{"id": "1213962122688626695", "title": "Tropical Cyclone Discussion", "adv_date": "2026-09-27T21:00:00Z", "msg": "076\nWTPZ42 KNHC 272050\nTCDEP2\n \nHurricane Polo Discussion Number  29\nNWS National Hurricane Center Miami FL       EP172026\n200 PM MST Sun Sep 27 2026\n \nA NOAA P-3 Hurricane Hunter aircraft was able to complete two fixes \ninto Polo earlier this afternoon, indicating the hurricane was more \nor less steady state. In the final fix, the aircraft reported a   \n22 n mi closed eyewall, though in the wind data there was some \nevidence of a double wind maximum at 700 mb even though the \nsecondary wind max was not seen in the Tail Doppler Radar wind \ndata. The peak flight-level winds were 117 kt, which typically \nreduces to 105 kt using a standard 0.9 reduction. However, the \naircraft did not fully sample the eastern quadrant where higher \nwinds may exist. In addition, subjective and objective satellite \nintensity estimates remain at or above 110 kt, so Polo's initial \nintensity will be held at 110 kt this advisory.\n\nPolo is continuing its turn, now moving northward at 355 degrees at \n10 kt. The synoptic setup and track reasoning has not chanced much \nthis cycle, with Polo expected to move between deep-layer ridging \ncentered over Mexico and a shortwave trough that will soon move into \nCalifornia. This trough is forecast to sweep southward, helping to \ncapture the smaller Polo, leading it to accelerating to the \nnortheast. The NHC track forecast this cycle is largely an update of \nthe previous one this morning, though there remains more along-track \nspread, related to Polo's speed of motion, than across-track spread. \nThis latest track lies closest to the Google DeepMind ensemble mean \n(GDMI). With the latest update to the track, a Hurricane Warning \nhas now been issued for portions of mainland Mexico along the Gulf \nof California. \n\nVertical wind shear in the SHIPS guidance is in the 5-10 kt range \nfor the next 12-24 h while the hurricane traverses 28-29 C \nsea-surface temperatures, so Polo's short-term intensity will likely \nbe controlled by inner-core fluctuations. Given the double wind \nmaxima that appeared in the earlier aircraft data, it is not out of \nthe question another eyewall replacement cycle (ERC) could occur \nbefore Polo makes landfall along the west Baja California Sur \ncoastline. The latest NHC intensity forecast shows very little \nchange in strength before Polo reaches the coast, and the latest \nforecast now anticipates Polo making landfall at near major \nhurricane intensity. In fact, both the 12z HAFS-A/B raw model output \nshow Polo making landfall as a major hurricane even if their \ninterpolated aids are a bit lower in intensity. Significant \nweakening should occur as it moves over the rugged terrain of the \nBaja California Peninsula, but Polo will likely still be a hurricane \nwhen it makes its second landfall in mainland Mexico. Rapid \nweakening is forecast thereafter and Polo will likely dissipate \nbefore the middle of this week over the Mexican Plateau. \n \nPolo is expected to dissipate before it reaches the southern U.S., \nbut distant moisture associated with it and Odalys will be \ntransported into the southwestern United States during the next few \ndays, and may indirectly contribute to a heavy rainfall and flash \nflood threat in the region. See products issued by the Weather \nPrediction Center for more information.\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 will \nlikely spread across Baja California through Monday and into \nmainland Mexico on early Tuesday. A storm surge is likely, \nespecially in areas of onshore winds.\n \n2. Heavy rainfall associated with Polo may begin to impact Baja \nCalifornia Sur later tonight into Tuesday and portions of Sonora \nlate Monday into Tuesday. This rainfall may produce life-threatening \nflooding and mudslides, especially in areas of steep terrain.  \nMoisture from Polo will support heavy rainfall and flooding \npotential across the Southwest U.S. into the Southern High Plains \nlate Monday into Tuesday.\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  27/2100Z 21.9N 114.1W  110 KT 125 MPH\n 12H  28/0600Z 23.2N 114.0W  110 KT 125 MPH\n 24H  28/1800Z 25.0N 113.0W  105 KT 120 MPH\n 36H  29/0600Z 27.0N 111.3W   75 KT  85 MPH...OVER WATER\n 48H  29/1800Z 29.9N 108.7W   35 KT  40 MPH...INLAND\n 60H  30/0600Z...DISSIPATED\n \n"}