness in the subtropical ridge in 48-60 h. Then, the cyclone should gradually turn northward and move through the weakness in 72-96 h. Late in the forecast period, Josephine or its remnants are expected to turn north-northeastward along the southern edge of the mid-latitude westerlies. Portions of the forecast track have been adjusted northward based mainly on the initial position, and the new forecast track lies close to the various consensus models.

The increasing shear means that Josephine is just about out of time to intensify. The intensity forecast calls for a little strengthening tonight in case a convective burst causes some spin up. After that, the cyclone should weaken, with the new forecast showing it becoming a depression in 48 h and a remnant low by 96 hr. The global models continue to forecast a faster weakening, and there is still the alternative scenario that Josephine could decay to a tropical wave before 96 h.

KEY MESSAGES:

  • 1. Josephine should pass far enough to the northeast of the Leeward Islands over the weekend to prevent major impacts. However, interests there should continue to monitor its progress until the storm has passed north of that area.
  • 2. Locally heavy rainfall is possible in the northern Leeward Islands, the Virgin Islands, and Puerto Rico as Josephine passes by to the northeast. Isolated minor flooding is possible in Puerto Rico through Monday.
FORECAST POSITIONS AND MAX WINDS

INIT  14/2100Z 17.8N  56.1W   35 KT  40 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 12H  15/0600Z 18.6N  58.0W   40 KT  45 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 24H  15/1800Z 19.9N  60.5W   40 KT  45 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 36H  16/0600Z 21.1N  62.9W   35 KT  40 MPH - Tropical Storm (ESE St. John's, Antigua)
 48H  16/1800Z 22.5N  65.1W   30 KT  35 MPH - Depression (ESE St. John's, Antigua)
 60H  17/0600Z 24.1N  66.7W   30 KT  35 MPH - Depression (ESE St. John's, Antigua)
 72H  17/1800Z 25.7N  67.7W   25 KT  30 MPH - Depression (ESE St. John's, Antigua)
 96H  18/1800Z 28.6N  67.5W   25 KT  30 MPH - Depression (ESE St. John's, Antigua)
120H  19/1800Z 32.1N  65.5W   20 KT  25 MPH - Low (Cockburn Town, Turks Caicos Islands)

NWS National Hurricane Center Miami FL 1100 AM AST Fri Aug 14, 2020 

Morning visible satellite imagery indicates that the center of Josephine is located to the south or southwest of the strongest area of convection, likely due to the onset of southwesterly vertical wind shear. A just-received scatterometer pass supports an initial intensity of 35 kt, but also suggests the possibility that the circulation is longer closed. An Air Force Reserve Hurricane Hunter aircraft is scheduled to investigate Josephine this afternoon to provide more information on the intensity and whether a closed circulation still exists.

The initial motion continues west-northwestward or 295/14 kt. Josephine should continue this general motion as it approaches a weakness in the subtropical ridge in 48-60 h. Then, the cyclone should turn northward and move through the weakness in 72-96 h. Late in the forecast period, Josephine or its remnants are expected to turn north-northeastward along the southern edge of the higher-latitude westerlies. The track guidance has not changed significantly since the previous advisory, and the new NHC forecast track is very similar to the previous forecast.

Southwesterly to westerly shear should markedly increase after 12-18 h due mainly to upper-level troughing over the southwestern Atlantic. The new intensity forecast leaves open the possibility of a little strengthening during the next 12 h, followed by weakening due to the shear. The intensity forecast follows the previous forecast showing the system decaying to a remnant low by 120 h. However, an alternative scenario, supported by several of the global models, is that the cyclone decays to a tropical wave well before that time.

osephine should pass far enough to the northeast of the Leeward Islands over the weekend to prevent major impacts. However, interests in the area should continue to monitor its progress until the storm has passed north of that area.

