{"id": "1213822068604141575", "title": "Tropical Cyclone Discussion", "adv_date": "2026-09-27T09:00:00Z", "msg": "329\nWTPZ42 KNHC 270857\nTCDEP2\n \nHurricane Polo Discussion Number  27\nNWS National Hurricane Center Miami FL       EP172026\n200 AM MST Sun Sep 27 2026\n \nThe satellite presentation of Polo has remained fairly steady since\nthe time the NOAA aircraft finished its mission about 7 hours ago.\nThere are still hints of an eye in geostationary and microwave\nsatellite images. The latest TAFB Dvorak currently intensity was\n6.5/127 kt with 5.5/102 kt for the final-T number.  Objective\nintensity estimates from UW-CIMSS have been running in the 105-110\nkt range.  The initial intensity is held at 105 kt for this\nadvisory.\n \nPolo has turned toward the north-northwest, with the current motion \nestimated at 330/9 kt.  A turn toward the north is expected later \ntoday, and then northeastward on Monday as the cyclone continues to \nmove around the ridge and becomes increasingly affected by a mid- to \nupper-level trough moving in from the northwest. The largest source \nof uncertainty in the forecast continues to be the forward speed of \nPolo as it makes its expected northeastward turn between the \naforementioned synoptic features. The model spread remains higher \nthan unusual between 48 and 72 h, more so for the along-track \nforward speed of the storm after landfall. The NHC forecast follows \nthe path of the GDMI and HCCA, but is a bit slower than those \nmodels.  This forecast is essentially on top of the previous NHC \nforecast.\n \nPolo will continue to travel through an environment of fairly weak \nvertical wind shear and sea-surface temperatures near 29C for the \nnext 24 h, but will be moving into a somewhat drier airmass.  By \nhour 36, which is about 6 hours before landfall, southwesterly \nvertical wind shear will increase.  Due to the favorable conditions \nuntil almost before the Baja California landfall, the NHC forecast \nis near the higher end of the guidance suite through hour 36, \nshowing only gradual weakening.  Thereafter, increasing wind shear \nand land interaction will cause rapid weakening.  Although waters \nare warm in the Gulf of California, Polo is not expected to \nrestrengthen there due to strong southwesterly vertical wind shear. \n The intensity forecast for the 2nd landfall (in mainland Mexico) \nis tricky.  There is some possibility that Polo could still be at\nhurricane strength for the 2nd landfall, as suggested by the latest \nHAFS-A forecast.  Polo should dissipate inland over northern Mexico \nby hour 72.\n \nPolo is expected to become a remnant low and then dissipate before\nit reaches the southern U.S., but distant moisture associated with\nit and Odalys will be transported into the southwestern United\nStates late this weekend and early next week, and may indirectly\ncontribute to a heavy rainfall and flash flood threat in the region.\nSee products issued by the Weather Prediction Center for more\ninformation.\n \n \nKey Messages:\n \n1. Polo is forecast to approach the west coast of the Baja\nCalifornia peninsula on Monday as a hurricane, and a Hurricane\nWarning is in effect for that region. Tropical storm conditions\ncould reach portions of the coast as soon as tonight or early\nMonday, making further preparations difficult. These conditions\nwill likely spread across Baja California through Monday. A storm\nsurge is likely, especially in areas of onshore winds.\n \n2. Heavy rainfall associated with Polo may begin to impact Baja \nCalifornia Sur tonight into Tuesday. This rainfall may produce \nlife-threatening flooding and mudslides, especially in areas of \nsteep terrain.\n \n3. Dangerous surf and rip currents are likely along portions of\nthe northwest coast of Mexico and Baja California for the next\nfew days.\n \n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  27/0900Z 20.3N 113.6W  105 KT 120 MPH\n 12H  27/1800Z 21.6N 114.0W  100 KT 115 MPH\n 24H  28/0600Z 23.4N 114.0W   95 KT 110 MPH\n 36H  28/1800Z 25.1N 113.1W   90 KT 105 MPH\n 48H  29/0600Z 26.8N 111.6W   70 KT  80 MPH\n 60H  29/1800Z 28.9N 109.3W   40 KT  45 MPH\n 72H  30/0600Z 31.3N 106.8W   25 KT  30 MPH...POST-TROP/INLAND\n 96H  01/0600Z...DISSIPATED\n \n"}