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Tropical Storm Eta Forecast Discussion Number 28
2020-11-07 16:01:19| National Hurricane Center (Atlantic)
Issued at 1000 AM EST Sat Nov 07 2020 000 WTNT44 KNHC 071501 TCDAT4 Tropical Storm Eta Discussion Number 28 NWS National Hurricane Center Miami FL AL292020 1000 AM EST Sat Nov 07 2020 Satellite imagery and surface data indicate that Eta has become a little better organized this morning, with the center re-forming to the northeast near an area of deep convection. Surface observations from Grand Cayman Island show that the system has regained tropical-storm strength, and the initial intensity is increased to 35 kt. The initial motion is uncertain dur to the reformation, with the best estimate of 055/15. This general motion should continue for the next 24 h or so as Eta is steered by a mid- to upper-level trough over the Gulf of Mexico. From 24-96 h, the trough is forecast to become a cut-off low, and Eta is expected to turn northward, northeastward, and eventually westward as it merges with the low. There remains some spread in the guidance in just where these turns will occur and how close the center will come to south Florida and the Florida Keys. This part of the new track is nudged just a little north of the previous track. After 96 h, Eta should move slowly across the eastern Gulf of Mexico, with the forecast track showing a northward motion as a compromise of the poorly-agreeing guidance. Although the storm is experiencing moderate to strong southwesterly shear, strong upper-level divergence caused by the trough should allow strengthening through about 48 h, although the cyclone may acquire some subtropical characteristics as it merges with the baroclinic system. After that time, dry air entrainment is likely to cause Eta to slowly weaken through the remainder of the forecast period. The new intensity forecast is unchanged from the old forecast. The new forecast track requires a Tropical Storm Warning for south Florida and the Florida Keys at this time. Key Messages: 1. Heavy rainfall will continue across the Cayman Islands, portions of Cuba and Jamaica, and will spread north into the Bahamas and southern Florida. This rain may result in significant, life-threatening flash flooding and river flooding in Cuba. Flash and urban flooding will also be possible for the Cayman Islands, Jamaica, the Bahamas and southern Florida. 2. Tropical storm conditions are expected today and Sunday in portions of the Cayman Islands, Cuba, and the northwestern Bahamas, where a Tropical Storm Warning is in effect. 3. Tropical storm conditions are expected by late Sunday in the Florida Keys and along portions of the southeast Florida coast, where a Tropical Storm Warning is in effect. Tropical storm conditions are possible elsewhere in portions of southern and central Florida beginning Sunday night, where a Tropical Storm Watch is in effect. Additional Tropical Storm Warnings will likely be needed later today. FORECAST POSITIONS AND MAX WINDS INIT 07/1500Z 19.6N 81.8W 35 KT 40 MPH 12H 08/0000Z 20.8N 80.6W 40 KT 45 MPH 24H 08/1200Z 22.5N 79.5W 45 KT 50 MPH...INLAND 36H 09/0000Z 23.8N 79.3W 50 KT 60 MPH...OVER WATER 48H 09/1200Z 25.0N 80.1W 55 KT 65 MPH 60H 10/0000Z 25.8N 81.9W 55 KT 65 MPH 72H 10/1200Z 26.2N 83.2W 50 KT 60 MPH 96H 11/1200Z 26.5N 84.0W 45 KT 50 MPH 120H 12/1200Z 28.5N 84.0W 40 KT 45 MPH $$ Forecaster Beven
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