000 AXPZ20 KNHC 250337 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Fri Dec 25 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 0000 UTC surface analysis and satellite imagery through 0300 UTC. ...SPECIAL FEATURES... Gulf of Tehunatepec Storm Warning: Winds to near 50 kt are likely over the Gulf of Tehuantepec to midday Fri, with seas building to as high as 24 ft. The storm force winds and dangerously high seas are result of strong high pressure and cold air moving across the western Gulf of Mexico, across the Tehuantepec isthmus and into the Gulf of Tehuantepec. Winds will diminish to strong gales by Fri afternoon as the high pressure shifts eastward. Gale conditions are forecast to persist for the rest of Fri into early Sat before diminishing. A large plume of seas of 8 ft or greater will extend well SW-W of the Tehuantepec region from this event. Marine interests transiting across or in the vicinity of the Gulf of Tehuantepec should be aware of this upcoming gap wind event, and take necessary action to avoid hazardous marine conditions over the affected waters. 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 extends from 09N78W to 05N95W. The ITCZ extends from 05N95W to 08N115W to beyond 07N140W. Scattered moderate isolated strong convection is noted from 08N to 12N between 120W and 125W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Features for details about an upcoming Gulf of Tehuantepec storm force gap wind event. Gulf of California: An earlier scatterometer satellite pass indicated near gale force winds off the eastern coast of Baja California Sur, mainly between Loreto and La Paz. This was due in part to high pressure north of the area over the Great Basin, but also probably due to strong high over north central Mexico. Seas are estimated to be as high as 9 ft in the area of strongest winds. These winds and seas are expected to gradually diminish through Fri afternoon as the areas of high pressure weaken and shift east, with moderate NW winds and 2 to 4 ft seas expected across the Gulf by Sat afternoon. Looking ahead, strong NW winds may again impact the northern Gulf of California Mon night into Tue as a cold front moves into the region. Fresh to strong northerly gap winds may be ongoing off the Pacific coast of Baja California Sur north of Los Inocentes, although this should be diminishing through early Fri morning. Elsewhere, mainly gentle to moderate NW-N winds will prevail across the offshore waters of Baja California through Fri. Winds will increase to moderate to fresh mainly north of Cabo San Lazaro toward the upcoming weekend as the pressure gradient tightens between a ridge west of the region and a trough over the Gulf of California. Large NW swell will propagate into the waters west of Baja California Sat night through Sun night with seas building to 8-12 ft. Looking ahead, fresh to strong NW winds will accompany a cold front moving through the area Mon into Tue. 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 the next several days as high pressure remains in place over the western Caribbean. Swell generated during a strong upcoming Gulf of Tehuantepec gap wind event is expected to affect the offshore waters of Guatemala and El Salvador late tonight through Sat. Seas will build up to 15-20 ft, especially tonight and Fri. Otherwise, gentle to moderate winds will prevail on either side of the monsoon trough, except occasionally fresh near the Gulf of Panama. REMAINDER OF THE AREA... Moderate to fresh winds prevail north of the ITCZ to 20N and west of 125W. A broad surface trough is along and north of the ITCZ near 125W, with locally strong winds as confirmed by an earlier scatterometer satellite pass. Seas are 6 to 9 ft across the trade wind belt, highest near the strongest winds. A cold front will move eastward across the waters north of 20N overnight. Fresh to strong SW winds will prevail ahead of the front through tonight. Fresh to strong northerly winds and rough seas will follow the front. By Fri night, the front is forecast to extend from 30N126W to 24N140W, then will gradually weaken and dissipate through the weekend. A reinforcing front may clip the waters north of 25N and east of 130W Sun and Sun night. Seas are forecast to peak around 12 to 14 ft behind the first front along 30N by Fri night into early Sat. Looking ahead, strong high pressure following this reinforcing front may support fresh to strong NE to E winds from 20N to 25N west of 135W Sun and Mon, with seas up to 12 ft in a mix of wind waves and longer period NW swell. $$ Christensen