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HURRICANE GONZALO DISCUSSION NUMBER 17
NWS NATIONAL HURRICANE CENTER MIAMI FL AL082014
1100 AM AST THU OCT 16 2014
A NOAA Hurricane Hunter aircraft investigating Gonzalo measured an
SFMR surface wind of 135 kt, but this observation was not supported
by the flight-level winds, which were only as high as 126 kt
in the northeastern quadrant, or SFMR data in subsequent passes in
that portion of the storm. The initial intensity is raised to 125 kt
on this advisory based on a compromise between the flight-level and
SFMR data, as well as satellite intensity estimates that range from
T5.5/102 kt from SAB and T6.6/130 kt from the UW-CIMSS ADT.
Fluctuations in intensity are likely during the next 12-24 hours
while Gonzalo remains in a relatively light-shear environment and
over warm sea surface temperatures. Some weakening is anticipated
on Friday once the vertical shear begins to increase, but Gonzalo is
not forecast to reach sub-26C water until about 48 hours.
Therefore, the hurricane is expected to maintain major
hurricane strength through the next 36 hours or so while it passes
Bermuda, with more rapid weakening forecast after 48 hours. The
official forecast is a little higher than the previous one during
the first 48 hours to account for the updated initial intensity.
This forecast is close to the SHIPS and LGEM guidance for the next
24 hours and then close to the intensity consensus thereafter.
Gonzalo is still forecast to be a post-tropical cyclone by day 3
while it passes near Newfoundland, and at that point it
should also be very close to taking on frontal characteristics.
Gonzalo should dissipate by day 5 while it moves eastward over the
The initial motion is 005/6 kt. Gonzalo is moving a little slower
than was previously forecast, which is having some downstream
effects on the track forecast. There is very little cross-track
spread among the model guidance, but nearly all of the track models
are slower than the previous forecast. Gonzalo is moving northward
to the east of a deep-layer trough over the eastern United States,
and the hurricane should begin to accelerate north-northeastward
ahead of this trough from this point forward. Since this
acceleration is somewhat delayed, the updated NHC track forecast is
a little slower than the previous one, and lies close to TVCA
and a GFS-ECMWF blend.
The post-tropical portion of the forecast has been coordinated with
the NOAA Ocean Prediction Center.
FORECAST POSITIONS AND MAX WINDS
INIT 16/1500Z 26.1N 68.6W 125 KT 145 MPH
12H 17/0000Z 27.5N 68.0W 125 KT 145 MPH
24H 17/1200Z 29.9N 66.6W 115 KT 130 MPH
36H 18/0000Z 32.6N 64.9W 105 KT 120 MPH
48H 18/1200Z 36.5N 62.4W 100 KT 115 MPH
72H 19/1200Z 46.5N 50.5W 70 KT 80 MPH...POST-TROPICAL
96H 20/1200Z 52.0N 29.0W 40 KT 45 MPH...POST-TROP/EXTRATROP