FORECAST POSITIONS AND MAX WINDS

INIT  14/1500Z 16.1N  54.7W   35 KT  40 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 12H  15/0000Z 17.1N  56.7W   40 KT  45 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 24H  15/1200Z 18.4N  59.3W   40 KT  45 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 36H  16/0000Z 19.7N  61.8W   40 KT  45 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 48H  16/1200Z 20.9N  64.1W   35 KT  40 MPH - Tropical Storm (ESE St. John's, Antigua)
 60H  17/0000Z 22.5N  66.0W   35 KT  40 MPH - Tropical Storm (ESE St. John's, Antigua)
 72H  17/1200Z 24.0N  67.0W   30 KT  35 MPH - Depression (ESE St. John's, Antigua)
 96H  18/1200Z 27.0N  67.5W   30 KT  35 MPH - Depression (ESE St. John's, Antigua)
120H  19/1200Z 30.6N  65.5W   25 KT  30 MPH - Low (Cockburn Town, Turks Caicos Islands)

NWS National Hurricane Center Miami FL 1100 PM AST Thu Aug 13 2020

Enhanced infrared GOES 16 imagery and a recent ASCAT-A overpass indicated that the center of circulation is still located to the south of a rather shapeless deep convective mass. Recent images show a small burst developing just to the west of the center, but the associated cloud tops are already warming. Based on the overall cloud pattern, light southerly shear and a dry, relatively stable surrounding environment continue to hamper significant development. There were no changes to the satellite intensity estimates from TAFB and SAB, and the initial intensity is once again held at a possibly generous 40 kt.

Josephine’s relatively small window of opportunity for further strengthening is within the next 18 to 24 hours. The forecast still shows a peak intensity of 50 kt at the time and is above all of the skilled guidance. After which, strong southwesterly shear produced by a northeast to southwest oriented deep-layer mid-Atlantic trough is expected to induce gradual weakening. This inhibiting upper wind pattern is forecast to affect the cyclone through day 5. The NHC forecast through 60 hours is based on the better performing IVCN consensus which consists of the Decay SHIPS, LGEM and the hurricane models. Beyond mid-period, the forecast is basically a blend of the IVCN and the global models which now shows Josephine degenerating into a remnant low at day 5.

The initial motion is estimated to be west-northwestward, or 300/15 kt within the southwestern periphery of a subtropical high situated to the northeast of Josephine. Weakening of the western portion of the ridge should cause Josephine to turn northwestward in 3 days, followed by a turn generally northward at day 4 in response to a major shortwave trough approaching the east coast of the U.S. and the western Atlantic. The official forecast is a little faster than the previous one through 5 days and is once again close to the HFIP Corrected Consensus model.

Josephine should pass far enough to the northeast of the Leeward Islands over the weekend to prevent major impacts. However, interests in the area should continue to monitor its progress until the storm has passed north of that area.

FORECAST POSITIONS AND MAX WINDS
 
INIT  14/0300Z 14.8N  52.2W   40 KT  45 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 12H  14/1200Z 15.8N  54.0W   45 KT  50 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 24H  15/0000Z 17.3N  56.7W   50 KT  60 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 36H  15/1200Z 18.8N  59.5W   45 KT  50 MPH - Tropical Storm (ESE St. John's, Antigua)
 48H  16/0000Z 20.0N  62.1W   40 KT  45 MPH - Tropical Storm (ESE St. John's, Antigua)
 60H  16/1200Z 21.3N  64.4W   40 KT  45 MPH - Tropical Storm (ESE St. John's, Antigua)
 72H  17/0000Z 22.8N  66.2W   35 KT  40 MPH - Tropical Storm (ESE St. John's, Antigua)
 96H  18/0000Z 26.0N  67.7W   30 KT  35 MPH - Depression (Cockburn Town, Turks Caicos Islands)
120H  19/0000Z 29.5N  66.9W   25 KT  30 MPH - Low (Cockburn Town, Turks Caicos Islands)

NWS National Hurricane Center Miami FL 1100 AM AST Thu Aug 13, 2020

A just-received ASCAT overpass showed an area of 35-40 kt winds about 70 n mi north of the center of Tropical Depression Eleven, and based on this the cyclone is being upgraded to Tropical Storm Josephine with an initial intensity of 40 kt. Satellite imagery shows that the convective pattern associated with Josephine has become a little better organized since the last advisory, with a ragged central convective feature and a weak band in the northern semicircle.

