Tropical Cyclone Discussion

433
WTPZ45 KNHC 100836
TCDEP5
 
Hurricane Simon Discussion Number  12
NWS National Hurricane Center Miami FL       EP202026
300 AM CST Sat Oct 10 2026
 
The very small inner-core of Simon remains very impressive as the
cyclone has continued to strengthen. The proxy-visible imagery has
started to show that the tiny eye of the hurricane is clearing
out.  The most recent TAFB Dvorak fix was a T6.0/115 kt,
while the objective raw T-number intensity estimates  from
UW-CIMSS have ranged from 120 to 132 kt. Based on a blend of the
objective and subjective intensity estimates, the initial intensity
has been increased to 120 kt for this advisory.  The wind radii has
been adjusted based on a recent ASCAT pass.
 
The hurricane is expected to continue to rapidly strengthen over
the next day or so, with a peak intensity of 135 kt forecast. Given
the small size of the inner core, there is a higher than normal
degree of uncertainty with the peak intensity. Therefore, it is
possible that Simon could become stronger than what is forecast.
Only a few changes were made for the current NHC forecast compared
to the previous forecast.
 
Simon's initial motion is estimated at 360/4 kt, northward.
The hurricane is being steered by the southerly mid-level flow
produced by high pressure over southern Mexico and a longwave
mid-tropospheric trough to the west stretching south-southwestward
from the southwest United States. There is still some uncertainty
about the track for Simon, as most of the skilled model guidance
including HCCA and GDMI forecast aids have been experiencing to the
left of the track bias. The current NHC track forecast has the
hurricane move inland over the Mexican states of Colima and
Jalisco; however, it is possible that the cyclone could remain just
offshore as it moves generally northward. Should Simon move inland,
then it should dissipate quickly due to the mountainous terrain.
However, if Simon were to stay offshore, then it would maintain
hurricane intensity for a longer period of time. The current track
forecast is similar to the previous one, with only a few small
adjustments being made.
 
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
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  10/0900Z 17.2N 104.6W  125 KT 145 MPH
 12H  10/1800Z 17.8N 104.7W  135 KT 155 MPH
 24H  11/0600Z 18.8N 104.9W  135 KT 155 MPH
 36H  11/1800Z 20.0N 105.1W  120 KT 140 MPH...INLAND
 48H  12/0600Z 21.7N 105.3W   70 KT  80 MPH...INLAND
 60H  12/1800Z 23.1N 105.6W   30 KT  35 MPH...POST-TROP/INLAND
 72H  13/0600Z...DISSIPATED