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HURRICANE DOLORES DISCUSSION NUMBER  12
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP052015
300 AM MDT TUE JUL 14 2015

The satellite presentation overnight shows an improved cloud
pattern with a well-developed symmetric Central Dense Overcast and
cloud tops of -80 degrees C. Microwave overpasses also indicate
developing spiral bands over the western portion of the cyclone.
Objective and subjective Dvorak satellite intensity estimates along
with an earlier AMSU-B estimate support increasing the initial
intensity to 70 kt.  There is some northerly shear that appears to
be impinging on the northwestern quadrant of the system but,
guidance indicates that the shear will relax within the next 12-24
hours and the upper flow pattern over the southern half of the
system is quite diffluent.  The intensity forecast continues to
reflect strengthening to a major hurricane in 36-48 hours as
indicated by the SHIPS model and the GFS, which has been exhibiting
some intensity skill this season.  Afterward, gradual weakening is
forecast as the cyclone moves over cooler water and into the
southern extent of a southward propagating stable air mass.

A series of microwave overpasses suggest that Dolores is moving
slightly to the left of track or, westward at 280/5 kt within
the weak peripheral flow of a ridge stretching over Texas and
northern Mexico.  Dynamical guidance indicates that this current
motion is temporary, however, and a turn back toward the
west-northwest is expected later today and should continue during
the next couple of days.  Beyond the 48 hour period, the global
models show the ridge strengthening and building westward into Baja
California.  This change in the synoptic steering pattern should
cause Dolores to gradually increase in forward speed while
continuing on a west-northwest heading through 96 hours.  At the
end of the period, the forecast indicates a turn toward the
northwest which is based on the GFEX, a blend of the GFS and ECMWF
global models.  The NHC forecast has been adjusted slightly to the
right of the previous forecast to correspond with the GFEX and TVCN
consensus models.


FORECAST POSITIONS AND MAX WINDS

INIT  14/0900Z 17.3N 107.5W   70 KT  80 MPH
 12H  14/1800Z 17.5N 108.1W   80 KT  90 MPH
 24H  15/0600Z 17.9N 108.9W   90 KT 105 MPH
 36H  15/1800Z 18.4N 109.7W  100 KT 115 MPH
 48H  16/0600Z 19.0N 110.7W  105 KT 120 MPH
 72H  17/0600Z 20.4N 113.4W   90 KT 105 MPH
 96H  18/0600Z 21.9N 116.7W   75 KT  85 MPH
120H  19/0600Z 24.5N 120.0W   55 KT  65 MPH

$$
Forecaster Roberts

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