000 AXPZ20 KNHC 201531 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Mon Dec 20 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 1500 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A ridge building across the eastern slopes of the Sierra Madre Mountains in Mexico and over the western Gulf of Mexico is supporting a gap wind event across the Tehuantepec region. Sustained winds of 20 to 30 kt are expected to continue today and further increase to minimal gale force tonight through Tue night. Seas will range between 8 to 11 ft in the Tehuantepec area. Fresh to strong northerly winds will continue to blow across the Gulf of Tehuantepec through early Fri morning. Seas 8 ft or greater generated by this gap wind event will reach as far west as 12N97W. Please read the latest NWS High seas Forecast issued by the National Hurricane Center at website: https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from central Costa Rica near 09N84W to 06N100W to 11N112W. The ITCZ begins near 11N112W to 09N125W to 11N130W. A surface trough extends from 16N133W to 10N139W. Scattered moderate isolated strong convection is seen from 13N- 15N between 106W-113W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO A Gale Warning is in effect for the Gulf of Tehuantepec. Please, see the Special Features section for details. High pressure of 1022 mb located near 28N120W extends a ridge across the offshore forecast waters on Baja California producing mainly light to gentle winds. Gentle to moderate N winds are noted between Las Maria Islands and los Cabos, including also the entrance to the Gulf of California. Light to gentle winds are observed elsewhere over the open waters off Mexico. High pressure over the SW CONUS is supporting moderate NW to N winds across the Gulf of California. Outside of the Tehuantepec region, seas are in the 3-5 ft, with seas of 1-3 ft in the Gulf of California. For the forecast, the aforementioned high pressure will lift N of the area as a cold front moves eastward across the northern forecast waters. A cold front will approach to the northern Baja California toward the end of the work-week. No significant swell event is expected over the next several days. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR Moderate to locally fresh NE winds are observed in the Gulf of Papagayo. Light to gentle winds are noted elsewhere north of the monsoon trough while gentle to moderate S to SW winds are noted south of the monsoon trough per scatterometer data. Seas are generally 3 to 5 ft across the offshore forecast waters. For the forecast, fresh to locally strong NE to E winds will continue to pulse in the Papagayo region through the next few days, particularly during the overnight and early morning hours. Gentle to moderate winds will prevail elsewhere. No significant swell events are forecast during the next several days. REMAINDER OF THE AREA... Surface high pressure of 1022 mb centered near 28N120W dominates the waters north of 15N while a cold front has reached the NW corner of the forecast region. The pressure gradient between the high pressure and lower pressure in the vicinity of the ITCZ is supporting an area of moderate to locally fresh trade winds from 14N to 20N W of 125W, and from 14N to 17N between 110W and 125W. Seas of 5-7 ft are within these areas of winds. The cold front extends from 30N133W to 25N140W. Fresh to strong winds are noted on either side of the front. A new set of long period NW follows the front, with seas in the 8-12 ft range. For the forecast, the cold front will move eastward across the northern forecast waters through Tue before dissipating. The swell event that follows the front will continue to propagate across the forecast area, with seas of 8-10 ft covering the waters W of a line from 30N125W to 24N125W to 19N131W to 15N140W. $$ GR