Tropical Weather Discussion

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Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Thu Nov 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 1800 UTC surface analysis and satellite imagery through 1940 UTC. ...SPECIAL FEATURES... Significant NW Swell Event: A series of NW swell sets will continue to impact the northern waters through the next several days. Currently, seas are 12 ft or greater W of 30N127W to 22N140W, with peak seas around 16 ft at 29N136W, and wave periods of 14-16 seconds. Seas of 12 ft or greater will cover the waters from W of 30N121W to 18N140W by early Fri morning. A reinforcing and larger set of NW swell will arrive later Fri, with peak seas around 22 ft near 30N138W by early Fri evening. By Sat afternoon, this set with seas of 12 ft or greater will reach across the waters W of 30N118W to 20N132W to 20N140W and peak seas of 22 ft near 30N126W. Those seas will keep spreading SE, while yet another set with seas of 12 ft or greater arrives to 30N140W by late Sat night, spreading across the majority of the waters into early next week. Please read the latest NHC High Seas Forecast at website: https://www.hurricanes.gov/text/HSFEP2.shtml for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from over the border of Nicaragua and Panama to the Gulf of Papagayo near 10.5N86W to 04N110W to 00N130W to 00N140W. Scattered moderate to isolated strong convection is observed between 300 nm and 600 nm SE of the monsoon trough between 77W and 90W, from 02S to 09N between 105W and 128W, and from 06N to 15N between 128W and 140W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Fresh northerly winds are in the Gulf of Tehuantepec supported by the pressure gradient between a high pressure system over the southern United States and lower pressures with the monsoon trough SE of the area. Seas in this waters are 4-7 ft. Meanwhile, a weak pressure gradient is present in the remainder of the Mexican offshore waters with mainly moderate or weaker winds, except locally fresh near Cabo Corrientes. Decaying NW swell is producing seas of 5-8 ft across much of the area, except for slight seas in the Gulf of California. For the forecast, fresh northerly winds and rough seas around 8 ft will pulse to strong at night across the Gulf of Tehuantepec through Fri night with locally rough seas. The next Tehuantepec gap wind event is forecast to begin early next week and continue through much of the next week. Winds may reach gale-force starting Tue night, if not sooner. Meanwhile, a cold front will move across the offshore waters of Baja California Fri, bringing fresh winds and a new batch of rough seas approaching 12 ft. Fresh to locally strong winds may also briefly impact the northern Gulf of California Fri. Then, a larger NW swell arriving Sat will produce high seas to 20 ft. Rough seas will reach all the way to past 100W by early next week, while additional and reinforcing NW swell sets continue to arrive. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... A broad subtropical ridge centered north of the area sustains moderate to locally fresh easterly winds and seas of 3-5 ft in the Gulf of Papagayo region. Elsewhere, moderate or weaker winds and moderate seas are prevalent, except locally rough seas SW of the Galapagos Islands in merging long period SW and NW swells. For the forecast, moderate to fresh winds may return to the Papagayo region by the end of the weekend into early next week, possibly reaching strong speeds by Mon night, then near gale- force by Tue night. Moderate to fresh NW-N winds may pulse in the Gulf of Panama early next week. Otherwise, moderate or weaker winds and moderate seas in merging SW and NW swell will prevail, except locally rough SSW of the Galapagos Islands through Fri night. Looking ahead, a set of NW swell may build seas to 8 ft or greater SSW of the Galapagos Islands by the middle of next week. ...REMAINDER OF THE AREA... Please refer to the Special Features section above for details on a series of significant NW swell sets which will impact much of the open waters. A cold front continues to move quickly southeastward across the NW waters, extending from 30N125W to 22N140W. The tight pressure gradient between high pressure centered well WNW of the area, and the aforementioned front sustains fresh to strong NW-N winds behind the front to near 134W. Old and decaying NW swell supports seas of 7-9 ft out ahead of the front. In the western trade waters, a surface trough analyzed just W of 140W extending to the monsoon trough E of 140W is producing a large area of showers and isolated thunderstorms as described above. Moderate to fresh easterly trade winds and rough seas are found from 12N to 18 and west of 132W. Merging SW and NW swells supports combined seas of 7-10 ft across much of the waters S of 10 between 94W and 133W. Elsewhere, winds are moderate or weaker with moderate seas, except locally fresh S of the Equator and W of 105W. For the forecast, the aforementioned cold front will move across the northern waters tonight into early Fri, bringing with it fresh to strong winds on either side of the front, and very large seas in NW swell north of 20N through Fri. Another cold front will sweep across the area Fri into the weekend, bringing even larger reinforcing NW swell, possibly reaching 24 ft along 30N. This set of swell with seas of 8 ft or greater will cover the waters N of 05N and W of 110W by late Sat night, then covering all of the waters W of 105W. Yet another set of large swell will arrive Sun, with seas of 8 ft or greater across the entire waters W of 105W by late Sun night, then across the waters W of 95W by Tue evening. Meanwhile, the mixed swell over the equatorial waters will diminish by the weekend. Looking ahead, another cold front may move into the NW waters by the end of the weekend into early next week bringing a large area of fresh to strong winds behind it as high pressure builds in.