000 AXPZ20 KNHC 310349 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Sun Dec 31 2023 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 0330 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Strong high pressure centered over NE Mexico is forcing gale force winds across the Gulf of Tehuantepec, confirmed by earlier ASCAT satellite data pass. The gale force northerly gap winds are expected to persist through early Sun morning, diminishing late Sunday morning. Seas of 12 to 13 ft will persist through early Sun morning. Seas will then subside by Sun night across the region. Large Swell Event Across Eastern Pacific: Large WNW to NW swell, with seas of 12 to 15 ft, is occurring north of 07N and west of 112W. The 8 ft seas extend southward beyond the Equator, and as far east as 97W. Reinforcing swell will continue to spread south and east across the waters through early Mon. Seas will subside below 12 ft by Sun night. Please refer to the High Seas Forecast issued by the National Hurricane Center at https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for details on both special features. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from the coast of Costa Rica near 08N83W to 05N95W. The ITCZ extends from 05N95W to 06N120W to beyond 07N140W. Scattered moderate convection is noted from 02N to 09N between 81W and 92W and from 03N to 09N between 107W and 140W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See the Special Features Section above for details on a Gale Warning for the Gulf of Tehuantepec. Moderate NNW winds prevail across the Baja California offshore waters. Large NW swell is impacting the waters, ranging from 10 to 16 ft. The 12 ft seas dominate the waters north of Punta Eugenia. In the Gulf of California, gentle winds and 1 to 2 ft seas are present. Light to gentle winds are elsewhere offshore Mexico outside of the Gulf of Tehuantepec. Seas across the southern Mexico offshore waters are 7 to 10 ft within NW swell. For the forecast, very large NW swell impacting the Baja California offshore waters will bring seas of 12 to 16 ft tonight, then subside below 12 ft Sun afternoon. Seas of 8 to 11 ft across most of the southwest and southern Mexico offshore waters will persist through the weekend. A second cold front will move through the Baja California offshore waters late Sun night through Mon. This will keep seas around 8 to 10 ft through Tue. In the Gulf of Tehuantepec, fresh to strong N winds are expected Sun afternoon through Sun night, briefly diminishing early Mon. Strong to near gale force N winds will then return Mon evening through early Tue before diminishing Tue afternoon. Looking ahead, the next gap wind event in the Gulf of Tehuantepec should begin Wed night or Thu, with strong to near-gale force N winds possible. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh NE to E winds are occurring in the Gulf of Papagayo region. Seas of 6 to 8 ft in N swell are occurring offshore Guatemala due to a Gulf of Tehuantepec gap wind event. Elsewhere, quiescent marine conditions dominate the waters with gentle to moderate winds and seas of 4-6 ft in mixed swell. For the forecast, a building ridge north of the area will support fresh to strong NE gap winds over the Gulf of Papagayo region late tonight through Wed. Seas will build to 8 ft by Sun. Meanwhile, gale-force gap winds in the Gulf of Tehuantepec will cause NW swell with seas 7 to 9 ft over the Guatemala and El Salvador offshore waters through Sun night. Fresh N winds will pulse at night in the Gulf of Panama from Sun night through Tue night. Otherwise, a weak pressure gradient will result in moderate or lighter winds across the rest of the area through early next week. ...REMAINDER OF THE AREA... See the Special Features Section above for details on the large NW swell across most of the forecast waters. The pressure gradient between a 1023 mb high at 26N138W and the ITCZ is yielding fresh to locally strong NE trades from 06N to 22N and west of 125W, with moderate to locally fresh trades elsewhere from the ITCZ to 22N, and west of 100W. South of the ITCZ and monsoon trough, winds are moderate or less. Seas of 12 to 16 ft prevail across most of the area north of 07N and west of 115W in NW swell. Elsewhere west of 100W, seas are 8 to 12 ft. East of 101W, seas are 5 to 7 ft. For the forecast, see the Special Features section above for details on the large swell over much of our forecast waters. The current NW swell will subside to the 8 to 12 ft range across most of the area by Sun afternoon. Elsewhere, another cold front will cross 30N140W tonight, reach from 30N124W to 26N130W Sun evening, then weaken by Mon evening as it approaches Baja California. Fresh to strong winds are expected north of 27N with this front. High pressure building across the northwest waters will enhance NE trades between the ITCZ and 20N, and to the west of 127W from Sun through most of the week, bringing fresh to strong winds and 8 to 12 ft seas to the area. $$ AReinhart