000
WTPZ42 KNHC 182039
TCDEP2

Tropical Storm Norma Discussion Number  18
NWS National Hurricane Center Miami FL       EP172017
300 PM MDT Mon Sep 18 2017

After Norma's brief resurgence this morning, cloud tops have begun
to warm.  Dvorak classifications are a little lower than they
were this morning, so the initial intensity has been lowered to 40
kt. No change has been made to the intensity forecast.  The tropical
storm should continue to gradually weaken while crossing over
progressively cooler SSTs.  The new NHC forecast shows Norma
becoming a remnant low in 36 h and dissipating entirely by 72 h, in
line with the latest guidance from the GFS and ECMWF.

Norma is moving slowly west, and the initial motion estimate is
270/5 kt.  The cyclone should continue moving west for the next day
or so, south of a mid-level ridge extending from northern Mexico
over the eastern Pacific.  Once Norma becomes a remnant low, the
low-level remnants are still expected to turn more northward.  The
models have shifted a little more toward the southwest for the
first 24 h the forecast, so the official forecast has been nudged in
that direction, and remains about halfway between the ECMWF and the
HFIP Corrected Consensus.


FORECAST POSITIONS AND MAX WINDS

INIT  18/2100Z 21.4N 112.8W   40 KT  45 MPH
 12H  19/0600Z 21.5N 113.6W   35 KT  40 MPH
 24H  19/1800Z 21.7N 114.8W   30 KT  35 MPH
 36H  20/0600Z 22.2N 115.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  20/1800Z 23.0N 116.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  21/1800Z...DISSIPATED

$$
Forecaster Zelinsky