Tropical Cyclone Discussion

106
WTPZ45 KNHC 110859
TCDEP5
 
Hurricane Simon Discussion Number  16
NWS National Hurricane Center Miami FL       EP202026
300 AM CST Sun Oct 11 2026

The Air Force Reserve Hurricane Hunters provided some valuable 
information on the structure of Simon overnight.  They found 
that the pressure had dropped to 928 mb, with maximum flight-level 
winds of 135 kt within the small inner core.  Similar to the 
afternoon flight, the whole wind field could not be observed. The 
initial intensity is kept at 135 kt for this advisory as a blend of 
the flight-level wind data, assuming a larger undersampling factor 
than normal, with a slight weight on earlier experimental Synthetic 
Aperture Radar (SAR) data, which showed category 5 strength. 

The hurricane has turned north-northwest at about 5 kt.  This 
motion is expected to continue today, bringing the core of the 
hurricane along the coast of southwestern Mexico.  While some of 
the models have shifted more offshore later today, it is simply too 
close to call whether landfall will occur.  Regardless of the exact 
track, dangerous wind, surge, and rainfall effects appear likely 
over portions of west-central Mexico today in the Hurricane Warning 
area.  After today, the model guidance is in poor agreement on what 
happens due to a weak ridge building just north of the cyclone.  
While the new forecast is nudged westward, it is east of the bulk 
of the model guidance, and we are just going to have to wait and 
see how much the high terrain of the Sierra Madre mountains affects 
the hurricane before having any significant forecast confidence.  

Some weakening should start soon due to the hurricane's close 
proximity to land, and recent satellite imagery could be indicative 
of that trend.  However, Simon is still expected to be an extremely 
dangerous hurricane as it passes near southwestern Mexico today.  
The intensity forecast is extremely sensitive to how close Simon 
passes to western Mexico during the next day or so.  With the 
forecast shifting somewhat offshore in a day or two, the weakening 
rate is lowered some from the last advisory.  This is a very low 
confidence forecast because only a small deviation either east or 
west could result in the hurricane rapidly dissipating after 
landfall or keeping more strength offshore.
 
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 El Roblito.
Preparations to protect life and property should be rushed to
completion.
 
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 over the next few days. 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  11/0900Z 18.7N 105.2W  135 KT 155 MPH...NEAR COAST
 12H  11/1800Z 19.5N 105.4W  125 KT 145 MPH...NEAR COAST
 24H  12/0600Z 20.5N 105.7W   90 KT 105 MPH...NEAR COAST
 36H  12/1800Z 21.2N 106.0W   75 KT  85 MPH
 48H  13/0600Z 22.0N 106.3W   50 KT  60 MPH
 60H  13/1800Z 23.2N 106.2W   35 KT  40 MPH...INLAND
 72H  14/0600Z...DISSIPATED