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| #1206457 (Received by flhurricane at: 9:45 AM 04.Nov.2024) TCDAT3 Tropical Depression Eighteen Discussion Number 4 NWS National Hurricane Center Miami FL AL182024 1000 AM EST Mon Nov 04 2024 Data from the Air Force Hurricane Hunters, satellite images, and surface observations indicate that the low pressure system over the south-central Caribbean Sea has developed a well-defined center and is producing organized deep convection. Therefore, the system now meets the criteria of a tropical depression. The maximum flight-level winds from the aircraft support holding the initial wind speed steady at 30 kt. Deep convection is gradually organizing near the center and in bands around it, especially on the south and east sides of the circulation. The depression has jogged a bit to the right of the previous track, and the initial motion estimate is now 010/8 kt. A turn to the northwest is expected later today, and that motion is forecast to continue during the next few days as a ridge builds over the southwestern Atlantic and northeastern Caribbean. This motion should take the center of the system near Jamaica tonight, near or over the Cayman Islands by late Tuesday, and across western Cuba on Wednesday. After that time, when the system reaches the Gulf of Mexico, the model solutions diverge, which appears to be due to differences in the steering patterns and vertical depth of the storm. The NHC track forecast is largely an update of the previous one and remains close to the various consensus models. However, it should be noted that the track forecast over the Gulf of Mexico is of low confidence. The environmental factors of low wind shear, high moisture, and warm SSTs support intensification, and since the system now has a well organized circulation, there is increasing confidence of steady strengthening until the system reaches Cuba or the southeastern Gulf of Mexico. In 3 or 4 days, when the system reaches the central Gulf, a sharp increase in southwesterly vertical wind shear, drier air, and slightly cooler waters should end the strengthening trend and induce weakening. The NHC intensity forecast lies near the middle of the guidance envelope, fairly close to the HCCA and IVCN consensus aids. Key Messages: 1. Hurricane conditions are expected in the Cayman Islands on Tuesday and are possible in portions of Cuba early Wednesday, where Hurricane Warnings and Watches are in effect. There is a risk of dangerous impacts from hurricane-force winds and storm surge in the Cayman Islands and portions of western Cuba. Tropical storm conditions are expected in Jamaica this evening. 2. Interests in the Florida Keys should closely monitor this system as tropical storm watches could be required for portions of these areas later today. 3. The system is forecast to enter the Gulf of Mexico later this week, but given significant uncertainties in the long-range forecast track and intensity, it is too soon to determine what, if any, impacts could occur. Residents in this area should regularly monitor updates to the forecast. 4. The system will bring areas of heavy rain across portions of the western Caribbean, including Jamaica and portions of Cuba through mid-week. Flooding and mudslides are possible in these areas. Heavy rainfall will spread north into Florida and adjacent areas of the Southeast United States mid to late week. FORECAST POSITIONS AND MAX WINDS INIT 04/1500Z 15.2N 76.9W 30 KT 35 MPH 12H 05/0000Z 16.5N 77.6W 35 KT 40 MPH 24H 05/1200Z 18.2N 79.0W 45 KT 50 MPH 36H 06/0000Z 19.9N 80.7W 60 KT 70 MPH 48H 06/1200Z 21.7N 82.4W 70 KT 80 MPH 60H 07/0000Z 23.4N 83.9W 70 KT 80 MPH 72H 07/1200Z 24.6N 85.1W 70 KT 80 MPH 96H 08/1200Z 26.1N 87.4W 65 KT 75 MPH 120H 09/1200Z 27.4N 89.5W 55 KT 65 MPH $$ Forecaster Cangialosi/Kelly |
