Tropical Cyclone Discussion
993 WTPZ45 KNHC 120251 TCDEP5 Hurricane Simon Discussion Number 19 NWS National Hurricane Center Miami FL EP202026 800 PM MST Sun Oct 11 2026 Simon is showing signs of weakening this evening, likely due to its prolonged close proximity to the Mexican coastline and the associated negative affects of nearby mountainous terrain. Infrared satellite imagery indicates warming cloud tops within the convection in the northeastern quadrant, with mid-level dry air beginning to wrap around the western side of the cyclone. Recent objective Dvorak intensity estimates have decreased over the past several hours and range from 99-110 kt. Based on the deteriorating satellite presentation and the lower intensity estimates, the initial intensity is set at 105 kt for this advisory. The major hurricane is moving slowly north-northwestward, steered by a mid-level ridge centered over the south-central United States. Simon is forecast to track parallel to the coast of west-central Mexico over the next day or so. However, its continued close proximity to land will likely bring hurricane conditions to portions of the warning area, particularly near Cabo Corrientes, even though the core is forecast to remain just offshore. Around midweek, a strong upper-level low moving across the western United States is expected to induce a turn toward the north and then northeast. Although there remains some model spread, an increasing number of the hurricane regional models and consensus aids, including HCCA, bring Simon onshore around midweek. The latest NHC forecast is very similar to the previous advisory, showing Simon moving inland and dissipating in the day 3-4 period. Gradual weakening is expected due to the proximity to the mountainous terrain, which could further disrupt the hurricane's structure along its eastern side. A slight increase in wind shear and the entrainment of drier mid-level air should further contribute to the weakening trend. However, as Simon turns northward then northeastward around midweek, it is forecast to move over very warm waters of 31-32 C, which could limit further weakening before landfall. The latest NHC forecast has been nudged upward slightly beyond 12 h, with Simon expected to maintain hurricane strength through landfall. This forecast lies near the middle of the intensity guidance envelope. Rapid weakening is expected once Simon moves inland, and dissipation is forecast by 96 h. Key Messages: 1. Catastrophic wind and life-threatening storm surge impacts are likely along a portion of the west-central coast of Mexico, and a Hurricane Warning is in effect from Playa Perula to El Roblito. Residents should continue to shelter in a safe room to ride out the storm as the most significant hazards are ongoing. 2. Simon is expected to approach the coast of western Mexico later this week, where hurricane conditions are possible. A Hurricane Watch is in effect from El Roblito to Bahia Tempehuaya. 3. Heavy rainfall associated with Simon will impact portions of southwestern and west-central Mexico over the next few days. This rainfall will produce life-threatening flooding and mudslides, especially in areas of steep terrain. 4. Swells will affect portions of the southwestern and west-central coast of Mexico over the next few days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 12/0300Z 19.8N 106.0W 105 KT 120 MPH 12H 12/1200Z 20.5N 106.3W 95 KT 110 MPH 24H 13/0000Z 21.2N 106.8W 85 KT 100 MPH 36H 13/1200Z 21.8N 107.1W 80 KT 90 MPH 48H 14/0000Z 22.4N 107.0W 80 KT 90 MPH 60H 14/1200Z 23.0N 106.7W 80 KT 90 MPH 72H 15/0000Z 23.4N 106.4W 65 KT 75 MPH...INLAND 96H 16/0000Z 24.0N 105.7W 30 KT 35 MPH...POST-TROP/INLAND 120H 17/0000Z...DISSIPATED