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| #1192786 (Received by flhurricane at: 4:54 AM 08.Aug.2024) TCDAT4 Tropical Storm Debby Discussion Number 24 NWS National Hurricane Center Miami FL AL042024 500 AM EDT Thu Aug 08 2024 Surface observations and satellite imagery suggest that Debby's circulation has become stretched out to the north and south, but the center appeared to make landfall around 0600 UTC in the Bulls Bay area of South Carolina. A shield of moderate to heavy rain has spread northward into North Carolina, while a trailing band of deep convection is located offshore the coast of South Carolina. An Air Force Reserve Hurricane Hunter mission that concluded around midnight measured peak 925-mb flight-level winds of 55 kt and SFMR winds of 40-45 kt well east of the center, and the current intensity is therefore estimated to be 45 kt. Debby's center has not yet made much headway into South Carolina since the initial motion is northwestward (325 deg) at only 4 kt. A strengthening ridge over the Atlantic should start giving Debby a push to the north today, with the center of the cyclone moving across eastern South Carolina and central North Carolina through tonight. A deep-layer trough over the Upper Midwest should then cause Debby to turn northeastward and accelerate over the Mid-Atlantic and Northeast U.S. Friday and Friday night and then over Atlantic Canada on Saturday. No significant changes were made to the NHC track forecast compared to the one in the previous advisory. Debby is expected to continue weakening as the center moves farther inland, and global model fields suggest that winds near the coast should fall below tropical storm force, with the cyclone becoming a depression, by this afternoon or evening. Model phase-space diagrams, and the convective pattern in simulated satellite imagery, then indicate that Debby will merge with a cold front and become extratropical over the Mid-Atlantic region on Friday. Debby is shown to be dissipated by day 4 based on continuity from the previous forecast, but it is possible that an area of low pressure could continue eastward over the north Atlantic for a few more days. Key Messages: 1. Heavy rainfall across portions of the Carolinas is expected to persist through today along with areas of considerable flooding. Heavy rainfall will also result in considerable flooding impacts across portions of the Mid-Atlantic States and Northeast through Saturday morning. 2. Tropical storm conditions will continue to affect portions of the South Carolina and North Carolina coasts today. 3. Coastal flooding due to storm surge is likely along portions of the South Carolina and North Carolina coastline through today. FORECAST POSITIONS AND MAX WINDS INIT 08/0900Z 33.2N 79.7W 45 KT 50 MPH...INLAND 12H 08/1800Z 34.2N 80.1W 35 KT 40 MPH...INLAND 24H 09/0600Z 36.3N 79.7W 30 KT 35 MPH...INLAND 36H 09/1800Z 40.0N 77.3W 30 KT 35 MPH...POST-TROP/EXTRATROP 48H 10/0600Z 44.5N 72.6W 30 KT 35 MPH...POST-TROP/EXTRATROP 60H 10/1800Z 48.7N 65.8W 30 KT 35 MPH...POST-TROP/EXTRATROP 72H 11/0600Z 51.6N 58.7W 30 KT 35 MPH...POST-TROP/EXTRATROP 96H 12/0600Z...DISSIPATED $$ Forecaster Berg |
