000
WTPZ41 KNHC 201437
TCDEP1

TROPICAL STORM RICK DISCUSSION NUMBER   9
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP212015
800 AM MST FRI NOV 20 2015

Rick's convective pattern remains rather unimpressive, with some
ragged banding in the western semicircle and a small area of more
concentrated convection south of the estimated center position. The
initial intensity remains 35 kt based on the earlier ASCAT data and
the latest Dvorak Data-T numbers from TAFB and SAB. While Rick is
still situated over warm waters in a low shear environment, mid-
level dry air and relatively meager instability appear to be
limiting intensification. All of the intensity guidance suggests
only modest strengthening in the next 24 to 36 hours before the
shear increases by 48 hours. The increasing shear and a track over
cooler waters should result in Rick weakening to a remnant low by
day 3. The NHC intensity forecast is close to the latest intensity
consensus.

The initial motion estimate is 290/10. Rick is forecast to continue
moving west-northwestward for the next 36 hours while being steered
by a mid-level ridge centered over southwestern Mexico. After that
time, the ridge will weaken as a deep-layer trough amplifies to the
northwest of the tropical cyclone, and Rick should recurve late in
the period, albeit as a shallow cyclone. The new NHC track forecast
is close to the previous one through 48 hours and then is a little
to the left and slower, trending toward the weaker ECMWF solution.
The official forecast is much slower than the latest GFS solution at
days 3 through 5, which appears too strong with Rick at those times.

FORECAST POSITIONS AND MAX WINDS

INIT  20/1500Z 16.1N 110.3W   35 KT  40 MPH
 12H  21/0000Z 16.7N 111.5W   40 KT  45 MPH
 24H  21/1200Z 17.3N 113.1W   40 KT  45 MPH
 36H  22/0000Z 17.8N 114.6W   40 KT  45 MPH
 48H  22/1200Z 18.6N 115.9W   35 KT  40 MPH
 72H  23/1200Z 20.5N 117.5W   30 KT  35 MPH...POST-TROP/REMNT LOW
 96H  24/1200Z 21.5N 117.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  25/1200Z 22.5N 117.0W   15 KT  15 MPH...POST-TROP/REMNT LOW

$$
Forecaster Brennan