000 AXPZ20 KNHC 160905 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Wed Dec 16 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... Gulf of Tehunatepec Gale Warning: A gap wind event is expected to begin in the Tehuantepec area late this afternoon, continuing through Sun night. Strong northerly winds will increase to gale force this evening as a cold front moves across the western Gulf of Mexico. Gale conditions and building seas to 12-14 ft will diminish by Fri morning. 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 07N99W to 10N104W. The ITCZ continues from 10N104W to 12N111W to beyond 07N140W. Scattered moderate convection is noted within 150 nm north of the ITCZ between 114W and 137W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A ridge dominates the offshore forecast waters of Baja California. The pressure gradient between the ridge and lower pressures over mainland Mexico is resulting in moderate to fresh northerly winds west of the Baja California peninsula. Large long period NW swell propagating across this region is supporting seas to 10-11 ft. The swell west of Baja California will slowly subside through Fri. A weakening cold front off the coast of southern California will push south of 30N Thu night. Gulf of California: Fresh NW-N winds will prevail in the Gulf of California through Sun, except for Thu and Fri, as a weakening cold front pushes southward across the northern and central Gulf. Light winds are expected in the Gulf of Tehunatepec today, then rapidly increase to gale-force this evening. Please see the Special Features section for more details. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Fresh to occasionally strong NE-E winds are expected across the Papagayo region Thu through Sun as high pressure builds in the western Caribbean. Northerly winds will pulse to 20 kt across Gulf of Panama Thu night and Fri night. Elsewhere, gentle to moderate winds will prevail south of the monsoon trough, with mainly gentle winds north of the trough axis. REMAINDER OF THE AREA... High pressure of 1029 mb located near 33N129W extends a ridge southeastward across the northern forecast waters to near the Revillagigedo Islands. The pressure gradient between the ridge and lower pressures in the vicinity of the ITCZ will continue to support a large area of fresh trade winds, with the strongest trades expected south of the high, between 120W and 140W, through this evening. Seas are currently 10 to 11 ft between 116W and 128W north of 22N, and 9 to 11 ft from 09N to 23N east of 125W, in long-period NW swell. Winds and seas will gradually diminish across the entire area through early Thu as the high pressure weakens ahead of an approaching cold front. The front will weaken along 30N on Thu, and high pressure will re-intensify north of the area on Fri. $$ Mundell