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Post-Tropical Cyclone Dorian Discussion Number 59
NWS National Hurricane Center Miami FL AL052019
500 PM AST Sat Sep 07 2019
Satellite imagery and surface observations indicate that Dorian has
lost tropical cyclone characteristics and is now a hurricane-force
extratropical low. The initial intensity is held at 85 kt based
mainly on the earlier scatterometer data.
The initial motion is 040/26. Strong mid-latitude southwesterly
flow should steer Dorian across Nova Scotia and other portions of
eastern Canada during the next 24-30 h. After that, the cyclone
should turn east-northeastward over the far north Atlantic, with
this motion continuing for the rest of the system's life.
Global model guidance indicates that the post-tropical cyclone
should gradually weaken as it moves across eastern Canada, and the
new intensity forecast brings the winds below hurricane force by 24
h. Additional weakening should then occur until the storm is
absorbed by a large extratropical low to its north.
The National Hurricane Center will continue to issue advisories on
Dorian as a post-tropical cyclone until the threat to eastern
Canada has ended.
Key Messages:
1. Although Dorian has lost tropical cyclone characteristics, it
will have significant impacts in portions of eastern Canada tonight
and Sunday. Dangerous storm surge impacts are likely in portions of
the Gulf of St. Lawrence, southwestern Newfoundland and eastern Nova
Scotia. Hurricane-force winds are also likely in Nova Scotia,
Prince Edward Island and Newfoundland later today and tonight. Refer
to information from the Canadian Hurricane Centre for more
information on these hazards.
FORECAST POSITIONS AND MAX WINDS
INIT 07/2100Z 43.9N 63.9W 85 KT 100 MPH...POST-TROPICAL
12H 08/0600Z 47.0N 61.1W 70 KT 80 MPH...POST-TROP/EXTRATROP
24H 08/1800Z 50.2N 56.9W 60 KT 70 MPH...POST-TROP/EXTRATROP
36H 09/0600Z 53.0N 50.9W 50 KT 60 MPH...POST-TROP/EXTRATROP
48H 09/1800Z 55.4N 43.7W 45 KT 50 MPH...POST-TROP/EXTRATROP
72H 10/1800Z...DISSIPATED
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Forecaster Beven
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