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TROPICAL STORM ESTELLE DISCUSSION NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP062016
300 PM MDT SUN JUL 17 2016

Recent satellite data have given mixed signals on the overall
structure of Estelle.  In visible satellite pictures, a band of
convection has wrapped around the center, and what looks like a
ragged eye has appeared.  However, recent microwave imagery
suggest that the structure is not as well organized with the
low-level center displaced to west of the mid-level center,
likely the result of continued northwesterly shear. Subjective
T-numbers of 4.0 from TAFB and SAB support an intensity of 65 kt,
but, given the lack of inner-core organization, the initial wind
speed is set to 60 kt.  Recent ASCAT data revealed a large radius of
maximum winds, and larger area of tropical-storm-force winds, which
required an outward adjustment of the wind radii.

Estelle continues to move westward to west-northwestward at about
7 kt. The track forecast reasoning remains the same as the
previous advisory.  The tropical storm is forecast to move
west-northwestward to the south of a strong subtropical ridge
during the next several days. Estelle will be nearing the western
portion of the ridge by day 5 and a turn toward the northwest is
predicted near the end of the period.  Although the guidance is
still in fairly good agreement, most of the models have shifted
northward this cycle.  The NHC track has been adjusted accordingly,
but it lies just south of the multi-model consensus and the latest
GFS and ECMWF tracks.

The moderate northwesterly shear over the tropical storm is expected
to weaken during the next 24 hours, which should allow for gradual
intensification.  Estelle is predicted to reach peak intensity in
36-48 hours, and the NHC intensity forecast is near the high end of
the guidance.  After that time, cooler water and a more stable
airmass should induce weakening, and Estelle is predicted to
become a post-tropical cyclone in about 5 days.


FORECAST POSITIONS AND MAX WINDS

INIT  17/2100Z 16.5N 112.5W   60 KT  70 MPH
 12H  18/0600Z 17.0N 113.7W   70 KT  80 MPH
 24H  18/1800Z 17.6N 115.4W   75 KT  85 MPH
 36H  19/0600Z 18.0N 117.2W   80 KT  90 MPH
 48H  19/1800Z 18.4N 119.1W   80 KT  90 MPH
 72H  20/1800Z 19.0N 123.3W   65 KT  75 MPH
 96H  21/1800Z 20.0N 128.2W   55 KT  65 MPH
120H  22/1800Z 22.0N 133.5W   35 KT  40 MPH...POST-TROPICAL

$$
Forecaster Brown

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