Tropical Storm Fred

Tropical Storm Fred Track 1900 Hours August 16 2021
Tropical Storm Fred Track 1900 Hours August 16 2021

Tropical Storm Fred Flash Flooding RiskTropical Storm FredNWS National Hurricane Center Miami FL 400 PM CDT Mon Aug 16, 2021 (see Monday 4:00 pm video below)

Radar data indicate that the center of Fred made landfall in the eastern Florida Panhandle a little while ago, and it is currently moving farther inland. Observations from the Air Force Hurricane Hunters indicate that the storm reached a peak intensity of 55 kt just before landfall. Assuming some weakening since crossing the coast, the current intensity estimate is 50 kt. Fairly rapid weakening will occur while the center moves over land, and the cyclone will probably be reduced to tropical depression status by tomorrow morning. The official intensity forecast for the next day or so is close to the latest Decay-SHIPS model guidance.

Radar fixes indicate that the motion is north-northeastward, or 020/8 kt. During the next day or two Fred should move, with increasing forward speed, between a mid-level subtropical high pressure area over the southwestern Atlantic and a weak trough over the east-central United states. The official track forecast is quite close to the latest NOAA corrected consensus model prediction, HCCA.

Although it is weakening, Fred is likely to bring flooding rains over portions of the southeastern and eastern United States during the next couple of days.

KEY MESSAGES:

  • 1. Through Tuesday, heavy rainfall may lead to considerable flash, urban, small stream, and isolated river flooding impacts across portions of the Florida Big Bend and Panhandle. By the middle of the week as Fred lifts north and inland, heavy rainfall and flooding will impact the southern and central Appalachians, the Piedmont of the Southeast and Mid-Atlantic. Landslides are possible across the mountains of North Carolina and Blue Ridge Escarpment on Tuesday.
  • 2. Dangerous storm surge inundation is ongoing along portions of the coast of the Florida Panhandle and the Florida Big Bend region.
  • 3. Tropical storm conditions will continue along the coastline within the warning area over the next few hours and will continue to spread farther inland later today and tonight across portions of the Florida Panhandle, southwestern Georgia, and southeastern Alabama.
FORECAST POSITIONS AND MAX WINDS

INIT  16/2100Z 29.9N  85.3W   50 KT  60 MPH - Tropical Storm (ESE Port St Joe,FL)
 12H  17/0600Z 31.5N  85.1W   35 KT  40 MPH - Tropical Storm (ESE Abbeville,AL)
 24H  17/1800Z 34.0N  84.3W   30 KT  35 MPH - Tropical Storm (ESE Roswell,GA)
 36H  18/0600Z 37.0N  82.5W   25 KT  30 MPH - Post Tropical (WNW Coeburn,VA)
 48H  18/1800Z 39.5N  80.0W   20 KT  25 MPH - Post Tropical (ESE Little Falls,WV)
 60H  19/0600Z...DISSIPATED

NWS National Hurricane Center Miami FL 1000 AM CDT Mon Aug 16, 2021 

Fred became better organized on satellite and radar images this morning, with the center fairly well embedded within a small CDO and a large convective band over the eastern portion of the circulation. The Air Force Hurricane Hunters found flight-level winds that supported an intensity of 50 kt, and data from the aircraft also found that the central pressure had fallen to 993 mb, although the most recent pressures appeared to have leveled off. The satellite and radar data also show a dry slot over the southeastern quadrant.

Fred is over very warm waters of near 30 deg C and within a fairly moist mid-level atmosphere. A little more strengthening is possible prior to landfall, but significant southwesterly shear is likely to limit strengthening. Also, the storm has little time remaining over water. The latest official intensity forecast is similar to the LGEM guidance.

Center fixes from the Hurricane Hunters and WSR-88D data from Tallahassee and Eglin AFB indicate that Fred is a little east of the previous track. It is not certain whether this is due to a slight reformation of the center nearer to the strongest convection, but that is certainly a possibility. Based on the most recent fixes, the current motion estimate is just slightly east of north, or 010/9 kt. Fred is moving between the western side of a mid-level subtropical high pressure area over the southwestern Atlantic and a weak trough over the east-central United States. A slight bend of the track toward the north-northeast with a little acceleration is expected during the next couple of days. The official forecast is just a bit to the east of the previous one, and follows the most recent multi-model consensus.

Users are reminded not to focus on the exact forecast track of Fred, since rainfall, storm surge, and wind hazards will extend over an area well east of the center.

KEY MESSAGES:

  • 1. Through Tuesday, heavy rainfall may lead to flash, urban, small stream, and isolated river flooding impacts across the Southeast. By the middle of the week as Fred lifts north and inland, heavy rainfall and flooding will impact the southern and central Appalachians, the Piedmont of the Southeast and Mid-Atlantic. Landslides are possible across the mountains of North Carolina and Blue Ridge Escarpment on Tuesday.
  • 2. Dangerous storm surge inundation is expected along portions of the coast of the Florida Panhandle and the Florida Big Bend region. Preparations to protect life and property should be rushed to completion in the Storm Surge Warning area.
  • 3. Tropical storm conditions are occurring in the warning area and will spread farther inland later today and tonight across portions of the Florida Panhandle, southwestern Georgia, and southeastern Alabama.
FORECAST POSITIONS AND MAX WINDS

INIT  16/1500Z 29.2N  85.7W   50 KT  60 MPH - Tropical Storm (WSW Cape San Blas,FL)
 12H  17/0000Z 30.5N  85.5W   55 KT  65 MPH - Tropical Storm (WNW Fountain,FL)
 24H  17/1200Z 32.6N  85.0W   30 KT  35 MPH - Tropical Storm (WNW Bibb City,GA)
 36H  18/0000Z 35.0N  84.3W   25 KT  30 MPH - Post Tropical (ESE Wolf Creek,NC)
 48H  18/1200Z 38.0N  82.5W   15 KT  15 MPH - Post Tropical (WSW Dunlow, WV)
 60H  19/0000Z...DISSIPATED

NWS National Hurricane Center Miami FL 1000 PM CDT Sun Aug 15, 2021 

Fred remains a sheared tropical cyclone however the overall organization of the system has improved somewhat since this afternoon. The low-level center is embedded near the western edge of the primary convective mass, and there has been an overall increase in deep convection near and to the east of the center. An Air Force Reserve reconnaissance aircraft that has been investigating Fred this evening has reported that the pressure has fallen to 999 mb and it has found winds to support an initial intensity of 45 kt. The plane found a very small area of slightly stronger flight-level and SFMR winds well east of the center, but those winds appear to have been associated with a strong convective cell and are likely not representative of the system’s overall intensity.

Fred is moving north-northwestward or 330/08 kt, and this motion should continue overnight. The dynamical model guidance indicates that the tropical cyclone will turn northward on Monday as it approaches the coast of the Florida panhandle. A north- northeastward motion around the western periphery of a subtropical ridge over the western Atlantic should commence by the time the system makes landfall, and this general heading should continue until the system dissipates in a couple of days. The dynamical models envelope did not change much and the latest consensus aids were essentially along the previous NHC track. As a result, little alteration was made to the previous official track forecast.

The cyclone is located within an area of moderate southwesterly vertical wind shear. However, most of the intensity guidance continues to suggest that Fred will strengthen a little over the next 12-18 hours. As the system nears the northern Gulf coast, the SHIPS guidance forecasts some increase in shear and the intensity models reflect this by showing a leveling off of Fred’s intensity at that time. After landfall, Fred should weaken quickly and dissipate over the Tennessee Valley in a little more than 48 hours. The updated NHC intensity forecast is in good agreement within the HCCA and IVCN consensus aids.

Users are reminded not to focus on the exact forecast track of Fred, since rainfall, storm surge, and wind hazards will extend over an area well east of the center.

KEY MESSAGES:

  • 1. Through Tuesday, heavy rainfall may lead to flash, urban, small stream, and isolated river flooding impacts across the Southeast, including portions of southern Florida, the Big Bend and Panhandle of Florida, southeast Alabama, portions of Georgia, and the western Carolinas. By the middle of the week as Fred lifts north and inland toward the Tennessee Valley, heavy rainfall and flooding may impact the southern and central Appalachians, and the Piedmont of the Southeast and Mid-Atlantic.
  • 2. Dangerous storm surge inundation is possible along portions of the coast of the Florida Panhandle and the Florida Big Bend region, and a Storm Surge Warning is in effect for this area. Interests in these areas should follow any advice given by local officials.
  • 3. Tropical storm conditions are expected in the Tropical Storm Warning area in the Florida Panhandle beginning on Monday.
FORECAST POSITIONS AND MAX WINDS

INIT  16/0300Z 27.3N  85.9W   45 KT  50 MPH - Tropical Storm (WSW Sarasota,FL)
 12H  16/1200Z 28.6N  86.2W   50 KT  60 MPH - Tropical Storm (WSW Panama City,FL)
 24H  17/0000Z 30.2N  86.1W   50 KT  60 MPH - Tropical Storm (ESE Seaside,FL)
 36H  17/1200Z 32.3N  85.7W   30 KT  35 MPH - Depression (ESE Tuskegee,AL)
 48H  18/0000Z 34.4N  84.9W   20 KT  25 MPH - Post Tropical (ENE Adairsville,GA)
 60H  18/1200Z...DISSIPATED

NWS National Hurricane Center Miami FL 400 PM CDT Sun Aug 15, 2021

Satellite imagery indicates that Fred has become a little better organized this afternoon. The low-level circulation has become better defined, and there is a burst of central convection with additional outer banding in the eastern semicircle. A ship near the outer band north of the center reported 40-kt winds, so the initial intensity is increased to 40 kt.

After the re-formation phase this morning, Fred appears to have resumed a north-northwestward motion of 330/9. The track guidance shows this motion continuing for another 12 h or so, followed by a turn toward the north that would bring the center to the coast of the Florida Panhandle in 24-36 h. A general north-northeastward motion is likely after 36 h until the system dissipates. The track guidance has shifted eastward again, this time due to the models forecasting an earlier turn to the north and a more east-of-north motion after landfall. The new NHC forecast track also is shifted a little to the east, but after 24 h it lies a little to the west of the various consensus models.

Upper-level southwesterly flow between a trough to the north and northwest of Fred and an anticyclone to the southeast of the storm should keep the tropical cyclone in moderate southwesterly vertical shear until landfall. However, the intensity guidance continues to forecast strengthening, and the GFS, HWRF, and HMON show a stronger Fred at landfall than they did 6 h ago. Based on that and the increased current intensity, the pre-landfall intensities have been nudged upward. After landfall, Fred should quickly weaken and dissipate as it moves into the Tennessee Valley just after 60 h.

Users are reminded not to focus on the exact forecast track of Fred, since rainfall, storm surge, and wind hazards will extend over an area well east of the center.

KEY MESSAGES:

  • 1. Today through Tuesday, heavy rainfall could lead to flash, urban, small stream, and isolated river flooding impacts across portions of southern Florida, the Big Bend and Panhandle of Florida, southeast Alabama, portions of Georgia, and the western Carolinas. From Tuesday onward, heavy rain and flood impacts could continue into other portions of the Southeast and into the southern and central Appalachians and Piedmont as Fred interacts with a front in the area.
  • 2. Dangerous storm surge inundation is possible along portions of the coast of the Florida Panhandle and the Florida Big Bend region, and a Storm Surge Warning is in effect for this area. Interests in these areas should follow any advice given by local officials.
  • 3. Tropical storm conditions are expected in the Tropical Storm Warning area in the Florida Panhandle beginning on Monday.
FORECAST POSITIONS AND MAX WINDS

INIT  15/2100Z 26.8N  85.3W   40 KT  45 MPH - Tropical Storm (WSW Venice,FL)
 12H  16/0600Z 27.8N  86.0W   45 KT  50 MPH - Tropical Storm (WSW Clearwater,FL)
 24H  16/1800Z 29.5N  86.1W   50 KT  60 MPH - Tropical Storm (WSW Cape San Blas,FL)
 36H  17/0600Z 31.3N  86.0W   35 KT  40 MPH - Tropical Storm (WSW Goodman,AL)
 48H  17/1800Z 33.3N  85.5W   25 KT  30 MPH - Depression (WSW Wedowee,AL)
 60H  18/0600Z 35.8N  84.3W   20 KT  25 MPH - Post Tropical (WNW Lenoir City,TN)
 72H  18/1800Z...DISSIPATED

NWS National Hurricane Center Miami FL 1100 AM EDT Sun Aug 15, 2021

Satellite imagery and reports from an Air Force Reserve Hurricane Hunter aircraft indicate that the remnants of Fred have re-developed into a tropical cyclone over the eastern Gulf of Mexico. Satellite imagery shows a well-defined low-level center near the northern end of a broadly curved convective band. The Hurricane Hunters reported a central pressure of 1008 mb, along with 925-mb flight-level winds of 52 kt and SFMR wind estimates near 35 kt about 70 n mi northeast of the center. Based on these developments and data, the system was upgraded back to Tropical Storm Fred a couple of hours ago.

