Tropical Weather Discussion

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Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Sun Dec 21 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 0000 UTC surface analysis and satellite imagery through 0305 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A tight pressure gradient between a persistent high pressure system over the southern United States and lower pressures in the deep tropics will support fresh to strong northerly winds across the Gulf of Tehuantepec through late this workweek. Moderate to locally rough seas can be expected with these winds. Early this week, high pressure will build in over the slopes of the Sierra Madre mountains in Mexico, forcing winds to pulse to gale speeds at night Mon through Wed, and possibly Thu. 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 axis extends from 07N78W to 08N97W. The ITCZ stretches from 08N97W to 10N117W to beyond 07N140W. Isolated moderate convection is observed from 09N to 15N and between 101W and 125W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... High pressure just off the eastern United States extends a ridge to the Gulf of America, supporting fresh to strong northerly winds in the Gulf of Tehuantepec. Moderate seas are noted in the area described. The rest of the Mexican offshore waters are dominated by a weak subtropical ridge centered well west of Baja California Norte. Moderate to locally fresh NW winds and moderate seas are found off Cabo Corrientes. Light to gentle winds and slight to moderate seas are noted in the offshore waters of Baja California and in the Gulf of California. Elsewhere, moderate or weaker winds and moderate seas prevail. For the forecast, high pressure north of the Gulf of Tehuantepec will support fresh to strong northerly winds and moderate to locally rough seas over the next several days. Winds are expected to pulse to gale-force at night from Mon through Wed and possibly Thu. Rough seas will develop with these winds. Elsewhere over the majority of the waters, a relatively weak pressure gradient will lead to moderate or weaker winds and seas into the early part of the upcoming week. Looking ahead, a cold front will approach the offshore waters of Baja California Norte by the middle portion of the upcoming week 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...Corrected The gradient related to high pressure off the eastern United States is allowing for fresh to locally strong northeast to east gap winds in the Gulf of Papagayo. These winds extend downstream to near 89W. Seas over these waters are 4-6 ft. Farther east, moderate to locally fresh north winds with seas of 2-4 ft are in the Gulf of Panama. Moderate or lighter winds and moderate seas prevail elsewhere. For the forecast, high pressure building southward along the United States eastern seaboard will support fresh to strong northeast to east winds, mainly during late night and into the early mornings in the Gulf of Papagayo over the next several days. In the Gulf of Panama, mainly gentle to moderate north winds are expected through the period, except for winds occasionally reaching fresh speeds at night as weak low pressure meanders off Colombia. 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 the upcoming week. ...REMAINDER OF THE AREA... A cold front located west of the far NW waters is producing moderate to locally fresh SW winds and seas of 7-8 ft north of 28N and west of 133W. The remainder of the basin is dominated by a broad subtropical ridge over the northern waters. Moderate to locally fresh easterly winds and seas of 6-8 ft are occurring from 10N to 20N and west of 110W. 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 north of the ITCZ/Monsoon Trough and west of about 110W through at least Sun, with little change in winds and seas. Beginning Sun night, a surface trough is expected to form along the ITCZ near 120W as a deep layer trough sharpen while digging southward toward the tropical region. This feature should enhance deep convection and strengthening winds for a couple of days. At the same time, a cold front will reach the NW waters near 30N140W, to be preceded and followed by fresh to strong winds. The front is expected to attendant to weak low pressure that may move to the northern waters near 29N135W by early on Mon. By the the middle portion of the upcoming week, broad low pressure north of the area is expected to produce strong to near gale-force westerly winds and rough to very rough seas north of about 23N.