Tropical Weather Discussion

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Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Sat Dec 20 2025 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 0600 UTC surface analysis and satellite imagery through 0915 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: The pressure gradient between a 1024 mb high pressure system over the eastern United States and lower pressures in the deep tropics result in fresh to near gale- force northerly winds across the Gulf of Tehuantepec. This was confirmed by a recent scatterometer satellite pass. Frequent gusts to gale force are occurring through late this morning. Seas are peaking around 8-9 ft (2.5-3 m). Fresh to strong winds will persist across the area through at least the middle of next week. Gale conditions will be possible, mainly at night, Mon through Wed as high pressure develops over the eastern slopes of the Sierra Madre mountains in Mexico. Rough seas are also likely to develop with the strongest winds. Please read the latest High Seas Forecast issued by the National Hurricane Center at website: https://www.nhc.noaa.gov/text/MIASFEP2.shtml for more information. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 08N78W to 09N98W. The ITCZ stretches from 09N98W to 10N117W to beyond 06N140W. Scattered moderate convection is observed from 07N to 13N and between 113W and 128W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... High pressure north of the Gulf of Tehuantepec sustains fresh to near gale-force northerly winds, along with frequent gusts to gale force and seas to 8-9 ft, across the Tehuantepec basin. Elsewhere, a 1022 mb subtropical ridge near 30N130W extends a ridge to the Revillagigedo Islands. Moderate northerly winds and moderate seas are present west of Guadalupe Islands, while light to gentle winds and moderate seas prevail in the rest of the Baja California offshore waters. Moderate northerly winds and seas of 2-4 ft are noted off Cabo Corrientes. In the rest of the Mexican offshore waters, light to gentle winds and slight to moderate seas are evident. For the forecast, high pressure north of the Gulf of Tehuantepec will support fresh to near gale-force northerly winds and moderate to locally rough seas over the next several days. Winds may pulse to gale-force at night Mon through Wed. Elsewhere, for most waters, a relatively weak pressure gradient will lead to moderate or weaker winds and seas into the start of next week. Looking ahead, a cold front will approach the offshore waters of Baja California Norte by midweek possibly producing fresh to strong southerly winds and rough seas. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... A 1024 mb high pressure system over the eastern United States supports fresh to locally strong easterly gap winds in the Gulf of Papagayo, extending downstream to 90W. Seas in these waters are 4-7 ft. Farther east, moderate to locally fresh northerly winds and seas of 2-4 ft are occurring in the Gulf of Panama. Elsewhere, moderate or lighter winds and moderate seas prevail. For the forecast, building high pressure north of the area will support fresh to strong NE to E winds, mainly during late night/early morning hours across the Gulf of Papagayo over the next several days. In the Gulf of Panama, mainly gentle to moderate N winds are expected through the middle of next week. Elsewhere, a weak pressure gradient will continue to only force moderate or weaker winds with slight to moderate seas across the remainder of the forecast waters into the start of next week. ...REMAINDER OF THE AREA... A 1022 mb subtropical ridge centered near 30N130W dominates the remainder of the tropical eastern Pacific. A recent scatterometer satellite pass showed moderate to locally fresh NE-E winds over much of the basin west of 120W and north of the ITCZ. Seas in these waters are 5-8 ft. East of 120W and north of the ITCZ and monsoon trough, moderate easterly breezes and seas of 3-5 ft are prevalent. South of the monsoon trough and ITCZ and west of 100W, moderate to locally fresh southerly winds and seas of 5-8 ft prevail. Elsewhere, moderate or weaker winds and moderate seas are evident. For the forecast, high pressure will remain in control of the weather pattern across the waters N of ITCZ/Monsoon Trough and W of 110W through at least Sun, with little change in winds and seas. Starting Sun night, a surface trough is expected to form along the ITCZ near 120W enhancing deep convection and strengthening winds for a couple of days. At the same time, a cold front will reach the NW waters near 30N140W, bringing fresh to strong SW winds ahead of the front and fresh to strong N winds behind the front early next week. A swell event will follow the front, building seas to 8-12 ft beginning late on Mon. By midweek, a broad low pressure north of the area will produce strong to near gale- force westerly winds and rough to very rough seas north of 23N.