Atlantic Hurricane Feed

Potential Tropical Cyclone Eight Forecast Discussion

Published Date and Time: 2024-09-16 04:46:07



830 
WTNT43 KNHC 160845
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




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