The center re-formed northward during the redevelopment process, and the initial position is re-located to the north of the previous advisory position. While the forecast guidance is basically unchanged in calling for a north-northwest motion followed by a turn toward the north near landfall on the northern Gulf coast, the new initial position requires the forecast track to be shifted about 40 n mi to the east of the previous track through the landfall time. Fred is now expected to make landfall in the western Florida Panhandle sometime Monday afternoon or evening.

Upper-level southwesterly flow between a trough to the north and northwest of Fred and an anticyclone to the southeast of the storm should keep the tropical cyclone in moderate southwesterly vertical shear until landfall. The intensity guidance forecasts gradual intensification before landfall, and the official intensity forecast follows the guidance in calling for a peak intensity of 45 kt. After landfall, Fred should quickly weaken and dissipate as it moves into the Tennessee Valley.

Users are reminded not to focus on the exact forecast track of Fred, since rainfall, storm surge, and wind hazards will extend over an area well east of the center.

KEY MESSAGES:

  • 1. Today through Tuesday, heavy rainfall could lead to areal, urban, small stream and river flooding impacts across southern Florida, the Florida Big Bend and Panhandle, southern Alabama, portions of Georgia, and the western Carolinas. From Tuesday onward, heavy rain and flood impacts could continue into other portions of the Southeast and into the southern and central Appalachians and Piedmont as Fred interacts with a front in the area.
  • 2. Dangerous storm surge inundation is possible along portions of the coast of the Florida Panhandle, and a Storm Surge Warning has been issued for this area. Interests in these areas should follow any advice given by local officials.
  • 3. Tropical storm conditions are expected in the Tropical Storm Warning area in the Florida Panhandle beginning on Monday.
FORECAST POSITIONS AND MAX WINDS

INIT  15/1500Z 26.1N  84.9W   35 KT  40 MPH - Tropical Storm (WSW Bonita Springs,FL)
 12H  16/0000Z 27.4N  85.8W   40 KT  45 MPH - Tropical Storm (WSW Clearwater,FL)
 24H  16/1200Z 28.9N  86.5W   45 KT  50 MPH - Tropical Storm (WSW Cape San Blas,FL)
 36H  17/0000Z 30.5N  86.5W   45 KT  50 MPH - Tropical Storm (WSW Niceville,FL)
 48H  17/1200Z 32.5N  86.4W   30 KT  35 MPH - Depression (WNW Millbrook,AL)
 60H  18/0000Z 34.7N  85.7W   20 KT  25 MPH - Post Tropical (WSW Ider,AL)
 72H  18/1200Z...DISSIPATED

NWS National Hurricane Center Miami FL 1100 PM EDT Sat Aug 14, 2021 

Deep convection has increased in association with the remnants of Fred this evening with some lose banding noted in both satellite imagery and radar data from Key West. Satellite imagery and surface observations also indicate that the circulation has become a little better defined since this afternoon, but the system still lacks a well-defined center. Therefore, the system has not regained tropical cyclone status yet. The initial intensity remains 30 kt and is based on a few buoy and C-MAN observations over the southeastern Gulf of Mexico and the Lower Florida Keys which have reported peak winds of 25-30 kt over the past several hours. The C-MAN site on Sand Key has reported slightly stronger winds, but that site is elevated.

The system has moved little during the past several hours, and since it lacks a well-defined center, the initial motion estimate is a highly uncertain 300/08 kt. The disturbance is expected to begin a more definitive northwestward motion overnight or Sunday morning as it moves around the western extent of a subtropical ridge over the western Atlantic. The system is forecast to turn northward on Monday as it nears the northern Gulf of coast. Although the track guidance is in good agreement on the overall motion scenario, there is some cross-track spread that appears to be related to where the center re-forms in the short term. Overall there was some eastward shift to the guidance envelope and the official forecast was nudged in that direction, but it still lies to the west of the consensus aids. The NHC track forecast is closest to the GFEX track, which is a consensus of the typically reliable GFS and ECMWF models.

The upper-level trough over the eastern Gulf of Mexico is forecast to weaken and move northward during the next 12-24 hours. This should allow for a somewhat more conducive environment for the system to regain tropical cyclone status and strengthen on Sunday. However, continued moderate southwesterly vertical wind shear is likely to hinder significant development, and the NHC intensity forecast only calls for gradual strengthening through 36-48 hours. After landfall, the system is forecast to weaken rapidly and the global models indicate the circulation will dissipate by 96 hours.

Although no coastal watches or warnings are currently in effect, the National Hurricane Center will continue 6-hourly advisories on the remnants of Fred in anticipation of re-development. Watches are very likely to be required for a portion of the northern Gulf coast early Sunday, and warnings may be required later in the day.

KEY MESSAGES:

  • 1. Today through Monday, heavy rainfall could lead to areal, urban, and small stream flooding impacts, and cause new and renewed river flooding across southern Florida, the Big Bend, and Panhandle. From Monday onward, heavy rain and flood impacts could extend into other portions of the Southeast and into the southern and central Appalachians and Piedmont as Fred interacts with a front in the area.
  • 2. Fred is forecast to regenerate as a tropical cyclone over the Gulf of Mexico on Sunday, and bring a risk of tropical storm conditions to portions of the northern Gulf coast, especially from coastal Mississippi to the Florida Panhandle beginning on Monday. Watches will likely be required for a portion of this area early Sunday, and warnings may be required later in the day.
FORECAST POSITIONS AND MAX WINDS

INIT  15/0300Z 23.8N  84.3W   30 KT  35 MPH - Depression (WSW Key West,FL)
 12H  15/1200Z 25.3N  85.7W   35 KT  40 MPH - Tropical Storm (WSW Marco Island,FL)
 24H  16/0000Z 26.8N  86.9W   40 KT  45 MPH - Tropical Storm (WSW Sarasota,FL)
 36H  16/1200Z 28.3N  87.8W   45 KT  50 MPH - Tropical Storm (WSW Gulf Shores,AL)
 48H  17/0000Z 29.7N  88.0W   45 KT  50 MPH - Tropical Storm (WSW Dauphin Island,AL)
 60H  17/1200Z 31.4N  87.9W   30 KT  35 MPH - Post Tropical (WSW Rockville,AL)
 72H  18/0000Z 33.1N  87.6W   20 KT  25 MPH - Post Tropical (ENE Fosters,AL)
 96H  19/0000Z...DISSIPATED

NWS National Hurricane Center Miami FL 500 PM EDT Sat Aug 14, 2021 

Satellite imagery this afternoon shows that a broad and elongated circulation has formed in association with the remnants of Fred, and that the convection has become more concentrated at the east end of the elongated center. However, neither the circulation nor the convection are organized enough to justify calling the system a tropical cyclone at this time. An Air Force Reserve Hurricane Hunter aircraft is scheduled to survey the remnants of Fred this evening to see how far the re-development has progressed.

The initial motion is a still very uncertain 300/11. The system is expected to move northwestward around the western periphery of the subtropical ridge, with a turn toward the north expected as the system nears and moves inland along the northern Gulf coast in 48-60 h. The forecast guidance remains in good agreement on this general scenario and the new NHC forecast track is close the the consensus models. However, some adjustments to the track forecast could occur depending on where the center of Fred re-forms.

Therefore, users should not concentrate on the details of the forecast track, which could change quite a bit during the next day or so. The global models are now in better agreement that the upper-level trough over the eastern Gulf of Mexico that has been hindering the development of Fred will move northward and weaken during the next 24 h. They also indicate that Fred is likely to re-form a well-defined closed circulation over the eastern Gulf of Mexico Sunday morning. Thus, the intensity forecast now calls for Fred to regain tropical cyclone status in about 12 h, followed by gradual strengthening until landfall in a less than ideal upper-level wind environment. After landfall, the system should weaken and dissipate between 96-120 h. The new NHC intensity forecast follows the overall trend of the intensity guidance.

Although no coastal watches or warnings are currently in effect, the National Hurricane Center will continue 6-hourly advisories on the remnants of Fred in anticipation of re-development. Watches could be required for portions of the northern Gulf coast tonight, and warnings may be required on Sunday.

KEY MESSAGES:

  • 1. Today through Monday, heavy rainfall could lead to areal, urban, and small stream flooding impacts, and cause new and renewed river flooding across southern Florida, the Big Bend, and Panhandle. From Monday onward, heavy rain and flood impacts could extend into other portions of the Southeast and into the southern and central Appalachians and Piedmont as Fred interacts with a front in the area.
  • 2. Fred is forecast to regenerate as a tropical cyclone over the Gulf of Mexico tonight or on Sunday, and bring a risk of tropical storm conditions to portions of the northern Gulf coast, especially from coastal Mississippi to the Florida Panhandle beginning on Monday. Watches may be required for a portion of this area tonight, and warnings may be required on Sunday.
FORECAST POSITIONS AND MAX WINDS

INIT  14/2100Z 24.0N  84.6W   30 KT  35 MPH - Depression (WSW Key West,FL)
 12H  15/0600Z 25.0N  85.7W   30 KT  35 MPH - Depression (WSW Key West,FL)
 24H  15/1800Z 26.6N  87.1W   35 KT  40 MPH - Tropical Storm (WSW Venice,FL)
 36H  16/0600Z 28.0N  87.9W   40 KT  45 MPH - Tropical Storm (WSW Gulf Shores,AL)
 48H  16/1800Z 29.4N  88.2W   45 KT  50 MPH - Tropical Storm (ESE Pascagoula,MS)
 60H  17/0600Z 30.9N  88.3W   35 KT  40 MPH - Tropical Storm (WSW Georgetown,AL)
 72H  17/1800Z 32.4N  88.2W   25 KT  30 MPH - Depression (WSW Intercourse,AL)
 96H  18/1800Z 36.0N  87.5W   20 KT  25 MPH - Post Tropical (WSW Eno,TN)
120H  19/1800Z...DISSIPATED

NWS National Hurricane Center Miami FL 1100 AM EDT Sat Aug 14, 2021

A combination of shear caused by an upper-level trough over the Gulf of Mexico and land interaction has caused Fred to degenerate into an open wave. Surface observations from Cuba do not show a closed circulation, and satellite imagery shows at least two vorticity centers embedded in a large trough. The strongest convection is currently near and southeast of a vorticity center near the Isle of Youth. The initial position is a mean position between the vorticity center, and the initial intensity of 30 kt is based on Air Force Reserve Hurricane Hunter aircraft data to the northeast of the estimated center position.

The global models forecast the upper-level trough to move northward and weaken during the next 24 h and indicate that Fred will re-form a closed circulation over the eastern Gulf of Mexico Sunday morning. Given the strength of the upper-level trough, that forecast may well be too bullish. However, given the agreement in the guidance, the revised intensity forecast will call for Fred to regain tropical cyclone status at about the 24 h point, followed by gradual strengthening in a less than ideal upper-level wind environment until landfall along the northern Gulf coast. After landfall, the system should weaken and dissipate between 96-120 h.

The initial motion is a very uncertain 300/10. The system is expected to move west-northwestward to northwestward around the western periphery of the subtropical ridge, with a turn toward the north as the system nears the northern Gulf coast in 60-72 h. While the forecast guidance is in good agreement on this general scenario, there is uncertainty as to where the center of Fred will be when it re-forms. Therefore, users should not concentrate on the details of the forecast track, which could change quite a bit during the next 24-36 h.

Although all coastal watches and warnings are discontinued at this time, the National Hurricane Center will continue 6-hourly advisories on the remnants of Fred in anticipation of re-development and the potential need for watches and warnings on the northern Gulf coast later in the weekend.

KEY MESSAGES:

  • 1. Today through Monday, heavy rainfall could lead to areal, urban, and small stream flooding impacts, and cause new and renewed river flooding, across southern Florida, the Big Bend, and Panhandle. From Monday onward, heavy rain and flood impacts could extend into other portions of the Southeast and into the southern and central Appalachians and Piedmont as Fred interacts with a front in the area.
  • 2. Fred is forecast to regenerate as a tropical cyclone over the Gulf of Mexico on Sunday, and bring a risk of tropical storm conditions to portions of the northern Gulf coast, especially from coastal Mississippi to the Florida Panhandle beginning on Monday. Watches may be required for a portion of this area later in the weekend.
FORECAST POSITIONS AND MAX WINDS

INIT  14/1500Z 23.3N  83.2W   30 KT  35 MPH - Depression (ENE Bahía Honda,Cuba)
 12H  15/0000Z 24.1N  84.2W   30 KT  35 MPH - Depression (WSW Key West,FL)
 24H  15/1200Z 25.7N  85.5W   30 KT  35 MPH - Depression (WSW Marco Island,FL)
 36H  16/0000Z 27.4N  86.7W   35 KT  40 MPH - Tropical Storm (WSW Clearwater,FL)
 48H  16/1200Z 28.7N  87.4W   45 KT  50 MPH - Tropical Storm (ESE New Orleans,LA)
 60H  17/0000Z 30.0N  87.7W   45 KT  50 MPH - Tropical Storm (WSW Gulf Shores,AL)
 72H  17/1200Z 31.5N  87.5W   35 KT  40 MPH - Tropical Storm (WSW Perdue Hill,AL)
 96H  18/1200Z 35.0N  86.5W   20 KT  25 MPH - Post Tropical (WSW New Hope,TN)
120H  19/1200Z...DISSIPATED

NWS National Hurricane Center Miami FL 1100 PM EDT Fri Aug 13, 2021 

Interaction with land and southwesterly shear has continued to take a toll on Fred this evening. It is very difficult to determine in infrared satellite imagery and recent surface observations from Cuba if a closed circulation still exists, however the system is maintained as a tropical depression for now. Scatterometer data, which should arrive very soon, and reconnaissance aircraft observations on Saturday morning should provide additional information on the system’s intensity and structure.

