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Tropical Storm Ophelia Discussion Number   7
NWS National Hurricane Center Miami FL       AL162023
1100 PM EDT Fri Sep 22 2023
 
Recent WSR-88D radar data from Wilmington and Morehead City, North
Carolina, show convection wrapping around Ophelia's center, which is
also embedded beneath a convective canopy in satellite imagery.
Soon after the previous advisory, the Air Force Reserve Hurricane
Hunters measured SFMR winds to hurricane force west of the center
within the deep convection, however those winds were not measured
again on their final pass through that area.  Radar imagery and
microwave data from that period showed that a mid-level eye feature
had been forming well to the west of the surface center, but that
feature has since dissipated, suggesting that it--and the
hurricane-force winds--may have been a transient occurrence.
Regardless, the SFMR and flight-level winds were strong enough to
support an intensity of 60 kt, and that remains the estimated
intensity right now.  Another Hurricane Hunter aircraft is
scheduled to investigate Ophelia in a couple of hours and should
provide a final estimate of the intensity before the storm reaches
land.
 
The current motion is north-northwestward (330 degrees) at 10 kt.
Ophelia is moving around the western periphery of the subtropical
ridge and is therefore expected to turn northward and then
northeastward during the next couple of days.  This track will take
Ophelia's center inland over North Carolina on Saturday, and then
across portions of southeastern Virginia and the Delmarva Peninsula
Saturday night and Sunday.  An additional westward shift was made
to the first 24 hours of the official track forecast, mainly due to
Ophelia's center being tugged westward by the deep convection
earlier this afternoon.
 
Ophelia's center is only expected to be over the warm waters of the
Gulf Stream for another 6 hours or so before moving inland, so the
window for strengthening is beginning to close.  It should be
stressed, however, that there is very little difference if Ophelia
reaches land as a 60-kt tropical storm or a 65-kt hurricane.
Weakening is expected once the center moves inland Saturday
morning, and the intensity guidance is in fairly good agreement
that the winds should drop below tropical storm force between 24
and 36 hours while Ophelia is over southeastern Virginia.  The
system is forecast to become extratropical by 36 hours, although
the latest phase-space diagrams and simulated satellite imagery
suggest this transition could happen as soon as 24 hours.  The
extratropical low is forecast to dissipate by 60 hours near the
Delmarva Peninsula when it becomes absorbed within its associated
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 Saturday night.  Hurricane conditions are
possible within the Hurricane Watch area early Saturday.
 
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 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  23/0300Z 33.6N  76.8W   60 KT  70 MPH
 12H  23/1200Z 35.0N  77.3W   50 KT  60 MPH...INLAND
 24H  24/0000Z 36.6N  77.5W   40 KT  45 MPH...INLAND
 36H  24/1200Z 38.0N  77.0W   30 KT  35 MPH...POST-TROP/EXTRATROP
 48H  25/0000Z 39.0N  76.1W   25 KT  30 MPH...POST-TROP/EXTRATROP
 60H  25/1200Z...DISSIPATED
 
$$
Forecaster Berg
 
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