000 AXPZ20 KNHC 112127 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2126 UTC Wed Dec 11 2019 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... A strong cold front has crossed the western Gulf of Mexico and the Isthmus of Tehuantepec, supporting gale force northerly gap winds across the Gulf of Tehuantepec region. These gale force winds are expected to peak around 45 kt this evening, with seas peaking around 17 ft. Gale force winds will then persist through tonight and Thu, while diminishing very slowly Thu, before gradually tapering off to strong Thu night through Fri, and then below 20 kt by Sat morning. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 08N78W to 1011 mb low pressure near 08N118W. The intertropical convergence zone continues to beyond 08N140W. Satellite derived data of lightning shows scattered moderate thunderstorms from 09N to 11N between 92W and 94W, and from 10N to 13N between 105W and 110W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... 1026 mb high pressure centered near 29N128W is maintaining moderate northerly flow off the coast of Baja California, depicted well in recent scatterometer data. The scatterometer data also showed fresh to strong NW winds across the Gulf of California between 25N and 28N between the high pressure to the west and resident troughing over northwest Mexico. Concurrent altimeter satellite passes indicated 4 to 6 ft seas off the coast of Baja California and 3 to 5 ft seas in the central and southern Gulf of California. The high pressure will persist west of the area through Fri, supporting moderate to occasionally fresh NW winds off Baja California. A new round of long period NW swell in excess of 8 ft will reach the waters around Guadalupe Island and the northern coast of Baja California Norte by Thu night, reaching the Revillagigedo Islands by late Sat. Looking ahead, a trough or weak front will move into the waters off northern Baja California Norte by late Fri into Sat, supporting fresh to strong NW winds in that area, but allowing winds to diminish over the Gulf of California. Seas may reach 13 ft in NW swell over open waters off Baja California. The front or trough will weaken as it moves southward through Sun, but high pressure in the wake of this boundary will support another round of fresh to possibly strong northerly flow over the Gulf of California early next week. Farther south, gentle to moderate winds and 3 to 5 ft seas will persist off the southern Mexico coast between Tehuantepec and Cabo Corrientes through Fri, increasing slightly mainly off the area around Cabo Corrientes Sat as the pressure gradient tightens. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to strong NE to E winds will pulse over the Gulf of Papagayo tonight with seas peaking near 8 ft, then moderate to fresh winds are expected for the remainder of the forecast period. Elsewhere, gentle to moderate S to SW monsoon flow will persist across the offshore waters of Costa Rica, Panama, Colombia, and Ecuador through Sat night, while moderate NW flow prevails across the Gulf of Panama. REMAINDER OF THE AREA... A 1026 mb high pressure center located near 29N128W is supporting fresh to strong tradewinds across the waters south of 25N and west of 115W. Recent altimeter data showed seas of 8 to 10 ft in the area of fresh trades. The high will move slightly southwest through Thu night and act to increase the pressure gradient to its south, and expand the area of strong tradewinds to S of 26N and W of 120W. A cold front will approach 30N140W and stall Thu. Large NW swell generated by gales behind the front are running ahead of front. Seas will build across the region, particularly where the longer period NW swell mixes with the shorter period easterly trade wind swell. Seas will eventually peak between 12 and 14 ft Thu night and Fri morning in this area. A surface trough or weak low pressure area heading west along will further tighten the pressure gradient just north of the ITCZ west of 130W Fri night and Sat. $$ Christensen