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| #1191946 (Received by flhurricane at: 11:03 AM 04.Aug.2024) TCDAT4 Tropical Storm Debby Discussion Number 9 NWS National Hurricane Center Miami FL AL042024 1100 AM EDT Sun Aug 04 2024 Hurricane Hunter aircraft observations indicate that Debby continues to intensify over the eastern Gulf of Mexico. Satellite imagery shows that the cloud pattern is becoming better developed with increasing deep convection near the center of circulation, and WSR-88D radar data indicate that an eyewall is beginning to form. The current intensity estimate is estimated to be 55 kt based on a significant drop in central pressure reported the aircraft. The cyclone has been turning gradually to the right and the initial motion is north-northwestward or 330/11 kt. Over the next day or so, Debby should move through a weakness in the mid-level subtropical ridge over the southeastern United States and reach the northeast Gulf of Mexico coast in the Florida Big Bend region on Monday. After the system makes landfall, the steering currents are likely to weaken as a trough over the northeastern U.S. moves eastward from the area, which should result in a decrease in forward speed. There is significant uncertainty in the track of Debby in the 2-5 day time frame. Much of the track guidance keeps the center over the southeastern U.S. for the next several days as a ridge builds in over the Carolinas. The official track forecast is similar to the previous one and close to the HFIP corrected consensus prediction. This keeps the slow-moving center near the Georgia and South Carolina coast in the 3 to 5 day time-frame. Debby will be moving over very warm waters and in a low-vertical shear environment prior to landfall. Therefore significant strengthening is likely through tonight, especially if the cyclone forms a well-defined inner core The official forecast is near the high side of the objective guidance and calls for the system to become a hurricane within 12 hours. The cyclone will weaken after it moves inland, but since the system will not be far from the coastline for the next few days, it is not predicted to fall below tropical storm strength through 72 hours. Key Messages: 1. Heavy rainfall will likely result in considerable flooding impacts from the Florida Big Bend region through southeast GA and the Coastal Plain of the Carolinas through Friday. Potentially historic heavy rainfall across southeast Georgia and South Carolina through Friday morning may result in areas of catastrophic flooding. Significant river flooding is also expected. 2. There is a danger of life-threatening storm surge along portions of the Gulf Coast of Florida, with 6 to 10 feet of inundation above ground level expected somewhere between Ochlockonee River and Suwannee River on Monday. Residents in the Storm Surge Warning area should follow any advice given by local officials. 3. Hurricane conditions are expected Monday along portions of the Florida Big Bend region where a Hurricane Warning is in effect, with tropical storm conditions beginning this evening. Tropical storm conditions are expected through Monday farther south within the Tropical Storm Warning along Florida's west coast, including the Tampa Bay area. 4. Impacts from storm surge and strong winds are possible along the southeast coast from Georgia to North Carolina through the middle of the week, and storm surge watches and tropical storm watches have been issued for portions of these areas. Additional watches and warnings will likely be required later today. FORECAST POSITIONS AND MAX WINDS INIT 04/1500Z 27.0N 84.3W 55 KT 65 MPH 12H 05/0000Z 28.3N 84.5W 65 KT 75 MPH 24H 05/1200Z 29.9N 84.1W 80 KT 90 MPH 36H 06/0000Z 30.9N 83.4W 60 KT 70 MPH...INLAND 48H 06/1200Z 31.6N 82.5W 40 KT 45 MPH...INLAND 60H 07/0000Z 31.9N 81.5W 35 KT 40 MPH...INLAND 72H 07/1200Z 32.2N 80.5W 45 KT 50 MPH...OVER WATER 96H 08/1200Z 33.5N 79.5W 40 KT 45 MPH...INLAND 120H 09/1200Z 35.5N 78.0W 30 KT 35 MPH...INLAND $$ Forecaster Pasch |
