000 AXPZ20 KNHC 142111 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Tue Dec 14 2021 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N84W to 09N88W to 07N100W. The ITCZ extends from 07N100W to 07N120W to beyond 08N140W. Convection is limited. OFFSHORE WATERS WITHIN 250 NM OF MEXICO A ridge across the eastern slopes of the Sierra Madre Mountains in Mexico continues to support a gap wind event across Tehuantepec region. Strong northerly winds to 30 kt are noted across the Gulf of Tehuantepec, with fresh to strong winds of 20-25 kt extending downwind to near 11.5N99W. Seas across this area are 8 to 10 ft. This strong gap wind event is expected to prevail through Wed night before diminishing significantly in strength and areal coverage. Winds are expected to diminish to fresh to strong and remain confined to the Gulf of Tehuantepec Thu through Friday morning before shutting down. A 1022 mb high pressure centered near 25N121W extends a ridge across the offshore forecast waters of Baja California and is promoting gentle to moderate NW to N winds. Light to gentle winds prevail elsewhere across the Mexican coast outside the Tehuantepec region. Moderate to locally fresh W to SW winds are noted per scatterometer data in the northern Gulf of California. An approaching cold front currently extending from 30N121W to 23N140W will move into the waters W of Baja California Norte by this evening. Moderate to fresh W to SW winds are expected ahead of the front N of Punta Eugenia while fresh to strong SW winds are forecast in the northern Gulf of California tonight. A brief period of fresh to locally strong NW winds will follow the front. The front will move across the northern Gulf of California tonight. Seas could build to 8-9 ft N of 30N and ahead of the front. Large and long period swell from the NW will continue to propagate across the offshore waters of Baja California building seas to 10-14 ft N of Punta Eugenia by tonight. This swell event, with seas of 8-9 ft, will reach the Revillagigedo Islands by Wed night into Thu morning. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR Fresh to strong NE to E are expected in the Papagayo region at night through Thu night, with seas of 7-8 ft. Gentle to moderate northerly winds and seas 3 to 4 ft in the Gulf of Panama are forecast to pulse nightly through Wed night. Moderate S to SW winds are south of the monsoon trough with seas to 6 ft in SW swell. Light to gentle variable winds are elsewhere. These conditions are forecast to remain for much of the week. REMAINDER OF THE AREA... High pressure of 1022 mb is centered near 25N121W. A cold front is moving SE across the northern waters and extends from 30N121W to 23N140W. This front is forecast to continue moving E-SE over the northern forecast waters through tonight before dissipating. A large swell event follows the front. A couple of altimeter passes showed seas of 10-18 ft roughly across the waters N of 22N between 118W-130W. A surface trough is analyzed from 24N126W to 16N129W. Another surface trough is forecast to move westward S of 20N and N of the ITCZ. The pressure gradient between building high pressure in the wake of the aforementioned cold front and the trough will bring a zone of fresh to locally strong trade winds from 10-20N between 110W and 140W by late Wed. Large NW swell, with seas on the 10-15 ft range will continue to propagate across the northern forecast waters tonight, covering most of the waters N of 20N and W of 118W. Seas will gradually subside to less than 12 ft from W to E on Wed. $$ GR