000 AXPZ20 KNHC 070242 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Thu Dec 7 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 0200 UTC. ...SPECIAL FEATURE... Gulf of Tehuantepec Gale Warning: Strong high pressure stretches over central Mexico, supporting northerly gale force winds across the Gulf of Tehuantepec. Strong winds likely stretch as far south as 12N. Seas currently range between 8 and 10 ft. This pattern will persist through Thu. Seas expected to reach as high as 12 ft tonight into Thu morning. Gale-force winds will end by Thu evening, with the strong winds diminishing by Fri. Seas will also subside below 8 ft on Fri. Please read the latest High Seas Forecast issued by the National Hurricane Center at https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from the coast of Colombia near 07N78W to 06N109W. The ITCZ extends from 06N109W to 09N120W and then from 08N127W to beyond 08N140W. Scattered moderate convection is noted from 04N to 09N between 133W and 140W. Scattered moderate convection is noted from 05N to 11N and W of 118W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please read the Special Features section for more information on the Gale Warning in the Gulf of Tehuantepec. A broad ridge extends across the offshore waters of Baja California from weakening high pressure. The pattern is supporting gentle to moderate northerly winds across most of the Baja California offshore waters. Moderate N to NW winds prevail over the southern Gulf of California, including the entrance of the Gulf with light to gentle winds in the northern Gulf. NW swell across the Baja California waters is bringing 8 to 11 ft seas mainly over the waters beyond 60 nm of the Baja California coastline. Seas range 2 to 4 ft across the Gulf of California. Farther south, light to gentle breezes persist off southern Mexico with 4 to 6 ft combined seas in mixed swell. For the forecast, outside of the gap winds in the Gulf of Tehuantepec, long-period NW swell will persist off Baja California and the Revillagigedo Islands through Sat. Seas as high as 12 ft could move across the Baja California Norte waters tonight. Reinforcing NW swell will arrive off Baja California Norte by Thu night into Fri, accompanying a decaying cold front moving into the region. Swells will subside later in the weekend. Strong winds could develop across most of the Gulf of California this weekend, producing rough seas. Another strong gale-force wind event could occur over the Gulf of Tehuantepec late this weekend into early next week with very rough seas. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to strong NE to E winds prevail across the Gulf of Papagayo, where seas are near 6 to 8 ft. Gentle to moderate winds elsewhere over the region. Seas range 5 to 7 ft in the Guatemala and El Salvador offshore waters mostly within N to NW swell due to the influence of the Gulf of Tehuantepec gap wind event. Elsewhere, seas range 3 to 5 ft seas primarily in S to SW swell. Scattered showers and thunderstorms are noted south of the monsoon trough off the coast of Colombia. For the forecast, high pressure north of the region will support pulsing strong winds across the Gulf of Papagayo at night through the weekend. Seas will reach 8 ft downwind of the event. Seas will build well offshore of Guatemala tonight into Thu due to swell generated by gale-force gap winds in the Gulf of Tehuantepec. Gentle to moderate winds are forecast elsewhere. Moderate combined seas will persist through the weekend in a mix of SW and NW swell. ...REMAINDER OF THE AREA... High pressure dominates the waters north of 20N. Fresh to strong trade winds persist south of the ridge, mainly 08N to 25N W of 115W. Seas in this region are 8 to 14 ft, in a mix of seas due to the trade wind flow, and long-period NW swell. A cold front stretches in the NW corner of the basin from 30N127W to 26N140W with scatterometer data depicting moderate to fresh N to NE winds behind the front. Seas to 12 ft are noted along the front. Combined seas of 8 to 10 ft cover much of the region elsewhere W of 112W, although with primarily S to SE swell S of 04N. Gentle to moderate winds and 4 to 7 ft seas are noted E of 112W. A surface trough is analyzed along 124W from 08N to 12N with scattered moderate convection near them. For the forecast, the cold front will continue to move across the waters tonight before decaying by Thu weakening the high pressure. This will allow for trade winds to diminish slightly W of 115W tonight. Large, long-period NW swell accompanying the front will continue to move across the waters N of 10N and W of 120W through tonight supporting seas to 14 ft N of 20N and W of 130W. E of 115W, the combination of the NW swell with shorter- period NE swell emerging from gap wind events and fresh E trade winds will support rough seas from 07N to 12N between 95W and 110W Thu and Fri. This swell event will begin to subside by the weekend and into early next week. $$ ERA