000 AXPZ20 KNHC 260315 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Sun Nov 26 2017 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 0315 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A tight gradient will set up across southern Mexico between high pressure north of the area and relatively lower pressure over the deep tropics. This will result in strong gap winds in the Gulf of Tehuantepec beginning toward sunrise, enhanced by local drainage effects. Winds will reach gale force by Sun afternoon with seas building to 12 ft. The gales will increase to 40 kt by early Mon with seas building to 17 ft downstream. Swell from the gap wind 8 ft or greater will reach more than 500 nm offshore of the Gulf of Tehuantepec by late Mon. The high pressure weakens and shifts east Tue, allowing gale force winds to diminish. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 08N78W to 09N95W to 08N105W, where it transitions to the intertropical convergence zone and continues through 10N120W to 10N140W. Scattered moderate isolated strong convection is noted within 120 nm either side of the ITCZ between 114W and 118W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Features paragraph above for information on the Gulf of Tehuantepec Gale Warning. A weak ridge centered around 450 nm off Baja California will maintain light to gentle breezes and slight seas through early Mon. The ridge will be replaced by a stronger area of high pressure building in behind a cold front moving across the region. This front will usher in fresh to strong NW winds off Baja California Norte late Mon and Mon night. Seas will build Mon as well as NW swell of 8 to 12 ft will move into the area off Baja California Norte, then continue to propagate off Baja California Sur late Mon, reaching the Revillagigedo Islands by mid week. Winds diminish Tue, but seas in excess of 8 ft will persist through late week as another round of reinforcing swell moves into the region. Strong NW winds will follow the front across the northern and central Gulf of California Mon night and Tue. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh NE winds are occurring across and downstream of the Gulf of Papagayo this evening. Seas have built to 6- 7 ft downstream of the gulf. Expect a typical nocturnal maximum of around 25 kt across the region through early Tue morning, diminishing to 15-20 kt by mid afternoon. Seas will maximize to around 7 ft each morning near sunrise, and will likely build locally to 8 ft early Monday morning with a more extensive area of 8 ft seas expected Tue morning. Moderate to locally fresh NE winds are expected across the Gulf of Fonseca each night through Tue. Light to gentle N to NE winds, and 3 to 5 ft seas are expected elsewhere through Sun night to the N of the monsoon trough which has been meandering between 09N and 11N. Moderate southerly winds, and 4 to 6 ft seas, are forecast S of the monsoon trough. REMAINDER OF THE AREA... A cold front is over the NW waters and extends from 30N131W to 19N140W while a reinforcing or secondary cold front is now entering the far NW corner of the discussion area near 30N140W. Fresh W to NW winds are noted N of 28N W of 135W. Fresh to strong NW winds and seas to 10 to 12 ft will follow the secondary front overnight into early Sun. The fronts are forecast to merge on Sun as they move eastward and approach 125W with seas building 12 to 14 ft over the far NW portion of the area. NWP and gridded wave data suggested an area of seas of 8 to 10 ft from 10N to 20N west of 125W. These seas will propagate southward across the equator while decaying through early Mon, just ahead of reinforcing NW swell entering the discussion area tonight, encompassing most of the region north of 10N through mid week. $$ Cobb