{"id": "1217288217287589895", "title": "Tropical Cyclone Discussion", "adv_date": "2026-10-09T15:00:00Z", "msg": "126\nWTPZ45 KNHC 091447\nTCDEP5\n \nHurricane Simon Discussion Number   9\nNWS National Hurricane Center Miami FL       EP202026\n900 AM CST Fri Oct 09 2026\n \nThe intensity of Simon has been hard to diagnose this morning. The \nmost recent TAFB Dvorak fix still supported an intensity of 80 kt \nat 1200 UTC, while all of the objective techniques from UW-CIMSS \nare lower. Since that time, a warm spot near the center of Simon's \nsmall CDO has recently appeared, which appears to be the early \ndevelopment of an eye. Based on the continued improvement in Simon's \nsatellite appearance, the initial intensity has been increased to 85 \nkt for the advisory.\n \nOver the next 24 hours, continued rapid intensification is expected. \nThe RI probabilistic guidance (both SHIPS and DTOPS) actually \ndecreased this cycle, but the hurricane is located in a low-shear, \nhigh-moisture, and high-SST environment that is conducive for \nexplosive deepening. Furthermore, recent microwave imagery, such as \nan AMSR3 pass just after 08Z suggests the hurricane has a small \ninner-core, which makes rapid changes in intensity more likely. \nTherefore, the NHC forecast is in line with the previous one, above \nmost of the guidance and shows Simon becoming a major hurricane \nlater today.\n \nSimon's forecast beyond that is extremely difficult, and this is a \ncase where it is important to not focus on the details of NHC's \ndeterministic forecast. Simon will turn northward this weekend, \nsteered between a deep trough to its northwest and a ridge to the \neast. This track will take the center of Simon very near or over the \nMexican states of Colima and Jalisco. If the center of Simon moves \nover land, it will quickly weaken and could even dissipate, \ndrastically lessening the risk of hurricane-force-winds farther \nnorth in Mexico. However, if the core of Simon remains offshore, it \nwill likely continue northward as a hurricane. A majority of the \nguidance this morning shows Simon remaining just offshore, however \nmost of these models have historically had a west bias in this \nregion. Likewise, ensemble means like GDM or even HCCA can be \nmisleading when some members move inland and dissipate. This \nresults in the mean being computed solely from the surviving, and \nin this case farther west, members. The NHC forecast therefore \nremains within, but on the east side of the guidance envelope, and \nis best characterized as a hedge between the aforementioned \npossibilities. \n \n \nKey Messages:\n \n1. Simon is expected to approach the west-central coast of Mexico\nas a major hurricane on Saturday.\n\n2. Catastrophic wind and life-threatening storm surge impacts are \nlikely along a portion of the west-central coast of Mexico, and a \nHurricane warning is in effect from Punta San Telmo to Punta Mita. \nPreparations to protect life and property should be completed by \nlate today.\n\n3. Heavy rainfall associated with Simon will impact portions of \nsouthwestern Mexico through this weekend. This rainfall may produce \nlife-threatening flooding and mudslides, especially in areas of \nsteep terrain.\n\n4. Swells will affect portions of the southwestern and west-central\ncoast of Mexico through the weekend. These swells are likely to\ncause life-threatening surf and rip current conditions. Please\nconsult products from your local weather office.\n\n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  09/1500Z 16.0N 104.7W   85 KT 100 MPH\n 12H  10/0000Z 16.5N 104.8W  105 KT 120 MPH\n 24H  10/1200Z 17.2N 104.9W  125 KT 145 MPH\n 36H  11/0000Z 18.2N 105.0W  125 KT 145 MPH\n 48H  11/1200Z 19.4N 105.2W  115 KT 130 MPH\n 60H  12/0000Z 20.7N 105.4W   95 KT 110 MPH...INLAND\n 72H  12/1200Z 21.9N 105.6W   75 KT  85 MPH...OVER WATER\n 96H  13/1200Z 23.6N 106.2W   55 KT  65 MPH...INLAND\n120H  14/1200Z 24.9N 106.9W   30 KT  35 MPH...POST-TROP/INLAND\n \n"}