566 AXPZ20 KNHC 150402 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Wed Dec 15 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 0000 UTC surface analysis and satellite imagery through 0300 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N75W to 10N85W to 06.5N103W. The ITCZ extends from 06.5N103W to 08N114W to 09N133W to beyond 07.5N140W. Widely scattered moderate isolated strong convection is noted from 07.5N to 14.5N between 96W and 113.5W. Scattered moderate to strong convection noted from 14N to 18N between 132W and 140W. 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 the 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 1020 mb high pressure centered near 25N120W extends a ridge across the offshore forecast waters of Baja California and is promoting gentle to moderate N to NE winds ahead of an approaching cold front. Light to gentle winds prevail elsewhere across the Mexican coast outside the Tehuantepec region. The cold front has entered the far NW offshore waters of Baja Norte in the past few hours, with SW 15-20 kt south of the front to 27.5N and NW winds 15-20 kt currently behind the front. Seas across the offshore waters are 6-9 ft in NW swell, increasing to 12-13 ft behind the front. W to SW winds have increased to 30 kt across the northern Gulf of California this evening, with westerly gap winds likely gusting to near gale force near the Baja coast from Isla El Muerto to Rancho Nuevo Mazatlan. Seas have built to 7 ft across this area of strong winds. The cold front currently extends from 30N117.5W to just north of Isla Guadalupe to beyond 28N120W and will move into the waters W of Baja California Norte tonight and reach near Punta Eugenia by sunrise. Moderate to fresh W to SW winds are expected ahead of the front N of Punta Eugenia while fresh to strong SW winds in the northern Gulf of California will prevail tonight. A brief period of fresh to locally strong NW winds will follow the front late tonight and early Wed across both the offshore waters and inside the Gulf of California. Large NW swell will continue to propagate across the offshore waters of Baja California and peak at 10-15 ft N of Punta Eugenia prior to sunrise. 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 6-8 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... The cold front extends from 30N117.5W to 23N130W, where it transitions to a shearline on to 20N140W. 1020 mb high pressure is SE of the front centered near 25N120W. This front is forecast to continue moving SE over the northern forecast waters through Wed before dissipating. The largest NW of the season thus far will follow the front into the regional waters tonight, and is currently peaking near 19 ft along 30N. A surface trough is analyzed from 19N132W to 12N133W. The pressure gradient between building high pressure in the wake of the aforementioned cold front and the trough will maintain a zone of fresh to locally strong trade winds from 12-24N between 118W and 140W through late Wed. The large NW swell will spread into the deep tropics by early Thu, with seas to 12 ft expected to reach as far S as 13N by early Thu and gradually subside across the regional waters through Fri. $$ Stripling