Eastern Pacific Tropical Weather Discussion
660 AXPZ20 KNHC 121534 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 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 1200 UTC surface analysis and satellite imagery through 1430 UTC. ...SPECIAL FEATURES... Hurricane Simon is centered near 20.1N 106.5W at 1500 UTC, moving northwest at 3 kt. Estimated minimum central pressure is 962 mb. Maximum sustained wind speed is 95 kt with gusts to 115 kt. Peak seas are near 20 ft. Numerous moderate to strong convection is within 60 nm of the center. Scattered to numerous moderate and isolated strong convection is elsewhere from 18N to 22N between 105W and 109W. Simon is moving slowly to the northwest and is forecast to continue moving slowly near the coast of Mexico for the next few days, turn northeastward and inland across Sinaloa on Thu. 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, as well as the southern Gulf of California. These swells are likely to cause large and powerful surf and life- threatening 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 93W-94W, north of 02N, moving westward around 10 kt. 1009 mb low pressure has formed near 08N93W in association with the wave. This system is producing a large area of showers and thunderstorms, with scattered to numerous moderate to strong convection noted from 04N to 12N between 88W and 100W. This system is gradually becoming better defined, and environmental conditions are forecast to be conducive for further development. A tropical depression is expected to form well south of southern Mexico in the next two days while the system moves generally west-northwestward at around 10 kt. There is a high chance for tropical cyclone development through next 7 days. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 11N75W to 08.5N84W to 10N89W to 1009 mb low pres near 08N93W to 13N101W, then resumes near 19N114W to 08N132W to beyond 08.5N140W. Scattered to numerous moderate to strong convection is noted from 00N to 10N E of 88W, and S of 03.5N between 128W and 135W. Scattered moderate convection is noted within 75 nm of the monsoon trough between 114W and 140W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section above for information on Hurricane Simon. A cold front extends from the far northern Gulf of California along 31.5N southwestward across Baja Norte to beyond 24.5N120W, and has become almost stationary in recent hours. Fresh to strong SW winds and moderate seas to 6 ft are impacting the northern Gulf of California ahead of the front. Gentle to locally moderate winds, and slight to moderate seas, are elsewhere over the Gulf, except for seas to 5 ft in S swell from Simon across the entrance. Gentle NW winds prevail across the Baja Norte waters behind the front, while light to gentle SW to W winds are south of the front across the remaining Baja waters, becoming moderate NW south of Cabo San Lucas. Seas are 6 to 8 ft in NW swell across the Baja offshore waters this morning, while seas generated from Simon are producing seas of 8 ft and greater south of Baja between 110W and the SW Mexican coast. Fresh to locally strong winds are in the Gulf of Tehuantepec. Elsewhere, moderate or weaker winds and moderate to rough seas prevail. For the forecast, Hurricane Simon is expected to move slowly northward and remain just off the Mexican coast, reaching near 20.4N 106.8W this afternoon, near 20.9N 107.3W Tue morning, near 21.3N 107.7W Tue afternoon, near 21.6N 107.7W Wed morning, near 22.2N 107.4W Wed afternoon, and inland near 24.1N 106.3W Fri morning. A cold front moving across the northern waters will become stationary and start to weaken today. The front will support fresh to strong SW winds across the northern Gulf of California today. Rough seas in NW swell lingering west of the Baja California peninsula will gradually diminish through early this week. Elsewhere, a broad area of low pressure has formed several hundred miles south of the coast of Guatemala, accompanied by numerous shower and thunderstorm activity. This system has become better defined since yesterday, and environmental conditions are forecast to be conducive for further development. A tropical depression is expected to form well south of southern Mexico in a few days while the system moves generally west- northwestward at around 10 kt. There is a high chance for tropical cyclone development 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 fresh E winds extend offshore from the papagayo region to 93W, where seas are 6 to 7 ft. A broad cyclonic circulation has developed associated with the tropical wave along 93W. Moderate to fresh SW to S winds are just W of the offshore waters S of 09N and near 90W. Gentle to moderate SW to S winds and moderate seas to 7 ft in SW swell are elsewhere S of 08N. For the forecast, a weak pressure gradient will support moderate or lighter winds and moderate seas across much of the forecast waters through the end of the week. Showers and thunderstorms are expected to remain active across the waters E of 85W through early Wed. Moderate to fresh NE to E winds are expected in the Papagayo region today, then gradually weaken through mid week as the tropical wave along 93W shifts westward away from the area. ...REMAINDER OF THE AREA... A cold front is moving across the NE waters followed by moderate to fresh northerly winds and rough seas of 8 to 10 ft in NW swell N of 24N. Light to gentle winds and seas of 6 to 8 ft in merging NW and SW swell generally prevail elsewhere S of 24N W of 120W. 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.