000 AXPZ20 KNHC 220706 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Thu Dec 22 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 0600 UTC surface analysis and satellite imagery through 0640 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Storm Warning: High pressure currently over eastern Mexico and the SW Gulf of Mexico behind a cold front is supporting fresh to strong N-NE winds in the Tehuantepec region as indicated by a recent ASCAT scatterometer pass. Seas are 8-10 ft. The pressure gradient will weaken here through early today allowing for winds to diminish and residual fresh seas to subside by tonight. The next cold front, much stronger, is forecast to cross the Gulf of Mexico by the end of the week. Stronger high pressure will arrive behind the front resulting in fresh to strong winds returning in the Gulf of Tehuantepec by early Fri, rapidly increasing to gale force Fri afternoon, then to storm force Fri evening into early Sat. Gales could then last through at least Mon night. Very large and dangerous seas will occur with this gap wind event, peaking to at around 20-21 ft late Fri night into early Sat. 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 near the border of Colombia and Panama at 07.5N78W to 10N84W to 05.5N105W. The ITCZ axis extends from 05.5N105W to 03.5N124W to 08N140W. Scattered moderate convection is noted from 06N to 10N between 127W and 132W. 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. High pressure ridging combined with a trough along the coast of mainland NW Mexico is contributing toward moderate to locally fresh NW winds in the Gulf of California. Seas are 3-5 ft. Elsewhere, winds are moderate or weaker with seas of 3-5 ft. For the forecast, aside from the Gulf of Tehuantepec storm force gap wind event, moderate to fresh NW winds in the Gulf of California will diminish by early this morning. Fresh NW winds should again develop Sat and Sat night in the Gulf of California. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to strong NE to E gap winds are occurring over the Gulf of Papagayo region with seas of 4-7 ft. Seas over the Guatemala offshores are 4-7 ft in mixed NW swell from an ending Gulf of Tehuantepec gap wind event, and 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. A larger NW swell is expected in the Guatemala offshore zone Fri night through at least Mon night due to a storm force Gulf of Tehuantepec gap wind event. REMAINDER OF THE AREA... A complex low pressure system northwest of the area has an associated cold front that is near 30N140W. The low and associated front will shift northeastward through today, remaining just outside of our forecast area. S winds to the east of the cold front are reaching fresh to strong north of about 27N between 133W and 138W. Seas reach up to 14-15 ft mixed wind waves and NW swell within the area of fresh to strong winds to 30N140W. Elsewhere, ridging extends from high pressure centered north of area through 30N127W to 22N140W, and from 30N127W to 17N110W. Moderate or weaker winds are under the ridge along with seas of 4-6 ft north of 20N and east of 130W. A surface trough is embedded in the ITCZ from 08N116W to 03N117W. A recent ASCAT scatterometer pass showed local winds of 20-25 kt near the trough with seas of 7-8 ft likely. The moderate pressure gradient between the ridge and low pressure over the ITCZ is forcing moderate to fresh NE to E trades elsewhere from 06N to 17N west of 116W. Seas are 6-9 ft. For the forecast, the fresh to strong S winds in our NW corner waters will shift north of the discussion area later this morning. Seas in the area will subside to below 12 ft by this afternoon, while residual NW swell of 7-11 ft west of about 125W will continue for the next few days. The NE to E trades are expected to have little change for the next few days. Reinforcing NW swell will build seas to 12-14 ft in the far NW corner by the end of the weekend into early next week. $$ Lewitsky