000
WTPZ42 KNHC 270849
TCDEP2
 
Tropical Storm Vance Discussion Number  24
NWS National Hurricane Center Miami FL       EP222026
200 AM MST Tue Oct 27 2026
 
Vance's satellite presentation has continued to deteriorate
overnight. Satellite imagery reveals a fully exposed low-level cloud
swirl that continues to become increasingly separated from the deep
convection to its southeast, with the nearest convection now
displaced over 100 n mi from the center. A 0411 UTC Metop-B
scatterometer pass sampled a small area of 45-kt winds within the
displaced convection, while winds closer to the center were
generally 30 to 35 kt. Given the increasingly disorganized structure
of the cyclone and recent objective intensity estimates ranging from
35 to 45 kt, the initial intensity is lowered to a possibly generous
40 kt.
 
The initial motion is northwestward, or 310/7 kt. This general
motion should continue today as Vance is steered by a weakening
mid-level ridge to its north. Falling heights aloft associated with
a series of shortwave troughs rotating through a broad mid- to
upper-level trough over the West Coast of the United States should
then cause the cyclone to gradually turn north-northwestward during
the next 12 to 24 h, northward between 24 and 36 h, and
north-northeastward thereafter. The latest NHC track forecast is
very similar to the previous prediction, but has been nudged
slightly westward toward the latest HCCA and GDMI aids.
 
Strong westerly to southwesterly vertical wind shear is expected to
persist and increase during the next several days as Vance gradually
moves northward. Despite warm sea surface temperatures, the
combination of increasing shear and relatively dry mid-level air
should continue to inhibit organized deep convection near the
center. Although some fluctuations in strength are possible,
intermittent convective bursts could help maintain Vance's intensity
during the next day or so before a gradual weakening trend begins.
Global model guidance generally supports this scenario, depicting
convection remaining displaced well east of the circulation. Vance
is forecast to become a post-tropical remnant low in about 60 h,
although this transition could occur sooner if organized deep
convection fails to redevelop near the center. The latest NHC
intensity forecast is similar to the previous prediction, with only
minor adjustments, and lies near the middle of the guidance
envelope.
 
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 coastal sections of Nayarit and
Jalisco, 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  27/0900Z 15.9N 106.9W   40 KT  45 MPH
 12H  27/1800Z 17.0N 107.8W   40 KT  45 MPH
 24H  28/0600Z 18.6N 108.4W   40 KT  45 MPH
 36H  28/1800Z 20.2N 108.6W   35 KT  40 MPH
 48H  29/0600Z 21.7N 108.5W   35 KT  40 MPH
 60H  29/1800Z 23.9N 107.9W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  30/0600Z...DISSIPATED
 
$$
Forecaster Gibbs