Hurricane SIMON

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HURRICANE SIMON DISCUSSION NUMBER  17
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP192014
200 PM PDT SUN OCT 05 2014

A NOAA Hurricane Hunter aircraft investigating Simon has found that
the cyclone's maximum winds continue to decrease quickly.  The
plane measured maximum 700-mb flight-level winds of 73 kt and
surface-based SFMR winds as high as 58 kt in the northeastern
quadrant.  Based on the aircraft data, the initial intensity is
lowered to 65 kt, which could be generous.  UW-CIMSS analyses and
the SHIPS output indicate that southwesterly shear has increased to
about 20 kt, and satellite imagery suggests that Simon's circulation
is beginning to decouple.  With the cyclone expected to remain over
24-25C water and in a highly sheared environment during the next few
days, continued rapid weakening is anticipated.  The updated NHC
forecast is lower than the previous forecast mainly due to the
adjusted initial intensity, and Simon is likely to become a tropical
depression in 36 hours and a remnant low by 48 hours, before it
reaches the Baja California peninsula.  Forecast fields from the
global models indicate that the cyclone will have dissipated over
northwestern Mexico by day 4, which is indicated in the official
forecast.

Simon has turned north-northwestward with an initial motion of
330/8 kt.  The hurricane is currently moving around the western
periphery of a mid-level high centered near the west coast of
Mexico, and it should turn northward and then northeastward
around this feature during the next 48-72 hours.  The model
guidance is in relatively good agreement on the future track of
Simon, but there continues to be disagreement on how fast Simon or
its remnants reach the Baja California peninsula.  For example, the
GFS and ECMWF solutions are about 24 hours apart on when they bring
the center of Simon to the coast.  The updated NHC track forecast
is a little faster than the previous one after 24 hours but is
relatively close to the multi-model consensus TVCE.

Even if Simon or its remnant circulation does not make it across the
rugged terrain of the Baja California peninsula, deep moisture
associated with the cyclone is expected to spread across the
northern Baja California peninsula, northwestern Mexico, and into
the U.S. Desert Southwest, which could trigger heavy rains in
those regions in a few days.

FORECAST POSITIONS AND MAX WINDS

INIT  05/2100Z 23.4N 117.5W   65 KT  75 MPH
 12H  06/0600Z 24.2N 117.7W   50 KT  60 MPH
 24H  06/1800Z 25.2N 117.5W   40 KT  45 MPH
 36H  07/0600Z 26.2N 117.1W   30 KT  35 MPH
 48H  07/1800Z 27.5N 116.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  08/1800Z 30.0N 114.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  09/1800Z...DISSIPATED

$$
Forecaster Berg

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