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Post-Tropical Cyclone Ophelia Discussion Number  11
NWS National Hurricane Center Miami FL       AL162023
1100 PM EDT Sat Sep 23 2023

Ophelia appears to have lost its tropical characteristics.  Surface 
observations show a well-defined wind shift associated with a 
frontal boundary extending across eastern Virginia, and the heaviest 
precipitation is now well north of the center, oriented along and 
to the north of the front.  In addition, phase space diagrams based 
on global model fields indicate that the system has entered the 
asymmetric cold-core regime.  Therefore, Ophelia is being declared a 
post-tropical cyclone.  Surface observations indicate that maximum 
winds have decreased to 30 kt, mainly over the ocean well east of 
the center.

With the last bit of convection having been sheared off to the 
north, the center appears to have slowed down since the last 
advisory, and the current estimate is northward at 360/7 kt.  The 
circulation is expected to turn northeastward on Sunday, but also 
become more diffuse while it moves across eastern Virginia and the 
Delmarva Peninsula.  The NHC forecast now shows the low becoming 
absorbed by the nearby frontal boundary by 36 hours.  Maximum winds 
are likely to remain around 30 kt until dissipation, mainly in 
a band to the north of the front off the coast of Long Island.

This is the last tropical cyclone discussion issued by the National 
Hurricane Center on Ophelia.  Future information on Ophelia can be 
found in discussions issued by the Weather Prediction Center 
beginning at 500 AM EDT, under AWIPS header TCDAT1, WMO header 
WTNT41 KWNH, and on the web at www.hurricanes.gov.

Key Messages:

1. Coastal flooding will continue along portions of Chesapeake Bay 
and its tidal rivers through Sunday.  Refer to statements from your 
local National Weather Service Forecast Office for additional 
information.

2. Heavy rainfall from Ophelia may produce localized flash and 
urban flooding impacts across portions of the Mid-Atlantic states 
from Virginia to New Jersey through Sunday.

3. Swells generated by Ophelia 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  24/0300Z 37.1N  77.6W   30 KT  35 MPH...POST-TROP/EXTRATROP
 12H  24/1200Z 38.2N  77.1W   30 KT  35 MPH...POST-TROP/EXTRATROP
 24H  25/0000Z 39.1N  75.7W   30 KT  35 MPH...POST-TROP/EXTRATROP
 36H  25/1200Z...DISSIPATED

$$
Forecaster Berg