000 AXPZ20 KNHC 090915 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 632 UTC Tue Jan 9 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 0915 UTC. ...SPECIAL FEATURE... Gulf of Tehuantepec Gale Warning: High pressure building southward along the Sierra Madre Oriental behind a cold front over the NW Gulf of Mexico is producing gale force winds over the Gulf of Tehuantepec. Gale force winds will continue until Tue evening. Seas are expected to peak near 14 ft. Modest winds and seas will then follow through Thu night. Looking ahead, another more robust Gulf of Tehuantepec gale event is expected to commence Fri morning. This event will continue to beyond Mon. Please refer to the latest high seas forecast issued under AWIPS/WMO headers HSFEP2/FZPN03 for additional details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 08N85W to 05N90W. The intertropical convergence zone continues from 05N90W to 07N110W to 08N123W. The ITCZ resumes from 11N130W to beyond 09N140W. Scattered moderate convection is from 07N to 09N between 81W and 85W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Feature section above for more details about the current gale force wind event over the Gulf of Tehuantepec. Weak 1018 mb high pressure currently centered near 20N116W will maintain light winds over the forecast waters tonight. A cold front extending from 30N123W to 24N127W to 22N135W will sweep E to NW Baja California Norte Tue, and to the northern Gulf of California Tue night. Fresh to locally strong NW winds and NW swell in excess of 8 ft will accompany the front. The swell will propagate into the offshore waters off Baja California Norte early Tue, with seas building to around 14 ft in the far NW waters by dawn on Wed. Strong SW winds will precede the front over the far northern portion of the Gulf of California from around midday Tue to midday Wed. Strong gap winds could be in the offing Tue night in the northern Gulf of California south of San Felipe. Looking ahead, the NW swell will gradually decay off Baja California through Wed, but long period swell to 8 ft will reach the Revillagigedo Islands by early Thu before subsiding. Fresh to possibly strong NW winds will follow the front across the central and southern Gulf of California Wed into Thu with seas to 6 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... High pressure north of the Caribbean Sea has weakened and shifted east. Only 15-20 kt winds are pulsing through the Gulf of Papagayo. Elsewhere 10-15 kt SW flow will persist S of Costa Rica and Panama. Seas will remain generally between 3 and 5 ft. Expect scattered nocturnal showers and thunderstorms south of Panama through Wed night. REMAINDER OF THE AREA... An upper-level trough is enhancing the surface front W of Baja Califirnia. The cold front will affect the waters N of 28N with strong NW winds until around midday Tue. Corresponding seas in this area will run between 12 and 14 ft during this time frame. Long period NW swell generated by NW winds behind the cold front will cause seas to build in excess of 8 ft north of 20N and west of 115W by Thu morning. This area of seas will slowly decay on Fri and Sat. $$ Formosa