000
WTPZ42 KNHC 252035
TCDEP2
 
Tropical Storm Vance Discussion Number  18
NWS National Hurricane Center Miami FL       EP222026
300 PM CST Sun Oct 25 2026
 
Vertical wind shear and relatively dry mid-level air are negatively 
impacting Vance's structure today. An earlier RCM-2 microwave pass 
indicated that the center was slightly elongated, with an opening 
on the southeastern side. Deep convection has been intermittent over 
the past 6 h or so, and has been concentrated primarily north and 
east of the center. However, an ASCAT-C pass indicated peak winds 
of 50-53 kt to the west and northwest of the center. Subjective and 
objective intensity estimates have continued to trend downward, 
ranging from 46-65 kt. The initial intensity is set at 60 kt for 
this advisory, based on a blend of these estimates and the available 
satellite data. 
 
Vance is moving at 330/06 kt, steered by a mid-level ridge centered 
over the south-central United States, along with a closed 
upper-level low moving across the southwestern U.S. The tropical 
storm is expected to move toward the northwest or west-northwest at 
a slower forward speed over the next couple of days as steering 
currents weaken. A turn toward the north is forecast around midweek 
as an amplified upper-level trough moves across the eastern Pacific. 
The latest NHC track forecast has been adjusted westward once again 
to reflect trends in the global and regional hurricane model 
guidance. However, the track still remains near the eastern edge of 
the guidance envelope, and additional westward adjustments may be 
needed in subsequent forecast cycles.

Westerly to southwesterly wind shear and relatively dry mid-level 
air are expected to support gradual weakening over the next several 
days. By midweek, the upper-level trough is forecast to produce a 
significant increase in wind shear, leading to further weakening. By 
late this week, simulated satellite imagery from the ECMWF and GFS 
suggests that Vance may struggle to sustain organized deep 
convection. The forecast calls for Vance to become post-tropical by 
96 h and degenerate into a remnant low by 120 h.
 
 
Key Messages:
 
1. Although the threat of impacts to Mexico is trending downward as 
the forecast track continues to shift westward and away from the 
coast, uncertainty remains in both the track and intensity 
forecasts. Interests in southwestern Mexico should continue to 
monitor the progress of Vance.
 
2. Periods of heavy rainfall associated with Vance will impact 
portions of western Mexico during much of this week. This rainfall 
may produce flooding and mudslides across Colima, Nayarit, and 
Sinaloa, along with western portions of Michoacán, Jalisco, and 
Durango, especially in areas along steep terrain.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  25/2100Z 14.9N 104.2W   60 KT  70 MPH
 12H  26/0600Z 15.0N 104.8W   60 KT  70 MPH
 24H  26/1800Z 15.4N 105.5W   55 KT  65 MPH
 36H  27/0600Z 16.0N 106.2W   50 KT  60 MPH
 48H  27/1800Z 16.9N 106.6W   45 KT  50 MPH
 60H  28/0600Z 17.7N 107.0W   45 KT  50 MPH
 72H  28/1800Z 19.0N 107.2W   45 KT  50 MPH
 96H  29/1800Z 21.0N 107.4W   40 KT  45 MPH...POST-TROPICAL
120H  30/1800Z 23.3N 107.2W   30 KT  35 MPH...POST-TROP/REMNT LOW
 
$$
Forecaster Adams