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TROPICAL STORM ESTELLE DISCUSSION NUMBER  17
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP062016
800 AM PDT TUE JUL 19 2016

Estelle has a well-defined low-level structure with an eye-feature
noted in an early morning GPM microwave overpass.  However, the
convection surrounding the low-level center has not been
particularity deep or persistent.  Subjective Dvorak T-numbers from
TAFB and SAB are 4.0, but objective estimates are lower and until
the convection is able to maintain itself around the center, I have
elected to maintain the previous intensity of 55 kt.

Estelle has a little more than 24 hours remaining over warm
water and in a low vertical wind shear environment.  Most of the
intensity guidance calls for little change in strength, but the NHC
forecast will once again show Estelle reaching hurricane strength
given the good low-level structure and seemingly favorable
conditions.  After 24 hours, Estelle will be moving over
progressively cooler SSTs and into a less favorable thermodynamic
conditions.  This should lead to steady weakening and degeneration
into a remnant low in 3 to 4 days.

The tropical storm is moving west-northwest at 10 kt. Estelle is
expected to move on a west to west-northwestward track to the south
of a mid-level ridge that extends westward from northern Mexico.  A
mid- to upper-level forecast to drop south-southwestward between
140W and 150W is expected to erode the western portion of the ridge
after day 3.  As a result, Estelle is predicted to turn
northwestward later in the forecast period.  The model guidance
continued to be in good agreement, and the new NHC track forecast
is essentially an update of the previous advisory.

FORECAST POSITIONS AND MAX WINDS

INIT  19/1500Z 18.8N 118.8W   55 KT  65 MPH
 12H  20/0000Z 19.2N 120.5W   65 KT  75 MPH
 24H  20/1200Z 19.6N 122.7W   60 KT  70 MPH
 36H  21/0000Z 20.0N 125.2W   55 KT  65 MPH
 48H  21/1200Z 20.7N 127.7W   45 KT  50 MPH
 72H  22/1200Z 22.9N 132.8W   30 KT  35 MPH
 96H  23/1200Z 26.0N 137.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  24/1200Z 29.5N 140.0W   20 KT  25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Brown

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