The initial motion is now west-northwestward or 295/13 kt. Josephine should continue this motion for the next several days as it moves toward a weakness in the western portion of the Atlantic subtropical ridge. The global models forecast the western end of the ridge to weaken even more after 72-96 h, which should cause the cyclone, or what is left of it by that time, to turn northwestward. The track guidance is tightly clustered, and the new forecast track lies a little to the right of the previous track and a little to the left of the consensus models.

Some additional strengthening appears likely during the next 24- 36 h as Josephine moves through an environment of light vertical wind shear. After that, the cyclone is expected to encounter moderate to strong southwesterly shear as it approaches an upper-level trough over the southwestern Atlantic, which should cause at least some weakening. The new intensity forecast is adjusted upward for the first 72 h based on the current intensity. After 72 h, it shows weakening similar to the previous forecast, but not as drastic as the global models that show the storm degenerating to a tropical wave before 120 h.

FORECAST POSITIONS AND MAX WINDS

INIT  13/1500Z 13.7N  49.2W   40 KT  45 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 12H  14/0000Z 14.5N  51.1W   45 KT  50 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 24H  14/1200Z 15.8N  53.6W   50 KT  60 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 36H  15/0000Z 17.1N  56.3W   50 KT  60 MPH - Tropical Storm (ESE St. John's, Antigua)
 48H  15/1200Z 18.5N  58.9W   50 KT  60 MPH - Tropical Storm (ESE St. John's, Antigua)
 60H  16/0000Z 19.9N  61.3W   45 KT  50 MPH - Tropical Storm (ESE St. John's, Antigua)
 72H  16/1200Z 21.3N  63.6W   40 KT  45 MPH - Tropical Storm (ESE St. John's, Antigua)
 96H  17/1200Z 24.0N  67.0W   30 KT  35 MPH - Depression (Cockburn Town, Turks Caicos Islands)
120H  18/1200Z 27.0N  68.0W   25 KT  30 MPH - Depression (Cockburn Town, Turks Caicos Islands)

NWS National Hurricane Center Miami FL 1100 PM AST Wed Aug 12, 2020 

Conventional satellite imagery and a fortuitous ASCAT-B scatterometer overpass indicate that the center of circulation is a little farther south than previously estimated and remains well to the southeast of the deep convective canopy. The latest UW-CIMSS shear analysis confirms modest east-southeasterly shear impinging on the cloud pattern. A compromise of the satellite intensity estimates from TAFB and SAB, and the aforementioned scatterometer pass retains the initial intensity at 30 kt.

Large-scale models and the statistical-dynamical intensity guidance still show the shear abating soon which should result in gradual strengthening with a peak intensity of 50 kt in 2 days. After that time, the cyclone is forecast to encounter moderate to strong southwesterly shear associated with a deep-layer trough stretching over the southwestern Atlantic. This change in the upper wind pattern should induce steady weakening. A number of the global models indicate that the cyclone will become a remnant low by day 4 and open up into a trough by day 5 which is certainly possible. The NHC forecast is similar to the previous advisory but indicates a more expeditious weakening trend beyond the 48 hour period in deference to the global model solution.

The initial motion is estimated to be westward, or 275/13 kt, within the low to mid-tropospheric easterly flow produced by a subtropical ridge anchored to the north of the depression. The song remains the same…there is virtually no change to the forecast philosophy and only a slight shift to the left of the previous track forecast was made in response to the southward initial position adjustment.

FORECAST POSITIONS AND MAX WINDS

INIT  13/0300Z 12.5N  47.1W   30 KT  35 MPH - Depression (WSW São Filipe, Cape Verde)
 12H  13/1200Z 13.0N  48.4W   35 KT  40 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 24H  14/0000Z 14.2N  51.0W   40 KT  45 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 36H  14/1200Z 15.7N  53.7W   45 KT  50 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 48H  15/0000Z 17.0N  56.4W   50 KT  60 MPH - Tropical Storm (ESE St. John's, Antigua)
 60H  15/1200Z 18.3N  58.9W   45 KT  50 MPH - Tropical Storm (ESE St. John's, Antigua)
 72H  16/0000Z 19.7N  61.4W   40 KT  45 MPH - Tropical Storm (ESE St. John's, Antigua)
 96H  17/0000Z 22.5N  65.6W   35 KT  40 MPH - Tropical Storm (ESE St. John's, Antigua)
120H  18/0000Z 25.6N  67.5W   30 KT  35 MPH - Tropical Storm (ESE Nassau, Bahamas)

