{"id": "1222877227381981186", "title": "Tropical Cyclone Discussion", "adv_date": "2026-10-29T09:00:00Z", "msg": "179\nWTPZ42 KNHC 290835\nTCDEP2\n \nTropical Storm Vance Discussion Number  32\nNWS National Hurricane Center Miami FL       EP222026\n200 AM MST Thu Oct 29 2026\n\nVance has had an unusual structure overnight.  While obviously still \na sheared tropical cyclone on satellite imagery, scatterometer data \nindicated that strong winds of about 40 kt were located well \nnortheast (over 120 n mi) of the center under very deep convection, \njust downstream of the Islas Marias.  This atypical pattern of winds \nvery distant from the center suggests that they were probably \ndowndraft induced (or convective scale), possibly enhanced by \nterrain and not representative of the tropical cyclone, especially \nwith rising pressures observed from the drifting buoy very near the \ncenter.  There were a couple of believable tropical-storm-force \nvectors closer to the center outside of the thunderstorm mass, so \nthe initial intensity is set to 35 kt on this advisory.  \n\nThe storm hasn't moved much since the last advisory, with the \ncenter generally moving north-northeastward slowly.  Basically all \nof the model guidance suggest that the very strong shear will cause \nany deep convection to cease later today.  The evolution would \ncause the system to become very shallow, and it could get caught in \nany area of lighter low-level steering currents, keeping the system \njust offshore of Mexico before it likely degenerates into a trough \nof low pressure later on Friday. The new forecast is nudged to the \nleft, toward the model consensus.  \n\nWhile Vance has re-strengthened slightly, extremely strong vertical \nshear is expected to strip away any remaining associated convection \nlater today and cause weakening before the winds could impact \nMexico.  The new NHC forecast is similar to the previous one and is \nconsistent with the latest ECMWF solution, which has had a good \nhandle on the temporary re-intensification.  It should be emphasized \nthat the main threat with Vance is the very heavy rainfall and high \nrain rates near the areas of very deep convection near the Islas \nMarias and southwestern Mexico.\n \n \nKey Message:\n \n1. Periods of heavy rainfall associated with Vance will impact\nportions of western Mexico during the next day or two. This rainfall\nmay produce flooding and mudslides across central and southern\nSinaloa, far southwestern Durango, and far northwestern Nayarit,\nespecially in areas along steep terrain.\n \n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  29/0900Z 21.0N 108.4W   35 KT  40 MPH\n 12H  29/1800Z 22.0N 108.0W   30 KT  35 MPH\n 24H  30/0600Z 23.4N 108.2W   25 KT  30 MPH...POST-TROP/REMNT LOW\n 36H  30/1800Z...DISSIPATED\n \n"}