|
Show Selection: |
| #1198634 (Received by flhurricane at: 5:00 AM 16.Sep.2024) TCDAT3 Potential Tropical Cyclone Eight Discussion Number 3 NWS National Hurricane Center Miami FL AL082024 500 AM EDT Mon Sep 16 2024 The structure of the area of low pressure off the coast of South Carolina has seemingly become less organized during the past few hours. Proxy-visible satellite imagery indicates that the low-level circulation is elongated from northeast to southwest, and the center has not become well defined. The associated deep convection has a generally linear orientation and has been displaced farther to the north and east of the center due to strong upper-level winds. Lastly, an Air Force Reserve Hurricane Hunter aircraft still measured a 2-3 degree Celsius temperature difference at 850 mb from north to south, indicating that the frontal boundary is diffuse but not totally gone. Therefore, the low is still not a tropical or subtropical cyclone. That said, the plane measured a peak wind of 54 kt at 6000 ft in the convection well northeast of the center, suggesting that the current intensity is about 45 kt. The low is drifting northwestward (325 degrees) at 3 kt, gradually approaching the South Carolina coast. A faster motion toward the northwest is expected to occur today as the low moves between mid-level high pressure over the northeastern U.S. and a trough over the southeastern U.S. The NHC track forecast shows the low crossing the coast later this afternoon, which is shown by most of the track models. The GFS remains the notable outlier since it initialized the low too far to the northwest and consequently has it crossing the coast around sunrise. After moving inland, the low is expected to continue moving slowly northwestward and then northward over the Carolinas through Wednesday. The new track forecast has been nudged westward from the previous forecast, although there is a modest amount of uncertainty given the ill-defined nature of the center. The chances of the system becoming a tropical or subtropical cyclone may be starting to decrease given the current structure, and since it only has another 12 hours or so before moving inland. Most of the intensity guidance also suggests that the maximum winds should gradually decrease as the low approaches the coast, although tropical-storm-force winds are still expected to occur within the warning areas today. Further weakening is forecast after the system moves inland, and it will likely dissipate over the Carolinas by late Wednesday. Key Messages: 1. Tropical storm conditions are expected along portions of the coasts of South Carolina and North Carolina within the Tropical Storm Warning area through this evening. 2. The system will bring the potential for locally considerable flash and urban flooding and minor river flooding across southeast North Carolina and northeast South Carolina through tonight. There is also a risk of isolated flash and urban flooding across much of the Mid-Atlantic region through Wednesday. 3. Coastal flooding and high surf are likely along portions of the southeastern U.S. coast over the next day or two. FORECAST POSITIONS AND MAX WINDS INIT 16/0900Z 32.4N 78.3W 45 KT 50 MPH...POTENTIAL TROP CYCLONE 12H 16/1800Z 33.0N 79.0W 40 KT 45 MPH...TROPICAL CYCLONE 24H 17/0600Z 33.7N 79.8W 30 KT 35 MPH...INLAND 36H 17/1800Z 34.5N 80.6W 20 KT 25 MPH...POST-TROP/REMNT LOW 48H 18/0600Z 35.2N 81.0W 15 KT 15 MPH...POST-TROP/REMNT LOW 60H 18/1800Z 35.7N 81.1W 15 KT 15 MPH...POST-TROP/REMNT LOW 72H 19/0600Z...DISSIPATED $$ Forecaster Berg |
