506 
WTPZ43 KNHC 081436
TCDEP3

Tropical Depression Eighteen-E Discussion Number   1
NWS National Hurricane Center Miami FL       EP182018
800 AM PDT Sat Sep 08 2018

The area of low pressure that NHC has been tracking for several
days has enough organized deep convection this morning to be
classified as a tropical depression.  Some northeasterly shear is
affecting the cyclone, with the apparent center on the northeastern
side of a growing area of deep convection.  The initial wind speed
is set to 30 kt, in accordance with the Dvorak classification from
TAFB.  Gradual strengthening is forecast while the cyclone remains
over warm waters within a light-to-moderate shear environment.
After 72 hours, the water temperatures drop off quite a bit and
weakening should begin.  The NHC forecast is close to, but a little
above, the model consensus near peak intensity to account for the
low bias the model guidance has had for many eastern Pacific storms
this year.

An uncertain initial motion estimate is 290/10.  All of the model
guidance turn the cyclone northwestward by tomorrow as the cyclone
rounds the southwestern side of a mid-level ridge located over
Mexico.  A turn back toward the west-northwest is anticipated in a
few days due to the system coming under the influence of the primary
eastern Pacific subtropical ridge.  For a first advisory, the model
guidance isn't in terrible disagreement, so the NHC prediction will
lie near close to the various consensus and corrected-consensus
aids.

FORECAST POSITIONS AND MAX WINDS

INIT  08/1500Z 16.1N 115.9W   30 KT  35 MPH
 12H  09/0000Z 16.6N 116.8W   35 KT  40 MPH
 24H  09/1200Z 17.7N 117.8W   40 KT  45 MPH
 36H  10/0000Z 18.9N 118.7W   45 KT  50 MPH
 48H  10/1200Z 20.1N 119.8W   50 KT  60 MPH
 72H  11/1200Z 21.5N 123.0W   65 KT  75 MPH
 96H  12/1200Z 23.0N 126.5W   60 KT  70 MPH
120H  13/1200Z 24.5N 129.0W   40 KT  45 MPH

$$
Forecaster Blake