000 AXPZ20 KNHC 230945 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Thu Nov 23 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 0600 UTC surface analysis and satellite imagery through 0945 UTC. ...SPECIAL FEATURE... Gulf of Tehuantepec Gale Warning: 30 to 40 kt gale force winds will continue into early Thu afternoon with minimal gale conditions then persisting through mid morning on Fri. Winds will diminish to 20 kt or less late Sat morning. Expect max seas of 17 ft near 14N96W tonight. The resultant NE swell will propagate SW, mixing with long- period cross equatorial swell, with seas 8 ft or higher well downstream of the Gulf of Tehuantepec along 08N between 95W and 105W on Fri night before beginning to subside. Expect winds 20 kt or less and seas less than 8 ft only briefly on Sat afternoon. Strong N winds are forecast to resume again on Sat evening with gale conditions just after sunrise on Sun. Latest guidance is suggesting another 30 to 40 kt event on Sun night with the gales diminishing late Mon. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends W between 09N and 11N across the SW Caribbean to the Pacific coast of Costa Rica at 09N84W, and continues W to 09N105W where scatterometer winds indicate a transition to an ITCZ, which continues NW to an embedded trough at 12n114w, then the ITCZ turns SW to beyond 07N140W. Isolated moderate to strong convection is noted within 90 nm either side of a line from 06N77W to 09N85W to 08N104W to 0N116W to 08N135W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Features paragraph above for information on the Gulf of Tehuantepec Gale Warnings. Light and variable winds and 2 to 4 ft seas expected W of Baja today, then seas will build from the NW with 4 to 7 ft seas at 13 to 15 seconds forecast across the waters W of Baja on Fri night, then subsiding some on Sat into Sun. Long-period NW swell in the form of 7 to 9 ft seas will reach 30N120W on Sun night, and spread S across the waters W of Baja with 8 to 13 ft seas at 17 to 19 seconds forecast W of Baja Mon night and Tue. Gulf of California: Gentle to moderate NW flow expected through tonight. The pressure gradient will then relax, with light and variable winds on Fri through Mon. Strong to near gale NW flow expected to develop N of 25N on Mon night through Tue night, with seas building to 12 ft across the long fetch waters. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Fonseca...Fresh NW winds forecast to begin around sunrise on Mon. Gulf of Papagayo: Fresh to locally strong NE nocturnal drainage flow forecast to begin tonight, with strong pulses through Tue. Seas of 8 ft or greater will propagate SW to neat 08N92W on Tue. Light and variable 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 NE flow expected N of the Gulf of Papagayo early Mon. Moderate southerly winds, and 3 to 6 ft seas, are forecast S of the monsoon trough. REMAINDER OF THE AREA... A cold front from 32N137W to 29N140W will stall today with a surface low developing along the front near 30N140W tonight. The low will move NE of the area on Fri night. Scattered moderate isolated strong convection is observed within 30 nm either sode of a line from 20N135W to 17N140W. Combined seas of 8 to 13 ft at 14 to 16 seconds is currently observed across the discussion waters W of a line from 32N128W to 22N140W. This long period NW swell, in the form of 8 to 11 ft seas at 13 to 15 seconds, will propagate across the waters W of a line from 32N122W to 12N137W early Fri before beginning to subside. Another cold front will move E in to the area reaching from 32N133W to 23N140W on Sat with 9 to 12 ft seas at 12 to 17 seconds in the wake of the front. $$ Nelson