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TROPICAL STORM ESTELLE DISCUSSION NUMBER  20
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP062016
200 AM PDT WED JUL 20 2016

Other than a brief warm spot appearing within the small CDO feature
around 0400Z, the overall convective structure of Estelle has
changed little since the previous advisory. Recent microwave
satellite data, especially a 0531Z AMSU pass, continue to indicate
that the cyclone has been unable to completely close off a mid-level
eye feature. The initial intensity remains 60 kt based on an average
of subjective and objective intensity estimates, and the lack of a
persistent, well-developed eye feature in microwave data.

Estelle has made a jog to the west, and the motion estimate is now
270/10 kt. Estelle is expected to continue on a westward track for
the next 12 h or so, followed by a turn toward the west-northwest by
this afternoon, a motion that is forecast to continue through 48 h.
By 72 h and beyond, Estelle is expected to turn northwestward and
move into a trough-induced break in the subtropical ridge around
130-135W longitude. The new NHC guidance is in good agreement on
this scenario, and the official forecast track lies close to the
previous advisory track and the consensus model TVCN.

It isn't out of the question that Estelle could still briefly reach
hurricane strength this morning. However, any strengthening that
might occur will be short-lived now that the cyclone is moving over
sub-26C sea-surface temperatures. Although the vertical wind shear
is forecast by both the GFS and ECMWF models to remain quite low,
sharply decreasing SSTs and much drier mid-level air should cause
Estelle to steadily weaken after 12 h. The cyclone is forecast to
become a post-tropical low in 48 h when Estelle will be moving over
22C SSTs, and dissipation is expected by 120 h. The new intensity
forecast is essentially just an update of the previous advisory, and
closely follows the intensity consensus model IVCN.

FORECAST POSITIONS AND MAX WINDS

INIT  20/0900Z 19.0N 122.0W   60 KT  70 MPH
 12H  20/1800Z 19.4N 124.1W   60 KT  70 MPH
 24H  21/0600Z 19.9N 126.7W   55 KT  65 MPH
 36H  21/1800Z 20.6N 129.4W   45 KT  50 MPH
 48H  22/0600Z 21.6N 132.0W   35 KT  40 MPH...POST-TROPICAL
 72H  23/0600Z 24.5N 136.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  24/0600Z 28.1N 140.6W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  25/0600Z...DISSIPATED

$$
Forecaster Stewart

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