599 AXPZ20 KNHC 152141 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 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 1800 UTC surface analysis and satellite imagery through 2030 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from the coast of Costa Rica near 10N85W to 06N98W. The ITCZ extends from 06N98W to 09N119W, then resumes W of a surface trough from 07N125W to 07N140W. Scattered moderate convection is noted from 06N to 09N between 77W and 86W and from 09N to 11N between 106W and 112W. A surface trough extends from 10N120W to 07N124.5W. Scattered moderate isolated strong convection is seen from 06N to 10N between 116W and 125W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO A weakening cold front extends across the Gulf of California from 29N112W to 28.5N113W. Fresh NNW winds are in the Gulf of California, where seas are 3-5 ft. Moderate to fresh N winds are west of Baja California, where seas are likely 9 to 13 ft in large NW swell. Altimeter data from 15/1330 UTC showed seas of 12 to 14 ft from 25N to 30N between 119W and 121W. Seas well offshore of Cabo San Lucas have continued to build in NW swell to 8-10 ft, north of 17.5N and west of 111W. Gentle winds and 4-5 ft seas prevail offshore Cabo Corrientes to offshore the Mexican state of Guerrero. ASCAT data from 15/1539 UTC shows 25 to 30 kt N winds over the Gulf of Tehuantepec region. Seas are 8-9 ft across this area. For the forecast, the cold front over the Gulf of California will dissipate later this afternoon. Fresh NW to N winds will continue through Thu morning on both sides of Baja California. A period of fresh to strong NW to N winds is expected west of Baja California Norte Thu night. Similar winds are forecast in the northern Gulf of California Fri night into Sat. Large NW swell will continue to propagate across the offshore waters of Baja California through tonight, and gradually subside to 8-11 ft on Thu. In the Gulf of Tehuantepec, the current strong to near gale force gap wind event is expected to prevail through tonight before diminishing significantly in strength and areal coverage Thu. Winds are expected to diminish to fresh to strong and remain confined to the Gulf of Tehuantepec Thu and Thu night before shutting down Fri. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR Fresh NE to E winds prevail across the Papagayo region, and are expected to pulse to strong at night through Thu night. Seas will generally persist at 5-6 ft. Gentle to moderate northerly winds and seas 3 to 4 ft in the Gulf of Panama are forecast to pulse nightly through tonight. Moderate S to SW winds are south of the monsoon trough with seas of 5-6 ft in SW swell. Light to gentle variable winds are elsewhere. These conditions are forecast to remain through the upcoming weekend. REMAINDER OF THE AREA... A high pressure ridge oriented east-west prevails along 31N. The large NW swell continues over the Pacific. An earlier altimeter pass from 15/1030 UTC showed seas of 14-17 ft across the Pacific from 24N-30N between 125W-130W. Since that time, seas have likely subsided to 12-14 ft north of 18N...highest near 26N126W. The swell will gradually subside as it builds southward, but seas of 12 ft will reach as far south as 15N latitude tonight into early Thu and gradually subside across the regional waters through Fri. Fresh to strong winds are noted in recent ASCAT data in the vicinity of 09N123W associated with a surface trough along the ITCZ. Fresh trades prevail elsewhere north of the ITCZ to 23N, and west of 117W to 140W. Fresh trades will continue through Sat north of the ITCZ to 23N and west of 120W. Looking ahead, a cold front is forecast to move southeast of 30N140W on Sun, with large swell behind it. $$ Hagen