Home › discussion
 

Keywords :   


Tag: discussion

Remnants of Fred Forecast Discussion Number 22

2021-08-15 04:48:46| National Hurricane Center (Atlantic)

Issued at 1100 PM EDT Sat Aug 14 2021 000 WTNT41 KNHC 150248 TCDAT1 Remnants Of Fred Discussion Number 22 NWS National Hurricane Center Miami FL AL062021 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 12H 15/1200Z 25.3N 85.7W 35 KT 40 MPH...TROPICAL CYCLONE 24H 16/0000Z 26.8N 86.9W 40 KT 45 MPH 36H 16/1200Z 28.3N 87.8W 45 KT 50 MPH 48H 17/0000Z 29.7N 88.0W 45 KT 50 MPH 60H 17/1200Z 31.4N 87.9W 30 KT 35 MPH...INLAND 72H 18/0000Z 33.1N 87.6W 20 KT 25 MPH...INLAND 96H 19/0000Z...DISSIPATED $$ Forecaster Brown

Tags: number discussion fred forecast

 

Tropical Storm Grace Forecast Discussion Number 6

2021-08-14 22:43:09| National Hurricane Center (Atlantic)

Issued at 500 PM AST Sat Aug 14 2021 000 WTNT42 KNHC 142043 TCDAT2 Tropical Storm Grace Discussion Number 6 NWS National Hurricane Center Miami FL AL072021 500 PM AST Sat Aug 14 2021 Grace is a poorly organized tropical storm this afternoon. The NOAA Hurricane Hunters were unable to close off a circulation, at least at their flight level of 5000 feet, but dropsonde observations and reports from some of the islands in the Lesser Antilles suggest that there's at least a broad cyclonic circulation at the surface. The various data also indicate that the center has sped up, or re-formed, and is located farther southwest than previously estimated. Based on the aircraft data and earlier ASCAT data, the initial intensity is set at 35 kt. Both the future track and intensity of Grace have a high level of uncertainty. For the track, the forecast is likely to be complicated by the fact that the system doesn't currently have a tight low-level circulation, and the center could always re-form at any time, especially with convection ongoing farther to the north. In addition, the storm has not yet slowed down, and in fact, the initial motion is estimated to be toward the west (275 degrees) at 23 kt. The guidance envelope has made a notable southward shift due to the adjustment of the initial position, and the models insist that Grace will primarily have a west-northwestward heading for much of the forecast period with the speed gradually decreasing during the next 48 hours or so. The NHC track forecast has been shifted southward accordingly, although any re-formations of the center could cause this track to shift again in future advisory cycles. If Grace slows down as forecast--which is obviously not a sure thing--environmental conditions should be conducive to allow for some strengthening before the system reaches the Greater Antilles. The southward adjustment in the official forecast now takes Grace over the Greater Antilles for a longer period of time, and the official intensity forecast is therefore lowered beyond 48 hours. This is a middle-of-the-road solution, and actually lower than most of the intensity guidance. If the forecast track shifts north or south, the system could strengthen further over water. Alternatively, Grace could go the way of Fred and dissipate before the end of the 5-day period. In the end, the exact track of the center and the intensity of the system will likely not be as important as the heavy rainfall that is forecast to fall across the Leeward Islands and the Greater Antilles during the next few days. Key Messages: 1. Tropical storm conditions are expected in portions of the Leeward Islands tonight, and the Virgin Islands and Puerto Rico on Sunday. Tropical storm conditions are possible over eastern parts of the Dominican Republic Sunday night and Monday. 2. Heavy rainfall could lead to flash and urban flooding over the Leeward and Virgin Islands. Across Puerto Rico, the Dominican Republic, and Haiti, heavy rainfall may lead to flash, urban and small stream flooding, along with the potential for mudslides. 3. There is a risk of wind and rainfall impacts across the rest of the Dominican Republic, Haiti, the Turks and Caicos Islands, the Bahamas, Cuba, and Florida next week, but forecast uncertainty remains higher than usual. Interests in those areas should monitor the progress of Grace and updates to the forecast. FORECAST POSITIONS AND MAX WINDS INIT 14/2100Z 15.9N 60.7W 35 KT 40 MPH 12H 15/0600Z 16.5N 63.3W 40 KT 45 MPH 24H 15/1800Z 17.1N 66.1W 45 KT 50 MPH 36H 16/0600Z 17.7N 68.5W 50 KT 60 MPH 48H 16/1800Z 18.3N 70.6W 50 KT 60 MPH...NEAR DOMINICAN REP. 60H 17/0600Z 19.2N 72.8W 40 KT 45 MPH...NEAR HAITI 72H 17/1800Z 20.2N 75.3W 40 KT 45 MPH...OVER CUBA 96H 18/1800Z 22.4N 80.1W 35 KT 40 MPH...OVER CUBA 120H 19/1800Z 24.8N 84.3W 45 KT 50 MPH...OVER WATER $$ Forecaster Berg

Tags: number discussion grace storm

 
 

Remnants of Fred Forecast Discussion Number 21

2021-08-14 22:39:58| National Hurricane Center (Atlantic)

