Home › discussion
 

Keywords :   


Tag: discussion

Hurricane Irma Forecast Discussion Number 38

2017-09-08 16:51:23| National Hurricane Center (Atlantic)

Issued at 1100 AM EDT Fri Sep 08 2017 000 WTNT41 KNHC 081451 TCDAT1 Hurricane Irma Discussion Number 38 NWS National Hurricane Center Miami FL AL112017 1100 AM EDT Fri Sep 08 2017 Recent data from both NOAA and Air Force reconnaissance planes indicate that Irma's intensity remains at 130 kt, although this value could be 5 kt higher or lower. The central pressure has been oscillating around 927 mb. The environment continues to be favorable for Irma to maintain its category 4 status, and only unpredictable eyewall replacement cycles could result in intensity fluctuations during the next 48 hours. Nevertheless, the NHC forecast brings Irma near south Florida as a category 4 hurricane. Thereafter, interaction with land and an increase in shear should induce gradual weakening. Plane, satellite and radar fixes from Cuba indicate that the eye of Irma is moving toward the west-northwest or 285 degrees at about 12 kt. The hurricane should continue on this track for the next 24 hours. After that time, Irma will reach the southwestern edge of the subtropical high and begin to turn north-northwestward and northward. This turn will occur, but the precise moment is still uncertain, and that is why NHC emphasizes that nobody should focus on the exact track of the center. The new NHC forecast was adjusted just a little bit westward and is on top the latest ECMWF model and the HFIP corrected consensus. In fact, these two aids are also very close to each other. KEY MESSAGES: 1. Irma is an extremely dangerous Category 4 hurricane and will continue to bring life-threatening wind, storm surge, and rainfall hazards to the Bahamas through Saturday. Hurricane conditions will spread over portions of the north coast of Cuba, especially over the adjacent Cuban Keys, through Saturday. 2. Irma is likely to make landfall in Florida as a dangerous major hurricane, and will bring life-threatening wind impacts to much of the state regardless of the exact track of the center. 3. There is the danger of life-threatening storm surge inundation in southern Florida and the Florida Keys during the next 36 hours, where a Storm Surge Warning is in effect. In particular, the threat of significant storm surge flooding along the southwest coast of Florida has increased, and 6 to 12 feet of inundation above ground level is possible in this area. This is a life-threatening situation. Everyone in these areas should take all actions to protect life and property from rising water and follow evacuation instructions from local officials. 4. Irma is expected to produce very heavy rain and inland flooding. Total rain accumulations of 4 to 12 inches, with isolated amounts of 20 inches are expected over the Florida peninsula Saturday through Monday. The highest amounts are expected over the eastern Florida peninsula and upper Florida Keys. Irma will likely bring periods of heavy rain to much of Georgia, South Carolina, and western North Carolina early next week, including some mountainous areas which are more prone to flash flooding. All areas seeing heavy rainfall from Irma will experience a risk of flooding and flash flooding. FORECAST POSITIONS AND MAX WINDS INIT 08/1500Z 22.0N 75.3W 130 KT 150 MPH 12H 09/0000Z 22.4N 77.1W 130 KT 150 MPH 24H 09/1200Z 22.8N 79.0W 130 KT 150 MPH 36H 10/0000Z 23.7N 80.3W 130 KT 150 MPH 48H 10/1200Z 25.0N 81.0W 125 KT 145 MPH...NEAR THE COAST 72H 11/1200Z 29.3N 82.3W 65 KT 75 MPH...INLAND 96H 12/1200Z 34.0N 85.0W 30 KT 35 MPH...INLAND 120H 13/1200Z 36.0N 87.0W 25 KT 30 MPH...INLAND $$ Forecaster Avila

Tags: number discussion forecast hurricane

 

Hurricane Katia Forecast Discussion Number 12

2017-09-08 16:40:35| National Hurricane Center (Atlantic)

Issued at 1000 AM CDT Fri Sep 08 2017 000 WTNT43 KNHC 081440 TCDAT3 Hurricane Katia Discussion Number 12 NWS National Hurricane Center Miami FL AL132017 Issued by the NWS Weather Prediction Center College Park MD 1000 AM CDT Fri Sep 08 2017 Infrared imagery and a GPM microwave composite data indicate improved banding over the western portion of the circulation with visible pictures showing the formation of a ragged eye. Subjective Dvorak satellite intensity estimates from TAFB and SAB both supported 80 kt winds earlier, and aircraft data suggested that Katia has continued to intensify, so the initial intensity has been increased to 85 knots. Further strengthening is possible, and Katia could be approaching major hurricane intensity prior to landfall Saturday morning. After landfall, rapid weakening is expected, and Katia is forecast to dissipate over the rugged terrain of the Sierra Madre mountains after the 48 hour period. The initial motion estimate is 240/4 kt. A continued slow west-southwestward motion under the influence of a mid-latitude high extending east from Texas is forecast until the cyclone makes landfall and quickly dissipates. The official track forecast has changed little from the previous one, and remains roughly in the middle of the guidance. In addition to the hurricane-force winds, very heavy rains associated with Katia are expected to affect eastern Mexico. These rains are likely to cause life-threatening flash floods and mudslides. FORECAST POSITIONS AND MAX WINDS INIT 08/1500Z 21.0N 95.8W 85 KT 100 MPH 12H 09/0000Z 20.6N 96.4W 90 KT 105 MPH 24H 09/1200Z 19.7N 97.4W 45 KT 50 MPH...INLAND 36H 10/0000Z 19.1N 98.4W 25 KT 30 MPH...POST-TROP/INLAND 48H 10/1200Z...DISSIPATED $$ Forecaster Bann/Carbin

