000 AXPZ20 KNHC 210859 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Mon Dec 21 2020 Tropical Weather Discussion for the eastern Pacific Ocean from the Equator to 32N, east of 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... Gulf of Tehunatepec Gale Warning: High pressure building along the eastern slopes of the Sierra Madre Mountains in Mexico behind a cold front currently moving across the SW Gulf of Mexico is inducing the next round of gale-force winds over the Tehuantepec region which will continue through Tue. Seas will peak around 12-13 ft with this event. Looking ahead, marine guidance suggests a stronger gap wind event in the Tehuantepec area by Thu. Strong gale force winds of 40-45 kt and very rough seas of 14-18 ft are possible Thu afternoon through Fri night. Marine interests should be aware of this upcoming gap wind event to avoid hazardous marine conditions. Please read the latest NWS High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northern Colombia near 09N73W to 05N79W to 08N88W to 06N93W. The ITCZ axis extends from 06N93W to 08N120W to 08N140W. Scattered moderate and isolated strong convection is noted from 04N to 06N between 99W and 101W, from 07N to 09N between 116W and 120W, and from 07N to 09N between 128W and 130W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Features for details about the Gulf of Tehuantepec Gale Warning, as well as an outlook on possible strong gale force conditions. Gulf of California: High pressure over the Great Basin region of the U.S. continues to support fresh to strong NW-N winds across the Gulf of California, particularly from 26N to 29N W of 110W as indicated by recent scatterometer data. Seas remain under 8 ft. These marine conditions will persist through the next few hours before diminishing. Moderate to fresh northerly winds are expected over the north and central Gulf waters Wed night and Thu as another high pressure area settles over the Great Basin area. Mainly gentle to moderate NW-N winds will prevail across the offshore waters of Baja California through the week, with moderate to fresh winds N of Cabo San Lazaro on Fri. This will be the result of the pressure gradient between a high pressure of 1021 mb over the NE waters near 26N128W and a meandering trough over the Gulf of California. Long period NW swell impacting the waters N of Cabo San Lazaro will continue to subside to 4-7 ft by tonight. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Fresh to strong NE-E winds will pulse across the Papagayo region through the next several days as high pressure remains in place over the W Caribbean. Gentle to moderate winds will prevail on either side of the monsoon trough. No significant swell events are forecast to reach the forecast area over the next several days. Looking ahead, swell generated in the Tehuantepec region are expected to affect the offshore waters of Guatemala and El Salvador Thu night through Fri night, with seas of up to 11-12 ft. REMAINDER OF THE AREA... High pressure located N of the area dominates the forecast waters N of the ITCZ. The pressure gradient between the high pressure and lower pressures near the ITCZ is supporting moderate to fresh NE to E trades, with the strongest winds from 09N to 20N W of 120W. Seas are in the 8-10 ft range based on altimeter data. A weak trough may develop over the west-central waters by mid-week increasing trades to fresh to strong. Another weak trough our low may develop near 07N105W by Tue afternoon with fresh to strong winds and seas of 8-10 ft, reaching to near 07N108W by early Wed. A decaying cold front may reach 30N140W by Thu night, and move across the NW corner of the forecast region on Fri. Moderate to fresh N winds and a new swell event are expected in the wake of the front. $$ Lewitsky