Official Discussion issued by the National Hurricane Center
Debby (AL042024) DATA RELEASED: 8/6/2024 9:00:00 PM UTC
Copy of official data Tropical Storm Debby Discussion Number 18 NWS National Hurricane Center Miami FL AL042024 500 PM EDT Tue Aug 06 2024 Surface, satellite, and radar data show that Debby continues to linger near the coastline in the vicinity of the Georgia/South Carolina border. The cyclone lacks strong convection near its center and the tropical-storm-force winds are mainly occurring in some bands well to the northeast and east of the center. This was also shown by an earlier ASCAT pass. The central pressure remains essentially unchanged, and the intensity is kept at 35 kt for this advisory. Debby remains trapped in a zone of weak steering currents within the subtropical ridge, and the current motion estimate is a very slow 070/3 kt. The track guidance shows a generally eastward motion for the next day or so, taking the center temporarily offshore. In 24-36 hours, a building mid-level ridge should cause the system to turn northward and move back inland early Thursday. After that, Debby is likely to accelerate northeastward over the eastern and northeastern U.S. ahead of an approaching mid-level trough. The official track forecast has been adjusted toward the latest consensus model guidance, and is somewhat to the left and faster than the previous one. Assuming that Debby moves back over water tonight and Wednesday, some re-strengthening is anticipated. However since the cyclone lacks an inner core and is not likely to move far enough east to interact with the high oceanic heat content of the Gulf Stream, re-intensification is likely to be limited. The official intensity forecast is at the high end of the model 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 considerable flooding impacts from central to the Upstate of South Carolina, western North Carolina, Southwest Virginia through portions of Mid-Atlantic States, western and northern New York State and northern New England through Saturday. 2 Tropical storm conditions will spread northward along the southeast U.S. coast from northeastern Georgia to North Carolina through Thursday. Tropical storm warnings and watches are in effect for portions of that area. 3. A dangerous storm surge is possible along the coast of South Carolina and southeastern North Carolina from South Santee River to Cape Fear. Residents in that area should follow any advice given by local officials. FORECAST POSITIONS AND MAX WINDS INIT 06/2100Z 32.1N 80.8W 35 KT 40 MPH 12H 07/0600Z 32.2N 79.8W 40 KT 45 MPH 24H 07/1800Z 32.6N 79.3W 45 KT 50 MPH 36H 08/0600Z 33.1N 79.3W 50 KT 60 MPH...INLAND 48H 08/1800Z 34.0N 79.5W 45 KT 50 MPH...INLAND 60H 09/0600Z 35.8N 79.6W 30 KT 35 MPH...INLAND 72H 09/1800Z 38.5N 78.5W 30 KT 35 MPH...POST-TROPICAL 96H 10/1800Z 45.0N 72.0W 30 KT 35 MPH...POST-TROP/EXTRATROP 120H 11/1800Z 52.0N 66.0W 30 KT 35 MPH...POST-TROP/EXTRATROP $$ Forecaster Pasch |