The system still appears to be moving westward or 280/11 kt. There has been no change to the track forecast reasoning from the previous advisory. The cyclone is approaching the western periphery of a subtropical ridge extending over the western Atlantic, and Fred should turn west-northwestward overnight, and then northwestward on Saturday. The track guidance has again shifted westward, but the shift is not as large as was noted on the previous cycle. The NHC track forecast has been adjusted to the left, closer to the consensus aids, but it still remains to the east of those models. Some additional westward adjustments in subsequent forecasts may be required.

As mentioned above, land interaction and southwesterly vertical will limit any attempt of re-organization overnight, however the system is expected to move off the northern coast of Cuba Saturday morning and the global model guidance suggests that a center re-formation could occur over the western portion of the Straits of Florida. The center re-formation shown by the guidance appears to be aided by an area of upper-level diffluent flow to the southeast of an upper-level trough currently located over the eastern Gulf of Mexico. Although only a little strengthening is indicated in the official forecast through 36 hours, the environment could become a little more conducive on Sunday, and the NHC wind speed forecast again calls for gradual strengthening while Fred moves northwestward over the eastern Gulf. The updated intensity forecast is unchanged from the previous advisory and is a blend of the statistical guidance and the HCCA model. The intensity forecast continues to be of lower-than-normal confidence given the current disorganized structure of the system.

KEY MESSAGES:

  • 1. Tonight through Monday, heavy rainfall could lead to areal, urban, and small stream flooding impacts, and cause new and renewed river flooding, across southern and central Florida into the Big Bend. From Sunday onward, heavy rain and flood impacts could extend into other portions of the Southeast and into the southern and central Appalachians and Piedmont as Fred interacts with a front in the area.
  • 2. Tropical storm conditions are expected in portions of the Lower Florida Keys on Saturday, where a Tropical Storm Warning is in effect.
  • 3. There is a risk of tropical storm conditions in the Florida Panhandle beginning on Monday. Watches may be required for a portion of this area on Saturday.
FORECAST POSITIONS AND MAX WINDS

INIT  14/0300Z 22.7N  80.6W   30 KT  35 MPH - Depression (WSW Felipe,Cuba)
 12H  14/1200Z 23.4N  81.9W   30 KT  35 MPH - Depression (ENE Havana,Cuba)
 24H  15/0000Z 24.8N  83.6W   35 KT  40 MPH - Tropical Storm (WNW Key West,FL)
 36H  15/1200Z 26.3N  85.0W   35 KT  40 MPH - Tropical Storm (WNW Naples,FL)
 48H  16/0000Z 27.8N  86.0W   40 KT  45 MPH - Tropical Storm (WSW Clearwater,FL)
 60H  16/1200Z 29.2N  86.6W   45 KT  50 MPH - Tropical Storm (ESE Panama City,FL)
 72H  17/0000Z 30.6N  86.8W   50 KT  60 MPH - Tropical Storm (ESE Parkerville,FL)
 96H  18/0000Z 34.0N  86.5W   25 KT  30 MPH - Depression (ENE Rosa,AL)
120H  19/0000Z 37.5N  84.0W   20 KT  25 MPH - Post Tropical (WSW Foxtown,KY)

NWS National Hurricane Center Miami FL 500 PM EDT Fri Aug 13, 2021

Although there has been a general increase in convection associated with Fred since this morning, the system remains disorganized with the low-level center moving farther inland over central Cuba. Earlier ASCAT data detected an area of 25-27 kt winds over water to the northeast of the center, and based on that data, the initial intensity is held at 30 kt, which could be a little generous.

Since the previous advisory, Fred has been moving nearly due westward, but the longer-term motion is estimated to be 280/10 kt. The cyclone is nearing the western periphery of a subtropical ridge that is centered over the western Atlantic. This should cause Fred to turn west-northwestward tonight, and then northwestward on Saturday. The latest interpolated guidance that was initialized with the more southward and westward 18Z initial position shows a wider or more gradual northwestward turn, and therefore has shifted significantly westward, especially in the short term. However, the global models fields track the 850-mb vorticity center more along the northern coast of Cuba and some of those models suggest a center re-formation could occur on Saturday near the north coast of Cuba or over the Straits of Florida. As a result, the first 24-36 hours of the track forecast has been adjusted about a degree westward, but it is not as far west as the trackers, leaving open the possibility that a center re-formation could occur. After that time, the NHC forecast lies along the eastern side of the guidance envelope in best agreement with the 12Z GFS. Some additional westward adjustments may be necessary until the track guidance stabilizes. It is worth noting that it isn’t too surprising to see these type of models shifts with a system that remains quite disorganized.

Fred remains within an area of moderate southwesterly vertical wind shear, and the model guidance generally indicates that this shear will continue during the next day or so. Since it will also take time for the system to recover after its passage over Cuba, only gradual strengthening is indicated during the next day or two. After that time, the system could be in a somewhat more favorable environment, and the NHC intensity forecast calls for some strengthening until Fred reaches the northern Gulf Coast, which now doesn’t occur until around 72 hours with the wider turn shown in the track forecast. The NHC intensity forecast lies between the various consensus aids, the statistical guidance, and the HWRF model, which all generally show the system peaking in 60-72 hours. The intensity forecast remains of lower-than-normal confidence due to Fred’s continued interaction with land.

Users are reminded to not focus on the exact forecast track as heavy rainfall, gusty winds, and a chance of tornadoes will extend far to northeast and east of the center, and those hazards are likely to still affect portions of the Florida peninsula, despite the recent shift in the forecast track.

KEY MESSAGES:

  • 1. Today through Monday, heavy rainfall could lead to areal, urban, small stream, and exacerbated river flooding across southern and central Florida into the Big Bend. From Sunday onward, heavy rain and flood impacts could extend into other portions of the Southeast and into the southern and central Appalachians and Piedmont as Fred interacts with a front in that area.
  • 2. Tropical storm conditions are expected in portions of the Florida Keys on Saturday, where a Tropical Storm Warning is in effect.
  • 3. Tropical storm conditions are possible late Saturday and early Sunday across portions of the west coast of Florida in the Tropical Storm Watch area. The risk of tropical storm conditions will spread northward along the Florida west coast and to the Florida Panhandle Sunday and Monday.
FORECAST POSITIONS AND MAX WINDS

INIT  13/2100Z 22.3N  79.6W   30 KT  35 MPH - Depression (ESE Placetas,Cuba)
 12H  14/0600Z 23.0N  81.0W   30 KT  35 MPH - Depression (WNW Marti,Cuba)
 24H  14/1800Z 24.2N  82.6W   35 KT  40 MPH - Tropical Storm (WSW Key West,FL)
 36H  15/0600Z 25.4N  83.7W   35 KT  40 MPH - Tropical Storm (WNW Key West,FL)
 48H  15/1800Z 27.0N  84.8W   40 KT  45 MPH - Tropical Storm (WSW Venice,FL)
 60H  16/0600Z 28.8N  85.7W   45 KT  50 MPH - Tropical Storm (ESE Panama City,FL)
 72H  16/1800Z 30.2N  86.2W   50 KT  60 MPH - Tropical Storm (WSW Seaside,FL)
 96H  17/1800Z 33.5N  86.5W   25 KT  30 MPH - Depression (ENE Vandiver,AL)
120H  18/1800Z 37.0N  85.0W   20 KT  25 MPH - Post Tropical (WSW Whittle,KY)

NWS National Hurricane Center Miami FL 1100 AM EDT Fri Aug 13, 2021 

Fred remains disorganized this morning. The low-level center, which is currently over the barrier islands of the north coast of Cuba, is exposed to the northwest of the main convective mass due to moderate southwesterly vertical shear. Reports from Air Force Reserve and NOAA Hurricane hunter aircraft show winds of 25-30 kt to the northeast of the center, so the initial intensity remains 30 kt. The central pressure is 1013 mb based on a combination of aircraft data and surface observations.

The center has jogged a bit to the left during the past several hours, which has brought it to the Cuban coast. The longer-term initial motion is 295/10. The cyclone should continue west-northwestward for the next 12-24 h, followed by a turn toward the northwest as Fred approaches the western periphery of the subtropical ridge. This motion should take the center along the northern coast of Cuba today, near the Florida Keys and the southwestern coast of Florida on Saturday, and near or over the coast of the Florida Panhandle Sunday night or Monday. After that, a northward turn is expected as Fred moves into a weakness in the ridge over the southeastern United States. With both the initial position and the track guidance shifting westward since the last advisory, the new forecast track is also nudged a little to the west. The new track is east of the consensus models, especially from 24-60 h, and thus some additional adjustments could occur later today if the current model trends continue.

Fred is continuing to experience about 20 kt of westerly or southwesterly vertical wind shear, and these conditions should continue for at least another 24 hours. Between that and land interaction, the intensity forecast calls for only modest strengthening during this time. After that, there is still relatively poor agreement on how much shear Fred will experience as it crosses the eastern Gulf of Mexico, with the ECMWF and the UKMET forecasting less shear than the GFS and CMC global models. Due to the uncertainty, the intensity forecast will keep the previous peak intensity of 45 kt. However, the intensity guidance during this period has trended a little higher, and the 45 kt peak is now a little below the upper edge of the guidance.

It should be noted that much of the Florida peninsula is expected to be on the east side of Fred, which is where the heaviest rains, strongest winds, and a chance of tornadoes will be.

KEY MESSAGES:

  • 1. Today through Monday, heavy rainfall could lead to areal, urban, small stream, and exacerbated river flooding across southern and central Florida into the Big Bend. From Sunday onward, heavy rain and flood impacts could extend into other portions of the Southeast and into the southern and central Appalachians and Piedmont as Fred interacts with a front in that area.
  • 2. Tropical storm conditions are expected in portions of the Florida Keys on Saturday, where a Tropical Storm Warning is in effect.
  • 3. Tropical storm conditions are possible late Saturday and early Sunday across portions of the west coast of Florida in the Tropical Storm Watch area. The risk of tropical storm conditions will spread northward along the Florida west coast and to the Florida Panhandle Sunday and Monday.
FORECAST POSITIONS AND MAX WINDS

INIT  13/1500Z 22.3N  78.4W   30 KT  35 MPH - Depression (ENE Moron,Cuba)
 12H  14/0000Z 23.0N  79.7W   30 KT  35 MPH - Depression (ESE Cayo Hicacal,Cuba)
 24H  14/1200Z 24.2N  81.3W   35 KT  40 MPH - Tropical Storm (ESE Key West,FL)
 36H  15/0000Z 25.6N  82.5W   35 KT  40 MPH - Tropical Storm (WSW Marco Island,FL)
 48H  15/1200Z 27.2N  83.6W   40 KT  45 MPH - Tropical Storm (WSW Siesta Key,FL)
 60H  16/0000Z 28.7N  84.6W   45 KT  50 MPH - Tropical Storm (ESE St George Island,FL)
 72H  16/1200Z 30.2N  85.4W   35 KT  40 MPH - Tropical Storm (ENE Panama City, FL)
 96H  17/1200Z 33.0N  86.5W   25 KT  30 MPH - Depression (ESE Wildwood Shores,AL)
120H  18/1200Z 36.5N  86.5W   20 KT  25 MPH - Post Tropical (ESE Portland,TN)

NWS National Hurricane Center Miami FL 1100 PM EDT Thu Aug 12, 2021 

Data from an Air Force Reserve reconnaissance aircraft this indicate that Fred’s inner-core wind field Fred remains poorly organized. Also, data from a NOAA reconnaissance aircraft suggests that the 650-mb mid-level circulation center is titled at least 40 nmi to the east of the low-level center. The maximum 925-mb flight-level wind measured thus far has been 43 kt and the highest reliable SFMR surface wind speed sampled has been 33 kt. A blend of these data support maintaining a solid 30-kt intensity for this advisory, but Fred is right on the cusp of regaining tropical storm status.

Fred has slowed down some more, with the initial motion estimate an uncertain 295/08 kt. The uncertainty in Fred’s forward motion is related to the speed due to the low-level center jumping around every time a small convective tower develops within the larger cloud mass. However, the general motion of the wind field and the associated pressure envelope is toward the west-northwest or 295 degrees. Otherwise, there is no significant changes to the previous track forecast or reasoning. Fred is expected to continue moving west-northwestward along the southwestern periphery of a deep-layer for the next 36 hours or so, followed by a northwestward motion near or just offshore the Florida west coast in the 48-to-72-hour period.

On days 4 and 5, a slower northward motion is forecast as Fred moves into a developing weakness in the ridge. The latest track guidance has become more divergent, with the GFS model dissipating and then redeveloping Fred over south Florida in about 48 hours, with the other models taking a weakening cyclone more westward. The exception is the westward-trending ECMWF model, which moves Fred along the Florida west coast. The new NHC track forecast was nudged slightly to the east or right of the previous advisory track after 24 hours, but lies to the left of the ECMWF model and between the NOAA-HCCA and TVCA consensus track models.

