000 AXPZ20 KNHC 290318 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Fri Dec 29 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 0230 UTC. ...SPECIAL FEATURES... Gale Warning Far NW Waters and Very Large Swell Event: A cold front stretches across the NW corner of the forecast waters from 20N135W to 26N140W. SW gales are noted ahead of the front and W gales behind the front with strong winds N of 25N and W of 127W. Very large NW swell is noted with this system, with seas currently peaking around 32 ft near 30N140W and the 12 ft seas extending as far south as 09N and as far west as 116W in the northern Baja California offshore waters. The 8 ft seas extend even farther south and east, towards 00N109W. The gales are expected to end by tonight. However, strong winds will continue through Fri night as the front reaches 30N124W to 20N138W. The front will dissipate by Sat night off the Baja California coast. However, the reinforcing swell will continue to spread across the waters over the next few days. Seas will subside below 12 ft by Sun evening, and continue to gradually subside through early net week. Gulf of Tehuantepec Gale Warning: Winds draining from the Chivela Pass are forcing fresh to locally strong N winds through tomorrow. By Fri night, a strong cold front pushing across the W Gulf of Mexico will induce a N gale-force gap wind over the Gulf of Tehuantepec. Gales should continue through the weekend before diminishing by Sun afternoon. Peak seas during the period of gales will be around 12 ft on Sun. Please refer to the High Seas Forecast, issued by the National Hurricane Center, at https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml, for details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends off the coast of Panama near 08N78W to 08N99W. The ITCZ extends 08N99W to 07N120W to beyond 07N140W. Scattered moderate convection is noted from 03N to 10N between 80W and 89W and from 04N to 09N between 106W and 140W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Features Section above for details on a Gale Warning for the Gulf of Tehuantepec. A 1022 mb high pressure is centered to the west of the Baja California offshore waters near 26N123W. The ridging from this high extends across most of the offshore waters of Mexico. The pressure gradient between this high pressure and lower pressure over Mexico is supporting moderate to fresh NW winds across the central and southern Gulf of California with seas 2-4 ft. Meanwhile, N to NW moderate to locally fresh winds are noted in the Baja California and southwest Mexico offshore waters. A large NW swell event is impacting the Baja California waters N of 25N, or just north of Cabo San Lazaro with seas 12-16 ft. S of 25N to the Cabo San Lucas offshore waters, seas range 8-11 ft. Elsewhere, light to gentle winds are noted with seas 5 to 7 ft in NW swell. No significant convection is noted at this time. For the forecast, high pressure over the U.S. Great Basin will force fresh NW winds over the Gulf of California through Fri. Very large NW swell with a 16-18 second period impacting the waters off of Baja California Norte will produce 12-16 ft seas through Fri night. These seas will be reinforced again Sat through Sun. Seas will subside again Sun night into Tue. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Quiescent marine conditions dominate the waters with gentle to moderate winds and seas of 3-5 f in mixed swell. Scattered thunderstorms are noted across the Costa Rica and Panama offshore waters. For the forecast, a weak pressure gradient will result in moderate or lighter winds into Sat. A building ridge north of the area should support fresh to strong NE gap winds over the Gulf of Papagayo region Sat night into Tue. Gale-force gap winds in the Gulf of Tehuantepec will cause NW swell with seas 7-9 ft over the Guatemala- El Salvador offshore waters Sat night into Sun night. ...REMAINDER OF THE AREA... See Special Features Section above for details on gales that will develop tomorrow over the far NW waters and subsequent very large NW swell. The weak pressure gradient between a 1022 mb high at 26N123W and the ITCZ is forcing only moderate to locally fresh NE trades from the ITCZ to 20N and west of 110W. Seas are 8-12 ft across the remainder of the waters west of 110W due primarily to NW swell. Elsewhere across the Pacific, winds are gentle and seas are 4-7 ft. For the forecast, see the Special Features section above for details on the cold front, that will cause gale conditions over the NW corner of our waters and very large swell over much of our forecast waters. Elsewhere, weak high pressure will dominate leading to generally moderate to fresh trades through Sat. From Sun into Tue, building high pressure near 30N will enhance the NE trades south of 20N. Expect fresh to strong trades to occur through early next week. $$ AReinhart