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| #1191673 (Received by flhurricane at: 10:51 PM 02.Aug.2024) TCDAT4 Tropical Depression Four Discussion Number 3 NWS National Hurricane Center Miami FL AL042024 1100 PM EDT Fri Aug 02 2024 Shortwave infrared satellite imagery, Cuban radar data, and surface observations from Cuba and the Cayman Islands suggest that the disturbance has developed a closed circulation, and the center is located just off the south coast of Cuba. Deep convection is still a bit fragmented, but there has been a persistent burst near the estimated center since earlier this afternoon. The wind and pressure field could still be a little elongated within the southern semicircle, but overall the system appears to have enough organization to now be designated as a tropical depression. The initial intensity remains 25 kt based on earlier observations. The depression has not begun to turn yet, and the initial motion is west-northwestward, or 285/15 kt. A turn toward the northwest and then north is expected over the weekend due to a break in the subtropical ridge caused by a trough over the eastern United States. Since the system has not started to turn yet, this has caused all of the track guidance to shift west, and the updated NHC forecast is a bit west of the previous forecast along the eastern edge of the main cluster of models. It is important to note that because of the forecast track being parallel to the west coast of Florida, the location and timing of a potential landfall cannot be pinned down at this time. One additional significant change to the forecast is that the models seem to be showing the aforementioned trough leaving the cyclone behind early next week, which causes a much slower motion while the system is near the coasts of Georgia and South Carolina. As a result, the new NHC forecast is notably slower than the previous forecast, particularly on days 4 and 5. The westward shift to the track forecast now also keeps the system over the warm waters of the Gulf of Mexico longer, giving the system additional time to potentially strengthen. In fact, the SHIPS guidance and all of the regional hurricane models show the cyclone reaching hurricane strength before reaching land in the Big Bend region of Florida in 2 to 3 days. As a result, the new NHC forecast brings the intensity to 60 kt at 60 hours as the system is reaching land, but if model trends continue, it's possible that future forecasts could explicit show the system becoming a hurricane before it reaches land. The intensity forecast is more uncertain on days 3 through 5 due depending on if the center moves back offshore or stays inland over the southeastern United States. Key Messages: 1. Heavy rainfall may result in locally considerable flash and urban flooding across portions of Florida and the coastal areas of the Southeast U.S. this weekend through Wednesday. Isolated river flooding will also be possible. 2. Tropical storm conditions are expected Saturday night within the Tropical Storm Warning area in southwest Florida from East Cape Sable to Boca Grande and on the Dry Tortugas. Tropical storm conditions are possible in the remainder of the Florida Keys on Saturday and along the Florida west coast north of Boca Grande to Suwannee River Saturday night and Sunday where a Tropical Storm Watch is in effect. 3. There is a possibility of life-threatening inundation from storm surge along portions of the west coast of Florida from Bonita Beach to Suwannee River, including Tampa Bay and Charlotte Harbor, where a Storm Surge Watch is in effect. 4. Impacts from storm surge, strong winds, and heavy rains are possible elsewhere in Florida and along the southeast coast of the United States from Georgia to North Carolina through the middle of next week, and interests in those areas should continue to monitor the progress of this system. Additional watches and warnings will likely be required on Saturday. FORECAST POSITIONS AND MAX WINDS INIT 03/0300Z 21.4N 79.7W 25 KT 30 MPH 12H 03/1200Z 22.6N 81.4W 30 KT 35 MPH...OVER CUBA 24H 04/0000Z 24.6N 83.3W 35 KT 40 MPH...OVER WATER 36H 04/1200Z 26.6N 84.1W 45 KT 50 MPH 48H 05/0000Z 28.4N 84.0W 55 KT 65 MPH 60H 05/1200Z 29.9N 83.4W 60 KT 70 MPH...INLAND 72H 06/0000Z 30.8N 82.5W 40 KT 45 MPH...INLAND 96H 07/0000Z 31.8N 80.9W 45 KT 50 MPH...OVER WATER 120H 08/0000Z 32.8N 79.4W 55 KT 65 MPH $$ Forecaster Berg |
