{"id": "1214173716837138439", "title": "Tropical Cyclone Discussion", "adv_date": "2026-09-28T15:00:00Z", "msg": "260\nWTPZ42 KNHC 281446\nTCDEP2\n \nHurricane Polo Discussion Number  32\nNWS National Hurricane Center Miami FL       EP172026\n800 AM MST Mon Sep 28 2026\n \nOn geostationary satellite, Polo still looks pretty healthy, \nwith a small central dense overcast with an embedded eye, though \nthe eye feature has been coming and going. Some of this evolution \nis likely due to inner-core structural changes near the center, \nwhere an earlier AMSR-3 microwave pass at 0928 UTC showed evidence \nof concentric rings suggesting an eyewall replacement cycle (ERC) \non the 37 GHz channel. The 12 UTC subjective Dvorak TAFB CI number \nremains 5.5/102 kt, though the objective intensity estimates have \nfallen some. For now, the initial intensity is being maintained at \n100 kt, pending another NOAA P-3 aircraft that should provide an \nupdate in the storms structure and intensity this afternoon. \n\nPolo appears to be making the turn to the northeast, with the \nestimated motion now at 35 degrees at 9 kt. This general heading in \nPolo's track should continue for the next 36 h, though with some \ngradual acceleration as the hurricane is captured by a short-wave \ntrough swinging into the southwestern United States. This track \nwill take Polo's core over the Baja California Peninsula this \nevening, then briefly moving over the Gulf of California overnight \nwit ha second landfall in northwestern mainland Mexico on Tuesday \nMorning. The latest NHC track forecast is very close to the \nprevious one, following the reliable HFIP corrected consensus \napproach (HCCA) and Google DeepMind ensemble mean (GDMI).\n\nThe vertical wind shear remains low over Polo at the moment, and has \nnow shifted out of the southwest, so the vector is in the same \ndirection as its component of motion. In addition sea-surface \ntemperatures actually warm as the hurricane approaches the \ncoastline. Thus, Polo's intensity will be primarily governed by \ninner-core structural changes today before landfall. While the \ninterpolated guidance shows a bit of modest weakening in 12 h, given \nthe favorable environment, it is probably more prudent to maintain \nthe hurricane's current intensity before it makes landfall in the \nBaja California Peninsula where it will likely be near or at major \nhurricane intensity. Land interaction with the peninsula and shear \nincreasing should lead to significant weakening, but Polo is still \nexpected to be a hurricane when it reaches mainland Mexico. Even \nmore rapid weakening is expected when Polo moves inland over the \nhigh rugged terrain of northwestern mainland Mexico and the storm \nwill likely dissipate over the higher terrain long before it reaches \nthe southwestern U.S. \n \nAlthough Polo is expected to dissipate before it reaches the \nsouthern U.S., distant moisture associated with it and the Post- \nTropical Cyclone Odalys will be transported into the southwestern \nUnited States during the next few days, 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 make landfall on the west coast of the Baja \nCalifornia Peninsula near major hurricane strength this evening. \nConditions will deteriorate shortly, making preparations difficult. \nHurricane and tropical storm conditions are expected to spread \nacross Baja California through tonight, and into mainland Mexico \nlate on early Tuesday. A dangerous storm surge is likely in areas of \nonshore winds. \n \n2. Heavy rainfall from Polo will impact Baja California Sur and \nsouthern and central portions of Sonora today into Tuesday. This \nrainfall may produce life-threatening flooding and mudslides, \nespecially in areas of steep terrain. Moisture from Polo will \nsupport heavy rainfall and flooding potential across the southwest \nU.S. into the southern High Plains late today into Tuesday.\n \n3. Even after Polo dissipates, its mid-level remnants may produce \ngusty winds well inland over the higher terrain of northwest\nMexico and the southwest United States. \n \n4. Dangerous surf and rip currents are likely along portions of\nthe northwest coast of Mexico and Baja California for the next\ncouple of days.\n  \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  28/1500Z 24.2N 113.5W  100 KT 115 MPH\n 12H  29/0000Z 25.4N 112.7W  100 KT 115 MPH\n 24H  29/1200Z 27.4N 111.0W   70 KT  80 MPH...OVER WATER\n 36H  30/0000Z 29.9N 108.8W   30 KT  35 MPH...POST-TROP/INLAND\n 48H  30/1200Z...DISSIPATED\n \n"}