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POST-TROPICAL CYCLONE COLIN DISCUSSION NUMBER   9
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032016
1100 AM EDT TUE JUN 07 2016

Satellite and surface observations indicate that Colin has become
post-tropical.  A pressure minimum has recently passed near NOAA
buoy 41013, but the circulation has become so elongated and ill
defined that the system can no longer be considered a tropical
cyclone.  However, strong winds are still occurring along the North
Carolina Outer Banks, so advisories will continue on a post-tropical
cyclone until these winds subside. The minimum pressure has fallen a
few millibars and recent buoy observations have recorded
tropical-storm-force winds near the western portion of the deep
convection.  Assuming stronger winds are occurring within the deep
convection and given the fast translational speed of the system, the
initial wind speed is increased to 50 kt.

The global models indicate that the post-tropical cyclone will
deepen due to baroclinic processes during the next day or so, and
the NHC intensity forecast calls for some additional strengthening.
After that time, the low is expected to gradually weaken over the
North Atlantic. The forecast intensities and wind radii of the
extratropical low are based on guidance provided by the Ocean
Prediction Center.

The post-tropical cyclone is moving northeastward at about 31 kt.
This general motion with some additional increase in forward speed
is expected during the next 24 to 36 hours.  After that time, the
cyclone should slow as it moves around and is eventually absorbed
by a larger low over the North Atlantic.


FORECAST POSITIONS AND MAX WINDS

INIT  07/1500Z 34.0N  77.0W   50 KT  60 MPH...POST-TROPICAL
 12H  08/0000Z 36.9N  70.5W   55 KT  65 MPH...POST-TROPICAL
 24H  08/1200Z 41.0N  61.5W   50 KT  60 MPH...POST-TROP/EXTRATROP
 36H  09/0000Z 45.0N  53.5W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  09/1200Z 48.0N  49.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  10/1200Z 51.5N  42.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 96H  11/1200Z 53.5N  36.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
120H  12/1200Z...Absorbed

$$
Forecaster Brown

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