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| #1193631 (Received by flhurricane at: 11:06 AM 13.Aug.2024) TCDAT5 Tropical Storm Ernesto Discussion Number 8 NWS National Hurricane Center Miami FL AL052024 1100 AM AST Tue Aug 13 2024 Ernesto`s center passed near or over Guadeloupe and Montserrat this morning and is now located just south of St. Kitts and Nevis. Aircraft data, satellite images, and radar data show that the storm is becoming better organized, and there are some indications that an inner core is developing. Earlier NOAA Hurricane Hunter data supported maximum winds of 40 kt, and given the improved structure since then (and consensus T3.0 Dvorak estimates from TAFB and SAB), the initial intensity is set at 45 kt. Ernesto has turned toward the west-northwest, and now has an initial motion of 290/16 kt. A break in the subtropical ridge over the western Atlantic is expected to cause Ernesto to turn toward the northwest and then north during the next couple of days, with the storm`s center passing near or over the Virgin Islands this evening and then moving northeast and north of Puerto Rico overnight and on Wednesday. A northward to north-northeastward motion is forecast after 48 hours as Ernesto interacts with a deep-layer trough off the U.S. East Coast, but this trough ends up bypassing Ernesto, resulting in the storm slowing down a bit when it is in the vicinity of Bermuda. The track guidance has been very consistent, and no changes were required to the official track forecast compared to the previous issuance. Sea surface temperatures near Ernesto in the northeastern Caribbean Sea are very warm--on the order of 29-30 degrees Celsius--and vertical shear in the atmosphere is relatively light. Combined with the thought that Ernesto is developing an inner core, these ingredients favor quick strengthening over the next day or so. SHIPS and the HFIP Corrected Consensus models indicate that Ernesto could be near or at hurricane strength in about 24 hours, and several of the Rapid Intensification (RI) indices are notably high. As a result, the updated NHC intensity forecast is more aggressive than the previous forecast, and brings Ernesto to hurricane strength by 24 hours when the center is north of Puerto Rico. Because there is some risk of the storm becoming a hurricane before that time, a Hurricane Watch has been issued for the Virgin Islands, Culebra, and Vieques. After moving north of Puerto Rico, additional strengthening is likely, and the NHC forecast is near the high end of the guidance. Ernesto is also likely to grow in size while over the western Atlantic, and that is reflected in the official forecast. Key Messages: 1. Tropical storm conditions are expected to continue over portions of the Leeward Islands today and spread westward to the Virgin Islands and Puerto Rico later today and tonight. Hurricane conditions are also possible on the Virgin Islands, Culebra, and Vieques this evening and tonight. 2. Heavy rainfall may result in locally considerable flash flooding and mudslides in areas of the Leeward Islands through today, and over the Virgin Islands into Puerto Rico by later today through Wednesday. 3. Ernesto is likely to bring impacts to Bermuda late this week, and interests there should monitor the progress of this system. FORECAST POSITIONS AND MAX WINDS INIT 13/1500Z 16.9N 62.6W 45 KT 50 MPH 12H 14/0000Z 18.0N 64.6W 55 KT 65 MPH 24H 14/1200Z 19.8N 66.6W 65 KT 75 MPH 36H 15/0000Z 22.0N 68.0W 75 KT 85 MPH 48H 15/1200Z 24.3N 68.5W 85 KT 100 MPH 60H 16/0000Z 26.3N 68.1W 90 KT 105 MPH 72H 16/1200Z 28.2N 67.0W 95 KT 110 MPH 96H 17/1200Z 31.4N 65.2W 95 KT 110 MPH 120H 18/1200Z 34.9N 64.5W 90 KT 105 MPH $$ Forecaster Berg |
