000
WTPZ43 KNHC 070234
TCDEP3

HURRICANE BLAS DISCUSSION NUMBER  17
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP032016
800 PM PDT WED JUL 06 2016

The satellite presentation of Blas remains quite impressive. The eye
of the hurricane is about 20-25 n mi wide with evidence of
mesovorticies within it.  The convective structure has changed
little throughout the day and remains fairly symmetric around the
center.  A blend of the latest Dvorak classifications from TAFB,
SAB, and the automated technique from CIMSS at the University of
Wisconsin suggest that the intensity of Blas is holding steady at
around 110 kt.

The major hurricane is not far away from cool water, and it
will likely be crossing the 26 C isotherm in about 12 hours.
These anticipated unfavorable oceanic conditions combined with a
progressively more stable air mass should promote a steady
weakening trend during the next several days.  The NHC intensity
forecast is an update of the previous one and is fairly close to the
intensity model consensus.  The system is forecast to become a
post-tropical cyclone in about 4 days when sea surface temperatures
beneath the cyclone will likely be around 24 C.

Blas is moving west-northwestward at about 10 kt on the
southwestern periphery of a sprawling mid-level ridge.  This general
motion should continue for the next couple of days as the ridge
remains the primary steering influence.  Beyond that time, the
forecast track is less certain as the model spread remains quite
large with the GFS-based guidance showing a northwestward motion
around the east side of a mid- to upper-level low northeast of
the Hawaiian Islands.  Conversely, the ECMWF and UKMET models show
less interaction with the upper low, resulting in a more westward
track.  The NHC track forecast remains near the middle of the
guidance envelope and is in best agreement with the consensus aids.

FORECAST POSITIONS AND MAX WINDS

INIT  07/0300Z 15.7N 125.4W  110 KT 125 MPH
 12H  07/1200Z 16.1N 126.8W  100 KT 115 MPH
 24H  08/0000Z 16.7N 128.4W   90 KT 105 MPH
 36H  08/1200Z 17.5N 129.8W   75 KT  85 MPH
 48H  09/0000Z 18.7N 131.2W   65 KT  75 MPH
 72H  10/0000Z 20.8N 134.1W   50 KT  60 MPH
 96H  11/0000Z 22.1N 138.2W   35 KT  40 MPH...POST-TROPICAL
120H  12/0000Z 22.2N 142.5W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Cangialosi