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HURRICANE BLAS DISCUSSION NUMBER  11
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP032016
800 AM PDT TUE JUL 05 2016

Blas has been intensifying rapidly this morning.  Satellite imagery
shows a ragged eye that has been warming and becoming better defined
in the middle of a large-sized central dense overcast (CDO).  A
special Dvorak satellite classification from TAFB suggests that the
cyclone is close to major hurricane status, so the initial intensity
is boosted to 95 kt, and this could be conservative.

Blas has been moving nearly due westward since the last advisory,
with a longer-term initial motion estimate of 280/13.  For about
the next 72 hours, the track model output is in good agreement that
Blas should be steered westward and then west-northwestward around
the southern and western periphery of a deep-layer ridge over the
subtropical eastern Pacific.  After that time, there is a rather
significant divergence in the track guidance.  The bulk of the model
solutions indicate a northwestward track when Blas interacts with
a cut-off low well northwest of it and encounters weaker ridging.
The ECMWF and its ensemble mean, however, predict a much more
southerly track in response to a stronger subtropical ridge. The
NHC forecast track is adjusted to the south of the previous one,
owing mostly to the more westerly initial motion.  The track
forecast is closer to the ECMWF solution beyond day 3, based on the
premise that Blas should weaken significantly and become a shallow
cyclone during that time.

Given that Blas is undergoing rapid intensification, the short-term
forecast shows a significant increase in intensity within the next
12 to 24 hours and is above all of the numerical guidance.  Later in
the period the hurricane should be moving over cooler waters, so a
gradual weakening trend is expected to commence in about 48 hours.
If Blas follows a more southern route than anticipated, however, it
could weaken more slowly than shown here.


FORECAST POSITIONS AND MAX WINDS

INIT  05/1500Z 14.1N 119.5W   95 KT 110 MPH
 12H  06/0000Z 14.4N 121.5W  110 KT 125 MPH
 24H  06/1200Z 14.8N 123.7W  120 KT 140 MPH
 36H  07/0000Z 15.4N 125.5W  110 KT 125 MPH
 48H  07/1200Z 16.0N 127.4W   95 KT 110 MPH
 72H  08/1200Z 17.4N 130.9W   75 KT  85 MPH
 96H  09/1200Z 19.1N 134.3W   45 KT  50 MPH
120H  10/1200Z 20.6N 137.7W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Kimberlain

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