000 AXPZ20 KNHC 081605 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1545 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 1200 UTC surface analysis and satellite imagery through 1430 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 tonight through Tue night. Seas are expected to peak around 14 ft around mid morning on Tue. Modest winds and seas will then follow through mid week. Looking ahead, another more robust gale event is expected Fri. This event will last into next week. 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 09N125W. The ITCZ resumes from 11N129W to beyond 09N140W. Scattered moderate and isoloated strong convection is present along and up to 60 nm N and up to 180 nm S of the trough axis. Scattered moderate convection is found from 09N to 11N between 125W and 129W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Feature section above for more details about the developing gale force wind event over the Gulf of Tehuantepec. Weak 1016 mb high pressure currently centered near 25N117W will generally maintaining light winds over the forecast waters today. A cold front will sweep SE from NW Baja California Norte Tue morning 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 morning. Fresh NW winds and NW swell in excess of 8 ft will accompany front. The swell will propagate into the offshore waters off Baja California Norte early Tue, with seas building to around 16 ft by Tue night. Strong SW winds will be over the far northern portion of the Gulf of California later on Tue due to the front, with the possibility of strong western gap winds 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 pulses expected into the Gulf of Papagayo through mid week. Elsewhere moderate SW flow will persist into Costa Rica and Panama, with light northerly flow off the remainder of the coast of Central America. Seas will remain generally 3 to 5 ft. Expect occasional scattered showers and thunderstorms south of Panama mainly at night. REMAINDER OF THE AREA... A sharp upper-level trough extending SW from 32N131W to beyond 24N140W remains the main weather maker, supporting a 1008 mb surface low just N of the area near 30.5N129.5W. A trough extends from the low to 30N129W, then to 23N127W to 16N128W. An area of rosh to strong NW winds is present W of the trough and N of 28N between 130W and 136W. The short term forecast through tonight has these winds across the region diminishing as the upper trough finally starts to dampen out and lift to the northeast. This will be ahead of another mid to upper level disturbance passing eastward to the north of the region through late Mon. An associated cold front will sweep across the waters north of 20N through Tue. This will be accompanied by strong NW winds and seas in excess of 12 ft mainly over the waters north of 28N. Long period NW swell in excess of 8 ft will also propagate across the region north of 20N through mid week, eventually cover the area north of 10N by late week. $$ CAM