Tropical Cyclone Discussion

221
WTPZ45 KNHC 100240
TCDEP5
 
Hurricane Simon Discussion Number  11
NWS National Hurricane Center Miami FL       EP202026
900 PM CST Fri Oct 09 2026
 
Small, compact Simon is rapidly intensifying this evening.  A
dreaded pinhole eye has formed and is now visible in the
infrared BD-curve enhancement.  Visible imagery shows that the tiny
eye is cloud-filled.  Based on the impressive satellite
presentation, the initial intensity is increased to 105 kt for this
advisory.  Simon's wind radii were adjusted based on an OSCAT-3
overpass.
 
Further rapid strengthening is expected over the next 24 hours, with
the forecast showing a peak intensity of 135 kt.  Because of
Simon's small inner core size, peak intensities are virtually
impossible to predict, and with just a slight warming of the
tiny eye, Simon could quickly become stronger than reflected in the
intensity forecast.  No changes worth noting were made to the NHC
intensity forecast, which continues to be above the guidance suite.
 
Simon's initial motion is estimated to be northward, or 360/6 kt.
The cyclone is moving within southerly mid-level steering flow
produced by high pressure over southern Mexico and a longwave
mid-tropospheric trough to the west stretching south-southwestward
from the southwest U.S.  It's still somewhat uncertain if Simon
will move inland over the Mexican states of Colima and Jalisco or
remain offshore.  The model fields of the skilled HiRes global
models (GFS/ECMWF/UKMET/CMC) show the cyclone moving inland
and rapidly weakening with dissipation over the rugged mountainous
terrain of the aforementioned states of Mexico in 60 hrs.  Of
course, if Simon's track remains just offshore, as a few of
the guidance indicates, it's likely that it will maintain hurricane
strength for a longer period of time.  As the previous
advisories indicated, the NHC forecast continues to favor the
former scenario (inland/weakening), sticking with the more skilled
consensus aids.
 
Key Messages:
 
1. Catastrophic wind and life-threatening storm surge impacts are
likely along a portion of the west-central coast of Mexico, and a
Hurricane warning is in effect from Punta San Telmo to Punta Mita.
Preparations to protect life and property should be completed by
late today.
 
2. Heavy rainfall associated with Simon will impact portions of
southwestern Mexico through this weekend. This rainfall will produce
life-threatening flooding and mudslides, especially in areas of
steep terrain.
 
3. Swells will affect portions of the southwestern and west-central
coast of Mexico through the weekend. These swells are likely to
cause life-threatening surf and rip current conditions. Please
consult products from your local weather office.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  10/0300Z 16.8N 104.6W  105 KT 120 MPH
 12H  10/1200Z 17.4N 104.7W  120 KT 140 MPH
 24H  11/0000Z 18.2N 104.9W  135 KT 155 MPH
 36H  11/1200Z 19.6N 105.0W  120 KT 140 MPH
 48H  12/0000Z 21.0N 105.1W   70 KT  80 MPH...INLAND
 60H  12/1200Z 22.4N 105.4W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  13/0000Z...DISSIPATED