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TROPICAL STORM KATE DISCUSSION NUMBER  13
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL122015
1100 PM AST WED NOV 11 2015

Kate continues to undergo extratropical transition. Satellite
imagery show that Kate's cloud pattern has become increasingly
elongated and asymmetric since the last advisory due to strong
westerly shear. The cloud pattern has also taken on a comma-shape
appearance, typically a precursor to frontogenesis and a completion
of extratropical transition.  The initial intensity is lowered to 60
kt, based on a blend of Dvorak CI-numbers from TAFB and SAB.  A mid-
to upper-level trough is forecast to merge with Kate in about 12
hours or so, which should result in Kate's becoming post-tropical.
After this occurs, baroclinic forcing from the trough should allow
the post-tropical cyclone to maintain its intensity or perhaps even
re-strengthen as indicated in the global models through about 24
hours.  Beyond this time, a slow decay is forecast, with the post-
tropical cyclone predicted to lose its identity in about 3 days
when a new baroclinic development over the far north Atlantic
becomes more dominant.  The new intensity forecast represents an
update of the previous one, with dissipation now shown a day sooner.

Kate continues to move rapidly east-northeastward but appears to
have slowed down some, and the initial motion estimate is 065/36.
As a post-tropical cyclone, Kate's motion is forecast to decrease
further during the next during 24 hours while it merges with the
extratropical system to the west.  A new and potent shortwave
trough reaching Atlantic Canada in 2 to 3 days should then cause
Kate to accelerate east-northeastward to northeastward until
dissipation. The new track forecast is generally slower relative
to the previous one, consistent with the multi-model consensus.


FORECAST POSITIONS AND MAX WINDS

INIT  12/0300Z 40.1N  52.3W   60 KT  70 MPH
 12H  12/1200Z 41.2N  50.0W   60 KT  70 MPH...POST-TROP/EXTRATROP
 24H  13/0000Z 42.2N  46.8W   55 KT  65 MPH...POST-TROP/EXTRATROP
 36H  13/1200Z 43.1N  43.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  14/0000Z 45.3N  37.2W   45 KT  50 MPH...POST-TROP/EXTRATROP
 72H  15/0000Z 53.8N  22.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 96H  16/0000Z...DISSIPATED

$$
Forecaster Kimberlain

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