NWS National Hurricane Center Miami FL 500 PM AST Wed Aug 12, 2020

Satellite imagery this afternoon shows some changes in the convection associated with Tropical Depression Eleven, as the showers and thunderstorms are now occuring more in curved bands and less in sheared bursts. This is likely due to the southeasterly shear which has been affecting the depression finally letting up. However, this change has not caused the satellite intensity estimates to change significantly since the last advisory, so the initial intensity is again 30 kt.

The initial motion remains a little north of due west, or 280/13 kt. There is almost no change to the forecast philosophy and little change to the forecast track since the last advisory. A westward motion is expected to continue for another 6-12 h due to easterly flow on the south side of a strong subtropical ridge situated to the north of the cyclone. After that, the global models forecast a slight weakness to develop within the ridge, allowing the cyclone to turn west-northwestward and continue that motion through 96 h. Between 96-120 h, the western end of the ridge is forecast to weaken more, which should cause a turn toward the northwest. The new NHC forecast track remains just to the left of the various consensus models.

The cyclone should be in an environment of light to moderate shear through the next 48 h or so. The intensity forecast again calls for a peak intensity of 50 kt during this time, which is at the high end of the intensity guidance. After 60 h, the cyclone is expected to encounter moderate to strong southwesterly shear associated with a large upper-level trough over the southwestern Atlantic. This should cause at least steady weakening, and several of the global models continue to forecast the cyclone to degenerate to a tropical wave before 120 h. The new intensity forecast again expects the system to last longer than the global models, but still shows weakening due to the shear after 72 h. The new forecast has only minor changes from the previous forecast.

FORECAST POSITIONS AND MAX WINDS

INIT  12/2100Z 12.7N  45.7W   30 KT  35 MPH - Depression (WSW São Filipe, Cape Verde)
 12H  13/0600Z 13.0N  47.5W   35 KT  40 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 24H  13/1800Z 14.0N  49.9W   40 KT  45 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 36H  14/0600Z 15.2N  52.2W   45 KT  50 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 48H  14/1800Z 16.6N  54.8W   50 KT  60 MPH - Tropical Storm (ESE St. John's, Antigua)
 60H  15/0600Z 17.8N  57.3W   50 KT  60 MPH - Tropical Storm (ESE St. John's, Antigua)
 72H  15/1800Z 19.1N  59.7W   50 KT  60 MPH - Tropical Storm (ESE St. John's, Antigua)
 96H  16/1800Z 21.5N  64.5W   40 KT  45 MPH - Tropical Storm (ENE Barbuda)
120H  17/1800Z 24.5N  67.0W   30 KT  35 MPH - Tropical Storm (ENE San Juan, Puerto Rico)

NWS National Hurricane Center Miami FL 1100 AM AST Wed Aug 12, 2020 

Satellite imagery indicates that the depression is a little better organized than 24 h ago, with a ragged central convective feature and a curved convective band in the northwestern semicircle. However, recent scatterometer data show this has not yet resulted in strengthening, with 25-30 kt winds occuring to the north of the center. Based on the scatterometer, the initial intensity remains 30 kt.

The initial motion remains a little north of due west, or 280/13 kt. There is little change to the forecast philosophy or the forecast track since the last advisory. A westward motion is expected to continue through tonight due to easterly flow on the south side of a strong subtropical ridge situated to the north of the cyclone. After that, the global models forecast a slight weakness to develop within the ridge, allowing the cyclone to turn west-northwestward, with that motion continuing through the end of the forecast period. The new NHC forecast is just to the left of the various consensus models.

