Official Discussion issued by the National Hurricane Center
Debby (AL042024) DATA RELEASED: 8/5/2024 3:00:00 PM UTC
Copy of official data Tropical Storm Debby Discussion Number 13 NWS National Hurricane Center Miami FL AL042024 1100 AM EDT Mon Aug 05 2024 Debby's center made landfall in the Florida Big Bend region earlier today around 1100 UTC with an estimated intensity of 70 kt. Since landfall, the system has moved over northern Florida while gradually weakening below hurricane intensity. Assuming a typical rate of weakening over land, the current intensity is set at 60 kt. WSR-88D Doppler velocities still show hurricane-force winds aloft, at an elevation of about 3500 ft, over the northeastern quadrant of the cyclone. Therefore, some damaging winds could still be brought down to the surface in the more vigorous convection near the inland path of Debby. Debby has been moving through a break in the subtropical ridge with an estimated initial motion of 030/7 kt. Steering currents are expected to weaken some more, resulting in a further decrease in forward speed. Most of the track guidance turns Debby eastward, with the center moving off the coast near the Georgia/South Carolina border in about 36 hours. Debby should move very slowly near the South Carolina coast through 60 hours or so. Then, a mid-level ridge builds slightly to the northeast of the cyclone, which should push the system back inland over the latter part of the forecast period. The official forecast track is a blend of the simple and corrected dynamical consensus models, TVCA and HCCA. Continued weakening is expected while the center of Debby remains over land tonight and Tuesday. By late Tuesday and thereafter, some restrengthening is anticipated as the center moves offshore. However the amount that the cyclone re-intensifies is dependent on how far out over the Atlantic the system moves and how long it remains over water. The current official forecast shows only modest restrengthening, given the uncertainties. Going forward, the biggest threat from this slow-moving system system is extreme precipitation and flooding over the southeastern United States. Key Messages: 1. Potentially historic heavy rainfall across southeast Georgia and the coastal plain of South Carolina through Saturday morning will likely result in areas of catastrophic flooding. Heavy rainfall will likely result in considerable flooding impacts from portions of central and northern Florida and across portions of central and northeast North Carolina through Saturday morning. 2. Dangerous storm surge inundation will continue in the Storm Surge warning area along the Gulf Coast of Florida, including the Tampa Bay area, through this afternoon. 3. Tropical storm conditions will continue along portions of the Gulf Coast of Florida today within the Tropical Storm warning area. 4. Dangerous storm surge and tropical storm conditions will spread northward along the southeast U.S. coast from northeastern Florida to North Carolina through the middle of the week. Storm Surge and Tropical Storm warnings have been issued for portions of these areas, and additional watches and warnings will likely be issued later today. Residents in the Storm Surge Warning area should follow any advice given by local officials. FORECAST POSITIONS AND MAX WINDS INIT 05/1500Z 30.2N 83.2W 60 KT 70 MPH 12H 06/0000Z 31.0N 82.5W 50 KT 60 MPH...INLAND 24H 06/1200Z 31.7N 81.5W 40 KT 45 MPH...INLAND 36H 07/0000Z 31.9N 80.6W 40 KT 45 MPH...OVER WATER 48H 07/1200Z 32.1N 79.7W 45 KT 50 MPH...OVER WATER 60H 08/0000Z 32.4N 79.2W 45 KT 50 MPH...OVER WATER 72H 08/1200Z 33.0N 79.0W 50 KT 60 MPH...OVER WATER 96H 09/1200Z 34.6N 79.1W 40 KT 45 MPH...INLAND 120H 10/1200Z 37.4N 76.9W 30 KT 35 MPH...INLAND $$ Forecaster Pasch |