Tropical Weather Discussion

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Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Wed Dec 17 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 1500 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N79W to 09N88W to 11N96W to 10N102W. The ITCZ continues from 10N102W to 07N130W to beyond 06.5N140W. Scattered moderate convection is noted from 04.5N to 09N between 77W and 83W, from 05N to 10.5N between 87W and 93W, and from 06.5N to 11.5N between 111W and 120W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A 1026 mb high center is analyzed just N of the area near 31N133W with the associated ridge extending 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 including the Gulf of California, except moderate to fresh winds in the outer Baja California Norte waters, near Cabo Corrientes, and in the Gulf of Tehuantepec. For the forecast, moderate to fresh N-NE winds in the Gulf of Tehuantepec will diminish this afternoon. Fresh to strong gap winds and associated rough seas may develop there Fri through the upcoming weekend as the pressure gradient tightens in the area. Moderate to fresh winds will pulse near Cabo Corrientes through tonight, then again this weekend. Similar winds will be well offshore Baja California Norte through the end of the week, along with locally rough seas. Moderate or weaker winds and slight to moderate seas are forecast elsewhere. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to locally strong NE winds prevail in the Gulf of Papagayo with as high pressure over northern Central America and lower pressures along the monsoon trough over southern Costa Rica and Panama. Light to gentle winds and moderate seas are elsewhere N of 05N. S of 05N, gentle to moderate southerly winds and moderate seas prevail, except slight seas nearshore Colombia and eastern Panama. Isolated to scattered showers and thunderstorms are present offshore Colombia northward per conventional satellite imagery. For the forecast, high pressure over interior northern Central America and lower pressures near the monsoon trough will support pulsing moderate to fresh easterly trade winds and moderate seas across the Gulf of Papagayo through Fri, then increasing to fresh to strong Fri night through the upcoming weekend as the gradient tightens. Moderate to fresh northerly winds will pulse in the Gulf of Panama through the next several days. Gentle to moderate winds and slight to moderate seas will prevail elsewhere. ...REMAINDER OF THE AREA... A 1026 mb high center is analyzed just N of the area near 31N133W with the associated ridge extending to near the Revillagigedo Islands. The pressure gradient between the high and relatively lower pressures near the ITCZ/Monsoon Trough is bringing fresh to locally strong trade winds from 10N to 20N and W of 120W where seas are 6-10 ft per multiple recent altimeter passes. Moderate to fresh NE winds are elsewhere from 06N to 22N and W of 115W. Moderate to fresh winds and building seas to rough are N of 25N between 119W and 130W. Moderate southerly winds and moderate seas are occurring S of the monsoon trough and ITCZ. Mainly gentle to moderate winds and moderate seas prevail across the remainder of the open waters. For the forecast, high pressure will continue over the northern waters through today leading to continuing fresh to locally strong easterly winds and rough seas over much of the tradewind belt west of 120W. A tight pressure gradient will persist offshore southern California leading to fresh to locally strong winds and rough seas in the N-central waters through the remainder of the work week. Marine conditions should improve overall during the upcoming weekend as the pressure gradient slackens due to a cold front approaching 30N140W.