000 AXPZ20 KNHC 120917 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Thu Jan 12 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 0600 UTC surface analysis and satellite imagery through 0800 UTC. ...SPECIAL FEATURES... NW waters Gale Warning: A cold front is moving across the far NW waters tonight, and extends from 30N137W to beyond 27N140W. Gale force SW winds, and scattered to numerous moderate thunderstorms, are occurring within 240 nm SE of the front, where seas are 16 to 25 ft in W to NW swell. Large NW swell behind the front is producing seas of 25 to 30 ft. The front will move E-SE through the northern waters through Fri before dissipating. Gale force winds are expected to persist ahead of the front through Thu afternoon, mainly north of 26N, with seas generally remaining in the 18-24 ft range. Reinforcing NW swell will move in with this system, with seas behind the front persisting around 30 ft near 30N140W through midday Thu before subsiding very slowly. Winds N of 26N will diminish to 20 kt or less Thu night. Gulf of Tehuantepec Gale Warning: Moderate N winds across the Gulf of Tehuantepec will diminish further Thu morning. Fresh to strong winds will return across Tehuantepec Thu evening, quickly increasing to gale force late Thu night, and continuing through Sat night, as high pressure surges across eastern Mexico behind a cold front moving through the Gulf of Mexico. This is expected to be a significant gale event, with a large area of offshore winds expected to reach to 40-45 kt Fri evening through Sat morning, with seas peaking 18-20 ft Fri night into early Sat. Fresh to strong winds will then be present Sun morning, quickly dimishing to 20 kt or less Sun afternoon. Please read the latest NHC High Seas Forecast at website www.hurricanes.gov/marine for more details on both Gale Warnings. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 07.5N75W to 10N84W to 05.5N94W. The ITCZ extends from 05.5N94W to 08N136W to beyond 08N140W. Scattered moderate isolated strong convection is noted from 01.5N to 07.5N E of 84W, and within 90 nm of ITCZ between 115W to 140W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the Special Features section for details on a developing Gulf of Tehuantepec Gale Warning. Elsewhere, troughing extends along the Sierra Madre Occidentales of Mexico. High pressure of 1022 mb located near 29N119W dominates the waters. The pressure gradient between the high and troughing is producing moderate to locally fresh winds northerly across the Baja California offshore waters from Cabo San Lazaro northward. Winds are moderate or weaker across the remainder of the waters. The latest pulse of NW swell across the Baja waters is producing seas of 8-13 ft from offshore of Cabo San Lucas northward, and 7-8 ft southward to the Revillagigedo Islands. Moderate to locally fresh NW winds have developing inside the Gulf of California, where seas are 3-6 ft. Elsewhere seas are 4-7 ft from Cabo Corrientes to Puerto Angel. For the forecast, outside the Gulf of Tehuantepec, moderate to locally fresh northerly winds will prevail across most of the Baja California waters through Thu morning, then will diminish slightly and veer N to NE through Thu night. Seas will remain 8 to 12 ft offshore of Baja Sur overnight, while slowly subsiding from N to S elsewhere across the Baja offshore waters through early Fri. Fresh NW winds will continue across central and southern portions of the Gulf of California will persist through Fri morning before diminishing slightly Fri night through Sat. Seas will build to 5-7 ft tonight before beginning to subside Fri. Another pulse of NW swell will arrive offshore Baja Norte Fri morning behind the decaying cold front, with even larger seas expected, up to 16 ft. Seas of 8 ft or greater will spread across the entire open offshore waters this weekend. Fresh to strong SW-W winds will develop from 29.5N to 31.5N in the Gulf of California ahead of the decaying front Sat night, increasing to near gale force early Sun before diminishing Sun night. Another cold front may approach Baja California Norte Mon night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to locally strong NE winds and 5-7 ft seas are across the Papagayo region. Moderate northerly winds prevail across the Gulf of Panama. Winds are moderate or weaker elsewhere. Seas are 3-5 ft offshore Colombia, 5-7 ft offshore Ecuador and SW of the Galapagos Islands, and 4-6 ft elsewhere. For the forecast, fresh to strong offshore winds will pulse across the Gulf of Papagayo region through the next several days, increasing to near gale early Sat through early Mon, as a Caribbean cold front moves into Central America. Seas will build to 7-10 ft during this time. Moderate to fresh N-NE winds will develop in the Gulf of Panama and near the Azuero Peninsula Thu night through Sun night, briefly strong near the Azuero Peninsula early Fri. A gap wind event in the Gulf of Tehuantepec will extend fresh to strong winds in the other offshore waters of Guatemala Fri evening through Sat morning, with associated seas building to 8-13 ft there. Winds will be moderate or weaker elsewhere through at least the next several days. REMAINDER OF THE AREA... Please refer to the Special Features section for details on a Gale Warning associated with a cold front that has entered the far NW waters. Strong S to SW winds prevail elsewhere southeast of the front, to the N of 24N and W of 129W. Seas are 11 to 18 ft in building NW swell across this area. Elsewhere, 1022 mb high pressure is centered near 29N119W, with ridging extending from southern California through the high to beyond 20N140W. Light to gentle anticyclonic winds are immediately under the ridge, with moderate to fresh trades north of the ITCZ to about 16N. Winds are moderate or weaker elsewhere, except ahead of the cold front. Seas of 9-15 ft in NW swell are found between 20N and 25N. This NW swell is mixing with NE wind waves from about 06N to 20N west of 116W to support 8-12 ft combined seas. Seas are 6-8 ft elsewhere. For the forecast, outside of the NW waters Gale Warning discussed in the Special Features section, pulses of NW swell will propagate through the discussion waters through the remainder of the week and into the weekend, with seas of 8 ft or greater covering the majority of the open waters by Sat night. High pressure and moderate to fresh winds will dominate the trade wind belt, increasing to fresh to strong Fri night into Sat west of 125W as the gradient tightens. Another pair of cold fronts with reinforcing swell may push just south of 30N by the end of the weekend into early next week. $$ Stripling