Hurricane Vance

338 
WTPZ42 KNHC 241454
TCDEP2
 
Hurricane Vance Discussion Number  13
NWS National Hurricane Center Miami FL       EP222026
900 AM CST Sat Oct 24 2026

The satellite appearance of Vance has deteriorated a bit during the 
past few hours, likely due to the combined effects of colder sea 
surface temperatures near the center and increasing southwesterly 
shear. While the eyewall cloud tops remain quite cold, the eye has 
become less distinct and the central dense overcast has become more 
ragged. The subjective and objective satellite intensity estimates 
have nudged downward, and the initial intensity is reduced to 90 kt.

The intensity forecast is still problematic and low confidence. 
Vance is likely to weaken during the next 24 h as it crosses a pool 
of colder water with temperatures near 27C that has been upwelled by 
several previous tropical cyclones, and at the same time 
southwesterly shear is forecast to increase to near 20-25 kt. The 
cyclone is likely to take 24 h or so to cross the cold pool, then it 
is expected to move over sea surface temperatures near 29C closer to 
the coast of Mexico. This should allow intensification if the shear 
is light enough. The GFS and ECMWF both show a period of reduced, 
but still marginal, shear that could allow some intensification, and 
this is reflected in the intensity forecast. The new intensity 
forecast has some adjustments from the previous forecast, 
particularly after 60 h. There are three issues that should be noted 
for this forecast. First the 06Z GFS calls for Vance to make 
landfall along the Mexican coast as a hurricane, although at the 
moment no other guidance explicitly shows this. Second, it is 
possible that Vance could weaken more than currently forecast during 
the next 24 h as it passes over the cold pool. Third, it is possible 
that the shear may increase to the point where no re-intensification 
could occur, as the UKMET and Canadian models show stronger shear 
than the GFS and ECMWF.

The initial motion is 340/5 kt.  Vance is being steered by a weak 
low- to mid-level ridge over eastern Mexico, and it is approaching a 
large mid-latitude trough over the western United States and 
northwestern Mexico. While neither of these features will change 
much during the next few days, Vance is likely to move into an area 
of lighter steering currents near the base of the trough and slow 
its forward motion during the next 24-36 h.  The track forecast 
after 36 h is dependent on how strong Vance is and how well Vance 
maintains its vertical structure. A weaker system that shears apart 
like shown in the UKMET and Canadian is likely to move 
west-northwestward to northwestward before resuming a more northerly 
motion, while a stronger and vertically deeper system is likely to 
continue slowly northward.  The new forecast track is on the east 
side of the guidance envelope near the HFIP corrected consensus, 
Google DeepMind, and Florida State Superensemble, and it has only 
minor adjustments from the previous forecast.

Key Messages:

1. Due to the uncertainties in both the track and intensity 
forecasts, it is too early to say what wind and storm surge  
impacts Vance may cause along the coast of Mexico. Interests in 
southwestern Mexico should continue to monitor the progress of the 
hurricane.

2. Heavy rainfall associated with slow-moving Hurricane Vance will 
impact the western coast of Mexico from Michoacán to Jalisco during 
much of next week. This rainfall may produce life-threatening 
flooding and mudslides across Colima and western portions of 
Michoacán and Jalisco, especially in areas along steep terrain.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/1500Z 12.9N 103.0W   90 KT 105 MPH
 12H  25/0000Z 13.6N 103.3W   85 KT 100 MPH
 24H  25/1200Z 14.6N 103.6W   80 KT  90 MPH
 36H  26/0000Z 15.5N 104.0W   80 KT  90 MPH
 48H  26/1200Z 16.0N 104.3W   85 KT 100 MPH
 60H  27/0000Z 16.3N 104.4W   90 KT 105 MPH
 72H  27/1200Z 16.7N 104.4W   80 KT  90 MPH
 96H  28/1200Z 17.7N 104.5W   65 KT  75 MPH
120H  29/1200Z 18.7N 104.7W   50 KT  60 MPH
 
$$
Forecaster Beven