Hurricane GONZALO

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HURRICANE GONZALO DISCUSSION NUMBER  26
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL082014
500 PM AST SAT OCT 18 2014

After an earlier degradation of the convective cloud pattern,
Gonzalo has made a recent comeback with the cloud shield having
become more symmetrical and the eye a little better defined. The
initial intensity of 80 kt is being maintained at 80 kt based on an
1443 UTC ASCAT-A overpass which showed a peak of 77 kt in the
eastern quadrant and the improved satellite presentation. The same
overpass also indicated that the 64-, 50-, and 34-kt wind radii had
expanded, and this is indicated in the new initial wind radii.

Gonzalo is accelerating rapidly northeastward and is now moving
at a brisk 035/31 kt. The hurricane has become deeply embedded
within the strong southwesterly flow on the east side of a high
amplitude trough located over the northeastern United States
and southeastern Canada. Gonzalo is expected to move northeastward
for the next 24 hours or so and then turn east-northeastward over
the far north Atlantic on Day 2. The official forecast track is
similar to the previous advisory track, and closely follows the
consensus model TVCA. The post-tropical portion of the track
forecast has been coordinated with the NOAA Ocean Prediction Center.

As Gonzalo continues to gain latitude, the cyclone's wind field
should continue to expand, accompanied by only slow weakening.
Gonzalo will be moving over sub-20C SSTs by 12 hours and be under
southwesterly vertical wind shear of more than 30 kt, which is
expected to result in transition to a strong post-tropical
extratropical cyclone by 24 hours. Gradual weakening is expected
after the transition occurs until dissipation occurs in about 72
hours. The NHC intensity forecast follows the Decay-SHIPS model
through 24 hours, and then is based on input from the Ocean
Prediction Center.

FORECAST POSITIONS AND MAX WINDS

INIT  18/2100Z 39.3N  60.0W   80 KT  90 MPH
 12H  19/0600Z 44.0N  54.9W   70 KT  80 MPH
 24H  19/1800Z 49.6N  45.1W   60 KT  70 MPH...POST-TROP/EXTRATROP
 36H  20/0600Z 52.5N  31.5W   55 KT  65 MPH...POST-TROP/EXTRATROP
 48H  20/1800Z 55.5N  17.5W   50 KT  60 MPH...POST-TROP/EXTRATROP
 72H  21/1800Z...DISSIPATED

$$
Forecaster Stewart

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