000 AXPZ20 KNHC 131005 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 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 0600 UTC surface analysis and satellite imagery through 0845 UTC. ...SPECIAL FEATURE... Gulf of Tehuantepec Storm Warning: Strong gale force northerly winds to around 40 kt extend across the gulf and downstream to near 12N96W tonight and will increase to around 50 kt, minimal storm force Sat evening and night. Seas across the gale area tonight have reached near 18 ft and will build to a maximum of 24 ft downstream of the gulf waters near 13.5N96W 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. Gulf of Papagayo Gale Warning: NE gap winds have begun to freshen to around 20 kt across the Papagayo region tonight, and will increase to strong around sunrise this morning, as a cold front moves SE across the NW Caribbean Sea. These NE winds will increase to near gale force, with frequent gusts to gale force, in and downstream of the Gulf of Papagayo tonight and then then to sustained gale force Sun night through late Mon morning. Seas are expected to build to 11 ft downstream of the region Sun night and continue through Mon. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends W from Colombia near 09N74W TO 05.5N92W, where overnight scatterometer winds indicated a transition to an ITCZ, which continues westward through a 1012 mb surface low at 07N110.5W to 08.5N121W to beyond 07N140W. Scattered moderate to strong convection is observed from 02N to 07.5N to the E of 88W to the Colombian coast, and from 06.5N to 09N between 104W and 113W. Widely scattered moderate isolated strong convection is noted from 07N to 15N between 126W and 140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gentle to moderate N to NW winds and 5 to 8 ft seas in moderate period NW swell prevail across the Pacific waters W of the Baja Peninsula tonight. Winds will diminish through this morning, becoming a gentle variable breeze around a weak N to S orientated trough developing 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 Sat night, but build back to 9 to 13 ft Tue through Wed in new 18-22 second long period NW swell. This large swell event will generate very large and dangerous surf across the regional outer reefs and coastlines, where breaking waves to 20 ft will be seen. 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... See special feature section above for information about the gale warning for the Gulf of Papagayo region. 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 late 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. Winds will pulse to near 30 kt just offshore of the coast during the evening hours of Sat and Sun with downwind seas building 8 to 9 ft. The resultant area of 7 to 11 ft NE swell from the gap winds from Papagayo and Fonseca will merge with N swell propagating S from the Gulf of Tehuantepec gap event Sun through Mon to produce a large area of 8 to 12 ft seas from 02N to 12N between 88W and 92W. 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 high pressure along 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 Sun. 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 and powerful NW swell producing seas of 10 to 20 ft, will propagate ESE across the discussion area Mon through Wed. The swell have just begun to reach the buoys to the NW of the Hawaiian Islands tonight in excess of 10 ft and 20 seconds. A secondary cold front will reach 32N140W on Sun night driving seas back up to 15 to 20 ft across NW portions along 32N. $$ Stripling