Official Discussion issued by the National Hurricane Center
Debby (AL042024) DATA RELEASED: 8/6/2024 9:00:00 AM UTC
Copy of official data Tropical Storm Debby Discussion Number 16 NWS National Hurricane Center Miami FL AL042024 500 AM EDT Tue Aug 06 2024 Debby's center is just inland of the Georgia coast while most of the deep convection is oriented in a couple of bands over the Atlantic waters feeding northwestward into South Carolina. Scatterometer data from late last evening indicated that the tropical-storm-force wind field had expanded eastward over the Atlantic waters, and that the maximum sustained winds were near 40 kt. This was confirmed by a few observations of 35-40 kt sustained winds along the coasts of Georgia and South Carolina. The initial intensity is therefore held at 40 kt. Debby continues to move northeastward, or 050/6 kt, but the storm will be trapped in a weak steering regime for the next couple of days. The center is likely to move offshore the Georgia coast later today, but then meander off the coast of South Carolina through early Thursday. After that time, a strengthening ridge over the western Atlantic and an approaching mid-latitude trough over the upper Midwest should cause Debby to move faster toward the north across the Carolinas and then into the Mid-Atlantic region late this week. The updated NHC track forecast is a bit west of the previous forecast starting at about 48 hours, trending in the direction of the HCCA and TVCA consensus aids. Little change in Debby's intensity is expected today and tonight as the center moves offshore. However, some strengthening is forecast beginning on Wednesday due to the storm being in a low-shear environment and over very warm waters of about 29 degrees Celsius. The NHC intensity forecast continues to show a peak intensity of 50 kt in 48 hours, just before the center reaches the coast again, which is near the top end of the guidance. Weakening is expected to begin in 60 hours once the center moves inland. The cyclone is likely to merge with a front over the eastern United States in 4 to 5 days. Key Messages: 1. Potentially historic heavy rainfall across southeast Georgia and 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 Florida to North Carolina through the middle of the week. Storm surge and tropical storm watches and warnings have been issued 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 06/0900Z 31.6N 81.6W 40 KT 45 MPH...INLAND 12H 06/1800Z 31.6N 81.0W 40 KT 45 MPH...OVER WATER 24H 07/0600Z 31.7N 79.9W 40 KT 45 MPH 36H 07/1800Z 31.9N 79.4W 45 KT 50 MPH 48H 08/0600Z 32.3N 79.5W 50 KT 60 MPH 60H 08/1800Z 33.1N 79.9W 45 KT 50 MPH...INLAND 72H 09/0600Z 34.1N 80.1W 35 KT 40 MPH...INLAND 96H 10/0600Z 38.5N 77.4W 30 KT 35 MPH...INLAND 120H 11/0600Z 43.4N 67.7W 35 KT 40 MPH...POST-TROP/EXTRATROP $$ Forecaster Berg |