Advisories

000
WTPZ42 KNHC 272051
TCDEP2
 
Tropical Storm Vance Discussion Number  26
NWS National Hurricane Center Miami FL       EP222026
200 PM MST Tue Oct 27 2026
 
Significant westerly wind shear and a dry mid-level environment are 
substantially impacting Vance this afternoon. Deep convection 
remains disorganized and displaced from the fully exposed low-level 
center, with the deepest thunderstorms located 50-100 mi east of the 
center. Recent objective and subjective satellite intensity 
estimates range from 26-36 kt. However, a recent METOP-B 
scatterometer pass indicated tropical-storm-force winds northeast 
and southeast of the center, and this was instrumental in 
determining the wind radii for this advisory. Based on the data, 
the intensity is maintained at 35 kt for this advisory.
 
Vance is moving northwestward at 305/08 kt, guided by a low-level
ridge centered over the south-central United States. A gradual turn
toward the north is forecast over the next couple of days as a
strong mid-level trough moves down the U.S. West Coast. This
steering pattern would bring Vance toward the entrance of the Gulf
of California by Thursday. The latest NHC track forecast has been
shifted slightly to the left and lies near the latest HFIP corrected
consensus aid (HCCA).
 
Despite moving over warm sea surface temperatures of 29-30 C over
the next couple of days, an increase in already significant wind
shear may offset any potential strengthening. However, intensity
guidance remains mixed, so the NHC forecast follows a consensus
approach and calls for no net change through midweek, although some
fluctuations are possible during this period. Vance is already
struggling to maintain organized deep convection near its center,
and simulated satellite imagery from the GFS and ECMWF suggests that
organized convection could become difficult to sustain by early
Thursday. Therefore, the latest NHC forecast calls for Vance to
become post-tropical by 36 h and degenerate into a remnant low by 60
h, around the time of its closest approach to west-central Mexico.
If Vance is unable to sustain organized convection closer to its
center, the transition to a post-tropical cyclone could occur even
sooner than currently forecast. Given this forecast, the threat of
tropical storm conditions over land remains low at this time.
 
 
Key Messages:
 
1. 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 central and southern
Sinaloa, western Durango, and northwestern Nayari, especially in
areas along steep terrain.
 
2. Interests along the southwestern and west-central coasts of
Mexico and the southern Baja California Peninsula should monitor the
progress of Vance.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  27/2100Z 17.2N 108.3W   35 KT  40 MPH
 12H  28/0600Z 18.1N 108.7W   35 KT  40 MPH
 24H  28/1800Z 19.7N 108.9W   35 KT  40 MPH
 36H  29/0600Z 21.2N 108.7W   35 KT  40 MPH...POST-TROPICAL
 48H  29/1800Z 22.9N 108.3W   35 KT  40 MPH...POST-TROPICAL
 60H  30/0600Z 24.7N 107.9W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  30/1800Z...DISSIPATED
 
$$
Forecaster Adams