035 AXPZ20 KNHC 240251 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Thu Dec 24 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: A strong cold front will move across the Gulf of Mexico Thu and Thu night, followed a large area of high pressure. Northerly winds in the Tehuantepec region will increase Thu afternoon rapidly reaching gale force by Thu evening, and then reaching storm force Thu night into early Fri. Gale conditions are then forecast to persist for the rest of Fri into early Sat before diminishing. Large seas of 20-24 ft are possible by early Fri while 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 09N83W to 07N90W. The ITCZ extends from 07N90W to 08N100W to 08N110W to 08N140W. Scattered moderate and isolated strong convection is noted from 06N to 09N between 110W and 120W, and from 06N to 10N between 121W 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: Winds will strengthen tonight through Thu night as high pressure builds north of the area over the Great Basin of United States. These winds are forecast to spread southward beyond the entrance of the Gulf and through Baja California Sur passages by Thu evening, when seas are forecast to briefly reach 8 ft. Winds will diminish by the end of the week into the weekend. 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 W of Baja California Sat night through Sun night with seas building to 8-12 ft. 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 W 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 Thu night through Sat. Seas will build up to 14-18 ft, especially Thu night 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... High pressure north of the area dominates the forecast waters north of 20N. The pressure gradient between this area of high pressure and lower pressure in the vicinity of the ITCZ is supporting fresh winds north of the ITCZ between 125W and 135W, with mostly moderate trades elsewhere N of the ITCZ to 20N. Seas are 6 to 9 ft across the trade wind belt, highest near the strongest winds. The high pressure will weaken ahead of a cold front expected to move eastward across the waters north of 20N by Thu night. Fresh to strong SW winds are expected ahead of the front Thu night. Fresh to strong northerly winds and very 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 by the end of the weekend. Seas are forecast to peak around 12 to 14 ft behind the first front along 30N by Fri night into early Sat. $$ Christensen