315 
 WTPZ41 KNHC 201436
 TCDEP1
 
 TROPICAL STORM ESTELLE DISCUSSION NUMBER  21
 NWS NATIONAL HURRICANE CENTER MIAMI FL       EP062016
 800 AM PDT WED JUL 20 2016
 
 Estelle has generally changed little since the previous advisory.
 The convective pattern still consists of a well organized curved
 band that covers much of the eastern half of the circulation and
 fragmented bands to the west of the center.  The initial wind speed
 is held at 60 kt for this advisory, which is an average of the
 Dvorak CI-numbers from TAFB and SAB.  Estelle is crossing the
 26 deg C isotherm and will be moving over progressively cooler water
 during the next few days.  In addition, the storm will also be
 moving into an atmosphere of drier air and increasing westerly
 shear.  Given these expected environmental conditions, steady
 weakening is forecast during the period, and Estelle will likely
 become a post-tropical cyclone in about 2 days when it is over SSTs
 around 22 deg C.
 
 The storm is moving westward at about 11 kt on the southwest side
 of a large subtropical ridge centered over the southern United
 States.  Estelle is forecast to reach the western periphery of the
 ridge in a couple of days, which should induce a turn to the
 northwest.  A northwestward motion is expected to continue until
 the system dissipates in 4 to 5 days.  The models are in good
 agreement on this overall scenario, and the new NHC track forecast
 is largely an update of the previous one.  This track prediction is
 in best agreement with a consensus of the GFS and ECMWF models.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  20/1500Z 19.2N 123.3W   60 KT  70 MPH
  12H  21/0000Z 19.5N 125.3W   55 KT  65 MPH
  24H  21/1200Z 20.2N 128.0W   50 KT  60 MPH
  36H  22/0000Z 21.0N 130.8W   40 KT  45 MPH
  48H  22/1200Z 22.1N 133.3W   35 KT  40 MPH...POST-TROPICAL
  72H  23/1200Z 25.6N 137.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
  96H  24/1200Z 29.4N 141.1W   20 KT  25 MPH...POST-TROP/REMNT LOW
 120H  25/1200Z...DISSIPATED
 
 $$
 Forecaster Cangialosi