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TROPICAL STORM BLANCA DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP022015
400 AM CDT TUE JUN 02 2015

The cloud pattern of Blanca has become a little better organized
overnight with increased banding and very deep convection over the
center.  However, there has been no recent microwave imagery to
assess the structure of the inner core.  Although the Dvorak
T-numbers are a little higher, a recent ASCAT pass suggest that
the maximum winds are still 40 to 45 kt.  Therefore, the initial
intensity remains 45 kt for this advisory.

The shear that has been affecting the cyclone during the past day
or so appears to have decreased with better anticyclonic outflow
noted over Blanca.  The tropical storm appears to be poised to
intensify as a favorable environment characterized by low shear,
warm water, and a moist atmosphere is expected during the next few
days.  The NHC forecast remains in good agreement with the SHIPS and
FSU Superensemble guidance, which both predict rapid strengthening
during the next day or two.  Late in the forecast period, increasing
shear and cooler SSTs should result in weakening.

The ASCAT data suggest that Blanca has drifted westward overnight,
however, little overall motion is forecast during the next couple
of days while the cyclone remains in an area of weak steering flow.
After 48 hours, a mid-level ridge is forecast to strengthen and
shift eastward over northern Mexico.  This should cause Blanca to
move northwestward at a faster forward speed beginning Thursday.
A northwestward to north-northwestward motion should continue on
days 3 through 5 while Blanca moves around the southwestern
periphery of the ridge.  The model guidance is in good agreement on
this scenario, but has shifted slightly westward this cycle. The
updated NHC forecast has been nudged in that direction, and lies
a little east of the model consensus.

FORECAST POSITIONS AND MAX WINDS

INIT  02/0900Z 13.3N 104.6W   45 KT  50 MPH
 12H  02/1800Z 13.3N 104.7W   60 KT  70 MPH
 24H  03/0600Z 13.1N 104.9W   75 KT  85 MPH
 36H  03/1800Z 12.9N 104.9W   90 KT 105 MPH
 48H  04/0600Z 12.9N 104.9W  105 KT 120 MPH
 72H  05/0600Z 15.0N 106.5W  120 KT 140 MPH
 96H  06/0600Z 17.9N 108.6W  100 KT 115 MPH
120H  07/0600Z 21.0N 110.0W   75 KT  85 MPH

$$
Forecaster Brown

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