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Post-Tropical Cyclone Idalia Discussion Number  29
NWS National Hurricane Center Miami FL       AL102023
500 PM AST Sat Sep 02 2023
 
Winds on Bermuda have been gradually decreasing since earlier this 
morning, and weather stations on the island are no longer measuring 
sustained tropical-storm-force winds (at standard elevation).  
Gusts to tropical storm force will likely continue on Bermuda into 
tonight while Idalia pulls away from the island, but the Bermuda 
Weather Service has elected to discontinue the Tropical Storm 
Warning in favor of local warnings.  Therefore, this will be the 
last NHC advisory on Idalia.

Earlier ASCAT showed that maximum winds remain 50 kt on the 
northwestern side of the attached frontal boundary.  Little change 
in strength is expected during the next few days.  The 
extratropical cyclone is likely to occlude again in about 3 days 
and begin to fill, at which point weakening is expected.  The NHC 
intensity forecast is between the HCCA and IVCN consensus aids.

Idalia appears to have turned toward the east-northeast, or 075/6 
kt.  A shortwave trough is expected to move off the coast of New 
England on Sunday, causing the cyclone to turn northeastward and 
the northward and speed up over the next 2-3 days.  Once it 
occludes, it is expected to slow down and meander to the southeast 
of Nova Scotia on days 4 and 5.

Additional information on this system can be found in High Seas
Forecasts issued by the National Weather Service, under AWIPS
header NFDHSFAT1, WMO header FZNT01 KWBC, and online at 
ocean.weather.gov/shtml/NFDHSFAT1.php
 
 
KEY MESSAGES:
 
1. Swells from Idalia are forecast to cause life-threatening surf
and rip current conditions along portions of the east coast of the
United States through Labor Day weekend.

2. Gusts to tropical storm force are likely to continue on Bermuda 
through tonight.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  02/2100Z 32.0N  62.7W   50 KT  60 MPH...POST-TROP/EXTRATROP
 12H  03/0600Z 32.5N  61.7W   50 KT  60 MPH...POST-TROP/EXTRATROP
 24H  03/1800Z 34.0N  60.0W   50 KT  60 MPH...POST-TROP/EXTRATROP
 36H  04/0600Z 36.0N  58.5W   50 KT  60 MPH...POST-TROP/EXTRATROP
 48H  04/1800Z 38.2N  57.6W   45 KT  50 MPH...POST-TROP/EXTRATROP
 60H  05/0600Z 40.1N  57.9W   45 KT  50 MPH...POST-TROP/EXTRATROP
 72H  05/1800Z 41.3N  58.9W   40 KT  45 MPH...POST-TROP/EXTRATROP
 96H  06/1800Z 43.2N  60.8W   35 KT  40 MPH...POST-TROP/EXTRATROP
120H  07/1800Z 45.1N  59.4W   30 KT  35 MPH...POST-TROP/EXTRATROP
 
$$
Forecaster Berg
 
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