****0000002648****
WTNT44 KNHC 271436

TCDAT4

 

Tropical Storm Helene Discussion Number  17

NWS National Hurricane Center Miami FL       AL092024

1100 AM EDT Fri Sep 27 2024

 

Helene has been racing northward and the low-level center is now

located over the southern Appalachians.  Strong bands of heavy rain

and very gusty winds continue off and along the South Carolina

coast.  In addition, wind gusts to around hurricane force have been

occurring this morning in portions of northeastern Georgia and the

western portions of the Carolinas, especially in areas of higher

terrain.  The initial intensity is set at 40 kt, and these sustained

winds are likely occurring off the south Carolina coast and over

the Appalachians.  The main hazard is the very heavy rainfall 

ongoing over portions of the southeastern U.S., which is 

causing historic and life-threatening flooding.

 

Helene is expected to move slower to the northwest later today and 

then stall over the Tennessee Valley tonight and through the weekend 

as it merges with a mid- to upper-level low.  This merger will also 

lead to extratropical transition, which is expected to occur later 

today.  The expected slow motion could result in significant 

flooding over the Ohio and Tennessee Valleys, and over the southern 

Appalachians through the weekend.

 

KEY MESSAGES:

 

1. Historic, catastrophic and life-threatening flash and urban 

flooding, including numerous significant landslides, will continue 

across portions of the Southern Appalachians through this evening. 

Widespread significant river flooding is ongoing, some of which will 

be major to record breaking.

 

2. Damaging wind gusts will continue over portions of Georgia, the

Carolinas, Tennessee, and Kentucky today, particularly over the

higher terrain of the southern Appalachians.

 

3. There is a possibility of long-duration power outages in

portions of the southeast U.S.  If you use a generator after the

storm, be sure it is placed outside at least 20 feet away from

doors, windows, and garages to avoid deadly carbon monoxide

poisoning.

 

 

FORECAST POSITIONS AND MAX WINDS

 

INIT  27/1500Z 35.1N  83.8W   40 KT  45 MPH

 12H  28/0000Z 37.3N  85.6W   30 KT  35 MPH...POST-TROP/EXTRATROP

 24H  28/1200Z 37.5N  86.5W   25 KT  30 MPH...POST-TROP/EXTRATROP

 36H  29/0000Z 37.5N  86.4W   20 KT  25 MPH...POST-TROP/EXTRATROP

 48H  29/1200Z 37.5N  86.1W   20 KT  25 MPH...POST-TROP/EXTRATROP

 60H  30/0000Z 37.6N  85.7W   20 KT  25 MPH...POST-TROP/EXTRATROP

 72H  30/1200Z...DISSIPATED

 

$$

Forecaster Cangialosi/Rosado