000 AXPZ20 KNHC 180356 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Fri Dec 18 2020 Tropical Weather Discussion for the eastern Pacific Ocean from the Equator to 32N, east of 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 0330 UTC. ...SPECIAL FEATURES... Gulf of Tehunatepec Gale Warning: High pressure over the Gulf of Mexico behind a stationary front are producing gale-force winds over the Gulf of Tehuantepec this evening and through Friday afternoon. These N winds should build seas to around 14 ft late tonight. Winds are expected to diminish below gale force by Fri afternoon. Please read the latest NWS High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 08N78W to 07N95W. The ITCZ continues from 07N95W to beyond 07N140W. Scattered moderate and isolated strong convection is noted from 08N to 13N west of 135W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Features for details about the Gulf of Tehuantepec Gale Warning. While the gale over the Gulf of Tehuantepec should end by Fri night, the gap winds will continue with fresh to strong N winds through Sun. A new cold front to move across the Gulf of Mexico Sun and Mon may force additional N gales over the Gulf of Tehuantepec Mon afternoon through Tue morning. Peak seas anticipated with this second gale event may reach around 15 ft Mon evening and Tue. Large, long period NW swell west of Baja California will slowly subside through Sun. An altimeter pass from the Sentinel 3A satellite showed peak seas near 10 ft west of the Baja California peninsula at 1830 UTC. Gulf of California: A weakening cold front will push across the Baja peninsula into the Gulf of California tonight and Fri. NW winds will build up to strong breeze across the Gulf of California Sat and Sun. Seas should peak around 6-8 ft in the central Gulf of California on Sun. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Fresh to occasionally strong NE to E winds will pulse across the Papagayo region during the next several days as high pressure remains in place over the W Caribbean. Seas offshore of Guatemala and El Salvador will increase to 6-8 ft through Fri night from swell generated by gale-force winds over the Gulf of Tehuantepec. Seas will again increase to 8-10 ft on Tue from a new Gulf of Tehuantepec gale event. REMAINDER OF THE AREA... A 1028 mb high is centered near 37N134W with surface ridging extending southeastward to 15N100W. The moderate pressure gradient between the high the the ITCZ is causing E to NE trades of up to fresh breeze. The high will strengthen some through Sat and increasing the trades to a large area of fresh to strong. Seas will peak around 8-10 ft on Fri and Sat due to combined wind waves and some NW swell. A cold front impinging on the high will allow the trades to weaken substantially Sun through at least Tue. No new large long-period swell is expected over forecast waters for the next several days. $$ Landsea