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| #1193472 (Received by flhurricane at: 11:03 AM 12.Aug.2024) TCDAT5 Potential Tropical Cyclone Five Discussion Number 4 NWS National Hurricane Center Miami FL AL052024 1100 AM AST Mon Aug 12 2024 Data from the NOAA Hurricane Hunter aircraft investigating the storm indicate a low-level center could be attempting to form closer to some increased convective activity within the northern semicircle of the disturbance. While the disturbance appears to be gradually becoming better organized in satellite imagery, the lack of a well-defined center means it will remain a potential tropical cyclone for this advisory. Based on the flight-level winds and some distant scatterometer data over the eastern part of the circulation, the initial intensity is set at 30 kt. An Air Force Reserve Hurricane Hunter aircraft will investigate the system this afternoon and help us assess any changes to the low-level wind field. Overall, the disturbance has moved a little faster to the west than previous estimates, and the initial motion remains quickly westward (280/23 kt). A westward to west-northwestward motion with some decrease in forward speed is expected during the next couple of days while the system moves around the southwestern extent of the subtropical ridge. This will bring the center over portions of the Leeward Islands late tonight into Tuesday, and then near or over the Virgin Islands and Puerto Rico late Tuesday night and Wednesday. By midweek, the system will reach a weakness in the mid-level ridge caused by a mid-latitude trough moving across the western Atlantic. This should induce a northwestward to northward motion during the latter half of the forecast period. The track guidance envelope has shifted to the left of the previous track, likely a product of the faster forward speed and the weaker initial state of the system. Only small adjustments were made to the near-term NHC track forecast, with a slightly larger westward adjustment at days 3-5. Until the disturbance becomes better organized, the large radius of maximum wind and some northeasterly shear should only allow for modest strengthening during the next 24-48 h. The NHC forecast shows it becoming a tropical storm in 24 h and continuing to slowly strengthen while it passes over the northeastern Caribbean Sea. Once the system reaches the western Atlantic, the intensity guidance favors more significant strengthening, and the system is forecast to become a hurricane in 3 days and continue intensifying thereafter. No major changes were made to the NHC intensity forecast this cycle, which remains close to the multi-model consensus. Key Messages: 1. The disturbance is expected to become a tropical storm as it reaches the Leeward Islands. Tropical Storm Warnings are in effect for most of these islands, where tropical storm conditions are expected to begin late tonight. 2. Heavy rainfall may result in locally considerable flash flooding and mudslides in areas of the Leeward and Virgin Islands by later today into Wednesday, and over Puerto Rico late Tuesday into Thursday. 3. A Tropical Storm Warning is now in effect for the Virgin Islands and Puerto Rico, where tropical storm conditions are expected to begin Tuesday night or early Wednesday. FORECAST POSITIONS AND MAX WINDS INIT 12/1500Z 15.1N 55.6W 30 KT 35 MPH...POTENTIAL TROP CYCLONE 12H 13/0000Z 15.5N 58.8W 35 KT 40 MPH...POTENTIAL TROP CYCLONE 24H 13/1200Z 16.3N 62.2W 35 KT 40 MPH 36H 14/0000Z 17.3N 64.6W 40 KT 45 MPH 48H 14/1200Z 18.8N 66.4W 45 KT 50 MPH 60H 15/0000Z 20.5N 67.6W 55 KT 65 MPH 72H 15/1200Z 22.7N 68.2W 65 KT 75 MPH 96H 16/1200Z 27.0N 67.5W 85 KT 100 MPH 120H 17/1200Z 31.5N 65.0W 95 KT 110 MPH $$ Forecaster Reinhart |