Issued at 500 PM EDT Sat Aug 14 2021 040 WTNT41 KNHC 142039 TCDAT1 Remnants Of Fred Discussion Number 21 NWS National Hurricane Center Miami FL AL062021 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...DISTURBANCE 12H 15/0600Z 25.0N 85.7W 30 KT 35 MPH...TROPICAL CYCLONE 24H 15/1800Z 26.6N 87.1W 35 KT 40 MPH 36H 16/0600Z 28.0N 87.9W 40 KT 45 MPH 48H 16/1800Z 29.4N 88.2W 45 KT 50 MPH 60H 17/0600Z 30.9N 88.3W 35 KT 40 MPH...INLAND 72H 17/1800Z 32.4N 88.2W 25 KT 30 MPH...INLAND 96H 18/1800Z 36.0N 87.5W 20 KT 25 MPH...POST-TROP/INLAND 120H 19/1800Z...DISSIPATED $$ Forecaster Beven

Tags: number discussion fred forecast

 

Hurricane Linda Forecast Discussion Number 19

2021-08-14 22:32:45| Tropical Depression LIDIA

Issued at 200 PM PDT Sat Aug 14 2021

Tags: number discussion linda forecast

 

Tropical Storm Grace Forecast Discussion Number 5

2021-08-14 16:54:03| National Hurricane Center (Atlantic)

Issued at 1100 AM AST Sat Aug 14 2021 000 WTNT42 KNHC 141453 TCDAT2 Tropical Storm Grace Discussion Number 5 NWS National Hurricane Center Miami FL AL072021 1100 AM AST Sat Aug 14 2021 Grace is sending mixed signals on its intensity this morning. The storm has been producing persistent convective bursting since overnight, which would suggest that some strengthening has occurred. The latest subjective data-T numbers are 2.5 (35 kt) from TAFB and SAB, while objective satellite estimates are higher, roughly between 45-50 kt. Then, an ASCAT pass from 1302 UTC showed winds between 35-40 kt. Given these data, the initial intensity is set at 40 kt. A NOAA Hurricane Hunter aircraft is scheduled to investigate Grace this afternoon to provide a better estimate of the storm's intensity. Grace is speeding along toward the west (280 degrees) at 19 kt. Mid-level ridging, entrenched over the western Atlantic, is expected to weaken slightly during the next couple of days. This evolution should cause Grace to slow down to 10-15 kt by Sunday night and Monday and take on a west-northwestward heading. That general trajectory should continue through the end of the forecast period. The track guidance is tightly clustered during the first 48-60 hours or so, showing Grace moving near or across the Leeward Islands, Puerto Rico, and the Dominican Republic. On days 3-5, there is a little more spread, with a few models keeping the system on a southern track across Cuba while others show tracks across the Bahamas. The NHC track forecast splits this difference and continues to show a track running between Cuba and the Bahamas, very close to the HCCA consensus solution. Deep-layer shear is forecast to be 10 kt or less for the next 36 hours or so while Grace is approaching the islands of the Greater Antilles. The thermodynamic environment also appears conducive for strengthening, but the system's continued fast motion is likely to be an inhibiting factor on the rate of intensification. The NHC intensity forecast remains on the conservative side, bringing Grace's intensity up to 50 kt by the time the storm reaches the Virgin Islands and Puerto Rico, but it should be noted that this forecast is on the lower side of the guidance. Only one model, the HWRF, brings Grace to hurricane strength, but it does this by having the storm move farther north and avoid land interaction altogether. The intensity forecast is highly uncertain on days 3-5 since it depends on exactly how much Grace moves over the Greater Antilles, and there is some model signal that increasing northeasterly upper-level winds over the Bahamas and Florida could become a negative factor. Key Messages: 1. Tropical storm conditions are expected in portions of the Leeward Islands tonight and early Sunday, and the Virgin Islands and Puerto Rico on Sunday. Tropical storm conditions are possible over eastern parts of the Dominican Republic by early Monday. 2. Heavy rainfall could lead to flash and urban flooding over the Leeward and Virgin Islands. Across Puerto Rico and the Dominican Republic, heavy rainfall may lead to flash, urban and small stream flooding, along with the potential for mudslides. 3. There is a risk of wind and rainfall impacts across the rest of the Dominican Republic, Haiti, the Turks and Caicos Islands, the Bahamas, and Florida next week, and interests in those areas should monitor the progress of Grace and updates to the forecast. FORECAST POSITIONS AND MAX WINDS INIT 14/1500Z 16.2N 57.9W 40 KT 45 MPH 12H 15/0000Z 16.8N 60.6W 45 KT 50 MPH 24H 15/1200Z 17.5N 63.8W 50 KT 60 MPH 36H 16/0000Z 18.1N 66.4W 50 KT 60 MPH...OVER PUERTO RICO 48H 16/1200Z 18.6N 68.6W 50 KT 60 MPH...OVER DOMINICAN REP. 60H 17/0000Z 19.4N 70.7W 45 KT 50 MPH...OVER DOMINICAN REP. 72H 17/1200Z 20.5N 72.8W 45 KT 50 MPH...OVER WATER 96H 18/1200Z 22.8N 77.3W 45 KT 50 MPH 120H 19/1200Z 25.4N 81.2W 45 KT 50 MPH $$ Forecaster Berg

Tags: number discussion grace storm

 

Sites : [60] [61] [62] [63] [64] [65] [66] [67] [68] [69] [70] [71] [72] [73] [74] [75] [76] [77] [78] [79] next »