Potential Tropical Cyclone Sixteen Forecast Discussion Number 2

By | September 21, 2023

WTNT41 KNHC 212051

Potential Tropical Cyclone Sixteen Discussion Number   2
NWS National Hurricane Center Miami FL       AL162023
500 PM EDT Thu Sep 21 2023

High-resolution visible satellite imagery and surface synoptic
observations indicate that the disturbance has not yet acquired a
well-defined center of circulation.  There is a distinct
comma-shaped curved band of convection over the eastern portion of
the system, with moderate southwesterly vertical wind shear over 
the area.  The current intensity is set at 30 kt based on surface 

Since there is still no distinct center the initial motion, 360/7 
kt, is an educated guess.  The dynamical model guidance suggests 
that there may be some center re-formations during the next day or 
two.  However, the system should move generally northward to 
north-northwestward over the next couple of days while embedded on 
the eastern side of a deep-layer trough over the eastern United 
States.  The official forecast is close to the previous one and is 
also close to the corrected dynamical model consensus.

Strong vertical wind shear is likely to persist over the system, 
but the global models show strengthening before landfall.  This 
intensification is probably at least partially due to baroclinic 
energy sources.  In fact the ECMWF forecast suggests that the 
system will retain at least some frontal cyclone characteristics 
through landfall.  Nonetheless, the system is likely to cause 
tropical-storm-force winds, locally heavy rainfall, and dangerous 
storm surges over the warned areas in the southeastern and 
mid-Atlantic United States.  Interests should be aware that 
hazardous conditions will extend well away from the forecast center 

Key Messages:

1. An area of low pressure is forecast to strengthen off the
southeastern U.S. coast and bring tropical-storm-force winds, storm 
surge, heavy rain, and high surf to large portions of the southeast 
and mid-Atlantic United States coast beginning Friday and continuing 
into the weekend.

2. There is a danger of life-threatening storm surge inundation 
over portions of eastern North Carolina and southeastern Virginia, 
including the Pamlico and Albemarle Sounds, and the lower 
Chesapeake Bay, where Storm Surge Warnings are in place.  Residents 
in these areas should follow advice given by local officials.

3. Tropical storm conditions are expected within portions of the
southeast and mid-Atlantic coasts within the Tropical Storm Warning
area beginning on Friday and continuing into Saturday.

4. Heavy rainfall from this system could produce localized urban
and small stream flooding impacts across the eastern mid-Atlantic
states from North Carolina to New Jersey Friday through Sunday.


INIT  21/2100Z 29.2N  75.9W   30 KT  35 MPH...POTENTIAL TROP CYCLONE
 12H  22/0600Z 30.8N  75.8W   40 KT  45 MPH...POTENTIAL TROP CYCLONE
 24H  22/1800Z 32.6N  76.0W   45 KT  50 MPH...POTENTIAL TROP CYCLONE
 36H  23/0600Z 33.8N  76.5W   50 KT  60 MPH
 48H  23/1800Z 35.6N  77.0W   50 KT  60 MPH
 60H  24/0600Z 37.3N  76.9W   35 KT  40 MPH
 72H  24/1800Z 38.7N  76.1W   30 KT  35 MPH...POST-TROPICAL
 96H  25/1800Z 40.0N  74.0W   25 KT  30 MPH...POST-TROPICAL
120H  26/1800Z...DISSIPATED

Forecaster Pasch

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