{"id": "1212193136605102087", "title": "Tropical Cyclone Discussion", "adv_date": "2026-09-21T15:00:00Z", "msg": "700\nWTPZ42 KNHC 211453\nTCDEP2\n \nTropical Storm Polo Discussion Number   4\nNWS National Hurricane Center Miami FL       EP172026\n900 AM CST Mon Sep 21 2026\n \nPolo is in the midst of a significant rapid intensification\nepisode.  Satellite images indicate a developing central dense\novercast with very deep convection in the core.  Additionally,\nmicrowave images indicate that a small eye has formed beneath the\novercast with hints of a banded eyewall.  The initial intensity\nis set to 55 kt, consistent with the latest TAFB classification,\nand a NOAA Hurricane Hunter aircraft is enroute to provide a better\nlook at the intensity.\n \nConditions look ideal for explosive intensification during the next\nday or two, with Polo's small inner core over very warm and\nuntapped waters above 30.5C, within light shear and plentiful\nmid-level moisture.  Every model responds to these conditions by\nshowing rapid intensification, and the SHIPS rapid intensification\nindex is showing percentages as high as I have ever seen them.\nThe new forecast is raised from the previous one and is very\naggressive, but still below the latest HCCA corrected-consensus\naid, which verbatim would be at least a 99th percentile event for\nintensification.  Polo is expected to be a small but very dangerous\nhurricane by tomorrow and beyond.\n \nThe storm is drifting eastward, and still caught in weak steering\ncurrents.  A mid-level ridge is expected to develop over Mexico by\nlate Tuesday, causing Polo to move towards the west-northwest or\nnorthwest by Wednesday into late week.  This could bring the core\nof the storm near or south of the coast of southwestern Mexico on\nThursday, and then south of the Baja California Peninsula on\nSaturday.  There is a large north-south spread in the guidance,\nwhich has both short and long-range implications.  Generally, the\nguidance has nudged southward again, and the NHC forecast is\nadjusted in that direction.  Given the spread in the track \nguidance, this is a low-confidence forecast.\n \n \nKey Messages:\n \n1. Heavy rainfall associated with Polo will impact coastal portions\nof southwest Mexico through Thursday. This rainfall may produce\nlife-threatening flooding and mudslides, especially in areas of\nsteep terrain.\n \n2. Polo is forecast to strengthen to a major hurricane while it\nmoves closer to the coast of southwestern Mexico during the next few\ndays. Although the core of the hurricane is forecast to stay\noffshore, it is too soon to determine the exact location or\nmagnitude of impacts. Residents in southwestern Mexico should\nclosely monitor its progress and updates to the forecast. A Tropical\nStorm Watch is in effect for portions of southwestern Mexico.\n \n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  21/1500Z 15.4N 103.4W   55 KT  65 MPH\n 12H  22/0000Z 15.2N 102.8W   85 KT 100 MPH\n 24H  22/1200Z 15.1N 102.3W  105 KT 120 MPH\n 36H  23/0000Z 15.4N 102.3W  125 KT 145 MPH\n 48H  23/1200Z 16.0N 102.8W  135 KT 155 MPH\n 60H  24/0000Z 16.8N 103.6W  140 KT 160 MPH\n 72H  24/1200Z 17.6N 104.8W  140 KT 160 MPH\n 96H  25/1200Z 18.6N 107.8W  130 KT 150 MPH\n120H  26/1200Z 20.3N 110.4W  120 KT 140 MPH\n \n"}