Tropical Weather Discussion

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Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Sat Dec 27 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 1200 UTC surface analysis and satellite imagery through 1515 UTC. ...SPECIAL FEATURES... Significant Swell and Developing Low Pressure: Large northwest swell continues to induce very rough seas over the waters north of 25N and west of about 120W, with seas peaking to around 15 ft (4.5 m) north of 28N and between 124W and 130W. This was confirmed by a recent altimeter satellite pass. Wave period with these seas is of 12-14 sec. Rough seas extend southward into the trades waters and eastward to the offshore waters of Baja California. The swell will slowly subside through late Sun south of 28N. Rough seas of 8 to 12 ft are likely to prevail through the weekend across the offshore waters of Baja California from 17N to 26N. Global models suggest that a surface trough with attendant low pressure will develop across the waters south of about 22N between 120W and 128W Sun into early next week. This will combine with high pressure building into the region resulting in a rather broad zone of increasing winds reaching to strong speeds roughly from 16N to 26N and west of the Revillagigedo Islands, accompanied by scattered showers and isolated thunderstorms. There is a possibility of these winds reaching gale-force speeds, especially in the squalls. Seas may reach 15 ft with these winds. Conditions will improve by midweek. Please read the latest High Seas Forecast issued by the National Hurricane Center at website: https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more information. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 08N82W to 07N97W. The ITCZ stretches from 07N97W to 08N120W and beyond 07N140W. Scattered moderate to isolated strong convection is occurring from 08N to 22N and between 120W and 131W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weak high pressure over the Gulf of America is supporting fresh to strong northerly winds and moderate seas across the Gulf of Tehuantepec. The remainder of the Mexican offshore waters are under the influence of a strong 1032 mb high pressure system near 40N139W that extends southeastward to the Revillagigedo Islands. A cold front extends from Arizona to near 26N117W. The pressure gradient between the aforementioned ridge and the front results in moderate to fresh northerly winds across the offshore waters of Baja California. Seas of 8-13 ft are noted north of Punta Eugenia, while moderate seas are found south of Punta Eugenia. Elsewhere, moderate or weaker winds and slight to moderate seas prevail. For the forecast, the gap wind event in the Gulf of Tehuantepec is forecast to end late this morning as the pressure gradient relaxes. Gale conditions may return to the Gulf of Tehuantepec region late Mon night and continue until Wed. Winds may peak around 40 kt, supporting rough seas. Meanwhile, northwest swell propagating through the waters north of Punta Eugenia will be spreading rough seas southward across the offshore waters of the Baja California peninsula through the weekend. High pressure will begin to build across the Baja waters through the weekend bringing a return to more typical northerly winds. Fresh to locally strong northwest winds are likely to develop in the Gulf of California Sun into Tue as high pressure strengthens across the region. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The subtropical ridge centered north of the Caribbean Islands continues to sustain fresh to locally strong easterly trade winds across the Gulf of Papagayo, extending downstream to 89W. Seas in these waters are 4-6 ft. Elsewhere, moderate or weaker winds and moderate seas prevail. For the forecast, the pressure gradient between high pressure north of the area and the eastern north Pacific monsoon trough will continue to support pulsing fresh to locally strong northeast to east gap winds in the Gulf of Papagayo region through the period. Mostly gentle to moderate north winds are expected in the Gulf of Panama during the period. Gentle or lighter winds and slight to moderate seas are expected elsewhere through the period. ...REMAINDER OF THE AREA... Please read the Special Features section for details on significant swell impacting much of the northern waters. Also on the developing low pressure in the region. A strong high pressure centered well north of the tropical eastern Pacific extends southward into our waters. Moderate to fresh NE-E winds are found over much of the basin north of 10N and west of 115W. Seas in these waters are 8-15 ft as discussed in the Special Features section. Elsewhere, moderate or weaker winds and moderate seas are prevalent. For the forecast, high pressure to build into the regional waters from the NW. Global models suggest that a surface trough with attendant low pressure will develop across the waters south of about 22N between 120W and 128W Sun into early next week. This will combine with high pressure building into the region resulting in a rather broad zone of increasing winds reaching to strong speeds roughly from 16N to 26N and west of the Revillagigedo Islands, accompanied by scattered showers and isolated thunderstorms. There is a possibility of these winds reaching gale-force speeds. Seas may reach 15 ft with these winds as long-period north swell gradually decays across the area. Conditions will improve by midweek, but before then, stay tuned to future weather forecast updates referencing the upcoming trough and low pressure feature.