Tropical Storm Vance

000
WTPZ42 KNHC 271441
TCDEP2
 
Tropical Storm Vance Discussion Number  25
NWS National Hurricane Center Miami FL       EP222026
800 AM MST Tue Oct 27 2026
 
The exposed low-level center of Vance has become further decoupled 
from the limited ongoing convection well to its southeast. This 
satellite structure indicates that strong westerly shear continues 
to affect the storm. Based on the latest objective and subjective 
satellite estimates, the initial intensity is lowered to 35 kt. An 
ASCAT-B pass expected around midday should help to reassess the 
intensity and size of the storm.
 
The storm is moving northwestward (305/7 kt) along the southwestern 
side of a low- to mid-level ridge to its northeast. Increased 
troughing over the western United States during the next day or two 
is expected to erode this ridge and cause Vance to turn northward. 
This should bring the center of the storm toward the entrance of the 
Gulf of California by Thursday. The updated NHC track forecast 
generally follows the latest HFIP corrected consensus aid (HCCA) and 
is similar to the previous prediction.
 
Although SSTs are generally warm along the forecast track, Vance is 
approaching an area of lower ocean heat content associated with the 
cool wake of prior storms. In addition, the vertical wind shear over 
the system is forecast to increase above 40 kt by Thursday. The 
model-simulated satellite imagery from the GFS and ECMWF suggest 
renewed bursts of convection are possible during the next day or 
two, but this seems unlikely to support much strengthening given the 
shear profile and drier mid-level air surrounding the storm. There 
are mixed signals in the intensity models, so the NHC forecast uses 
a consensus approach and shows no net change through midweek, though 
small fluctuations could be possible during this period. If Vance 
cannot sustain organized convection closer to its center, its 
transition to a post-tropical cyclone could occur even sooner than 
predicted. Based on this forecast, the threat of tropical storm 
conditions on 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 Nayarit, 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  27/1500Z 16.3N 107.7W   35 KT  40 MPH
 12H  28/0000Z 17.3N 108.2W   35 KT  40 MPH
 24H  28/1200Z 19.0N 108.6W   35 KT  40 MPH
 36H  29/0000Z 20.7N 108.6W   35 KT  40 MPH
 48H  29/1200Z 22.4N 108.3W   35 KT  40 MPH...POST-TROPICAL
 60H  30/0000Z 24.3N 107.8W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  30/1200Z...DISSIPATED
 
$$
Forecaster Reinhart