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Post-Tropical Cyclone Ian Forecast Discussion


000
WTNT44 KNHC 302044
TCDAT4

Post-Tropical Cyclone Ian Discussion Number  33
NWS National Hurricane Center Miami FL       AL092022
500 PM EDT Fri Sep 30 2022

Deep convection has ceased now that Ian has lost its energy source 
from the Atlantic Ocean, and the circulation has wrapped into cooler 
surface air.  Thus, Ian has transitioned into an extratropical low. 
The initial wind speed is set to 60 kt based on elevated 
hurricane-force winds still being observed on radar offshore of 
eastern South Carolina.

Ian continues to move faster to the north, around 13 kt, and should
turn to the north-northwest later today due to a shortwave trough
over the southeastern United States.  Ian should rapidly weaken in
the cool airmass and dissipate by early Sunday over western North
Carolina or Virginia.  No significant changes were made to the
track or intensity forecast.

It should be emphasized that just because Ian has become a 
post-tropical cyclone that the danger is not over.  Dangerous storm 
surge, flash flooding and high winds are still in the forecast from 
this cyclone.  

Key Messages:

1. There is a danger of life-threatening storm surge this evening 
along the coasts of the Carolinas within the Storm Surge Warning 
areas.

2. Tropical-storm-force winds are expected along the coasts of South
Carolina and southeastern North Carolina within the warning area
through early Saturday.

3. Ongoing major-to-record river flooding will continue through
next week across portions of central Florida. Considerable flooding
is expected today across portions of coastal and northeast South
Carolina, coastal North Carolina and southeast Virginia. Locally
considerable flooding is possible across portions of northwest North
Carolina and southern Virginia today into early Saturday.


FORECAST POSITIONS AND MAX WINDS

INIT  30/2100Z 33.9N  79.2W   60 KT  70 MPH...POST-TROPICAL
 12H  01/0600Z 35.8N  79.6W   35 KT  40 MPH...POST-TROP/EXTRATROP
 24H  01/1800Z 37.5N  80.0W   20 KT  25 MPH...POST-TROP/EXTRATROP
 36H  02/0600Z...DISSIPATED

$$
Forecaster Blake



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