Eastern Pacific Tropical Weather Discussion
055 AXPZ20 KNHC 120255 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Mon Oct 12 2026 Tropical Weather Discussion for the eastern Pacific Ocean from 03.4S to 30N, east of 120W including the Gulf of California, and from the Equator to 30N, between 120W and 140W. The following information is based on satellite imagery, weather observations, radar, and meteorological analysis. Based on 0000 UTC surface analysis and satellite imagery through 0230 UTC. ...SPECIAL FEATURES... Hurricane Simon is centered near 19.8N 106.0W at 12/0300 UTC, moving northwest at 4 kt. Estimated minimum central pressure is 956 mb. Maximum sustained wind speed is 105 kt with gusts to 130 kt. Peak seas are near 22 ft. Numerous moderate to scattered strong convection is within 60 N of the center. Scattered moderate and isolated strong convection is elsewhere from 15N to 22N between 103W and 110W. Simon is moving slowly north- northwestward, and is forecast to track parallel to the coast of west-central Mexico over the next day or so. Gradual weakening is expected due to the proximity to the mountainous terrain, which could further disrupt the hurricane's structure along its eastern side. Simon is expected to produce additional rainfall totals of 2 to 4 inches with isolated additional amounts of 8 inches over portions of the states of Colima, Jalisco, Nayarit and Sinaloa through early Thursday. Isolated maximum storm totals of 30 inches are possible over portions of the states of Michoacan, Colima, and Jalisco. This rainfall will produce life-threatening flooding and mudslides or worsen any on-going flooding, especially in areas of steep terrain. Swells generated by Simon will affect portions of the coast of southwestern and west- central Mexico during 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. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and the latest Simon NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...TROPICAL WAVES... The axis of a tropical wave is near 91W, north of 02N. The wave is is producing disorganized showers and thunderstorms. Environmental conditions are expected to be conducive for gradual development, and a tropical depression is expected to form well south of southern Mexico by the middle or latter half of the week as the system moves generally west-northwestward at around 10 mph. There is a medium chance for tropical cyclone development in the next 48 hours, and a high chance through next 7 days. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N84W to 07N91W to 12N102W, then resumes near 16N115W to 08N140W. Scattered moderate and isolated strong convection is noted from 00N to 15N E of 100W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section above for information on Hurricane Simon. Fresh to strong SW winds and rough seas are impacting the northern Gulf of California. Gentle to locally moderate winds, and slight to moderate seas, are elsewhere over the Gulf. Fresh to strong winds are in the Gulf of Tehuantepec. Elsewhere, outside of the areas impacted by Hurricane Simon, moderate or weaker winds and moderate to rough seas prevail. For the forecast, Hurricane Simon is near 19.8N 106.0W at 8 PM PDT, and is moving northwest at 4 kt. Maximum sustained winds are 105 kt with gusts to 130 kt, and the minimum central pressure is 956 mb. Simon will move to 20.5N 106.3W Mon morning, 21.2N 106.8W Mon evening, 21.8N 107.1W Tue morning, 22.4N 107.0W Tue evening, 23.0N 106.7W Wed morning, and inland to 23.4N 106.4W Wed evening. A cold front moving across the northern waters will start to weaken today. The front will support fresh to strong SW winds across the northern Gulf of California through Mon. Rough seas lingering west of the Baja California peninsula will gradually diminish through early this week. Elsewhere, disorganized showers and thunderstorms are associated with a tropical wave moving across the waters of southern Mexico. Environmental conditions are expected to be conducive for gradual development, and a tropical depression is expected to form well south of southern Mexico by the middle or latter half of the week as the system moves generally west- northwestward at around 10 mph. There is a medium chance for tropical cyclone development in the next 48 hours, and a high chance through next 7 days. Regardless of development, expect an increase in winds and seas across the waters off southern Mexico by midweek. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to locally fresh winds and moderate seas prevail over the Papagayo region. Light to gentle winds and moderate seas are elsewhere N of 04N. Gentle to moderate southerly winds and moderate seas in SW swell prevail S of 04N. For the forecast, a weak pressure gradient will support moderate or lighter winds and moderate seas across much of the forecast waters through the middle of next week. Moderate to fresh NE to E winds are expected in the Papagayo region tonight. ...REMAINDER OF THE AREA... A cold front is moving across the NE waters followed by moderate to fresh northerly winds and rough seas. Similar marine conditions are noted elsewhere N of 20N W of 120W. Moderate or lighter winds and moderate seas prevail across the remainder of the discussion waters. For the forecast, the cold front will move across the NE waters through Tue while gradually dissipating. Large SW swell will affect the waters S of the Equator and west of 105W over the next couple of days.