000
WTPZ42 KNHC 160849
TCDEP2

Hurricane Norma Discussion Number   8
NWS National Hurricane Center Miami FL       EP172017
300 AM MDT Sat Sep 16 2017

Norma has a broad circulation but lacks an inner core. The deep
convection has weakened a little bit and is occurring in a few
cyclonically curved bands spiraling around the center. The initial
intensity is kept at 65 kt in this advisory, but Dvorak numbers,
both objective and subjective, are decreasing. The environment is
favorable for strengthening and most of the models suggest that
modest intensification will occur. The NHC forecast follows such
guidance.

Norma has barely moved during the past several hours, but most of
the global models forecast the building of a mid-level high pressure
system over the Gulf of Mexico, and this pattern should induce a
slow northward motion during the next day or so. As the high builds
westward, it will force Norma to move on a more north-northwesterly
track, parallel to the Baja California peninsula.  The confidence
in the track forecast is good for the next day or two. After that
time, the guidance envelope expands considerably and becomes bounded
by the easternmost GFS over Baja California and the westernmost
ECMWF over water. These two models are in competition once again.

Given that the circulation of Norma is large and tropical storm
force winds will likely reach the Baja California peninsula, the
government of Mexico has issued tropical storm warnings and watches
accordingly.


FORECAST POSITIONS AND MAX WINDS

INIT  16/0900Z 19.0N 110.2W   65 KT  75 MPH
 12H  16/1800Z 19.7N 110.3W   70 KT  80 MPH
 24H  17/0600Z 20.4N 110.4W   75 KT  85 MPH
 36H  17/1800Z 21.5N 110.8W   75 KT  85 MPH
 48H  18/0600Z 22.5N 111.3W   70 KT  80 MPH
 72H  19/0600Z 23.5N 112.3W   60 KT  70 MPH
 96H  20/0600Z 24.0N 113.0W   45 KT  50 MPH
120H  21/0600Z 24.5N 112.5W   30 KT  35 MPH

$$
Forecaster Avila