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Potential Tropical Cyclone Sixteen Discussion Number   5
NWS National Hurricane Center Miami FL       AL162023
1100 AM EDT Fri Sep 22 2023
 
Surface observations indicate the low pressure system off the 
southeast U.S. coast is deepening this morning. Recent pressure and 
wind data from NOAA buoy 41002 suggest the pressure has fallen to 
around 996 mb. While surface analyses indicate there is still a 
front in close proximity to the low, deep convection has become more 
concentrated to the north of the center. In fact, GOES-16 1-min 
visible imagery suggests the low-level center is re-forming closer 
to the convection. The broad wind field is asymmetric, with the 
strongest observed winds occurring to the north and west of the 
frontal feature. A NOAA Saildrone sampling the system reported a 
sustained wind of 40 kt and a gust around 50 kt earlier this 
morning. Based on the available observations, the initial intensity 
is held at 45 kt. An Air Force Reserve Hurricane Hunter aircraft is 
scheduled to investigate the system this afternoon.

The initial motion of the cyclone is just west of due north (350/10 
kt). The system is forecast to move north-northwestward to northward 
through Saturday along the west side of a subtropical ridge over the 
western and central Atlantic. This motion will take the center of 
the cyclone inland over eastern North Carolina on Saturday morning 
and over the Mid-Atlantic region Saturday night and Sunday. The 
track guidance is in good agreement for this forecast. Based on the 
slight northward adjustment to the initial position, the updated NHC 
forecast is slightly faster than the previous one, showing the 
cyclone center just inland in 24 h.

Based on recent satellite and observational trends, the cyclone 
appears likely to strengthen during the next 12 h over the warm Gulf 
Stream waters. The more organized convective structure should also 
facilitate its transition to a tropical storm during the next 6-12 h 
as it starts to become separated from its frontal features and 
develops a smaller inner core. The near-term intensity forecast has 
been bumped up slightly (55 kt) before the system moves inland early 
Saturday. After landfall, the system is expected to weaken due to 
the negative influences of land interaction, drier air, and strong 
upper-level winds. This forecast shows extratropical transition by 
48 h with dissipation by 72 h, in good agreement with the GFS and 
ECMWF models. 

 
Key Messages:
 
1. Tropical storm conditions are expected along portions of the 
southeastern and mid-Atlantic U.S. coasts within the Tropical Storm 
Warning area today into Saturday night.
 
2. There is a danger of life-threatening storm surge inundation
over portions of eastern North Carolina and southeastern Virginia,
including Pamlico and Albemarle Sounds, the Neuse and Pamlico 
Rivers, the lower James River, and the lower Chesapeake Bay, where 
Storm Surge Warnings are in place.  Residents in these areas should 
follow advice given by local officials.
 
3. Heavy rainfall from this system could produce flash, urban, and 
small stream flooding impacts across portions of the Mid-Atlantic 
states from North Carolina to New Jersey through Sunday.
 
4. Swells generated by this system will affect much of the U.S.
east coast through the weekend, likely causing life-threatening
surf and rip currents.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  22/1500Z 32.3N  75.6W   45 KT  50 MPH...POTENTIAL TROP CYCLONE
 12H  23/0000Z 33.2N  76.3W   55 KT  65 MPH...TROPICAL CYCLONE
 24H  23/1200Z 34.9N  76.8W   50 KT  60 MPH...INLAND
 36H  24/0000Z 36.8N  77.0W   40 KT  45 MPH...INLAND
 48H  24/1200Z 38.3N  77.0W   30 KT  35 MPH...POST-TROP/EXTRATROP
 60H  25/0000Z 39.3N  76.5W   25 KT  30 MPH...POST-TROP/EXTRATROP
 72H  25/1200Z...DISSIPATED
 
$$
Forecaster Reinhart
 
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