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HURRICANE BLAS DISCUSSION NUMBER  12
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP032016
200 PM PDT TUE JUL 05 2016

Blas has the classic appearance of a powerful hurricane in satellite
imagery this afternoon, with a 20 n mi wide eye embedded in a
symmetric central dense overcast which in turn is almost surrounded
by outer convective bands.  Satellite intensity estimates are 115
kt from SAB and 102 kt from TAFB, and a recent CIMSS Advanced
Dvorak Technique estimate is 110 kt.  Based on these data, the
initial intensity is increased to 110 kt, making Blas the first
major hurricane of the eastern Pacific season.

Blas continues its westward movement with an initial motion of
275/14.  For the next 72 hours or so, the hurricane should be
steered generally westward to west-northwestward by a deep-layer
ridge over the subtropical eastern Pacific.  This portion of the
new forecast track is an update of the previous track.  After 72
hours, the forecast confidence decreases as the track guidance
diverges.  The GFS, UKMET, NAVGEM, and Canadian models turn Blas
northwestward between the ridge and a large mid- to upper-level low
centered to the northeast of the Hawaiian islands.  In contrast
to the other models, the ECMWF forecasts the low to move westward
with mid-level ridging developing between it and Blas.  Thus, it
forecasts Blas to turn westward by 120 hours.  The new forecast
track is similar to the old track in showing a west-northwestward
motion at 96 and 120 hours, with the track lying between the ECMWF
and the other models.

Blas should remain in a light-shear environment over warm water for
the next 12-24 hours or so, and some additional strengthening is
possible during this time.  While the shear is expected to be
light to moderate during the forecast period, the cyclone should
move over decreasing sea surface temperatures after 24 hours which
should cause a steady weakening.  The new forecast intensity is
similar to that of the previous advisory and calls for Blas to decay
to a remnant low over cold water by 120 hours. However, if the ECMWF
track verifies, the system would stay over warmer water and likely
remain a tropical cyclone at 120 hours and beyond.


FORECAST POSITIONS AND MAX WINDS

INIT  05/2100Z 14.3N 120.9W  110 KT 125 MPH
 12H  06/0600Z 14.6N 122.7W  120 KT 140 MPH
 24H  06/1800Z 15.1N 124.8W  120 KT 140 MPH
 36H  07/0600Z 15.7N 126.8W  110 KT 125 MPH
 48H  07/1800Z 16.3N 128.6W   95 KT 110 MPH
 72H  08/1800Z 17.5N 131.5W   75 KT  85 MPH
 96H  09/1800Z 20.0N 135.0W   50 KT  60 MPH
120H  10/1800Z 21.1N 139.0W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Beven

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