000 AXPZ20 KNHC 130348 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Sat Jan 13 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 0245 UTC. ...SPECIAL FEATURE... Gulf of Tehuantepec Storm Warning: Strong gale force northerly winds extend across the gulf downstream to near 13.5N95.5W early tonight and will increase to around 50 kt, minimal storm force by late Sat afternoon, with seas building to a maximum of 25 ft downstream of the gulf waters near 14N95.5W on Sat night. Winds are then forecast to diminish below storm force late Sun morning. Strong high pressure will dominate the Gulf of Mexico early next week, and be reinforce by another strong cold front by mid week. Winds across the Gulf of Tehuantepec are not forecast to diminish below gale force through at least Thu. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends W from Colombia near 08.5N75W TO 05N93W, where afternoon scatterometer winds indicated a transition to an ITCZ, which continues westward through a 1011 mb surface low at 07N109W to 09N121W TO 07.5N133W to beyond 08N140W. Widely scattered moderate isolated strong convection is observed from 05.5N to 08.5N between 83W and 110W. Scattered moderate to strong convection is noted within 75 nm either side of ITCZ between 125W and 133W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gentle to moderate northerly winds and 5 to 8 ft seas in moderate period NW swell prevail across the Pacific waters W of the Baja Peninsula early tonight. Winds will diminish overnight through Sat, becoming a gentle variable breeze around a weak N to S orientated trough develop along 114W. The trough will shift slowly W through the upcoming weekend and dissipate along 119W late Mon. Seas will subside to 4 to 7 ft on Sat night, but build back to 8 to 13 ft N of 24N on Mon through Tue in new 18-22 second long period NW swell. Gulf of California: Fresh to strong NW winds, and 5 to 8 ft seas, will continue across the central gulf waters from 25N to 28N tonight, then diminish slightly to 15 to 20 kt Sat before diminishing further to a moderate to NW breeze that will continue through late Tue. See special feature section above for information about the storm warning and long-lived gale event in the Gulf of Tehuantepec. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Moderate to locally fresh NE winds are expected tonight, increasing to a strong NE breeze surging across the Gulf of Papagayo around sunrise on Sat, as a cold front moves SE into the western Caribbean Sea. These NE winds will increase to minimal gale force, with frequent gusts to gale force, in and downstream of the Gulf of Papagayo on Sat night and continue through Mon afternoon. Gulf of Fonseca: Strong N to NE winds will develop across the Pacific waters to the N of 11N and E of 92W, including the Gulf of Fonseca, beginning on Sat evening, and continuing through Sun morning, as strong high pressure behind the Caribbean cold front blasts northerly gap winds across Central America and into the eastern Pacific. The resultant area of 7 to 11 ft NE swell from the gap winds will merge with N swell propagating S from the Gulf of Tehuantepec gap event on Sun. Elsewhere, light to moderate SW winds will persist S of Costa Rica and Panama through Sat with seas generally between 3 and 5 ft. Fresh N winds are forecast across the Gulf of Panama beginning on Sat evening, continuing through sunrise on Mon. REMAINDER OF THE AREA... The pressure gradient between a 1031 mb high pressure center just off the coast of northern California, and broad low pressure across the deep tropics, is supporting fresh NE trades from 08N to 19N between 120W and 140W. NW swell in the form of 6 to 9 ft seas is currently observed across the Pacific waters N of 08N W of 115W. These seas will continue to subside from the E through Sat. Strong to near gale force southerly winds will develop across the waters from 29N to 32W W of 138W on Sat, in advance of a cold front that will reach 32N140W on Sat night. Although the front will nearly stall from near 32N125W to 27N140W on Tue, large NW swell producing seas of 12 to 22 ft, will propagate SE across the discussion area on Tue and Wed. A secondary cold front will reach 32N140W on Sun night driving seas back up to 22 ft along 32N. $$ Stripling