{"id": "1222523373744488455", "title": "Tropical Cyclone Discussion", "adv_date": "2026-10-28T03:00:00Z", "msg": "816\nWTPZ42 KNHC 280235\nTCDEP2\n \nTropical Storm Vance Discussion Number  27\nNWS National Hurricane Center Miami FL       EP222026\n800 PM MST Tue Oct 27 2026\n\nThe structure of Vance continues to be heavily sheared and ragged \nbased on the current visible satellite imagery. Some of the most \nrecent images have shown that a small convective burst has occurred \nnear the center, however it is also being blown away by the westerly \nwind shear at this point. In addition to the shear, there is dry air \nthat is getting into the core of the storm, which is keeping the \ncenter of Vance fully exposed. The most recent objective intensity \nestimates from UW-CIMSS are in the range of 28-33 kt, while the \nlatest TAFB Dvorak fix is a T2.0/30 kt. Given the available data the \ninitial intensity has been held at 35 kt for this advisory. \n\nVance is moving northwestward at 310/07 kt, as the storm is being \nsteered by a low-level ridge centered over the south-central United \nStates. A gradual turn toward the north is forecast over the next \nfew days due to a strong mid-level trough moving across the U.S. \nWest Coast. As a result, Vance should move toward the Gulf of \nCalifornia by Thursday. The current NHC track forecast is very \nsimilar to the previous one, with some minor adjustments being made \nbased on the latest HCCA and GDMI forecast aids. \n \nThe intensity portion of the forecast has plenty of uncertainties \ndue to a variety of variables. The cyclone is over warm waters of \n29-30 C for the next several days, but the wind shear is expected to \nbe around 40 kt based on the GFS and ECMWF SHIPS guidance. This \ncould allow for convection to develop near the center, but that \nconvection will then be blown away by the shear. This could also \nmean that there could be brief fluctuations in intensity at times \ndue to the convection. The most recent GFS and ECMWF simulated \nsatellite guidance shows that there could be one or two more \nconvective bursts from Vance due to some upper-level divergence \nsometime tomorrow. However, the impacts that this convection could \nhave on the storm are still uncertain. At this point, the cyclone is \nstill expected to become post-tropical around 36 h. By 60 h, it is \nexpected to be a post-tropical remnant low, and finally by 72 h the \ncirculation of Vance is forecast to dissipate. If the storm cannot \nmaintain organized deep convection, it is possible that Vance could \ntransition to a post-tropical cyclone sooner than currently \nforecast.  \n \n \nKey Messages:\n \n1. 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 central and southern \nSinaloa, western Durango, and northwestern Nayarit, especially in \nareas along steep terrain.\n \n2. Interests along the southwestern and west-central coasts of\nMexico and the southern Baja California Peninsula should monitor the\nprogress of Vance.\n \n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  28/0300Z 17.3N 108.4W   35 KT  40 MPH\n 12H  28/1200Z 18.5N 108.7W   35 KT  40 MPH\n 24H  29/0000Z 20.2N 108.5W   35 KT  40 MPH\n 36H  29/1200Z 21.7N 108.1W   35 KT  40 MPH...POST-TROPICAL\n 48H  30/0000Z 23.5N 107.7W   35 KT  40 MPH...POST-TROPICAL\n 60H  30/1200Z 25.3N 107.0W   30 KT  35 MPH...POST-TROP/REMNT LOW\n 72H  31/0000Z...DISSIPATED\n \n"}