Advisories

000
WTPZ45 KNHC 131459
TCDEP5
 
Hurricane Simon Discussion Number  25
NWS National Hurricane Center Miami FL       EP202026
800 AM MST Tue Oct 13 2026
 
Small stubborn Simon continues to defy expectations this morning. 
First light visible satellite imagery shows the hurricane still has 
a small eye, and is also located farther south than was analyzed by 
satellite imagery last night. This is further supported by microwave 
images from AMSR-3 at 09 UTC and SSMIS at 1125 UTC which both show 
an eyewall that is little better organized, though it remains open 
on the west side. This structure could be due to some residual shear 
or dry air that was ingested into the circulation. Satellite 
intensity estimates are all over the place this morning, ranging 
from as low as 47 kt from UW-CIMSS ADT, and as high as 95 kt by 
SATCON. Given the small eye signature surrounded by -65 to -70 C 
cold cloud tops, the initial intensity will be held at 80 kt, on the 
upper side of these estimates, but should be considered more 
uncertain than usual. 
 
Simon continues to move south of the previous forecast track, and 
the initial motion is a slow westward drift at 270/2 kt. The farther 
south initial position and current motion necessitates some pretty 
significant changes to the short-term track forecast. As mentioned 
yesterday, Simon is very close to a saddle point, or col, in the 
deep-layer steering flow. This feature means that Simon's future 
track is very sensitive to which side of the saddle point the storm 
is located. Yesterday, a plurality of the guidance was maintaining 
Simon on a northwestward to northward track, causing it to be on the 
north side of the saddle point, resulting in continued poleward 
motion. However, Simon has gained very little latitude over the past 
24 h, and thus now finds itself on the south side of the saddle 
point. Consequently, the track guidance over the past few cycles has 
shifted substantially southward. The NHC track forecast is now 
shifted in a similar fashion, showing a very slow motion over the 
next 36-48 h as Simon makes a small cyclonic loop. The first part of 
the track forecast is substantially farther south than the prior 
one, but still not as far south as the HFIP Corrected Consensus 
Approach (HCCA), or any of the latest hurricane-regional models. 
After 48 h, deep-layer steering finally begins to shift out of the 
south as a deep-layer cutoff low digs into southern California, and 
Simon will finally start moving northward in earnest during the 
48-72 h time frame. Towards the end of the forecast, Simon could 
bend back more north-northwestward, potentially entering the Gulf of 
California and finally making landfall in Mexico between 96-120 h. 
However, this forecast should be considered very low confidence at 
that time frame, as there are a host of solutions from landfall in 
mainland Mexico even before reaching the Gulf of California, direct 
impacts to Baja California Sur, or solutions that stay south of 
Mexico entirely over the next 5 days.
 
The intensity forecast is not much easier either. Simon has managed 
to maintain a small inner-core and hurricanes of this size are known 
to be sensitive to small changes in their environmental conditions 
that could result in rapid changes in intensity, either up or down. 
This is also exhibited in the intensity guidance this morning, which 
ranges from Simon weakening to a tropical depression all the way to 
it regaining major hurricane intensity over the next 48-60 h. While 
shear over Simon is expected to remain low for the next 48 h and 
sea-surface temperatures (SSTs) are in the 29-30 C range, one wild 
card is how Simon's slow motion might cause some cool ocean 
upwelling. There is one ocean glider providing subsurface ocean 
temperature data near Simon, and it depicts 28 C waters down to 
about 80 m below the ocean surface. Assuming Simon does not 
completely stall, this is likely to support it maintaining hurricane 
intensity for the next 48-72 h. Given all this information, the NHC 
intensity forecast will show Simon maintaining its intensity as an 
80 kt hurricane for the next 48 h. Afterwards, southwesterly 
vertical wind shear is forecast to increase in earnest, and the 
small Simon is forecast to quickly weaken even as it moves over 
warmer SSTs. This latest forecast is initially on the high side of 
the guidance above HCCA, but not as high as the latest HAFS-A, 
COAMPS-TC, or HMON runs. After 48 h this forecast falls back to the 
middle of the guidance envelope. 
 
It is worth stressing that this is a very low confidence forecast 
for both track and intensity, and interests in west-central Mexico 
and Baja California Sur should continue to closely monitor the 
latest updates. Changes to watches and warnings could be required 
later today based on the latest forecast trends.
 
 
Key Messages:
 
1. Simon could approach Las Islas Marias on Wednesday and the coast 
of western Mexico later this week at or near hurricane strength, and 
a Hurricane Watch is in effect for a portion of these areas. 
Interests in west-central Mexico and Baja California Sur should 
continue to closely monitor the latest updates to Simon's forecast. 
Changes to watches and warnings could be required later today based 
on the latest forecast trends.

2. Large swells will affect portions of the southwestern and
west-central coasts of Mexico over the next several days. These
swells are likely to cause life-threatening surf and rip current
conditions.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  13/1500Z 20.3N 107.3W   80 KT  90 MPH
 12H  14/0000Z 20.3N 107.6W   80 KT  90 MPH
 24H  14/1200Z 20.3N 107.8W   80 KT  90 MPH
 36H  15/0000Z 20.1N 107.9W   80 KT  90 MPH
 48H  15/1200Z 20.1N 107.7W   80 KT  90 MPH
 60H  16/0000Z 21.0N 107.8W   75 KT  85 MPH
 72H  16/1200Z 22.8N 108.2W   70 KT  80 MPH
 96H  17/1200Z 25.2N 109.6W   55 KT  65 MPH
120H  18/1200Z 28.5N 110.5W   30 KT  35 MPH...POST-TROP/INLAND
 
$$
Forecaster Papin