[Tropical] Tropical Cyclone Discussion

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WTNT41 KNHC 230850
TCDAT1

Tropical Storm Ophelia Discussion Number   8
NWS National Hurricane Center Miami FL       AL162023
500 AM EDT Sat Sep 23 2023

WSR-88D radar data from Wilmington and Morehead City, North
Carolina, show that the center of Ophelia is approaching the North
Carolina coastline with landfall likely within the next couple of
hours.  The Air Force Hurricane Hunters have been investigating the
system during the last several hours and have found that central
pressure of  Ophelia has dropped a few millibars to 980 mb this
morning, with highest flight-level winds on the eastern side of the
system. Using the standard surface wind reduction from flight-level
suggest that maximum surface winds are likely between 60-65 kt. The
initial intensity is held at 60 kt based on a combination of the
flight-level winds and velocity data from Doppler radar.

Ophelia's motion has been fairly erratic the past several hours as
it approaches the coast. The current estimated motion is is
north-northwestward (345 degrees) at 8 kt. Ophelia is moving around
the western periphery of the subtropical ridge and is expected to
turn more northward today and then northeastward the next few days.
On this track the center of Ophelia will move inland over North
Carolina in a few hours, and then across portions of southeastern
Virginia and the Delmarva Peninsula tonight and Sunday. There was
very little change in the forecast with just a slight rightward
shift in about 36 h over the Delmarva.  This forecast is in fairly
good agreement with the global model guidance.

Ophelia will be making landfall in North Carolina within a few hours
and the intensity guidance is in fairly good agreement with steady
weakening and winds should drop below tropical-storm-force in about
a day or so. The system is forecast to become extratropical by 36
hours, although simulated satellite imagery and models suggest this
transition could happen near or just beyond 24 h.  The extratropical
low will dissipate over the Delmarva Peninsula when it becomes
absorbed within a frontal zone.


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 through tonight.  Hurricane conditions are possible
within the Hurricane Watch area early this morning.

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 may produce locally considerable
flash, and urban 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  23/0900Z 34.3N  76.9W   60 KT  70 MPH
 12H  23/1800Z 35.5N  77.5W   45 KT  50 MPH...INLAND
 24H  24/0600Z 37.0N  77.3W   35 KT  40 MPH...INLAND
 36H  24/1800Z 38.2N  76.3W   30 KT  35 MPH...POST-TROP/EXTRATROP
 48H  25/0600Z 39.0N  75.2W   25 KT  30 MPH...POST-TROP/EXTRATROP
 60H  25/1800Z...DISSIPATED

$$
Forecaster Kelly/Cangialosi
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