Tropical Weather Discussion

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Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Mon Dec 15 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 0230 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: The pressure gradient between the high pressure over Mexico and the eastern north Pacific monsoon trough will lead to gale-force northerly winds to prevail across the Gulf of Tehuantepec through Tue morning. By that time, the high pressure will begin to shift eastward and weaken. Rough seas will are expected with the strongest winds, peaking 14 ft on Mon night. Please read the latest High Seas 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 08N78W to 07N101W to 08N120W. A surface trough is analyzed from 12N125W to 07N128W. The ITCZ then extends to the west of the trough from 08N131W to beyond 06N140W. Scattered moderate convection is within 120 nm on either side of the trough and E of 89W, and from 07N-13N between 92W-113W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A Gale Warning is in effect for the Gulf of Tehuantepec. Please see the Special Feature section for more details. A 1022 mb high center is analyzed near 30N130W. Its associated ridge extends to near the Revillagigedo Islands. The related pressure gradient is allowing for gentle to moderate northwest to north winds and slight to moderate seas over the Mexican offshore waters N of 16N. Light and variable winds and slight seas prevail elsewhere between 13N to 16N outside of the Tehuantepec area. For the forecast, gale-force winds over the Gulf of Tehuantepec will prevail through early Tue. Elsewhere, mainly gentle to moderate winds and moderate seas will prevail through the middle of the upcoming next week. Fresh to strong northerly winds and rough seas will develop over the offshore waters of Baja California Norte by the middle part of the upcoming week as well. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to strong northeast to east winds prevail in the Gulf of Papagayo region as high pressure builds in north of the Caribbean. Moderate seas is noted in these waters. Farther south, gentle to moderate southerly winds and moderate seas are present south of 05N. Elsewhere, moderate or lighter winds and moderate seas are prevalent. For the forecast, building high pressure north of the Caribbean will continue to support pulsing fresh to strong easterly trade winds and moderate seas across the Gulf of Papagayo through midweek. Rough seas will develop in the far offshore waters of Guatemala Mon into Tue due to the Tehuantepec gale force gap event. Moderate to fresh northerly winds will pulse in the Gulf of Panama this upcoming week. Gentle to moderate winds and slight to moderate seas will prevail elsewhere. ...REMAINDER OF THE AREA... A 1022 mb high center is located near 30N130W. This feature is controlling the wind regime over the northern waters of the tropical eastern Pacific. The pressure gradient between the high and relatively lower pressures associated to a trough that extends from 12N125W to 07N128W is bringing moderate to fresh trade winds from 08N to 19N and W of 123W as was confirmed by latest scatterometer data. Rough seas prevail over these waters in mixed swell along with wind generated seas. Elsewhere, moderate to fresh southerly winds and moderate seas are occurring south of the monsoon trough and ITCZ. Gentle to moderate south to southwest winds are south of the monsoon trough, and moderate to fresh east to southeast winds are south of the ITCZ. Moderate seas prevail over these waters in southwest swell east of 99W, and in merging northwest and southwest swell west of 99W. For the forecast, the surface trough will move westward through the early part of the upcoming week while weakening. High pressure will build further over the northern waters into the middle portion of the week leading to a tightening of the pressure gradient that will cause fresh to strong easterly winds and rough seas over much of the tradewind belt west of 120W. Over the eastern part of the area, fresh to strong easterly winds and rough seas associated with the gale-force gap wind event in the Gulf of Tehuantepec will spread westward to near 106W from 09N to 11N Mon through Tue. Moderate to fresh southwest winds along with rough seas will develop over the northwest part of the area Mon night and continue through Tue.