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TROPICAL STORM DOLORES DISCUSSION NUMBER   6
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP052015
400 PM CDT SUN JUL 12 2015

There has been no significant change in Dolores' organization
during the past several hours.  Satellite imagery continues to
show most of the cyclone's deep convection remaining in a band over
the northeastern semicircle of the circulation. This convective
asymmetry is likely related to some west-northwesterly shear as
diagnosed by UW-CIMSS and SHIPS shear analyses. An ASCAT-B pass
showed the center barely underneath the convective mass, with peak
uncontaminated winds around 45 kt. Based on the ASCAT data, the
initial intensity is raised to 45 kt.

The ASCAT pass showed the center of Dolores to be a bit farther
south than previous estimates, and the heading is estimated to be
more westerly or 295/09.  A subtropical ridge over the south-central
United States should guide Dolores generally west-northwestward
with a decrease in forward speed during the next 48 hours.  The
cyclone's heading should become more northwesterly by 72 hours, when
Dolores reaches the western periphery of the ridge. Later in the
forecast period, Dolores' track should bend back toward the west-
northwest as the subtropical ridge reasserts itself.  The
official track forecast is similar to but a little to the left of
the previous one through 48 hours and slightly to the right after
that.  The track forecast after 48 hours is near a multi-model
consensus that excludes the GFDL solution which unrealistically
takes Dolores toward the Baja California peninsula.

Thermodynamic variables in the near-storm environment are quite
conducive for intensification, with sea surface temperatures of
29-30 deg C and plenty of deep-layer moisture.  Some west-
northwesterly shear is forecast to persist and perhaps even
increase over the next day or so before decreasing from 72 hours
through the remainder of the forecast period.  However, the shear
is not expected to be strong enough to impede steady
intensification.  With a sharp gradient in SSTs along 20N, the
intensity late in the period is very much dependent on how much
latitude Dolores gains by that time.  The NHC intensity forecast is
about the same as the previous one and is very similar to the
multi-model consensus (ICON) through 48 hours but above ICON
after that, closest to the SHIPS model guidance.

FORECAST POSITIONS AND MAX WINDS

INIT  12/2100Z 15.6N 103.0W   45 KT  50 MPH
 12H  13/0600Z 16.2N 104.5W   55 KT  65 MPH
 24H  13/1800Z 16.8N 106.0W   65 KT  75 MPH
 36H  14/0600Z 17.2N 107.1W   75 KT  85 MPH
 48H  14/1800Z 17.7N 108.0W   80 KT  90 MPH
 72H  15/1800Z 18.9N 109.7W   95 KT 110 MPH
 96H  16/1800Z 20.0N 112.0W   90 KT 105 MPH
120H  17/1800Z 20.9N 114.9W   85 KT 100 MPH

$$
Forecaster Kimberlain

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