WTNT43 KNHC 032054 TCDAT3 Potential Tropical Cyclone Eighteen Discussion Number 1 NWS National Hurricane Center Miami FL AL182024 400 PM EST Sun Nov 03 2024 The Air Force Hurricane Hunters have been investigating the disturbance over the south-central Caribbean Sea and their data indicates that the system has developed a closed center. However, deep convection is not quite organized enough to designate the system a tropical depression at this time. Given the potential for development and impacts to Jamaica and the Cayman Islands during the next day or two, advisories are being issued on Potential Tropical Cyclone Eighteen. The initial motion is northeastward at 6 kt, but this is uncertain given that the system has only recently closed off. A turn to the north and then northwest is expected over the next couple of days as a mid-level ridge builds across the southwestern Atlantic and the eastern Caribbean. This motion should take the disturbance near Jamaica by late Monday and near or over the Cayman Islands and Cuba on Tuesday and Wednesday. The models are in relatively good agreement during that time period, and the official track forecast lies near the various consensus models. Once the system reaches the Gulf of Mexico by the middle of the week, the model solutions diverge due to differences in the predicted steering patterns and vertical depth of the system by that time. Therefore, the NHC track forecast during that time period is of notably lower confidence. The environmental conditions appear conducive for strengthening during the next few days, and it seems likely that the system will become a tropical storm before it reaches Jamaica and a hurricane before it reaches Cuba. However, later in the week, southwesterly vertical wind shear and intrusions of dry air should end the strengthening process and likely induce some weakening once the system reaches the Gulf of Mexico. The hurricane regional models are very aggressive, however, their intensity predictions appear overdone, at least in the short term. The NHC intensity forecast is closer to the statistical-dynamical models DSHP and LGEM and near the IVCN consensus aid. Key Messages: 1. The disturbance is expected to become a tropical storm Monday and pass near Jamaica on Monday night and Tuesday where a Tropical Storm Warning is now in effect. The system is forecast to become a hurricane by Tuesday night and there is a risk of dangerous impacts from hurricane-force winds and storm surge in the Cayman Islands and portions of Cuba. 2. Interests in the Florida Keys should closely monitor this system as tropical storm watches could be required for portions of the Florida Keys tonight or early Monday. 3. The system is forecast to approach the northern Gulf Coast as a tropical storm later this week, but given uncertainties in the long-range forecast, 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 the southern and western portions of Cuba through mid-week. Flooding could occur over portions of Jamaica and Cuba, with mudslides possible. Heavy rainfall could then spread northward into Florida and adjacent areas of the Southeast United States during the middle to late portions of the week. FORECAST POSITIONS AND MAX WINDS INIT 03/2100Z 13.0N 77.1W 30 KT 35 MPH...POTENTIAL TROP CYCLONE 12H 04/0600Z 14.3N 77.1W 35 KT 40 MPH...TROPICAL CYCLONE 24H 04/1800Z 16.0N 77.7W 40 KT 45 MPH 36H 05/0600Z 17.7N 78.6W 50 KT 60 MPH 48H 05/1800Z 19.6N 80.4W 60 KT 70 MPH 60H 06/0600Z 21.5N 82.6W 70 KT 80 MPH 72H 06/1800Z 23.3N 84.5W 65 KT 75 MPH 96H 07/1800Z 25.4N 86.6W 60 KT 70 MPH 120H 08/1800Z 26.9N 88.6W 50 KT 60 MPH $$ Forecaster Cangialosi