Tropical Cyclone Discussion
192 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