The southeasterly shear that has so far prevented intensification should diminish in the next 12 h or so, which should allow the cyclone to become a tropical storm. The system should then remain in light to moderate shear through about 48 h, and the intensity forecast calls for a peak intensity of 50 kt during that time. Later in the forecast period, moderate to strong southwesterly shear should develop over the cyclone due to an upper-level trough over the southwestern Atlantic. This shear should cause the system to weaken, and several of the global models forecast it to degenerate to a tropical wave before 120 h. The new intensity forecast will not call for that quick of a demise, but will show weakening due to the shear after 72 h. The new forecast, which has only minor changes from the previous forecast, is near the upper edge of the intensity guidance.

FORECAST POSITIONS AND MAX WINDS

INIT  12/1500Z 12.4N  44.2W   30 KT  35 MPH - Depression (WSW São Filipe, Cape Verde)
 12H  13/0000Z 12.8N  46.1W   35 KT  40 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 24H  13/1200Z 13.5N  48.4W   40 KT  45 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 36H  14/0000Z 14.5N  50.8W   45 KT  50 MPH - Tropical Storm (ESE St. John's, Antigua)
 48H  14/1200Z 15.7N  53.3W   50 KT  60 MPH - Tropical Storm (ESE St. John's, Antigua)
 60H  15/0000Z 17.0N  55.7W   50 KT  60 MPH - Tropical Storm (ESE St. John's, Antigua)
 72H  15/1200Z 18.2N  58.1W   50 KT  60 MPH - Tropical Storm (ESE St. John's, Antigua)
 96H  16/1200Z 20.5N  63.0W   40 KT  45 MPH - Tropical Storm (ENE Barbuda)
120H  17/1200Z 23.5N  66.5W   35 KT  40 MPH - Tropical Storm (ENE San Juan, Puerto Rico)

NWS National Hurricane Center Miami FL 1100 PM AST Tue Aug 11, 2020 

After weakening in the early evening hours, deep convection has returned to the western semicircle of the tropical cyclone. While this is quite a strong burst, it appears that the convective pattern is indicative of the shear it is encountering, rather than any strengthening. This is confirmed by ASCAT-B data from a few hours ago, which supported maintaining an initial wind speed of 30 kt.

By this time tomorrow, the depression is forecast to become a tropical storm due to decreasing vertical wind shear, and this environmental change should also keep some of the surrounding mid-level dry air from mixing near the center. Gradually warming SSTs and relatively low shear conditions suggest further intensification through about 2-3 days. Thereafter, increasing southwesterly shear while the small cyclone moves through fairly dry air aloft is forecast to cause a weakening trend, and it wouldn’t be surprising if the cyclone even degenerates to a trough by day 5 as it traverses the hostile environment. The new NHC wind speed prediction is near but slightly higher than the previous advisory through 60h, similar afterwards, and lies near the NOAA corrected-consensus mean.

The depression continues moving westward, or 280/12 kt, to the south of a large mid-tropospheric high centered over the central Atlantic. A break developing in the ridge should steer the depression more west-northwestward from 36 hours until the end of the forecast period. For a second advisory, the track models are in remarkably good agreement, and the forecast is near or northeast of the model consensus. The HWRF solution that takes the cyclone near the Leeward Islands is considering less likely at this time, hence the official forecast is shaded toward the other model solutions.

FORECAST POSITIONS AND MAX WINDS

INIT  12/0300Z 12.0N  41.5W   30 KT  35 MPH - Depression (WSW São Filipe, Cape Verde)
 12H  12/1200Z 12.3N  43.4W   30 KT  35 MPH - Depression (WSW São Filipe, Cape Verde)
 24H  13/0000Z 12.8N  45.9W   35 KT  40 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 36H  13/1200Z 13.5N  48.3W   40 KT  45 MPH - Tropical Storm (WSW São Filipe, Cape Verde)
 48H  14/0000Z 14.5N  50.8W   45 KT  50 MPH - Tropical Storm (ESE St. John's, Antigua)
 60H  14/1200Z 15.7N  53.3W   50 KT  60 MPH - Tropical Storm (ESE St. John's, Antigua)
 72H  15/0000Z 17.0N  55.7W   45 KT  50 MPH - Tropical Storm (ESE St. John's, Antigua)
 96H  16/0000Z 19.5N  60.5W   40 KT  45 MPH - Tropical Storm (ENE Barbuda)
120H  17/0000Z 22.0N  65.0W   35 KT  40 MPH - Tropical Storm (ENE San Juan, Puerto Rico)

