ZCZC MIATCDEP4 ALL
TTAA00 KNHC DDHHMM

HURRICANE SIMON DISCUSSION NUMBER  12
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP192014
800 AM PDT SAT OCT 04 2014

Infrared satellite imagery indicates that Simon has undergone rapid
intensification during the past several hours.  A small eye has
formed, and the cloud tops surrounding the eye are in the -75C to
-85C range.  Satellite intensity estimates have increased to 102 kt
from TAFB and 90 kt from SAB, and the latest estimated from the
CIMSS ADT is 90 kt.  Based on these, the initial intensity is
increased to 95 kt, and this could be conservative.  A NOAA
Hurricane Hunter aircraft is scheduled to investigate Simon later
today.

The initial motion is now 295/11.  Simon is expected to move
west-northwest to northwestward for the next 36 hours or so as is
approaches a weakness in the subtropical ridge to its north.  After
that, the system is expected to turn northward and northeastward,
although there remains significant spread in the track guidance on
when and how fast this will occur.  The GFS, GFS ensemble mean,
NAVGEM, and the GFDL show Simon moving quickly to the northeast,
eventually making landfall on the Baja California peninsula and in
northwestern Mexico.  The ECMWF, UKMET, and CMC models show the turn
occurring later and farther west, and these models forecast the
cyclone to dissipate over water west of the Baja California
peninsula.  The forecast track continues to compromise between these
two extremes in showing a slow northeastward motion after
recurvature. The new forecast track is similar to the previous track
and is slower than the model consensus.

How long the current rapid intensification will continue is
uncertain, as Simon is now moving over decreasing sea surface
temperatures.  The new intensity forecast follows the guidance trend
of showing 12 hours more strengthening.  Simon is now forecast to
become a major hurricane, and it would not be a surprise if it
reached a higher peak intensity than currently forecast. After 12
hours, cooler waters under the forecast track should result in a
weakening trend, and this should become more pronounced after 48
hours due to increasing shear.  The new intensity forecast shows
rapid weakening after 48 hours, with Simon expected to become a
remnant low by the end of the forecast period. It should be noted
that, if Simon follows the GFS forecast track, it would likely
weaken more slowly than currently forecast since it would stay over
warmer water and encounters less shear.

FORECAST POSITIONS AND MAX WINDS

INIT  04/1500Z 20.2N 113.8W   95 KT 110 MPH
 12H  05/0000Z 21.0N 115.3W  105 KT 120 MPH
 24H  05/1200Z 22.2N 116.8W  100 KT 115 MPH
 36H  06/0000Z 23.1N 117.4W   90 KT 105 MPH
 48H  06/1200Z 23.7N 117.6W   80 KT  90 MPH
 72H  07/1200Z 24.5N 117.5W   55 KT  65 MPH
 96H  08/1200Z 25.5N 117.0W   35 KT  40 MPH
120H  09/1200Z 26.5N 116.0W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Beven

NNNN