{"id": "1221886466041806851", "title": "Tropical Cyclone Discussion", "adv_date": "2026-10-25T21:00:00Z", "msg": "656\nWTPZ42 KNHC 252035\nTCDEP2\n \nTropical Storm Vance Discussion Number  18\nNWS National Hurricane Center Miami FL       EP222026\n300 PM CST Sun Oct 25 2026\n \nVertical wind shear and relatively dry mid-level air are negatively \nimpacting Vance's structure today. An earlier RCM-2 microwave pass \nindicated that the center was slightly elongated, with an opening \non the southeastern side. Deep convection has been intermittent over \nthe past 6 h or so, and has been concentrated primarily north and \neast of the center. However, an ASCAT-C pass indicated peak winds \nof 50-53 kt to the west and northwest of the center. Subjective and \nobjective intensity estimates have continued to trend downward, \nranging from 46-65 kt. The initial intensity is set at 60 kt for \nthis advisory, based on a blend of these estimates and the available \nsatellite data. \n \nVance is moving at 330/06 kt, steered by a mid-level ridge centered \nover the south-central United States, along with a closed \nupper-level low moving across the southwestern U.S. The tropical \nstorm is expected to move toward the northwest or west-northwest at \na slower forward speed over the next couple of days as steering \ncurrents weaken. A turn toward the north is forecast around midweek \nas an amplified upper-level trough moves across the eastern Pacific. \nThe latest NHC track forecast has been adjusted westward once again \nto reflect trends in the global and regional hurricane model \nguidance. However, the track still remains near the eastern edge of \nthe guidance envelope, and additional westward adjustments may be \nneeded in subsequent forecast cycles.\n\nWesterly to southwesterly wind shear and relatively dry mid-level \nair are expected to support gradual weakening over the next several \ndays. By midweek, the upper-level trough is forecast to produce a \nsignificant increase in wind shear, leading to further weakening. By \nlate this week, simulated satellite imagery from the ECMWF and GFS \nsuggests that Vance may struggle to sustain organized deep \nconvection. The forecast calls for Vance to become post-tropical by \n96 h and degenerate into a remnant low by 120 h.\n \n \nKey Messages:\n \n1. Although the threat of impacts to Mexico is trending downward as \nthe forecast track continues to shift westward and away from the \ncoast, uncertainty remains in both the track and intensity \nforecasts. Interests in southwestern Mexico should continue to \nmonitor the progress of Vance.\n \n2. Periods of heavy rainfall associated with Vance will impact \nportions of western Mexico during much of this week. This rainfall \nmay produce flooding and mudslides across Colima, Nayarit, and \nSinaloa, along with western portions of Michoac\u00e1n, Jalisco, and \nDurango, especially in areas along steep terrain.\n \n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  25/2100Z 14.9N 104.2W   60 KT  70 MPH\n 12H  26/0600Z 15.0N 104.8W   60 KT  70 MPH\n 24H  26/1800Z 15.4N 105.5W   55 KT  65 MPH\n 36H  27/0600Z 16.0N 106.2W   50 KT  60 MPH\n 48H  27/1800Z 16.9N 106.6W   45 KT  50 MPH\n 60H  28/0600Z 17.7N 107.0W   45 KT  50 MPH\n 72H  28/1800Z 19.0N 107.2W   45 KT  50 MPH\n 96H  29/1800Z 21.0N 107.4W   40 KT  45 MPH...POST-TROPICAL\n120H  30/1800Z 23.3N 107.2W   30 KT  35 MPH...POST-TROP/REMNT LOW\n \n"}