Fred is forecast to remain under the influence of westerly to southwesterly vertical wind shear for the next 72 hours. It is the magnitude of the shear that is in question. The GFS maintains 15-20 kt of shear for the next three days, whereas the ECMWF model decreases the shear to around 10 kt in the 24-to-60-hour period, with the latter scenario favoring some strengthening if Fred doesn’t interact too much with the Florida peninsula. Due to the uncertainty in the amount of shear and land interaction that will be encountered, latest official intensity forecast remains similar to the previous advisory and a blend of the HCCA and TVCA consensus model intensity forecasts.

KEY MESSAGES:

  • 1. From Friday into Monday, heavy rainfall could lead to areal, urban, small stream, and exacerbated river flooding, across southern and central Florida, and into the Big Bend of Florida. By early next week, heavy rain and flood impacts could extend into other portions of the Southeast and into the southern and central Appalachians and Piedmont.
  • 2. Tropical storm conditions are possible beginning Friday night and Saturday in the Florida Keys and portions of southern Florida, where a Tropical Storm Watch is in effect. The risk of tropical storm conditions will spread northward along portions of the Florida west coast and to the Florida Panhandle Saturday night through Monday.
FORECAST POSITIONS AND MAX WINDS

INIT  13/0300Z 21.5N  75.6W   30 KT  35 MPH - Depression (ENE Banes,Cuba)
 12H  13/1200Z 22.2N  77.1W   35 KT  40 MPH - Tropical Storm (ENE Nuevitas,Cuba)
 24H  14/0000Z 23.0N  79.0W   35 KT  40 MPH - Tropical Storm (ENE Cayo Santa Maria,Cuba)
 36H  14/1200Z 24.2N  80.6W   40 KT  45 MPH - Tropical Storm (ESE Marathon,FL)
 48H  15/0000Z 25.5N  82.1W   40 KT  45 MPH - Tropical Storm (WSW Marco Island,FL)
 60H  15/1200Z 27.2N  83.1W   45 KT  50 MPH - Tropical Storm (WSW Siesta Key,FL)
 72H  16/0000Z 29.1N  84.2W   45 KT  50 MPH - Tropical Storm (WSW Cedar Key,FL)
 96H  17/0000Z 31.8N  85.6W   35 KT  40 MPH - Tropical Storm (WNW Louisville,AL)
120H  18/0000Z 34.4N  85.5W   25 KT  30 MPH - Depression (ESE Fort Payne,AL)

NWS National Hurricane Center Miami FL 500 PM EDT Thu Aug 12, 2021

Fred remains poorly organized at this time. While the low-level circulation looks more closed than it did earlier, the center is broad and may have multiple vortices rotating around it. Also, while convection has increased from earlier today, there is only minimal convection near the center and little evidence of banding. The initial intensity remains 30 kt, with those winds likely occurring in squalls to the northeast of the center.

Fred has slowed its forward speed, with the initial motion now 295/10. There is little change to the track forecast philosophy from the previous advisory. The subtropical ridge to the northeast should steer Fred west-northwestward for the first 24-36 h, followed by a turn toward the northwest as the cyclone approaches the western periphery of the ridge. By 96-120 h, a northward motion is expected as Fred moves into a weakness in the ridge. The track guidance has shifted westward since the previous advisory, most notably after about 24 h. Thus, that portion of the new forecast track has also been nudged a little westward, but it still lies to the east of the various consensus models.

Fred remains in an environment of about 20 kt of westerly vertical wind shear. The shear is expected to persist during the next day or so, and this combined with the current disorganization of the system should prevent significant strengthening during that time. After that, there remains disagreement between the global models on the evolution of the upper-level trough over Florida and the upper-level anticyclone southeast of Fred. Some shear is likely to continue, but there may be a period of more conducive conditions from 36-72 h. The new intensity forecast is similar to the previous one in calling for slow strengthening through the first 36 h, with a little faster strengthening from 36-72 h. With that being said, the forecast 45-kt peak intensity is near the high end of the intensity guidance.

KEY MESSAGES:

  • 1. From Friday into Monday, heavy rainfall could lead to areal, urban, small stream, and exacerbated river flooding across southern and central Florida, and into the Big Bend of Florida. By early next week, heavy rain and flood impacts could extend into other portions of the Southeast and into the southern and central Appalachians and Piedmont.
  • 2. Tropical storm conditions are possible beginning Friday night and Saturday in the Florida Keys and portions of southern Florida, where a Tropical Storm Watch is in effect. The risk of tropical storm conditions will spread northward along portions of the Florida west coast and to the Florida Panhandle Saturday night through Monday.
FORECAST POSITIONS AND MAX WINDS

INIT  12/2100Z 21.3N  75.3W   30 KT  35 MPH - Depression (ENE Banes,Cuba)
 12H  13/0600Z 22.0N  77.0W   30 KT  35 MPH - Depression (WNW Puerto Padre,Cuba)
 24H  13/1800Z 23.0N  79.0W   30 KT  35 MPH - Depression (ENE Cayo Fragoso,Cuba)
 36H  14/0600Z 24.0N  80.6W   35 KT  40 MPH - Tropical Storm (ESE Marathon,FL)
 48H  14/1800Z 25.2N  81.9W   35 KT  40 MPH - Tropical Storm (WNW Key West,FL)
 60H  15/0600Z 26.4N  83.1W   40 KT  45 MPH - Tropical Storm (WSW Captiva,FL)
 72H  15/1800Z 28.1N  84.1W   45 KT  50 MPH - Tropical Storm (WNW Clearwater,FL)
 96H  16/1800Z 31.0N  85.5W   40 KT  45 MPH - Tropical Storm (ESE Fadette,AL)
120H  17/1800Z 33.5N  85.5W   25 KT  30 MPH - Depression (ENE Folsom,AL)

NWS National Hurricane Center Miami FL 1100 AM EDT Thu Aug 12, 2021 

Fred is poorly organized this morning. Reports from Air Force Reserve and NOAA Hurricane Hunter aircraft, along with 1-minute imagery from GOES-16, indicate that the circulation is barely closed. Dropsondes in the area reported surface pressures of 1013-1014 mb, and the maximum winds of near 30 kt are well to the northeast of the center. In addition, there is currently no organized convection anywhere near the center. Based on the evidence of the closed circulation, the system will be maintained as tropical depression for this advisory. However, the structure is currently closer to that of an open wave than a normal tropical cyclone.

The initial motion is now 300/12. The subtropical ridge over the western Atlantic north of Fred should steer the cyclone west-northwestward during the next 36 h or so. This motion should take the depression away from the southeastern Bahamas and bring it near the north coast of Cuba. After that time, Fred should approach the western periphery of the ridge, which should cause the cyclone to turn northwestward and slow its forward speed. There remains some uncertainty as to the when and where of the turn, with the track guidance models remaining spread across a region from over Florida to the east-central Gulf of Mexico. The new track forecast is little changed from the previous NHC track, and it lies a little to the east of the consensus models for the first 72 h or so.

Fred remains in an environment about 20 kt of westerly vertical wind shear. This shear is expected to persist during the next day or so, and this combined with the current disorganization should prevent significant strengthening during this time. While there is still disagreement between the global models on the forecast upper-level winds over the Gulf of Mexico, the shear could lessen after 36 h and allow some intensification as the cyclone nears south Florida and moves into the eastern Gulf. The intensity guidance has trended weaker since the last advisory, with none of the guidance currently calling for Fred to reach hurricane strength. The new intensity forecast is similar to the previous one while Fred is over water, and it follows the overall trend of the intensity guidance.

KEY MESSAGES:

  • 1. Heavy rainfall today could lead to flash, urban, and small stream flooding, along with possible rapid river rises and the potential for mudslides in the Dominican Republic and Haiti.
  • 2. Tropical storm conditions are possible in the southeastern Bahamas and portions of Cuba today.
  • 3. Beginning Friday, heavy rainfall could lead to areal, urban, and small stream flooding, along with possible rapid river rises across southern Florida. Heavy rainfall associated with Fred will impact the remainder of Florida and parts of the Southeast this weekend and into next week.
  • 4. There is a risk of tropical storm conditions beginning early Saturday in the Florida Keys and south Florida. This risk will spread northward along portions of the Florida west coast and to the Florida Panhandle through Monday. A Tropical Storm Watch will likely be issued for portions of the Florida Keys and the southern Florida Peninsula this afternoon.
FORECAST POSITIONS AND MAX WINDS

INIT  12/1500Z 20.9N  74.4W   30 KT  35 MPH - Depression (ENE Moa,Cuba)
 12H  13/0000Z 21.8N  76.2W   30 KT  35 MPH - Depression (ENE Puerto Padre,Cuba)
 24H  13/1200Z 22.8N  78.3W   30 KT  35 MPH - Depression (ESE Cayo Coco,Cuba)
 36H  14/0000Z 23.8N  79.9W   35 KT  40 MPH - Tropical Storm (ESE Marathon,FL)
 48H  14/1200Z 24.8N  81.2W   35 KT  40 MPH - Tropical Storm (WNW Marathon,FL)
 60H  15/0000Z 26.0N  82.4W   40 KT  45 MPH - Tropical Storm (WSW Naples,FL)
 72H  15/1200Z 27.5N  83.6W   45 KT  50 MPH - Tropical Storm (WSW St Petersburg,FL)
 96H  16/1200Z 30.5N  85.0W   50 KT  60 MPH - Tropical Storm (ENE Blountstown,FL)
120H  17/1200Z 33.5N  85.0W   25 KT  30 MPH - Depression (ESE Carrollton,GA)

NWS National Hurricane Center Miami FL 500 AM EDT Thu Aug 12, 2021 

The rugged terrain of Hispaniola has taken a toll on Fred. Satellite images and surface observations indicate that the circulation is stretched out and seems to resemble a trough at the surface. The system is now emerging back over water and is located between Haiti, eastern Cuba, and the southeastern Bahamas. Most of the associated showers and thunderstorms are located to the east of the estimated center, with heavy rains continuing over portions of Hispaniola. The initial intensity is estimated to be 30 kt, but there is limited data to confirm this. Both the NOAA and Air Force Hurricane Hunters will be investigating Fred later this morning, and the data from both planes will be helpful in estimating Fred’s strength and structure.

Fred appears to be moving west-northwestward at about 14 kt. The track forecast reasoning has not changed much. A subtropical ridge currently situated to the north of Fred over the western Atlantic should continue to steer the system west-northwestward for the next 36 to 48 hours. This motion should take the storm just north of or across Cuba and the southeastern Bahamas during that time period. By the weekend, the models suggest that Fred will be rounding the western periphery of the ridge, which will likely a cause a slow down and a gradual turn to the northwest and then the north across portions of the Florida Keys, the Florida peninsula, and the eastern Gulf of Mexico. There is uncertainty in exactly where and when Fred will make that turn to the right, with models currently spanning a region from over Florida to the east-central Gulf of Mexico. The NHC track forecast remains on the right side of the guidance envelope, near the typically more skillful global models and consensus aids.

Fred is currently in an environment of about 20 kt of westerly vertical wind shear. This shear is expected to persist during the next day or so, and those unfavorable winds combined with some land interaction with Cuba should prevent the system from strengthening much, if at all, during that time period. The shear could lessen on Friday and since SSTs are very warm and there is abundant environmental moisture, some strengthening seems likely when Fred is approaching the Florida Keys and south Florida Friday night and Saturday. After that time, the intensity forecast becomes more complicated by how much land interaction there will be with Florida. Since the official forecast shows a track over the eastern Gulf, additional strengthening is predicted before Fred makes its final landfall along the Florida Big Bend region or Florida panhandle late in the weekend or early next week. However, that part of the intensity forecast, since it will be very track dependent, is more uncertain.

