{"id": "1214245691993391111", "title": "Tropical Cyclone Discussion", "adv_date": "2026-09-28T21:00:00Z", "msg": "226\nWTPZ42 KNHC 282052\nTCDEP2\n \nHurricane Polo Discussion Number  33\nNWS National Hurricane Center Miami FL       EP172026\n200 PM MST Mon Sep 28 2026\n \nNOAA Hurricane Hunters investigated Polo this afternoon, finding the \nhurricane was still well organized with a 23 n mi wide eye, though \nthe eyewall was open to the southwest and there was a subtle \nincrease in the vertical tilt comparing the 1-5 km Tail Doppler \nRadar (TDR) wind data from the aircraft. The highest 700 mb \nflight-level winds were 106 kt in the southeast quadrant, which \nusing a typical 0.9 reduction factor would suggest an intensity of \n95 kt. However, the TDR data has also been useful to diagnose the \nintensity of Polo since it samples a larger wind field swath, and \nthe final southwest to northeast leg through the hurricane indicated \n0.5 km winds up to 112 kt in the northeast eyewall. Experimental \nreduction data from this TDR analysis in this region reduced these \nboundary layer winds down to 100 kt at 10 meters. Thus, the initial \nintensity remains 100 kt for this advisory.\n \nPolo continues to move northeastward, but it is starting to \naccelerate some with an current motion of 40 degrees at 10 kt. This \ngeneral motion should continue over the next day with gradual \nacceleration as the hurricane is captured by a strong shortwave \ntrough swinging into the southwestern United States. This track will \ntake Polo's core over the Baja California Peninsula this evening \nvery close to Puerto San Andresito. The hurricane will then briefly \nmove over the Gulf of California overnight, finally making a second \nlandfall in northwestern mainland Mexico on Tuesday morning. The NHC \ntrack forecast is essentially an update from this morning, and is in \nthe middle of the tightly clustered guidance. \n\nSea-surface temperatures actually increase a bit as Polo approaches \nBaja California Sur. Vertical wind shear, while also increasing, is \nunlikely to get strong enough over the next 3-6 h to cause much \nweakening. Thus, Polo is likely to maintain its current intensity \nand be at or near major hurricane intensity when it makes landfall \non the west coast of Baja California Sur this evening. Weakening \nwill likely begin immediately after it moves over the rugged terrain \nof the peninsula, though Polo is still expected to be a hurricane \nwhen it makes its second landfall in mainland Mexico on the Gulf of \nCalifornia coast. Rapid weakening is expected when Polo moves fully \ninland over the high rugged terrain of northwestern Mexico, and the \ntropical cyclone is expected to degenerate into a trough  before its \nremnants reach the southwestern United States.\n\nHowever Polo's remnant vorticity will ultimately interact and phase \nwith a strong cutoff low digging into the the four corners region of \nthe U.S. on Tuesday into Wednesday, contributing to heavy rainfall, \nflash flooding, and gusty winds the southwestern U.S. and southern \nPlains. See products issued by the Weather Prediction Center and \nlocal National Weather Service offices for more information.\n \n \nKey Messages:\n \n1. Polo is forecast to make landfall on the west coast of the Baja \nCalifornia Peninsula near major hurricane strength this evening. \nConditions will deteriorate quickly, and residents are urged to seek \nsafe shelter.  Hurricane and tropical storm conditions will spread \ninland across Baja California tonight, and into mainland Mexico late \ntonight and early Tuesday. A dangerous storm surge is expected in \nareas of onshore winds. \n \n2. Heavy rainfall associated with Polo will impact Baja California \nSur along with southern and central portions of Sonora today into \nTuesday. This rainfall may produce life-threatening flooding and \nmudslides, especially in areas of steep terrain. Moisture from Polo \nwill support heavy rainfall and flooding potential across the \nSouthwest U.S. into the Southern High Plains late today into \nTuesday.\n \n3. Even after Polo dissipates, its mid-level remnants may produce \nstrong gusty winds well inland over the higher terrain of northwest \nMexico and southern New Mexico and far western Texas. \n  \n4. Dangerous surf and rip currents are likely along portions of the \nnorthwest coast of Mexico and Baja California for the next day or \nso. \n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  28/2100Z 25.0N 113.0W  100 KT 115 MPH\n 12H  29/0600Z 26.2N 112.1W   80 KT  90 MPH...INLAND OVER BAJA CA\n 24H  29/1800Z 28.7N 109.8W   40 KT  45 MPH...INLAND OVER MEXICO\n 36H  30/0600Z...DISSIPATED\n \n"}