Tags: number discussion forecast hurricane

 
 

Hurricane Irma Forecast Discussion Number 37

2017-09-08 10:46:56| National Hurricane Center (Atlantic)

Issued at 500 AM EDT Fri Sep 08 2017 000 WTNT41 KNHC 080846 TCDAT1 Hurricane Irma Discussion Number 37 NWS National Hurricane Center Miami FL AL112017 500 AM EDT Fri Sep 08 2017 Microwave images and data from an Air Force Reserve Hurricane Hunter aircraft indicate that Irma is currently undergoing an eyewall replacement cycle. A recent GMI overpass showed an 50 nmi wide outer eyewall, with the inner eyewall weakening. The Hurricane Hunter aircraft reported peak 700-mb winds of 147 kt in the outer eyewall near 0500 UTC, and maximum SFMR winds were in the 125-130 kt range. Based on these data, the initial intensity is reduced to 135 kt. Irma is forecast to remain in a favorable warm water, light shear environment for the next 36-48 h. The intensity guidance shows a slow weakening during this time, but Irma is expected to remain at least a Category 4 hurricane until landfall in Florida. After landfall, a fairly quick decay in maximum winds is expected due to land interaction and increased shear, although Irma's large wind field is likely to still produce hurricane-force winds over a large area. There are two caveats to the intensity forecast. First, some additional weakening could occur during the eyewall replacement, followed by re-intensification as the cycle completes. Second, the ECMWF, UKMET, and NAVGEM forecast a track over or close to the coast of Cuba that is not currently a part of the track forecast. If this occurs, Irma could be weaker than currently forecast along the later parts of the track. The initial motion is west-northwestward or 285/14. Irma should maintain this general trajectory for the next 24-36 h as it moves along the southwestern side of the subtropical ridge. After that time, the guidance is in good agreement that the ridge should break and allow Irma to turn north-northwestward to northward. There remains some spread between the models on when the turn will occur, with the GFS/Canadian being on the eastern side of the guidance and the UKMET/NAVGEM on the left side. The ECMWF, Florida State Superensemble, and the HFIP Corrected consensus are in the middle of the guidance envelope, and the new track forecast is in best agreement with those models. Overall, the new forecast track is similar to the previous forecast, with minor westward adjustments at 36 and 48 h. KEY MESSAGES: 1. Irma is an extremely dangerous Category 4 hurricane and will continue to bring life-threatening wind, storm surge, and rainfall hazards to the Turks and Caicos Islands and the Bahamas through Saturday. Heavy rainfall is still possible across portions of Hispaniola through today. Hurricane conditions will also spread over portions of the north coast of Cuba, especially over the adjacent Cuban Keys through Saturday. 2. Severe hurricane conditions are expected over portions of the Florida peninsula and the Florida Keys beginning Saturday night. Irma is likely to make landfall in southern Florida as a dangerous major hurricane, and bring life-threatening storm surge and wind impacts to much of the state. A Hurricane Warning is in effect for southern Florida, the Florida Keys, Lake Okeechobee, and Florida Bay, while Hurricane Watches have been issued northward into central Florida. 3. A Storm Surge Warning is in effect for southern Florida and the Florida Keys. A Storm Surge Warning means there is a danger of life-threatening inundation, from rising water moving inland from the coastline, during the next 36 hours. This is a life-threatening situation. Persons located within these areas should take all necessary actions to protect life and property from rising water and the potential for other dangerous conditions. Promptly follow evacuation and other instructions from local officials. A Storm Surge Watch has been issued north of the Storm Surge Warning area for portions of the central Florida coast. 4. There is a chance of direct impacts in portions of Georgia, South Carolina, and North Carolina, but it is too early to specify the magnitude and location of these impacts. FORECAST POSITIONS AND MAX WINDS INIT 08/0900Z 21.7N 73.8W 135 KT 155 MPH 12H 08/1800Z 22.1N 75.7W 135 KT 155 MPH 24H 09/0600Z 22.6N 77.8W 135 KT 155 MPH 36H 09/1800Z 23.3N 79.4W 135 KT 155 MPH 48H 10/0600Z 24.5N 80.4W 130 KT 150 MPH 72H 11/0600Z 28.0N 81.5W 90 KT 105 MPH...INLAND 96H 12/0600Z 33.0N 84.0W 40 KT 45 MPH...INLAND 120H 13/0600Z 36.0N 87.0W 25 KT 30 MPH...INLAND $$ Forecaster Beven

