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TROPICAL STORM ESTELLE DISCUSSION NUMBER 9
NWS NATIONAL HURRICANE CENTER MIAMI FL EP062016
900 AM MDT SUN JUL 17 2016
A large burst of deep convection developed over the center of
Estelle overnight and continues this morning. A timely SSMIS
microwave overpass was very helpful in examining the structure and
center location of the tropical cyclone. The microwave data
revealed a well-defined low-level ring located near the northwestern
edge of the primary convective band, but there was no evidence of a
mid-level eye. The latest Dvorak T-numbers from SAB and TAFB
are 3.5 and 4.0, respectively, and UW/CIMSS ADT estimates have
risen to T3.5/55 kt. These data support an initial wind speed
of 55 kt for this advisory.
The initial motion estimate is 285/7 kt. A strong subtropical ridge
to the north of Estelle should keep the tropical cyclone moving on
a westward to west-northwestward heading during the next several
days. Near the end of the forecast period, Estelle will be
approaching the western portion of the ridge, which should allow the
tropical cyclone to gain more latitude. The guidance is more
tightly clustered today than it was 24 hours ago, so there is
increased confidence in the track forecast. The new NHC track is
near the Florida State Superensemble and an average of the GFS/ECMWF
models.
There appears to be some north or northwesterly shear still
affecting Estelle, but the shear is not expected to be strong
enough to prevent intensification during the next day or so. After
that time, the shear is forecast to relax, and Estelle is forecast
to strengthen at a faster rate on Monday. The track of the tropical
cyclone brings it over cooler waters in 2 to 3 days, which should
start the weakening process, and it should continue throughout the
remainder of the forecast period. The updated intensity forecast is
similar to the previous advisory, and is closest to the Florida
State Superensemble and the intensity consensus IVCN.
FORECAST POSITIONS AND MAX WINDS
INIT 17/1500Z 16.3N 111.8W 55 KT 65 MPH
12H 18/0000Z 16.6N 112.9W 65 KT 75 MPH
24H 18/1200Z 17.2N 114.6W 70 KT 80 MPH
36H 19/0000Z 17.6N 116.3W 80 KT 90 MPH
48H 19/1200Z 17.9N 118.1W 85 KT 100 MPH
72H 20/1200Z 18.2N 122.2W 80 KT 90 MPH
96H 21/1200Z 19.0N 127.0W 65 KT 75 MPH
120H 22/1200Z 20.8N 132.5W 45 KT 50 MPH
$$
Forecaster Brown
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