Official Discussion issued by the National Hurricane Center
Debby (AL042024) DATA RELEASED: 8/6/2024 3:00:00 PM UTC
Copy of official data Tropical Storm Debby Discussion Number 17 NWS National Hurricane Center Miami FL AL042024 1100 AM EDT Tue Aug 06 2024 Surface synoptic data, satellite imagery, and WSR-88D radar observations indicate that the center of the cyclone is near the coastline in the vicinity of the Georgia/South Carolina border. As a result of its interaction with land, Debby's intensity has decreased to near 35 kt. Most of the deep convection is occurring in bands well to the east and northeast of the center as drier air has been impinging on the southwestern quadrant of the circulation. Debby has been gradually turning to the right and slowing down, with a current motion estimate of around 060/5 kt. The cyclone is situated in an area of weak steering currents within the subtropical ridge. The track guidance shows a slow, generally eastward motion during the next day or so, bringing the center out over the South Carolina coastal waters. By late tomorrow and early Thursday, the global models predict a strengthening mid-level ridge to the east of Debby. This evolution should cause the system to turn northward and north-northwestward and move back over the coastline in 36 to 48 hours. Thereafter, Debby is expected to move northeastward near the northeast U.S. coast at an increasing forward speed, ahead of a mid-tropospheric trough moving into the Ohio Valley region. The official forecast is a blend of the latest model consensus predictions. Although the center of Debby is forecast to be over water later today, the lack of an inner core should allow only slow re-strengthening for the next day or so. Since the system is not expected to move far enough offshore to interact significantly with the Gulf Stream, this should limit the amount of oceanic heat content available to the storm. The official intensity forecast is near or slightly above the latest statistical/dynamical DSHIPS and LGEM guidance. Key Messages: 1.Potentially historic heavy rainfall across eastern South Carolina through Friday will likely result in areas of catastrophic flooding. Heavy rainfall will likely result in flooding impacts from northern North Carolina through portions of Mid-Atlantic States and southern New England through Sunday morning. 2. Dangerous storm surge and tropical storm conditions will spread northward along the southeast U.S. coast from northeastern Georgia to North Carolina through Thursday. Storm surge and tropical storm watches and warnings are in effect for portions of these areas. Residents in the storm surge watch and warning area should follow any advice given by local officials. 3. In portions of Florida where Debby has passed, deadly hazards remain, including downed power lines and flooded areas. Ensure generators are properly ventilated to avoid carbon monoxide poisoning. Exercise caution when using chainsaws and power tools, and drink plenty of water to avoid heat exhaustion. FORECAST POSITIONS AND MAX WINDS INIT 06/1500Z 31.9N 81.0W 35 KT 40 MPH 12H 07/0000Z 32.0N 80.2W 40 KT 45 MPH 24H 07/1200Z 32.2N 79.4W 45 KT 50 MPH 36H 08/0000Z 32.6N 79.3W 50 KT 60 MPH 48H 08/1200Z 33.2N 79.6W 50 KT 60 MPH...INLAND 60H 09/0000Z 34.2N 79.9W 40 KT 45 MPH...INLAND 72H 09/1200Z 35.7N 79.6W 35 KT 40 MPH...INLAND 96H 10/1200Z 40.2N 75.3W 30 KT 35 MPH...POST-TROPICAL 120H 11/1200Z 45.0N 69.0W 30 KT 35 MPH...POST-TROP/EXTRATROP $$ Forecaster Pasch |