000
WTPZ43 KNHC 071439
TCDEP3

HURRICANE BLAS DISCUSSION NUMBER  19
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP032016
800 AM PDT THU JUL 07 2016

Satellite imagery indicates that Blas is beginning to weaken.  The
eye has become a little less distinct this morning, and the
surrounding ring of deep convection has warmed over the
northwestern portion of the circulation.  A blend of the various
Dvorak T- and CI-numbers from SAB, TAFB, and UW-CIMSS yields an
initial wind speed of 105 kt. Blas is currently moving over
gradually decreasing SSTs, which should result in continued
weakening, however, given the annular hurricane characteristics of
Blas the rate of weakening is expected to be gradual today.  A more
rapid spin down should begin tonight or Friday when Blas moves over
even cooler water and into a more stable environment.  The hurricane
is forecast to become post-tropical in about 72 hours, and weaken to
a remnant low by day 5.

Blas is moving west-northwestward or 290/9.  The hurricane is
expected to continue moving west-northwestward today, but is
forecast to turn northwestward on Friday between a mid-level ridge
over northern Mexico and a mid-/upper-level low to the northeast of
the Hawaiian Islands.  The track guidance has come into better
agreement through this time period, and the NHC forecast is near
the middle of the guidance envelope through 72 hours.  After Blas
weakens and becomes a shallower system, the ECMWF takes the cyclone
west-southwestward while the remainder of the guidance shows a more
westward track. The NHC forecast favors the latter scenario and
remains north of the ECMWF solution at days 4 and 5.


FORECAST POSITIONS AND MAX WINDS

INIT  07/1500Z 16.2N 127.1W  105 KT 120 MPH
 12H  08/0000Z 16.8N 128.2W   95 KT 110 MPH
 24H  08/1200Z 17.7N 129.6W   80 KT  90 MPH
 36H  09/0000Z 18.9N 131.0W   65 KT  75 MPH
 48H  09/1200Z 20.1N 132.4W   50 KT  60 MPH
 72H  10/1200Z 21.9N 135.5W   35 KT  40 MPH...POST-TROPICAL
 96H  11/1200Z 22.0N 139.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  12/1200Z 22.0N 144.0W   20 KT  25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Brown