KEY MESSAGES:

  1. 1. Continued heavy rainfall today could lead to flash, urban, and small stream flooding, along with possible rapid river rises and potential mudslides in the Dominican Republic and Haiti.
  • 2. Tropical storm conditions are possible in northern Haiti and the southeastern Bahamas this morning, and in portions of Cuba later today.
  • 3. Beginning Friday, heavy rainfall could lead to areal, urban, and small stream flooding, and possible rapid river rises across southern Florida. Heavy rainfall associated with Fred will impact the remainder of Florida and parts of the Southeast this weekend and into next week.
  • 4. There is a risk of tropical storm conditions beginning early Saturday in the Florida Keys and south Florida. These conditions are expected to spread northward along portions of the Florida west coast and the Florida Panhandle through Monday.
FORECAST POSITIONS AND MAX WINDS

INIT  12/0900Z 20.2N  73.5W   30 KT  35 MPH - Depression (WSW Maisí,Cuba)
 12H  12/1800Z 21.0N  75.1W   30 KT  35 MPH - Depression (WNW Moa,Cuba)
 24H  13/0600Z 22.0N  77.2W   30 KT  35 MPH - Depression (ESE Cayo Romano,Cuba)
 36H  13/1800Z 23.0N  79.1W   35 KT  40 MPH - Tropical Storm (ENE Cayo Fragoso,Cuba)
 48H  14/0600Z 23.8N  80.3W   35 KT  40 MPH - Tropical Storm (ESE Marathon,FL)
 60H  14/1800Z 25.1N  81.4W   40 KT  45 MPH - Tropical Storm (WNW Big Pine Key,FL)
 72H  15/0600Z 26.6N  82.6W   45 KT  50 MPH - Tropical Storm (WNW Pine Island,FL)
 96H  16/0600Z 29.5N  84.4W   50 KT  60 MPH - Tropical Storm (ESE Alligator Point,FL)
120H  17/0600Z 32.2N  84.7W   35 KT  40 MPH - Tropical Storm (ESE Cusseta,GA)

NWS National Hurricane Center Miami FL 1100 PM EDT Wed Aug 11, 2021 

The center of Fred is estimated to be located over extreme eastern Haiti. This position is based on continuity with the previous forecast and a small low-level cyclonic circulation noted in cloud-drift wind vectors that were based on the last few GOES-16 high-resolution visible satellite images. A NOAA reconnaissance aircraft performed a quasi-synoptic surveillance mission this evening and released dropsondes while circumnavigating Hispaniola. Some of the dropsondes measured surface winds of 24-27 kt about 150 nmi north and northwest (in the Windward Passage) of the center, and these data support maintaining an intensity of 30 kt for this advisory. The main convective cloud mass has been displaced to the southeast of the low-level center due to the west-northwesterly vertical wind shear of about 20 kt.

The initial motion estimate is 300/13 kt. The global and regional models remain in surprisingly good agreement on Fred maintaining a steady west-northwestward motion through 48-60 hours as a strong ridge remains entrenched over the western Atlantic during that time period. Thereafter, however, the NHC model guidance diverges significantly, with the now much weaker HWRF model taking Fred more westward, while the GFS and ECMWF models move the cyclone northwestward over the eastern Gulf of Mexico near or just offshore the Florida west coast; the UKMET model lies between these two track extremes. The weaker HWRF track has been discounted given the NHC forecast that Fred will remain vertically coherent and restrengthen after moving back over water. Thus, the new NHC track forecast is essentially just an update of the previous advisory track, and lies close to the NOAA-HCCA corrected-consensus model. NOTE: the aforementioned NOAA WP-3D reconnaissance aircraft has been releasing dropsondes from approximately the 450-mb level and has also been collecting tail-Doppler radar data. These data should have been assimilated into the 0000 UTC model runs, which hopefully will provide better track and intensity model forecasts for the next advisory package.

Fred is forecast remain within a moderate to strong westerly to southwesterly vertical wind shear regime throughout the forecast period by almost all of the global and regional models. As a result, rapid strengthening is not expected after Fred moves back over water. There is one caveat, however, and that is the ECMWF model forecasting the shear to weaken to 5-10 kt during the 36-72 hour period, which could allow for a little more strengthening than what the official forecast is currently indicating. The new NHC intensity prediction is identical to the previous one owing to the expectation that some degree of westerly shear will be affecting Fred throughout the entire forecast period. The official forecast follows a blend of the IVCN and HCCA consensus intensity models.

KEY MESSAGES:

  • 1. Through early Thursday morning, heavy rainfall could lead to flash, urban, and small stream flooding, along with possible rapid river rises and potential mudslides in the Dominican Republic.
  • 2. Tropical storm conditions are possible in northern Haiti, the Turks and Caicos, and the southeastern Bahamas tonight, and in portions of Cuba Thursday.
  • 3. Beginning Friday, heavy rainfall could lead to areal, urban, and small stream flooding, and possible rapid river rises across southern Florida. Heavy rainfall associated with Fred will impact the remainder of Florida and parts of the Southeast this weekend and into next week.
  • 4. There is a risk of tropical storm conditions beginning early Saturday in the Florida Keys and spreading northward along portions of the Florida west coast and the Florida Panhandle through Monday.
FORECAST POSITIONS AND MAX WINDS

INIT  12/0300Z 19.5N  72.2W   30 KT  35 MPH - Depression (ESE Dondon,Haiti)
 12H  12/1200Z 20.4N  73.9W   30 KT  35 MPH - Depression (ENE Sabana,Cuba)
 24H  13/0000Z 21.6N  76.1W   30 KT  35 MPH - Depression (ENE Puerto Padre,Cuba)
 36H  13/1200Z 22.5N  78.1W   35 KT  40 MPH - Tropical Storm (ENE Cayo Coco,Cuba)
 48H  14/0000Z 23.5N  79.8W   35 KT  40 MPH - Tropical Storm (WNW Caibarién,Cuba)
 60H  14/1200Z 24.7N  81.2W   40 KT  45 MPH - Tropical Storm (WNW Marathon,FL)
 72H  15/0000Z 26.2N  82.4W   45 KT  50 MPH - Tropical Storm (WSW North Naples,FL)
 96H  16/0000Z 29.2N  84.2W   50 KT  60 MPH - Tropical Storm (ESE Alligator Point,FL)
120H  17/0000Z 31.7N  84.7W   35 KT  40 MPH - Tropical Storm (ESE Cuthbert,GA)

NWS National Hurricane Center Miami FL 500 PM EDT Wed Aug 11, 2021 

During the past several hours, the center of Fred has moved inland over the Dominican Republic. The storm continues to produce an area of convection near and southeast of the center. However, the low-level circulation is losing some organization as it passes over mountainous terrain. There have been no observations near the center recently, so the initial intensity of 35 kt is based mainly on weakening from the previous over water intensity.

The initial motion is a somewhat uncertain 290/13. Some erratic motion is expected during the next 12 h or so as the center moves over the mountains of Hispaniola. After reaching the water, the cyclone is expected to moves west-northwestward on the south side of the subtropical ridge through about 60 h. After that, a northwestward motion is expected through the end of the forecast period as Fred moves toward a weakness in the ridge. The track guidance becomes a bit divergent during this time, with the ECMWF, Canadian, and HWRF models showing a track near or over the Florida Peninsula, while the GFS, UKMET, and HMON models show the center passing south and west of the Florida Keys, followed by a more northward motion over the Gulf of Mexico. The new forecast track is between these extremes, and it has only minor adjustments from the previous NHC track.

Fred is expected to weaken to a depression over Hispaniola during the next 12 h. Once back over water, the cyclone is expected to be in a moderate westerly shear environment through at least 60 h. Due to that, and the uncertainty in how well organized the system will be after crossing Hispaniola, the intensity forecast shows only modest intensification during this time. After that time, the global models forecast that an upper-level trough over Florida will gradually move to the north, with an large upper-level anticyclone following near or to the southeast of Fred. How close this anticyclone gets to Fred will determine how much the shear decreases while the system is over the eastern Gulf of Mexico, and the global models are not in great agreement on this. The GFS and Canadian keep the high far enough to the east to expose Fred to southwesterly upper-level winds, while the UKMET and ECMWF move it closer to the storm. The intensity forecast will show a slightly faster rate of strengthening after 72 h to match the guidance and the previous forecast. However, there is lower than normal confidence in this part of the intensity forecast.

KEY MESSAGES:

  • 1. Tropical storm conditions are ongoing across portions of the Dominican Republic. Tropical storm conditions are possible in northern Haiti and the southeastern Bahamas this evening, and in portions of Cuba by tonight.
  • 2. Through early Thursday morning, heavy rainfall could lead to flash, urban, and small stream flooding, along with possible rapid river rises and potential mudslides in the Dominican Republic.
  • 3. There is a risk of wind and rainfall impacts elsewhere in portions of Hispaniola, the Bahamas, and Cuba during the next few days, although the forecast is more uncertain than usual since Fred is forecast to interact with Hispaniola through tonight.
  • 4. There is an increasing risk of wind and rainfall impacts in Florida beginning Friday night or early Saturday in the Keys and spreading northward through portions of the Peninsula and the Panhandle Saturday through Monday. Beginning Friday, heavy rainfall could lead to areal, urban, and small stream flooding, and possible rapid river rises across southern Florida. Interests throughout Florida should monitor Fred’s progress and check updates to the forecast.
FORECAST POSITIONS AND MAX WINDS

INIT  11/2100Z 18.9N  71.0W   35 KT  40 MPH - Tropical Storm (WNW Los Frios,DR)
 12H  12/0600Z 19.8N  72.7W   30 KT  35 MPH - Depression (ENE Mayombe,Haiti)
 24H  12/1800Z 20.9N  75.0W   30 KT  35 MPH - Depression (WNW Moa,Cuba)
 36H  13/0600Z 21.9N  77.1W   35 KT  40 MPH - Tropical Storm (WNW La Boca,Cuba)
 48H  13/1800Z 22.9N  79.2W   35 KT  40 MPH - Tropical Storm (ENE Cayo Fragoso,Cuba)
 60H  14/0600Z 23.9N  80.6W   40 KT  45 MPH - Tropical Storm (ENE Varadero,Cuba)
 72H  14/1800Z 25.3N  82.0W   40 KT  45 MPH - Tropical Storm (WNW Key West,FL)
 96H  15/1800Z 28.5N  84.0W   50 KT  60 MPH - Tropical Storm (WNW Hudson,FL)
120H  16/1800Z 31.0N  85.0W   45 KT  50 MPH - Tropical Storm (ESE Marianna,FL)

NWS National Hurricane Center Miami FL 1100 AM AST Wed Aug 11, 2021

Morning satellite imagery and reports from a NOAA Hurricane Hunter aircraft indicate that the circulation of Fred has become better defined south of the eastern Dominican Republic. The NOAA plane reported maximum flight-level winds of 40-45 kt, and SFMR winds of up to 50 kt, although these were measured near the coast and the reliability is unknown. The central pressure is near 1006 mb. Based on these data and a dropsonde northeast of the center, the initial intensity is increased to 40 kt. The low-level center is partly exposed near the western edge of the convection, which has decreased in coverage since yesterday.

The center has been moving more westward for the past few hours. However, the longer term motion is 290/14. There is no change in the track forecast philosophy since the previous advisory. Fred should continue moving generally west-northwestward for the next 72 h or so, followed by a turn toward the northwest as the cyclone nears the western periphery of the ridge. The new forecast track is little changed from the previous advisory and lies near the various consensus models. However, some adjustments to the track may be necessary as the center interacts with the mountains of Hispaniola during the next 12-24 hours.

Fred is now in an environment of 15-20 kt of westerly vertical shear produced in part by an upper-level trough near the Florida Peninsula, and the global models suggests that moderate shear should persist for at least the next 48-60 h. This, combined with land interaction, should cause Fred to weaken as it crosses Hispaniola, and then at best slowly re-intensify after it emerges over the water. After that time, the global models suggest the trough should weaken as a large upper-level anticyclone forms near or just southeast of Fred. This evolution could let the shear decrease a little and allow a little more strengthening, particularly when Fred is over the Gulf of Mexico. The new intensity forecast is similar to the previous forecast and follows the overall trend of the intensity guidance.

KEY MESSAGES:

  • 1. Tropical storm conditions are spreading across portions of the Dominican Republic. Tropical storm conditions are possible in northern Haiti and the southeastern Bahamas by late today, and in portions of Cuba by tonight.
  • 2. Heavy rainfall could lead to flash, urban, and small stream flooding, along with possible rapid river rises and the potential for mudslides in the Dominican Republic. Heavy rainfall could lead to flash, urban, and small stream flooding, along with possible rapid river rises across southern Florida.
  • 3. There is a risk of wind and rainfall impacts elsewhere in portions of Hispaniola, the Bahamas, and Cuba during the next few days, although the forecast is more uncertain than usual since Fred is forecast to interact with Hispaniola today and tonight. Interests in these areas should monitor Fred’s progress and updates to the forecast.
  • 4. There is an increasing risk of wind and rainfall impacts in Florida beginning Friday night or early Saturday in the Keys and spreading northward through portions of the Peninsula and the Panhandle Saturday through Monday. Interests throughout Florida should monitor Fred’s progress and check updates to the forecast.
FORECAST POSITIONS AND MAX WINDS

INIT  11/1500Z 18.2N  69.7W   40 KT  45 MPH - Tropical Storm (ESE Santo Domingo,DR)
 12H  12/0000Z 19.2N  71.4W   30 KT  35 MPH - Depression (WSW Sabaneta,DR)
 24H  12/1200Z 20.3N  73.7W   30 KT  35 MPH - Depression (ESE Baracoa,Cuba)
 36H  13/0000Z 21.4N  76.0W   35 KT  40 MPH - Tropical Storm (ENE Gibara,Cuba)
 48H  13/1200Z 22.3N  78.1W   35 KT  40 MPH - Tropical Storm (WSW Cayo Romano,Cuba)
 60H  14/0000Z 23.3N  79.9W   40 KT  45 MPH - Tropical Storm (ENE Cayo Hicacal,Cuba)
 72H  14/1200Z 24.6N  81.4W   40 KT  45 MPH - Tropical Storm (WSW Little Torch Key,FL)
 96H  15/1200Z 27.5N  83.5W   50 KT  60 MPH - Tropical Storm (WSW St Petersburgh,FL)
120H  16/1200Z 30.5N  85.5W   55 KT  65 MPH - Tropical Storm (WNW Fountain,FL)

NWS National Hurricane Center Miami FL 1100 PM AST Tue Aug 10, 2021 

Data from satellites, the San Juan NOAA Doppler weather radar, and an Air Force Reserve Unit reconnaissance aircraft indicate that the low-level circulation has become better defined since the previous advisory and,thus, the disturbance has been upgraded to Tropical Storm Fred. Although the surface and low-level circulations are vertically aligned, radar data indicate that the mid-level circulation is still tilted about 40 n mi to the south. However, that mid-level feature has been steadily gaining ground from its earlier 100-nmi southeastward displacement. Radar Doppler velocity data, aircraft 850-mb flight-level wind data of 43 kt and SFMR surface winds of 33 kt, plus earlier surface observations of sustained 33-kt winds, support an initial intensity of 35 kt.

