000 AXPZ20 KNHC 230329 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Fri Dec 23 2022 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 0300 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Storm Warning: A strong Arctic cold front will cross the Gulf of Mexico through Fri evening. Very strong high pressure is building behind the front across eastern Mexico and through the Chivela Pass, resulting in fresh to strong winds returning in the Gulf of Tehuantepec by sunrise Fri, rapidly increasing to gale force by early Fri afternoon, then to storm force Fri evening into early Sat. Gales could then last through at least Tue night. This event will produce a very large plume of winds by Fri night, expanding across the Tehuantepec region between 93.5W and 95.5W and extending offshore to near 11N. Very large and steep seas will quickly develop with this gap wind event, peaking at around 20-21 ft Fri night through Sat morning. Please read the latest High Seas Forecast issued by the the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 07N78W to 06N90W. The ITCZ axis extends from 06N90W to 08N100W to beyond 05N140W. Scattered moderate convection is noted from 07N to 09N between 100W and 105W. Scattered moderate to isolated strong convection is noted from 04N to 06N between 121W and 123W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for information about an upcoming storm force gap wind event in the Gulf of Tehuantepec. A ridge extends from 1020 mb high pressure centered west of Baja California near 28N128W to Baja California Sur. This pattern is supporting moderate northerly winds across the southern Gulf of California, with gentle breezes elsewhere over Mexican offshore waters north of 20N. Light to gentle breezes persist farther south off southern Mexico as well. Moderate seas are in place across the open offshore waters, except for 1 to 2 ft over the northern Gulf of California. For the forecast, high pressure will remain generally stationary west of the offshore waters through Fri before weakening and shifting northward over the weekend. The associated ridge will change orientation and build southeastward Fri through Sat, and act to strengthen local winds to moderate to locally fresh across the Baja offshore waters, and fresh to locally strong inside the Gulf of California. High pressure will weaken Sun night through Mon to produce a weakening trend in winds across the waters N of Cabo Corrientes. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh NE to E gap winds are occurring over the Gulf of Papagayo region, and extend offshore to 88W, with 5-7 ft seas. Light winds prevail elsewhere north of 10N, where seas are 4-6 ft in mixed swell including E swell from the Gulf of Papagayo. Elsewhere winds are moderate or weaker with seas 3-5 ft. For the forecast, fresh to strong NE to E gap winds will continue to pulse in the Papagayo region through the rest of the forecast period. Gentle to occasionally moderate winds will continue elsewhere for the next several days. Large NW swell is expected in the Guatemala offshore zone early Sat through at least Mon night due to the large area of gale to storm force winds that will develop across the Gulf of Tehuantepec region over the next several days. REMAINDER OF THE AREA... High pressure dominates the waters north of 20N. Farther south, a trough is analyzed near 122W in the deep tropics from 02N to 10N, supporting scattered showers and isolated thunderstorms within 60 nm of the trough axis where it intersects the ITCZ. A broad area of fresh trade winds persist north of the ITCZ to 15N west of 120W. Recent altimeter satellite passes indicated large area of 7 to 10 ft wave heights mainly west of 125W. These large waves are mostly due to W-NW swell over the region, but include short period waves in the trade wind belt deeper into the tropics. Farther east, a recent ship observation from RV Atlantis confirmed at least fresh trade wind near 10N105W. This is part of an area of fresh to strong winds with 8 to 9 ft seas near small circulation in this area along the ITCZ, associated with a mid to upper trough northeast of this region. For the forecast, the feature near 105W will move westward along 10N over the next several days, with fresh to strong winds and rough seas persisting within 90 nm to its north. Little change is expected elsewhere, with trade winds and 7 to 10 ft seas persisting. Seas will build north of 25N and west of 130W by late Sat/early Sun as a new round of NW swell moves into the area. Southerly winds will increase Sun as well in this area, ahead of a cold front approaching from the northwest. The front will likely stall before reaching the discussion area but swell will continue to build through early next week along with shorter period waves from the increased southerly flow, reaching as high as 15 ft Sun night. Meanwhile farther east, northeast swell will emerge from storm force gap winds in the Gulf of Tehuantepec, mixing with easterly swell from Papagayo, with combined wave heights of 8 to 11 ft reaching as far west as 105W from 05N to 12N. $$ Christensen