{"id": "1221604197431476226", "title": "Tropical Cyclone Discussion", "adv_date": "2026-10-24T21:00:00Z", "msg": "963\nWTPZ42 KNHC 242040\nTCDEP2\n \nHurricane Vance Discussion Number  14\nNWS National Hurricane Center Miami FL       EP222026\n300 PM CST Sat Oct 24 2026\n\nVance has become significantly less organized since the last \nadvisory due to a combination of cold water near the center and \nincreasing southwesterly shear. Microwave data indicates that the \neyewall has broken open, with the remaining convection limited to \nnorth of the center. In addition, visible imagery shows the \nlow-level center to be near or a little south of the southern edge \nof the convective mass. The various satellite intensity estimates \nhave dropped, and based on them the initial intensity is lowered to \n80 kt.  This could be quite generous, as the current structure does \nnot look much like a hurricane.\n \nThe intensity forecast is still problematic, but perhaps a little \nless so than earlier. Vance is likely to weaken during the next \n12-18 h as it crosses a pool of colder water with temperatures near \n27C that has been upwelled by several previous tropical cyclones, \nwhile at the same time it experiences at least moderate \nsouthwesterly shear.  Beyond that time, the center is expected to \nmove over sea surface temperatures near 29C closer to the coast of \nMexico. This could allow intensification if the shear is light \nenough and the storm structure is still good enough to allow it. The \nGFS and ECMWF continue show a period of reduced, but still marginal, \nshear that could allow some intensification, and based on this and \ntrends in the guidance slight re-intensification is shown at 48 h. \nBy the end of the forecast period, increasing shear is likely to \ncause Vance to steadily weaken. It is still possible that Vance \ncould weaken more than forecast before reaching warmer water and \nthat the shear may be too strong to allow re-intensification after \n36 h. The new intensity forecast has major downward adjustments from \nthe previous forecast.\n\nThe initial motion remains north-northwestward or 340/5 kt.  Vance \nis being steered by a weak low- to mid-level ridge over eastern \nMexico, and it is approaching a large mid-latitude trough over the \nwestern United States and northwestern Mexico. While neither of \nthese features will change much during the next few days, Vance is \nlikely to move into an area of lighter steering currents near the \nbase of the trough and slow its forward motion during the next \n24 or so.  The track forecast beyond that time is dependent on the \ncyclone's strength and vertical structure. A weaker system that \nshears apart like shown in the UKMET and Canadian is likely to move \nwest-northwestward to northwestward before resuming a more northerly \nmotion, while a stronger and vertically deeper system is likely to \ncontinue slowly northward or north-northwestward.  The track \nguidance envelope has shifted westward since the previous advisory, \nand the new forecast track has been nudged westward as well. \nAdditional westward adjustments to the track may be necessary if \nVance continues to lose organization.\n\n\nKey Messages:\n \n1. Due to the uncertainties in both the track and intensity\nforecasts, it is too early to say what wind and storm surge\nimpacts Vance may cause along the coast of Mexico. Interests in\nsouthwestern Mexico should continue to monitor the progress of the\nhurricane.\n \n2. Heavy rainfall associated with slow-moving Hurricane Vance will \nimpact the western coast of Mexico from Michoac\u00e1n to Jalisco during \nmuch of next week. This rainfall may produce life-threatening \nflooding and mudslides across Colima and western portions of \nMichoac\u00e1n and Jalisco, especially in areas along steep terrain.\n \n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  24/2100Z 13.3N 103.3W   80 KT  90 MPH\n 12H  25/0600Z 14.0N 103.6W   75 KT  85 MPH\n 24H  25/1800Z 14.9N 104.0W   70 KT  80 MPH\n 36H  26/0600Z 15.6N 104.4W   70 KT  80 MPH\n 48H  26/1800Z 16.0N 104.6W   75 KT  85 MPH\n 60H  27/0600Z 16.4N 104.8W   70 KT  80 MPH\n 72H  27/1800Z 17.0N 104.9W   65 KT  75 MPH\n 96H  28/1800Z 18.1N 105.2W   50 KT  60 MPH\n120H  29/1800Z 19.3N 105.6W   40 KT  45 MPH\n \n"}