The initial motion estimate is westward or 270/15 kt. However, this should be a short-term motion overnight due to interaction with the mountainous terrain of Puerto Rico to the north. By early Wednesday morning, Fred is expected to resume a west-northwestward motion and pass through the Mona Passage, reaching the eastern Dominican Republic shortly after sunrise. A strong subtropical ridge to the north of the cyclone is forecast by the global models to basically remain static across the central and western Atlantic Ocean for the next five days. Given this pattern, Fred is expected to maintain a west-northwestward motion through 96 hours, remaining just offshore the north coast of Haiti and Cuba during that time. After emerging over the southeastern Gulf of Mexico on day 4, Fred is forecast to gradually turn more north-northwestward as the cyclone rounds the southwestern periphery of the aforementioned ridge. The latest NHC track forecast models strongly support this track scenario, although there was a slight northward shift in the guidance envelope on this cycle. The new official track forecast was shifted a little north of the previous one through 72 hours, and then lies down the middle of the tightly packed track consensus models.

Conditions remain favorable for some strengthening before Fred reaches Hispaniola in about 12 h, but the intensity likely won’t be much stronger than 40-45 kt at landfall. Interaction with the mountainous terrain of Hispaniola on Wednesday should result in some weakening, but tropical-storm-force winds could occur along the the north coast of the island if the center shifts a little more to right of the forecast track. After emerging back over water by late Wednesday, only slow strengthening is forecast in the 36-60-h time period due to westerly vertical wind shear of about 20 kt expected to affect the cyclone. On days 4 and 5, however, Fred is expected to be moving over warmer sea-surface temperatures and into a much weaker wind shear regime, which would favor more robust strengthening. As a result, some of the regional and statistical- dynamical intensity models bring Fred near or to hurricane strength during that time. However, there is uncertainty Fred’s structure after interaction with Hispaniola and possibly Cuba, and continued disagreement between the global models on how the upper-level wind flow pattern near the cyclone will evolve, which ranges from favorable anticyclonic outflow to strong southwesterly shear. Given these factors, the NHC intensity forecast was only nudged slightly higher than the previous advisory, and lies between the consensus models HCCA and IVCN, and the SHIPS and LGEM models.

KEY MESSAGES:

  • 1. Tropical storm conditions are expected in portions of the U.S. Virgin Islands and Puerto Rico tonight, and are expected to begin in the Dominican Republic Wednesday morning. Tropical storm conditions are possible in northern Haiti and the southeastern Bahamas by late Wednesday.
  • 2. Heavy rainfall could lead to flash, urban, and small stream flooding, along with possible rapid river rises and the potential for mudslides across the U.S. Virgin Islands, Puerto Rico, and the Dominican Republic. The greatest threat for flooding impacts will be across eastern and southern Puerto Rico.
  • 3. There is a risk of wind and rainfall impacts elsewhere in portions of Hispaniola, the Bahamas, and Cuba during the next several days, although the forecast is more uncertain than usual since Fred is forecast to interact with Hispaniola on Wednesday. Interests in these areas should monitor Fred’s progress and updates to the forecast.
  • 4. There is a risk of wind and rainfall impacts in Florida beginning Friday in the Keys and spreading northward through portions of the Peninsula and the Panhandle this weekend. However, it is too soon to determine the exact timing, location, and magnitude of any potential impacts. Interests throughout Florida should monitor Fred’s progress and check updates to the forecast.
FORECAST POSITIONS AND MAX WINDS

INIT  11/0300Z 17.4N  66.8W   35 KT  40 MPH - Tropical Storm (WSW Ponce,Puerto Rico)
 12H  11/1200Z 18.6N  68.9W   40 KT  45 MPH - Tropical Storm (WSW Batey Cuchilla,DR)
 24H  12/0000Z 19.9N  71.4W   35 KT  40 MPH - Tropical Storm (WSW Villa Vásquez,DR)
 36H  12/1200Z 20.9N  73.7W   35 KT  40 MPH - Tropical Storm (WSW Matthew Town,Bahamas)
 48H  13/0000Z 21.8N  76.0W   35 KT  40 MPH - Tropical Storm (WSW Duncan Town,Bahamas)
 60H  13/1200Z 22.8N  78.0W   35 KT  40 MPH - Tropical Storm (ENE Cayo Coco,Cuba)
 72H  14/0000Z 23.8N  79.9W   40 KT  45 MPH - Tropical Storm (ESE Key West,FL)
 96H  15/0000Z 26.5N  82.8W   45 KT  50 MPH - Tropical Storm (WNW Captiva,FL)
120H  16/0000Z 29.3N  84.6W   55 KT  65 MPH - Tropical Storm (ESE St George Island,FL)

NWS National Hurricane Center Miami FL 500 PM AST Tue Aug 10, 2021

Corrected speed of motion in second paragraph.

Satellite imagery this afternoon continues to show that the disturbance has an organized convective pattern, with satellite intensity estimates of tropical-storm strength from SAB and TAFB. However, the circulation still appears to not be well defined, with the San Juan WSR-88D Doppler radar showing multiple mid-level centers and several convective cells with small-scale rotation. Based on this, the system will not be upgraded to a tropical cyclone at this time. The initial intensity remains 30 kt based on mainly on continuity from earlier data. It should be noted that squalls with short-lived winds to tropical-storm force have been reported in bands over the northern Leeward Islands.

The initial motion remains west-northwestward or 295/15 kt. A strong low- to mid-level ridge to the north should steer the system generally west-northwestward for the next 72 h with some decrease in forward speed after 24 h. Beyond that time, a turn toward the northwest with an further decrease in forward speed is likely while the system moves near the western periphery of the ridge. There has been some increase in the spread of the track guidance from 72-120 h, with the GFS shifting to the right and the other models not changing very much. The new NHC forecast track has only minor changes from the previous one and lies near the various consensus models.

Conditions continue to appear favorable for strengthening before the system reaches Hispaniola in about 18 h, although there may be dry air entraining into the system in the southeastern quadrant. The intensity forecast will follow the previous prediction in calling for the disturbance to become a tropical storm before landfall, followed by weakening to a depression. From 24-60 h, the models have come into better agreement that the system will encounter westerly vertical wind shear, and based on that and the possibility of land interaction the intensity forecast shows little re-intensification during that time. After 60 h, the models still disagree on the evolution of the upper-level winds near the system, but they are in better agreement that conditions over the eastern Gulf will become more conducive for development. Thus, the intensity forecast calls for intensification during that time. The new intensity forecast is almost the same as the previous one.

KEY MESSAGES:

  • 1. The system is forecast to become a tropical storm as it moves over the northeastern Caribbean Sea tonight. Tropical storm conditions are expected in portions of the U.S. Virgin Islands and Puerto Rico tonight, and are expected to begin in the Dominican Republic by Wednesday. Tropical storm conditions are possible in northern Haiti and the southeastern Bahamas by late Wednesday.
  • 2. Heavy rainfall could lead to flash, urban, and small stream flooding, along with possible rapid river rises and the potential for mudslides across the U.S. Virgin Islands, Puerto Rico, and the Dominican Republic. The greatest threat for flooding impacts will be across the eastern and southern portions of Puerto Rico.
  • 3. There is a risk of wind and rainfall impacts elsewhere in portions of Hispaniola, the Bahamas, and Cuba during the next several days, although the forecast is more uncertain than usual since the system is still in its formative stage. Interests in these areas should monitor the system’s progress and updates to the forecast.
  • 4. There is a risk of wind and rainfall impacts in portions of Florida beginning Friday through the weekend. However, given the uncertainty in the long-range forecast it is too soon to determine the timing, location, and magnitude of any potential impacts. Interests in Florida should monitor updates to the forecast.
FORECAST POSITIONS AND MAX WINDS

INIT  10/2100Z 16.9N  65.5W   30 KT  35 MPH - Depression (ESE Guayama,Puerto Rico)
 12H  11/0600Z 17.8N  67.8W   35 KT  40 MPH - Tropical Storm (WSW Isla de Mona,PR)
 24H  11/1800Z 19.0N  70.4W   35 KT  40 MPH - Tropical Storm (ENE Bonao,DR)
 36H  12/0600Z 20.2N  72.8W   30 KT  35 MPH - Depression (ESE Pointe Quest,Haiti)
 48H  12/1800Z 21.2N  75.0W   30 KT  35 MPH - Depression (WNW Moa,Cuba)
 60H  13/0600Z 22.1N  77.2W   35 KT  40 MPH - Tropical Storm (ENE Versailles,Cuba)
 72H  13/1800Z 23.1N  79.1W   35 KT  40 MPH - Tropical Storm (WSW Cayo Fragoso,Cuba)
 96H  14/1800Z 25.5N  82.5W   40 KT  45 MPH - Tropical Storm (WSW Marco Island,FL)
120H  15/1800Z 28.5N  84.5W   50 KT  60 MPH - Tropical Storm (WNW Spring Hill,FL)

NWS National Hurricane Center Miami FL 1100 AM AST Tue Aug 10, 2021 

Satellite imagery shows that the disturbance has become better organized since yesterday, and satellite intensity estimates from TAFB and SAB are at tropical storm strength. However, reports from a NOAA Hurricane Hunter aircraft and surface observations indicate that the system does not yet have a well-defined closed circulation, with the wind and pressure fields more resembling an open wave, The maximum flight-level winds at 925 mb were 35-40 kt, and reliable SFMR wind estimates were near 30 kt. Based on these data, the system remains at potential tropical cyclone status with an initial intensity of 30 kt.

The initial motion remains west-northwestward or 295/16 kt. A strong low- to mid-level ridge to the north should steer the system generally west-northwestward for the next 72 h with some decrease in forward speed after 24 h. Beyond that time, a turn toward the northwest with an further decrease in forward speed is likely while the system moves near the western periphery of the ridge. The track guidance has changed little since the previous advisory. So, the new NHC track also has little change, and it lies near the various consensus models. Users are reminded that the average track errors at days 4 and 5 are 175 miles and 200 miles, respectively.

Conditions continue to appear favorable for strengthening before the system reaches Hispaniola in about 24 h, although there may be dry air entraining into the system in the southeastern quadrant. The intensity forecast will follow the previous prediction in calling for the disturbance to become a tropical storm before landfall, followed by weakening to a depression. The remainder of the intensity forecast has lower confidence due to possible land interaction with Cuba and differences in the upper-level wind forecasts among the various global models. The new intensity forecast will call for slow intensification from 60 h onward, similar to the previous one.

KEY MESSAGES:

  • 1. The system is forecast to become a tropical storm as it moves over the northeastern Caribbean Sea today or tonight Tropical storm conditions are expected in portions of the U.S. Virgin Islands and Puerto Rico beginning this afternoon, and in the Dominican Republic by Wednesday. Tropical storm conditions are possible in northern Haiti and the southeastern Bahamas by late Wednesday.
  • 2. Heavy rainfall could lead to flash, urban, and small stream flooding, along with possible rapid river rises and the potential for mudslides across the U.S. Virgin Islands and Puerto Rico. The greatest threat for flooding impacts will be across the eastern and southern portions of Puerto Rico.
  • 3. There is a risk of wind and rainfall impacts elsewhere in portions of Hispaniola, the Bahamas, and Cuba later this week, although the forecast is more uncertain than usual since the system is still in its formative stage. Interests in these areas should monitor the system’s progress and updates to the forecast.
  • 4. Interests in Florida should monitor updates to the forecast for this system, but it is too soon to determine what if any impacts could occur there by late this week or this weekend given the uncertainty in the long-range forecast.
FORECAST POSITIONS AND MAX WINDS

INIT  10/1500Z 16.3N  63.8W   30 KT  35 MPH - Depression (ENE Deshaies, Guadeloupe)
 12H  11/0000Z 17.3N  66.1W   35 KT  40 MPH - Tropical Storm (ESE Ponce, Puerto Rico)
 24H  11/1200Z 18.5N  68.9W   40 KT  45 MPH - Tropical Storm (WNW Batey Santoni, DR)
 36H  12/0000Z 19.6N  71.4W   30 KT  35 MPH - Depression (WSW Guayubín, DR)
 48H  12/1200Z 20.7N  73.9W   30 KT  35 MPH - Depression (WSW Matthew Town, Bahamas)
 60H  13/0000Z 21.7N  76.0W   35 KT  40 MPH - Tropical Storm (WSW Gibara, Cuba)
 72H  13/1200Z 22.7N  78.1W   35 KT  40 MPH - Tropical Storm (ENE Cayo Coco, Cuba)
 96H  14/1200Z 25.0N  82.0W   40 KT  45 MPH - Tropical Storm (WSW Key West, FL)
120H  15/1200Z 27.5N  84.0W   50 KT  60 MPH - Tropical Storm (WSW Clearwater, FL)

NWS National Hurricane Center Miami FL 1100 PM AST Mon Aug 09, 2021 

The disturbance is now very near the Leeward Islands and it is expected to produce gusty winds and heavy rains across portions of those islands during the next several hours. Satellite and radar data indicate that deep convection continues to gradually organize in curved bands across the northern half of the circulation, but the system still seems to lack a well-defined center. Therefore, the disturbance remains a potential tropical cyclone for now. The initial intensity is held at 30 kt based on Dvorak estimates from TAFB and SAB.

