000 AXPZ20 KNHC 082116 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1956 UTC Mon Jan 8 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 1800 UTC surface analysis and satellite imagery through 2030 UTC. ...SPECIAL FEATURE... Gulf of Tehuantepec Gale Warning: High pressure building southward along the Sierra Madre Oriental behind a cold front currently moving into the NW Gulf of Mexico on will cause gap winds to increase to gale force into the Gulf of Tehuantepec around 03Z. Gale force winds will then continue tonight through Tue night. Seas are expected to peak near 15 ft around mid morning on Tue. Winds will quickly subside from gale force Tue morning and become light by Wed afternoon. Modest winds and seas will then follow through Thu night. Looking ahead, another more robust gale force gap wind event is expected to commence Fri morning. This event will continue at least through 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 09N82W to 05N93W. The intertropical convergence zone continues from 05N93W to 07N112W to 08N121W. The ITCZ resumes from 11N131W to beyond 08N140W. Scattered moderate and isolated strong convection is present from 04N to 08N between 81W and 85W. A surface trough extending from 07N124W to 13N123W bisects the ITCZ. Scattered moderate and isolated strong convection is present from 07N to 12N between 120W and 125W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Feature section above for more details about the gale force wind event set to begin over the Gulf of Tehuantepec tonight. Weak 1020 mb high pressure currently centered near 29N115W will maintain light winds over the forecast waters this evening. A cold front extending from 32N130W to 28N136W to 26N140W will sweep SE to NW Baja California Norte by Tue morning, then through the northern Gulf of California Tue, before slowing and eventually dissipating over southern Baja and the southern Gulf of California and southwest of Los Cabos by Wed evening. 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 fresh overnight episodes of wind pulsing from moderate to fresh speeds are expected over the Gulf of Papagayo through mid week. Elsewhere light to moderate SW flow will persist S of Costa Rica and Panama, with light northerly flow expected elsewhere off the remainder of the coast of Central America. 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... The sharp upper-level trough that previously extend S along 130W is being ejected towards the NE by an approaching mid to upper- level trough that supports a cold front currently entering the NW corner of the discussion area. The old upper-level trough is still reflected by the surface trough that extends from 30N125W to 25N124W to 17N128W. An area of fresh to strong NW winds is present W of the trough and N of 28N between 130W and 136W. 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. $$ CAM