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| #1191754 (Received by flhurricane at: 10:48 AM 03.Aug.2024) TCDAT4 Tropical Depression Four Discussion Number 5 NWS National Hurricane Center Miami FL AL042024 1100 AM EDT Sat Aug 03 2024 Tropical Depression Four has become somewhat better organized this morning, with the circulation becoming better defined over western Cuba and curved convective bands forming close to the center in the southern semicircle. However, the circulation is still somewhat elongated with multiple low-level vorticity centers rotating around the mean center. The initial intensity has been increased to 30 kt based on surface observations in the Florida Keys and a satellite intensity estimate from TAFB. The depression appears to be starting its northwestward turn with the initial motion now 300/13 kt. A large mid- to upper-level trough over the central United States is creating a break in the subtropical ridge, and the cyclone is expected to turn northward into this break by 24-36 h. This should be followed by a gradual turn toward the northeast through 60 h. This motion should bring the center near or over the northern Gulf coast in roughly 48 h. After landfall, weakening steering currents should cause the cyclone to slow down while it moves northeastward over parts of northern Florida and Georgia. The uncertainty in the forecast increases significantly after 72 h as the cyclone interacts with a portion of the U.S. trough. The current GFS and ECMWF forecast the system to move into the Atlantic, and then turn back toward the southeastern U.S. coast by 120 h. On the other hand, the Canadian model moves the cyclone slowly northeastward across the southeastern states and does not bring it over the Atlantic. This portion of the new forecast track shows a slower forward motion than the previous track due to changes in the GFS forecast since the previous advisory. After the system crosses Cuba and emerges over the eastern Gulf of Mexico, the environmental and oceanic conditions appear favorable for intensification. Due to the lack of internal organization, the initial intensification is likely to be slow. However, a faster rate of development is likely once the system gets better organized, and the cyclone is likely to be near or at hurricane strength when it reaches to the northern Gulf coast. Weakening is forecast after landfall while the system moves over the southeastern United States. Beyond 72 h, the intensity forecast remains quite uncertain due to uncertainty of whether the center will reach the Atlantic and how much interaction will occur with the aforementioned mid-latitude trough interaction. Key Messages: 1. Heavy rainfall will likely result in locally considerable flash and urban flooding across portions of Florida and the coastal areas of the Southeast this weekend through Thursday morning. River flooding is also expected. 2. Hurricane conditions are possible late Sunday in portions of the Florida Gulf Coast and Big Bend region where a Hurricane Watch is in effect. Tropical storm conditions are expected farther south along Florida’s west coast, including the Tampa Bay area, and in the Dry Tortugas where Tropical Storm Warnings are in effect. 3. There is a danger of life-threatening storm surge inundation along portions of the west coast of Florida from Aripeka to the Aucilla River. Life-threatening storm surge is possible west of Aucilla River to Indian Pass and south of Aripeka to Bonita Beach, including Tampa Bay and Charlotte Harbor. 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 later today. FORECAST POSITIONS AND MAX WINDS INIT 03/1500Z 22.8N 82.0W 30 KT 35 MPH 12H 04/0000Z 24.3N 83.4W 30 KT 35 MPH 24H 04/1200Z 26.3N 84.3W 40 KT 45 MPH 36H 05/0000Z 28.2N 84.3W 50 KT 60 MPH 48H 05/1200Z 29.8N 83.8W 60 KT 70 MPH 60H 06/0000Z 30.7N 83.1W 40 KT 45 MPH...INLAND 72H 06/1200Z 31.4N 82.0W 35 KT 40 MPH...INLAND 96H 07/1200Z 31.5N 80.5W 40 KT 45 MPH...OVER WATER 120H 08/1200Z 32.5N 80.0W 55 KT 65 MPH $$ Forecaster Beven |
