Tropical Cyclone Discussion
301 WTPZ42 KNHC 250245 TCDEP2 Hurricane Vance Discussion Number 15 NWS National Hurricane Center Miami FL EP222026 900 PM CST Sat Oct 24 2026 Vance continues to look disorganized on satellite images, and it seems that southwesterly shear is keeping the convection displaced from the center. The hurricane is also moving over cool waters, which is also inhibiting intensification as well. GPM microwave images show that the structure of the cyclone is vertically tilted due to the aforementioned shear. Despite the system's ragged appearance, the Dvorak intensity estimate from TAFB is still T5.0/90 kt while the objective intensity estimates are in the range of 68-81 kt. Therefore, the initial intensity has been kept to 80 kt based on a combination of that data, however, it could be generous. The intensity forecast still has plenty of uncertainties. Vance is generally expected to weaken during the next 12 h due to the continuous of shear while it remains over cool SSTs. After that time, the hurricane's intensity could fluctuate when Vance moves over warmer waters, but the wind shear will likely remain elevated. After 48 h, the wind shear is expected to increase even further and that should result in a gradual weakening trend. It is possible that Vance could weaken more than forecast given the expected increasing shear and intrusions of dry air. The NHC intensity forecast is generally similar to the previous one with only a few minor adjustments made. The initial motion remains slowly north-northwestward or 340/4 kt. The cyclone is currently being steered by a weak low- to mid-level ridge over eastern Mexico, and it is moving toward a large mid-latitude trough over the western United States and northwestern Mexico. Vance should move into an area where the steering currents are light, thus the hurricane is expected to move even slower over the next few days. The latest guidance shifted significantly to the west compared to the previous forecast, including the highly skilled forecast aids HCCA and GDMI, which has added some uncertainty in the track forecast. The new track forecast was adjusted slightly to the west and is a little slower than the previous one. However, the current track is on the eastern side of the guidance envelope, and additional adjustments to the west could be needed. Key Messages: 1. Due to the uncertainties in both the track and intensity forecasts, it is too early to say what wind and storm surge impacts Vance may cause along the coast of Mexico. Interests in southwestern Mexico should continue to monitor the progress of the hurricane. 2. Heavy rainfall associated with slow-moving Hurricane Vance will impact the western coast of Mexico from Michoacán to Jalisco during much of next week. This rainfall may produce life-threatening flooding and mudslides across Colima and western portions of Michoacán and Jalisco, especially in areas along steep terrain. FORECAST POSITIONS AND MAX WINDS INIT 25/0300Z 13.7N 103.4W 80 KT 90 MPH 12H 25/1200Z 14.2N 103.7W 70 KT 80 MPH 24H 26/0000Z 15.1N 104.2W 70 KT 80 MPH 36H 26/1200Z 15.6N 104.6W 70 KT 80 MPH 48H 27/0000Z 16.1N 104.8W 70 KT 80 MPH 60H 27/1200Z 16.5N 105.0W 65 KT 75 MPH 72H 28/0000Z 17.3N 105.2W 55 KT 65 MPH 96H 29/0000Z 18.4N 105.6W 45 KT 50 MPH 120H 30/0000Z 19.6N 106.1W 35 KT 40 MPH