The system is moving west-northwestward at about 14 kt. The main steering feature for the system will continue to be the subtropical ridge that is situated to its north across the central and western Atlantic. The flow on the south side of the ridge should keep the depression moving relatively briskly to the west-northwest during the next couple of days, taking it across the Leeward Islands overnight, near or over the U.S. Virgin Islands and Puerto Rico Tuesday and Tuesday night, and then near or over Hispaniola on Wednesday. Beyond that time, the storm is forecast to gradually slow down, when it nears the southwestern portion of the ridge, as it moves near Cuba and the Bahamas late this week. By the weekend, most of the models show the depression reaching a weakness in the ridge, which will likely cause a gradual turn to the right near the Florida Keys or southern Florida. The models are in quite good agreement, especially during the next 3 or 4 days, and the NHC track forecast lies near the various consensus models. Users are reminded that the average track errors at days 4 and 5 are 175 miles and 200 miles, respectively.

The disturbance is currently in conducive conditions for intensification with the cyclone currently over fairly warm 28 C waters and in low wind shear conditions. The only negative factor for the storm is some dry air in its vicinity. Overall, these environmental factors, and the model guidance, support strengthening during the next 24 hours or so, but the potential land interaction with Puerto Rico could limit the amount of intensification. By Wednesday, the potential land interaction with the mountainous island of Hispaniola and an increase in westerly shear should cause some weakening. However, the environmental conditions could become more favorable for strengthening again by the end of the week, which is the reason why the forecast shows slightly higher wind speeds at those time periods. The NHC intensity forecast generally follows the IVCN and HCCA models, which are typically the most skillful aids. It should be noted that the intensity forecast is of low confidence since the cyclone’s future strength will be quite dependent on the exact track and the degree of land interaction.

KEY MESSAGES:

  • 1. The system is forecast to become a tropical storm as it moves through the Leeward Islands tonight, and tropical storm conditions are possible there. Tropical storm conditions are expected in portions of the U.S. Virgin Islands and Puerto Rico beginning Tuesday afternoon, and in the Dominican Republic by Wednesday. Tropical storm conditions are possible in northern Haiti by late Wednesday.
  • 2. Heavy rainfall could lead to flash, urban, and small stream flooding and potential mudslides across the U.S. Virgin Islands and Puerto Rico. The greatest threat for flooding impacts will be across the eastern and southeastern portions of Puerto Rico.
  • 3. There is a risk of wind and rainfall impacts elsewhere in portions of Hispaniola, the Turks and Caicos, the southeastern Bahamas, and Cuba later this week, although the forecast is more uncertain than usual since the system is still in its formative stage. Interests in these areas should monitor the system’s progress and updates to the forecast.
  • 4. Interests in the remainder of the Bahamas and Florida should monitor updates to the forecast for this system, but it is too soon to determine what if any impacts could occur there by late this week or this weekend given the uncertainty in the long-range forecast.
FORECAST POSITIONS AND MAX WINDS

INIT  10/0300Z 15.1N  60.8W   30 KT  35 MPH - Depression (ENE Bridgetown, Barbados)
 12H  10/1200Z 16.2N  63.1W   35 KT  40 MPH - Tropical Storm (WSW Deshaies, Guadeloupe )
 24H  11/0000Z 17.5N  66.0W   45 KT  50 MPH - Tropical Storm (WSW Guayama, Puerto Rico)
 36H  11/1200Z 18.7N  68.8W   40 KT  45 MPH - Tropical Storm (WNW Higüey, DR)
 48H  12/0000Z 19.9N  71.5W   35 KT  40 MPH - Tropical Storm (ENE Monte Cristi, DR)
 60H  12/1200Z 20.9N  74.0W   35 KT  40 MPH - Tropical Storm (WSW Matthew Town, Bahamas)
 72H  13/0000Z 21.7N  76.1W   35 KT  40 MPH - Tropical Storm (WSW Gibara, Cuba)
 96H  14/0000Z 23.4N  79.9W   40 KT  45 MPH - Tropical Storm (ENE Varadero, Cuba)
120H  15/0000Z 26.1N  82.4W   45 KT  50 MPH - Tropical Storm (WSW Naples, FL)

NWS National Hurricane Center Miami FL 500 PM AST Mon Aug 09, 2021 

Deep convection associated with the area of low pressure located northeast of Barbados has continued to consolidate this afternoon, with several bands noted in both satellite and radar data from Barbados and Martinique. ASCAT data from this morning revealed a sharp trough axis, but the system lacked a well-defined circulation. However, recent visible satellite imagery hints that a better defined center may be forming just southwest of the primary convective mass. These trends suggest the system is likely to become a tropical depression or storm tonight or Tuesday when it moves near the Lesser Antilles and into the eastern Caribbean. Therefore, advisories are being initiated on the system in order to issue Tropical Storm Watches for portions of the Lesser Antilles, the U.S. Virgin Islands, Puerto Rico and parts of the Dominican Republic.

Since the system is still in its formative stage the initial motion estimate is a somewhat uncertain 290/13 kt. A mid-tropospheric ridge anchored over the western Atlantic should steer the system west-northwestward through the forecast period. Although there is high confidence in the overall steering pattern over the next several days, there is lower than normal confidence in the details of the track forecast, especially in the short-range due to the lack of a well-defined center. Exactly where the center forms will have some downstream implications on the exact forecast track, especially across the eastern Caribbean. Regardless of the exact track, locally heavy rainfall and gusty winds are expected to spread across portions of the Leeward Islands, the Virgin Islands, Puerto Rico, and the Dominican Republic over the next day or two, hence the need for Tropical Storm Watches for portions of those areas.

The disturbance is embedded within an area of low vertical wind shear and SSTs of around 28C. These conditions favor additional development, but the occasional entrainment of dry mid-level air located just west of the system is likely to prevent more rapid organization. By Wednesday, the system is likely to be near Hispaniola, where subtle differences in the forecast track could have large implications on the intensity of the storm later this week. A track directly over Hispaniola would likely significantly disrupt the circulation, while a track more poleward of the island could allow the system to stay more intact. An additional caveat beyond 48 hours is that vertical wind shear out of the southwest may also increase, which could limit the intensity after the system moves past Hispaniola, although uncertainty exists in how much the shear will increase given differences between the more favorable ECMWF and less favorable GFS model solutions. The NHC intensity forecast brings the system up to a 45 kt tropical storm before potential land interaction with Hispaniola and afterwards is conservative given the possibility of additional land interaction and less favorable environmental conditions towards the end of the forecast period.

KEY MESSAGES:

  • 1. The system is forecast to become a tropical storm as it moves through the Lesser Antilles tonight. Tropical storm conditions are possible in portions of the southern Leeward Islands tonight and Tuesday and in the Virgin Islands and Puerto Rico beginning Tuesday afternoon, and in the Dominican Republic by Wednesday.
  • 2. Heavy rainfall could lead to flash, urban, and small stream flooding and potential mudslides across the U.S. Virgin Islands and Puerto Rico. The greatest threat for flooding impacts will be across the eastern and southeastern portions of Puerto Rico.
  • 3. There is a risk of wind and rainfall impacts in portions of Hispaniola, the Turks and Caicos, the southeastern Bahamas, and Cuba later this week, although the forecast is more uncertain than usual since the system is still in its formative stage. Interests in these areas should monitor the system’s progress and updates to the forecast.
  • 4. Interests in the remainder of the Bahamas and Florida should monitor updates to the forecast for this system, but it is too soon to determine what if any impacts could occur there by late this week or this weekend given the uncertainty in the long-range forecast.
FORECAST POSITIONS AND MAX WINDS

INIT  09/2100Z 14.2N  59.2W   30 KT  35 MPH - Depression (ENE Bridgetown, Barbados)
 12H  10/0600Z 15.4N  61.4W   35 KT  40 MPH - Tropical Storm (WNW Warner, Dominica)
 24H  10/1800Z 16.8N  64.5W   40 KT  45 MPH - Tropical Storm (WSW Frederiksted, USVI)
 36H  11/0600Z 17.9N  67.3W   45 KT  50 MPH - Tropical Storm (WSW Cabo Rojo, PR)
 48H  11/1800Z 19.2N  70.2W   35 KT  40 MPH - Tropical Storm (WNW Las Guáranas, DR)
 60H  12/0600Z 20.3N  72.8W   35 KT  40 MPH - Tropical Storm (ESE Baracoa, Cuba)
 72H  12/1800Z 21.1N  75.0W   35 KT  40 MPH - Tropical Storm (WNW Moa, Cuba)
 96H  13/1800Z 22.8N  78.8W   40 KT  45 MPH - Tropical Storm (WSW Cayo Guillermo, Cuba)
120H  14/1800Z 24.5N  82.0W   40 KT  45 MPH - Tropical Storm (WSW Key West, FL)

NWS National Hurricane Center Miami FL 800 AM EDT Mon Aug 9, 2021

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

  • 1. Showers and thunderstorms have become more concentrated this morning in association with a low pressure system located about 150 miles east of Barbados. Environmental conditions are expected to be conducive for additional development, and a tropical depression is likely to form later today or tonight while the low moves west-northwestward at 10 to 15 mph. The disturbance is forecast to reach portions of the Lesser Antilles tonight, then move near the Virgin Islands and Puerto Rico on Tuesday, and be near Hispaniola around the middle of this week. Tropical storm watches or warnings could be required today with shorter-than-normal lead times for portions of the Lesser Antilles, the Virgin Islands, and Puerto Rico. In addition, heavy rains and flooding are likely for the Leeward Islands, Virgin Islands, and Puerto Rico. Interests in those areas should monitor the progress of this system. * Formation chance through 48 hours…high…70 percent. * Formation chance through 5 days…high…70 percent.
  • 2. Disorganized showers and thunderstorms have changed little in association with an elongated low pressure area located several hundred miles east of the Lesser Antilles. Development of this system is becoming less likely during the next few days while it moves toward the west or west-southwest at around 10 mph. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…low…20 percent.

NWS National Hurricane Center Miami FL 800 PM EDT Sun Aug 8, 2021

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

  • 1. A low-pressure system located about 400 miles east-southeast of the Leeward Islands is producing disorganized showers and thunderstorms. However, environmental conditions are expected to be conducive for gradual development over the next few days, and a tropical depression could form while the low moves west-northwestward at about 15 mph. The disturbance is forecast to reach portions of the Lesser Antilles by late Monday, and then move near the Virgin Islands and Puerto Rico on Tuesday, and be near Hispaniola around the middle of this week. Tropical storm watches or warnings could be required with shorter-than-normal lead times for the Leeward Islands, Virgin Islands, and Puerto Rico. In addition, heavy rains and flooding are likely for the Leeward Islands, Virgin Islands, Puerto Rico. Interests in those areas should monitor the progress of this system. * Formation chance through 48 hours…medium…50 percent. * Formation chance through 5 days…medium…60 percent.
  • 2. Disorganized showers and thunderstorms have changed little in association with an elongated low pressure system located over the tropical Atlantic about midway between the Cabo Verde Islands and the Lesser Antilles. Although environmental conditions appear to be only marginally conducive for development, this system could still become a tropical depression later this week while it moves toward the west or west-southwest at around 10 mph. * Formation chance through 48 hours…low…30 percent. * Formation chance through 5 days…medium…40 percent.

NWS National Hurricane Center Miami FL 200 PM EDT Sun Aug 8, 2021

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

  • 1. An elongated area of low pressure located several hundred miles east of the Windward Islands continues to produce disorganized showers and thunderstorms. Environmental conditions are expected to be favorable to support some gradual development over the next few days, and this system could become a tropical depression while it moves west-northwestward at 10 to 15 mph. The disturbance is forecast to reach portions of the Lesser Antilles late Monday, and then move near the Virgin Islands and Puerto Rico on Tuesday, and near Hispaniola around the middle of this week. Interests in those areas should monitor the progress of this system, as it could bring locally heavy rainfall and gusty winds to portions of that area. * Formation chance through 48 hours…medium…40 percent. * Formation chance through 5 days…medium…50 percent.
  • 2. Showers and thunderstorms associated with an area of low pressure located over the tropical Atlantic about midway between the Cabo Verde Islands and the Lesser Antilles have diminished this morning. Although environmental conditions appear to be only marginally conducive for development, this system could still become a tropical depression later this week while it moves toward the west-southwest or west at around 10 mph. * Formation chance through 48 hours…low…30 percent. * Formation chance through 5 days…medium…40 percent.

