000 AXPZ20 KNHC 121559 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Sun Dec 12 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 1200 UTC surface analysis and satellite imagery through 1550 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Strong surface high pressure building in the wake of a cold front extending from Cedar Key, Florida to Veracruz, Mexico this morning will support the next gale force gap wind event in the region of Tehuantepec. Strong to near gale force N-NE winds are already ongoing across Tehuantepec, and will increase to gale force this afternoon. Gale conditions will continue through near midnight today, and then diminish to around 30 kt through Mon morning. Peak seas during the highest winds are expected to build up to 11 ft. Please refer to the latest High Seas Forecast product issued by the National Hurricane Center at the website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. Heavy showers and isolated tstorms prevail across the western slopes of the mountainous of extreme NW Colombia and across the adjacent nearshore coastal waters within 60 nm of the coast. Active weather is forecast to continue across NW Colombia and extend across the Colombia and Panama offshore waters through tonight. Rainfall totals forecast to be within 3 to 10 inches across the western slopes of the mountains and adjacent coastal zones. Rough marine conditions are also expected during this period and mariners should exercise caution. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 08N78W to 07N90W to 06N107W. The ITCZ extends from 06N107W to 08N120W to beyond 08N140W. Scattered moderate convection is from 06N to 13N between 79W and 95W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO See the Special Features section above for details on an upcoming gale force gap wind event in the region of Tehuantepec. Gentle to moderate northerly winds are across the Baja California offshore waters with 5-7 ft seas in NW swell. A ridge to the northwest of Baja California has weakened and the gradient against a surface trough along the coast of western Mexico has reduced, thus resulting in gentle to moderate N to NW winds along the Gulf of California all the way to Jalisco offshore waters. Seas in these regions range between 3-5 ft. In Tehuantepec, strong to near gale force winds are ongoing with seas to 9 ft. Gale conditions are expected to begin this afternoon. Looking ahead, a strong cold front will move into the northern waters Tue. Fresh to strong SW winds are expected ahead of the front across the offshore waters N of 27N Tue afternoon before the front arrives Tue night. NW swell will move into the northern offshore waters early Tue and raise seas 8 to 12 ft by Tue afternoon, and peak at 14-15 ft across the waters of Baja Norte Wed morning. Meanwhile, similar strong SW to W gap winds will develop inside the N Gulf of California Tue and reach around 30 kt Tue evening, when seas will build to 8 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR Fresh gap winds continue across the Papagayo region with seas to 6 ft. Moderate N winds continue across the Gulf of Panama where seas are 3-5 ft. 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. Otherwise, see the Special Features Section for details on heavy rainfall over the Colombia and Panama offshore waters through the weekend. Fresh NE gap winds will continue to pulse to strong at night across the Papagayo region through Wed. Gentle to moderate winds will prevail elsewhere the next several days. REMAINDER OF THE AREA... High pressure ridging dominates the forecast waters N of 14N and W of 110W, centered on a 1023 mb high near 30N128W. The remnants of a cold front in the form of a shear line has become ill defined W of 120W along 21N to 22N. However fresh E winds 15 to 20 kt from 21N to 25N are mixing with N swell to produce seas of 7-8 ft across this area. A low level trough has developed from 14N120W to 17.5N138W. The pressure gradient between it and high pressure to the north is also producing a zone of 15-20 kt winds within 120 nm N of this trough, and scattered moderate isolated strong convection. Elsewhere mainly gentle to moderate NE to E winds are N of 25N with seas to 7 ft in NW swell. Moderate to fresh SE winds are S of the ITCZ W of 118W with seas 6 to 7 ft. A strong cold front is forecast to move across the far NW waters Sun through early next week, accompanied by very large NW swell. This large NW swell will enter the NW waters Sun night and move east of 120W Tue afternoon. Seas are expected to peak at 18-19 ft across the far NW waters early Tue. $$ Ramos