NWS National Hurricane Center Miami FL 200 PM EDT Tue Aug 11, 2020 

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

1. A low pressure system is located over the eastern tropical Atlantic more than a thousand miles east of the Lesser Antilles. Shower and thunderstorm activity decreased somewhat this morning, but new activity is now forming near the system’s center of circulation. If these storms persist, then advisories would likely be initiated on a tropical depression later today or tonight. Even if a depression does not form by tonight, environmental conditions are expected to become more conducive for development while the system moves west-northwestward at around 15 mph during the next couple of days. Conditions are expected to become less conducive for development by the end of the week.

* Formation chance through 48 hours…high…90 percent. * Formation chance through 5 days…high…90 percent.

NWS National Hurricane Center Miami FL 800 AM EDT Tue Aug 11, 2020 

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

1. First-light visible satellite imagery shows that a better-defined center of circulation is forming in association with a low pressure system located about 900 miles west-southwest of the Cabo Verde Islands. In addition, the associated shower and thunderstorm activity has become more organized since yesterday.

Environmental conditions are expected to become more conducive for additional development, and advisories could be initiated on a tropical depression as early as later today if these development trends continue. The disturbance is forecast to move west-northwestward at around 15 mph across the tropical Atlantic during the next few days, and conditions are expected to become less conducive for development by the end of the week.

* Formation chance through 48 hours…high…90 percent. * Formation chance through 5 days…high…90 percent.

NWS National Hurricane Center Miami FL 800 PM EDT Mon Aug 10, 2020

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

1. Shower and thunderstorm activity associated with a broad area of low pressure located about 700 miles west-southwest of the Cabo Verde Islands has changed little in organization since yesterday. However, environmental conditions are expected to be somewhat conducive for development to occur, and a tropical depression could form during the next couple of days while the disturbance moves generally westward to west-northwestward at 10 to 15 mph across the tropical Atlantic. Conditions are forecast to become less conducive for development by the end of the week.

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

NWS National Hurricane Center Miami FL 200 PM EDT Mon Aug 10, 2020

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

1. A broad area of low pressure located almost 700 miles west-southwest of the Cabo Verde Islands is not currently showing signs of additional organization, with satellite-derived wind data from this morning still showing the system having an elongated surface circulation. However, environmental conditions are expected to be somewhat conducive for development to occur, and a tropical depression could form during the next couple of days while the disturbance moves generally westward to west-northwestward at 10 to 15 mph across the tropical Atlantic. Conditions are forecast to become less conducive for development by the end of the week.

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

NWS National Hurricane Center Miami FL 800 AM EDT Mon Aug 10, 2020

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

1. Showers and thunderstorms associated with a tropical wave and broad area of low pressure located about 600 miles west-southwest of the Cabo Verde Islands have changed little in organization since yesterday. Environmental conditions are expected to be somewhat conducive for development to occur, and a tropical depression could form during the next day or two while the disturbance moves generally westward to west-northwestward at 10 to 15 mph across the tropical Atlantic. Conditions are forecast to become less conducive for development by the end of the week.

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

NWS National Hurricane Center Miami FL 200 PM EDT Sun Aug 9, 2020

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

1. Showers and thunderstorms associated with a tropical wave located a few hundred miles south-southwest of the Cabo Verde Islands continue to show signs of organization. However, satellite-derived wind data from earlier this morning indicated that the circulation remains elongated. Environmental conditions appear conducive enough to support additional development of this system, and a tropical depression could form during the next few days while it moves generally westward at 15 mph across the tropical Atlantic. Conditions are likely to become less conducive for development late this week.

* Formation chance through 48 hours…medium…40 percent. * Formation chance through 5 days…medium…50 percent.

If this system is named, it will be Tropical Storm Josephine.

Article Resources:

Recent Tropical Cruise Weather:

Video: Tracking the Tropics: Post-Tropical Kyle, TS Josephine, latest tropical waves