000 AXPZ20 KNHC 190306 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Fri Jan 19 2018 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 0300 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A tight pressure gradient across southern Mexico is expected to relax on Friday. Gap winds will gradually diminish below gale force by Friday afternoon as a result. A plume of northerly swell associated with the strong winds the past few days will propagate well away from the Gulf of Tehuantepec waters, mixing with long period NW swell. Maximum seas tonight will remain around 13-15 ft near strongest winds, gradually subsiding through the weekend. No new gale force wind events are likely until Tue at the earliest. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough axis extends from 06N77W to 06N93W. The ITCZ continues from 06N93W to 07N114W to 06N140W. Scattered moderate convection is from 06N to 10N between 115W and 127W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the special features section for information about the ongoing gale warning in the Gulf of Tehuantepec. In the Gulf of California, winds will become southerly Friday evening ahead of an approaching cold front, then become fresh to strong in the northern gulf Friday night, shifting to NW to N behind the front. The front will gradually become ill defined Sat as it moves southward with moderate to fresh NW flow in its wake. The pressure gradient will begin to tighten across the area Sun, leading to fresh to strong winds across the entire gulf Sunday evening and night. Elsewhere across the offshore waters of Mexico, large NW swell continues to propagate SE across the waters, with seas of 8-11 ft. This large swell continues to generate high surf along the coasts and outer reefs of Baja California and mainland Mexico. Another pulse of NW swell associated with a intense low pres system north of the area will reach offshore waters of Baja California Norte tonight. Seas will peak near 13-15 ft Friday, while seas of 12 ft or greater will spread across the offshore waters this weekend. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh NE gap winds prevailing between Papagayo and Tehuantepec will pulse to strong each night through Saturday morning, then diminish thereafter. Winds will be strongest offshore Papagayo early Friday. Elsewhere, mainly light to gentle offshore winds will prevail N of 09N, with light to gentle southerly flow S of 09N. NW swell originating from the gale wind event in the Gulf of Tehuantepec along with longer period NW swell will spread across the area through Fri, building seas offshore to 5-7 ft. REMAINDER OF THE AREA... Large long period NW swell continues to propagate SE across the forecast waters, with seas of 8-12 ft. A weakening cold front from 30N129W to 24N140W has a reinforcing set of NW swell with seas up to 13-16 ft. The front will re-energize as high pressure builds to the NW, with N-NE winds increasing to fresh to strong. The front will then wash out to a shear line this weekend as it approaches southern California and NW Mexico. $$ Mundell