{"id": "1213255588535140359", "title": "Tropical Cyclone Discussion", "adv_date": "2026-09-25T09:00:00Z", "msg": "936\nWTPZ42 KNHC 250856\nTCDEP2\n \nHurricane Polo Discussion Number  19\nNWS National Hurricane Center Miami FL       EP172026\n200 AM MST Fri Sep 25 2026\n\nSince the previous advisory, Polo's eyewall and core cloud-top \ntemperatures have cooled with a very wide and complete ring of \ncloud-top temperatures below -70C surrounding the eye, with a \ngrowing area of cloud-top temperatures colder than -75C surrounding \nmost of the eye.  In addition, GOES-18 infrared eye temperatures \nhave warmed significantly since the previous advisory, recently \nmeasured near 19C.  The latest TAFB Dvorak number is 7.0/140 kt, \nwhile DMINT and SATCON have been hovering around 135-136 kt.  Based \non the improved structure, Polo is assigned an initial intensity of \n140 kt for this advisory, making it a category 5 hurricane again.\n\nThe initial motion is westward, or 275 degrees at 10 kt, so this \nmotion continues to take the hurricane farther away from mainland \nwestern Mexico.  There is little change to the track forecast \nphilosophy from the previous advisory.  Polo is currently being \nsteered by the flow on the south side of a well-defined \nmid-tropospheric ridge that is building westward over northern \nMexico.  This steering regime should continue through today.  After \nthat, a mid-latitude trough moving eastward across the northeastern \nPacific should prevent the ridge from building farther west, with \nPolo is expected to recurve northward and northeastward around the \nwestern periphery of the ridge.  The track guidance is generally in \nagreement on this scenario, although there are still notable \ndifferences in forward speed among the models in the 3-5 day time \nframe.  The official forecast is similar to the previous one through \n72 hours, but is faster toward the northeast at day 4-5 compared to \nthe previous forecast.  The NHC forecast is slightly to the left of \nthe HCCA and Google DeepMind Ensemble Mean through 96 hours, but is \nto the right of the simple consensus TVCN.  Confidence is high that \nPolo will make landfall in Baja California Sur and then mainland \nMexico, after moving through the Gulf of California.\n \nPolo will continue to move over very warm waters and in a low \nvertical wind shear environment through today.  Fluctuations in \nintensity are possible through today.  By Saturday, a gradual \nweakening trend is expected to begin due to some increase in shear.  \nThe official intensity forecast is on the high side of the model \nguidance, and shows the system still near major hurricane strength \nwhile it approaches the Baja California peninsula.  Rapid weakening \nis expected when the cyclone crosses the peninsula and moves into \nmainland Mexico due to land interaction and a further increase in \nvertical wind shear.\n \nIt should be noted that moisture from Hurricane Polo and Odalys will \nbe carried a long distance into the southwestern United States this \nweekend and early next week, and may indirectly contribute to a \nheavy rainfall and flash flood threat in the region. See products \nissued by the Weather Prediction Center for more information.\n \n \nKey Messages:\n\n1. Polo is forecast to approach the Baja California Peninsula early\nnext week as a hurricane.  Interests there should closely monitor\nthe latest updates and ensure that they have their preparedness\nplan in place.\n \n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  25/0900Z 17.2N 107.5W  140 KT 160 MPH\n 12H  25/1800Z 17.3N 108.9W  140 KT 160 MPH\n 24H  26/0600Z 17.6N 110.7W  130 KT 150 MPH\n 36H  26/1800Z 18.5N 112.2W  120 KT 140 MPH\n 48H  27/0600Z 20.0N 113.2W  110 KT 125 MPH\n 60H  27/1800Z 21.7N 113.7W  100 KT 115 MPH\n 72H  28/0600Z 23.3N 113.5W   95 KT 110 MPH\n 96H  29/0600Z 26.4N 111.2W   80 KT  90 MPH\n120H  30/0600Z 29.0N 107.5W   30 KT  35 MPH\n \n"}