Tags: number discussion forecast hurricane

 

Hurricane Jose Forecast Discussion Number 12

2017-09-08 10:38:56| National Hurricane Center (Atlantic)

Issued at 500 AM AST Fri Sep 08 2017 000 WTNT42 KNHC 080838 TCDAT2 Hurricane Jose Discussion Number 12 NWS National Hurricane Center Miami FL AL122017 500 AM AST Fri Sep 08 2017 Jose's satellite presentation has improved overnight. Cold cloud tops of -75C now surround the clearer and more distinct warming eye. The initial intensity is increased to 110 kt and is based on a compromise of the subjective and objective satellite intensity T-numbers and recent cloud pattern trends. Some increase in strength is still possible during the next day or so while the cyclone remains in a marginally conducive environment. Through the remainder of the forecast period, however, gradual weakening is expected due to an increase in northerly wind shear and an intruding drier more stable thermodynamic environment. The NHC forecast is close to the HWRF model through 48 hours, and then closely follows the IVCN multi-model consensus. The initial motion is estimated to be west-northwestward, or 285/14 kt. Large-scale models are quite similar on a subtropical ridge steering Jose west-northwestward during the next 48 hours, placing the cyclone very near the northern Leeward Islands tonight and Saturday. Through day 5, Jose is expected to move northwestward and then northward in response to a large amplitude mid-tropospheric trough approaching the tropical cyclone from the northwest. The new NHC track forecast is just an update of the previous package and is based on a blend of the HFIP Corrected Consensus model and the ECMWF. FORECAST POSITIONS AND MAX WINDS INIT 08/0900Z 16.0N 55.3W 110 KT 125 MPH 12H 08/1800Z 16.6N 57.3W 110 KT 125 MPH 24H 09/0600Z 17.3N 59.6W 105 KT 120 MPH 36H 09/1800Z 18.5N 61.6W 100 KT 115 MPH 48H 10/0600Z 20.0N 63.6W 95 KT 110 MPH 72H 11/0600Z 23.5N 67.2W 85 KT 100 MPH 96H 12/0600Z 26.4N 68.6W 75 KT 85 MPH 120H 13/0600Z 27.9N 67.9W 70 KT 80 MPH $$ Forecaster Roberts

Tags: number discussion jose forecast

 

Hurricane Katia Forecast Discussion Number 11

2017-09-08 10:38:28| National Hurricane Center (Atlantic)

Issued at 400 AM CDT Fri Sep 08 2017 000 WTNT43 KNHC 080838 TCDAT3 Hurricane Katia Discussion Number 11 NWS National Hurricane Center Miami FL AL132017 400 AM CDT Fri Sep 08 2017 Enhanced BD-curve infrared imagery and a GPM microwave composite image indicate improved banding over the western portion of the circulation and the earlier ragged eye presentation has become much more distinct. Subsequently, Dvorak satellite intensity estimates have increased along with the Objective ADT T-number, and the initial intensity is bumped up to 80 kt. Further strengthening is possible, and Katia could be near major hurricane intensity prior to landfall Saturday morning. After landfall, rapid weakening is expected, and Katia is forecast to dissipate over the rugged terrain of the Sierra Madre mountains after the 48 hour period. The initial motion estimate is west-southwestward, or 250/3 kt. A continued slow west-southwestward motion under the influence of a mid-latitude high extending east from Texas is forecast until the cyclone makes landfall and quickly dissipates. The official forecast has changed little from the previous one, and is based primarily on the HFIP Corrected Consensus multi-model. In addition to the hurricane-force winds, very heavy rains associated with Katia are expected to affect eastern Mexico. These rains could cause life-threatening flash floods and mudslides. FORECAST POSITIONS AND MAX WINDS INIT 08/0900Z 21.3N 95.4W 80 KT 90 MPH 12H 08/1800Z 21.0N 96.0W 85 KT 100 MPH 24H 09/0600Z 20.3N 97.0W 90 KT 105 MPH...INLAND 36H 09/1800Z 19.3N 98.2W 40 KT 45 MPH...INLAND 48H 10/0600Z...DISSIPATED $$ Forecaster Roberts

Tags: number discussion forecast hurricane

 

Sites : [687] [688] [689] [690] [691] [692] [693] [694] [695] [696] [697] [698] [699] [700] [701] [702] [703] [704] [705] [706] next »