NWS National Hurricane Center Miami FL 800 AM EDT Sun Aug 8, 2021

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

  • 1. An area of low pressure is producing disorganized showers and thunderstorms over the tropical Atlantic several hundred miles east of the Windward Islands. Environmental conditions are expected to be favorable to support some gradual development, and this system could become a tropical depression while it moves west- northwestward at 10 to 15 mph. The disturbance is forecast to reach portions of the Lesser Antilles late Monday and then move across the eastern Caribbean Sea and Greater Antilles through the middle of this week. Interests in those areas should monitor the progress of this system, as it could bring locally heavy rainfall and gusty winds to portions of that area. * Formation chance through 48 hours…low…30 percent. * Formation chance through 5 days…medium…40 percent.
  • 2. Showers and thunderstorms associated with an area of low pressure located over the tropical Atlantic about midway between the Cabo Verde Islands and the Lesser Antilles have become more concentrated since yesterday. Environmental conditions are expected to become a little more favorable for gradual development, and this system could become a tropical depression within the next few days. The system is forecast to move slowly toward the west-southwest or west during the next couple of days, and then move a little faster toward the west by mid-week. * Formation chance through 48 hours…low…30 percent. * Formation chance through 5 days…medium...40 percent.
  • 3. Showers and thunderstorms associated with a broad area of low pressure located about a hundred miles west of the southwesternmost Cabo Verde Islands have diminished since yesterday. Strong upper-level winds and cooler waters are expected to prevent the development of this system while it moves toward the west or west-northwest. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…near 0 percent.

NWS National Hurricane Center Miami FL 800 PM EDT Sat Aug 7, 2021

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

  • 1. Showers and thunderstorms associated with a broad area of low pressure located about a hundred miles southwest of the southwesternmost Cabo Verde Islands have been decreasing during the past several hours. Strong upper-level winds and cooler waters are expected to prevent significant development of this system while it moves toward the west or west-northwest at about 10 mph during the next few days. Regardless of development, locally heavy rainfall and gusty winds still are possible over portions of the westernmost Cabo Verde Islands through Sunday. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…low…20 percent.
  • 2. A small but well-defined area of low pressure located over the tropical Atlantic about a thousand miles west of the Cabo Verde Islands continues to produce limited shower activity. Environmental conditions are expected to become a little more favorable for gradual development over the next several days, and this system could become a tropical depression by the middle of next week. The system is forecast to drift toward the west-southwest or west during the next couple of days, and then move a little faster toward the west-northwest by mid-week. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…medium…40 percent.
  • 3. A surface trough of low pressure is producing disorganized showers and thunderstorms over the central tropical Atlantic several hundred miles east of the Windward Islands. Some gradual development of this system is possible while it moves west-northwestward at 10 to 15 mph, reaching portions of the Lesser Antilles late Monday and then moving across the eastern Caribbean Sea and Greater Antilles through the middle of next week. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…low…20 percent.

NWS National Hurricane Center Miami FL 800 AM EDT Sat Aug 7, 2021

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

  • 1. A broad area of low pressure located a couple hundred miles south of the Cabo Verde Islands is producing disorganized showers and thunderstorms. Although environmental conditions are only marginally conducive, some slow development of this system is possible during the next few days while the system moves west-northwestward to westward across the eastern and central tropical Atlantic at 10 to 15 mph. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…low...30 percent.
  • 2. A small but well-defined area of low pressure located over the eastern tropical Atlantic about a thousand miles west of the Cabo Verde Islands continues to produce limited shower activity. Some development of this low is possible while it drifts toward the west-southwest or west over the weekend and then moves a little faster toward the west-northwest over the central tropical Atlantic by the middle of next week. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…low…30 percent.
  • 3. A tropical wave located over the west-central tropical Atlantic is producing limited shower activity. Significant development of this system is not anticipated as it moves west-northwestward across the Lesser Antilles and eastern Caribbean Sea during the early to middle part of next week. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…10 percent.

NWS National Hurricane Center Miami FL 800 PM EDT Fri Aug 6, 2021

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

  • 1. A broad area of low pressure located a few hundred miles south of the Cabo Verde Islands is producing a large area of disorganized cloudiness and showers. Environmental conditions are expected to be somewhat conducive for development, and a tropical depression could form by the early to middle part of next week while the system moves west-northwestward to westward across the eastern and central tropical Atlantic at 10 to 15 mph. * Formation chance through 48 hours…low…30 percent. * Formation chance through 5 days…medium…50 percent.
  • 2. A small but well-defined area of low pressure located over the eastern tropical Atlantic about a thousand miles west of the Cabo Verde Islands is producing limited shower activity. Development of this system, if any, is expected to be slow to occur while it drifts toward the west-southwest or west over the central tropical Atlantic through the middle of next week and potentially interacts with the broader area of low pressure to its east. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…low…20 percent.
  • 3. A tropical wave located over the west-central tropical Atlantic is producing limited shower activity. Significant development of this system is not expected as it moves west-northwestward across the Lesser Antilles and eastern Caribbean Sea during the early to middle part of next week. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…10 percent.

NWS National Hurricane Center Miami FL 200 PM EDT Fri Aug 6, 2021

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

  • 1. A large area of disorganized cloudiness and showers located a few hundred miles south of the Cabo Verde Islands is associated with a tropical wave and an associated broad area of low pressure. Environmental conditions appear somewhat conducive for gradual development over the next several days, and a tropical depression could form late this weekend or early next week while the system moves generally west-northwestward across the tropical Atlantic. * Formation chance through 48 hours…low…30 percent. * Formation chance through 5 days…medium…60 percent.
  • 2. A tropical wave located over the west-central tropical Atlantic is producing limited shower activity. Development, if any, of this system is expected to be slow to occur as it moves west- northwestward and approaches the Lesser Antilles early next week. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…20 percent.

NWS National Hurricane Center Miami FL 800 AM EDT Fri Aug 6, 2021

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

  • 1. A large area of disorganized cloudiness and thunderstorms located a few hundred miles south of the Cabo Verde Islands is associated with a tropical wave interacting with a broader surface trough. Environmental conditions appear somewhat conducive for gradual development over the next several days, and a tropical depression could form late this weekend or early next week while the system moves generally west-northwestward across the tropical Atlantic. * Formation chance through 48 hours…low…30 percent. * Formation chance through 5 days…medium…60 percent.
  • 2. A trough of low pressure located over the central tropical Atlantic continues to produce some disorganized showers and thunderstorms. This system is expected to move slowly west-northwestward, and some slow development is possible early next week as it approaches the Lesser Antilles. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…20 percent.

NWS National Hurricane Center Miami FL 800 PM EDT Thu Aug 5, 2021

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

  • 1. A large area of disorganized showers and thunderstorms over western Africa and the far eastern tropical Atlantic is associated with a tropical wave. Environmental conditions appear somewhat conducive for gradual development, and a tropical depression is likely to form this weekend or early next week while the system moves generally west-northwestward across the eastern tropical Atlantic. * Formation chance through 48 hours…medium…40 percent. * Formation chance through 5 days…high…70 percent.
  • 2. A tropical wave located over the central tropical Atlantic continues to produce some disorganized showers and thunderstorms. This system is expected to move west-northwestward at 10 to 15 mph, and some slow development is possible early next week when it is expected to be near the Lesser Antilles. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low...20 percent.

NWS National Hurricane Center Miami FL 200 PM EDT Thu Aug 5, 2021

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

  • 1. A tropical wave near the west coast of Africa is producing a large area of disorganized showers and thunderstorms. The wave is expected to move off the coasts of Senegal, The Gambia, and Guinea-Bissau later tonight. Environmental conditions appear somewhat conducive for gradual development, and a tropical depression is likely to form over the eastern tropical Atlantic south of the Cabo Verde Islands by late Saturday or early Sunday while the system moves westward to west-northwestward at about 15 mph. * Formation chance through 48 hours…medium…40 percent. * Formation chance through 5 days…high...70 percent.
  • 2. A tropical wave located over the central tropical Atlantic continues to produce a broad area of disorganized showers and thunderstorms. Environmental conditions are expected to be marginally conducive for some slow development east of the Lesser Antilles by early next week while the disturbance moves west-northwestward at 10 to 15 mph. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low...20 percent.

NWS National Hurricane Center Miami FL 800 AM EDT Thu Aug 5, 2021

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

  • 1. A westward-moving tropical wave just inland over Africa is producing a large area of disorganized showers and thunderstorms. The wave is expected to move off of the west African coast later today. Environmental conditions appear somewhat conducive for gradual development, and a tropical depression could form over the eastern tropical Atlantic by late Sunday or early next week while the system moves westward to west-northwestward at about 15 mph. * Formation chance through 48 hours…low…20 percent. * Formation chance through 5 days…medium…60 percent.
  • 2. A tropical wave located over the central tropical Atlantic continues to produce a broad area of disorganized showers and thunderstorms. Environmental conditions are expected to be marginally conducive for some slow development east of the Lesser Antilles by early next week while the disturbance moves west-northwestward at 10 to 15 mph. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…20 percent.

NWS National Hurricane Center Miami FL 800 PM EDT Wed Aug 4, 2021

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

  • 1. A tropical wave located over the central tropical Atlantic is producing a broad area of disorganized showers and thunderstorms. Environmental conditions are expected to be marginally conducive for some slow development east of the Lesser Antilles by Sunday and into early next week while the disturbance moves west-northwestward at 10 to 15 mph. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…20 percent.
  • 2. A tropical wave is forecast to move off the west coast of Africa by late Thursday. Environmental conditions appear somewhat conducive for gradual development thereafter over the eastern tropical Atlantic through the weekend into early next week while the system moves westward to west-northwestward at about 15 mph. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…medium…40 percent.

NWS National Hurricane Center Miami FL 200 PM EDT Wed Aug 4, 2021

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

  • 1. A small low pressure area with limited shower and thunderstorm activity is meandering over or near the Cabo Verde Islands. Significant development of this system is not expected during the next day or so due to unfavorable environmental conditions. However, locally heavy rainfall and gusty winds will be possible over portions of the Cabo Verde Islands through today while the system moves little. Additional information on the low can be found in high seas forecasts issued by Meteo-France. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…near 0 percent.
  • 2. A tropical wave located over the central tropical Atlantic is producing a broad area of disorganized showers and thunderstorms. Environmental conditions are expected to be marginally conducive for some slow development east of the Lesser Antilles by Sunday and into early next week while the disturbance moves west-northwestward at 10 to 15 mph. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…20 percent.
  • 3. A tropical wave is forecast to move off of the west coast of Africa by late Thursday. Environmental conditions appear somewhat conducive for gradual development thereafter over the far eastern tropical Atlantic through the weekend into early next week while the system moves generally westward at about 15 mph. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…medium…40 percent.

NWS National Hurricane Center Miami FL 800 AM EDT Wed Aug 4, 2021

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

  • 1. A small and weak area of low pressure, with limited shower and thunderstorm activity, is passing near the Cabo Verde Islands. Significant development of this system is not expected during the next day or so due to unfavorable environmental conditions. Thereafter, this system is forecast to move northward or north-northwestward over cooler waters, ending its development chances. Locally heavy rainfall and gusty winds are possible over portions of the Cabo Verde Islands through today. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…near 0 percent.
  • 2. A tropical wave located over the central tropical Atlantic is producing a broad area of disorganized showers and thunderstorms. Environmental conditions are expected to be marginally conducive for some slow development east of the Lesser Antilles by Sunday and into early next week while the disturbance moves west-northwestward at 10 to 15 mph. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…20 percent.
  • 3. A tropical wave is forecast to move off the west coast of Africa by late Thursday. Environmental conditions appear somewhat conducive for some slow development over the far eastern Atlantic through the weekend into early next week while the system moves generally westward at about 15 mph. * Formation chance through 48 hours…low…near 0 percent. * Formation chance through 5 days…low…30 percent.

NWS National Hurricane Center Miami FL 800 PM EDT Mon Aug 2, 2021

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

  • 1. A surface trough of low pressure over the far eastern Atlantic Ocean located a few hundred miles south of the Cabo Verde Islands is producing disorganized showers and thunderstorms. Some slow development of this system is possible during the next couple of days while it moves northward or northwestward before the system moves over cool waters by Thursday. Locally heavy rainfall and gusty winds are possible over portions of the Cabo Verde Islands through Wednesday. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…low...20 percent.

NWS National Hurricane Center Miami FL 800 PM EDT Mon Aug 2, 2021

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

  • 1. A surface trough of low pressure over the far eastern Atlantic Ocean located a few hundred miles south of the Cabo Verde Islands is producing disorganized showers and thunderstorms. Some slow development of this system is possible during the next couple of days while it moves northward or northwestward before the system moves over cool waters by Thursday. Locally heavy rainfall and gusty winds are possible over portions of the Cabo Verde Islands through Wednesday. * Formation chance through 48 hours…low…10 percent. * Formation chance through 5 days…low…20 percent.

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