000 AXPZ20 KNHC 230901 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0901 UTC Sat Dec 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 0845 UTC. ..SPECIAL FEATURES... ...Eastern Pacific Gale-Force Winds... A 1010 mb extratropical low centered west of the discussion area near 26N144W is expected to intensify and head NE during the next 24 hours. The low will then weaken and slow down as it loses upper-level support. Satellite-derived wind data and scatterometer data indicated that fresh to strong winds had already moved over the forecast waters N of 19N and W of 135W. This system will pass very close to the NW corner of the discussion area and produce a brief period of gale-force winds from around 12 UTC Sat to 00 UTC Sun. By Sunday evening, strong winds associated with the low will prevail to the N of 30N. Combined SE wind waves and NW swell should produce peak seas up to 15 feet near 30N140W on Saturday. A lingering NW swell of about 8 to 12 ft Sun evening will move southeastward and decay through Tuesday, then merge with an area of 8 ft seas associated with trade-wind waves and swell W of 110W from 10N to 20N. Please refer to the latest high seas forecast issued under AWIPS/WMO headers HSFEP2/FZPN03 for more details. ...Gulf of Tehuantepec Gale-Force Winds... A strong cold front entering the NW Gulf of Mexico today will induce a gap wind event in the Gulf of Tehuantepec. Strong N to NE winds will develop over the Gulf of Tehuantepec by Sat evening, then quickly pulse to gale-force between Sun 00Z and dawn. Gale-force winds will return to the Gulf by Sunday night, then likely continue through Tue morning before gradually diminishing. Seas in the Gulf should peak around 12 ft on Monday morning, then remain 8 ft or greater through at least Wednesday morning. Please refer to the latest high seas forecast issued under AWIPS/WMO headers HSFEP2/FZPN03 for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 07N78W TO 07N110W. The ITCZ continues from 09N120W TO 09N140W. Scattered moderate convection is observed from 07N to 11N and W of 131W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of California: Satellite-derived winds and surface observations indicate fresh to strong NW to N winds are continuing throughout the area. Seas in the southern Gulf near 25N110W are as high as 8 ft. Gaps in the Baja California mountains are allowing some strong NE winds to bleed through to the Pacific coast. Strong NW to N winds are also funneling along the coast near Cabo Corrientes. These winds will gradually weaken by Sunday morning as the high pressure over the SW United States weakens. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to occasionally strong gap winds over the Gulf of Papagayo will continue pulsing through Wednesday night. Seas will peak around 8 ft. NE swell to 9 ft will clip the western offshore waters of Guatemala Monday and Tuesday as swell disperse from the Gulf of Tehuantepec gap wind event. Otherwise, gentle to moderate winds and seas of 5 to 7 ft can be expected during the next several days. REMAINDER OF THE AREA... See the Special Features section above for details about the gale-force wind events expected on Saturday for the waters near 30N140W and the Gulf of Tehuantepec Sun morning through Tue morning. Elsewhere, moderate to fresh winds will prevail with seas between 6 and 8 ft. Early next week, NW swell generated by the Special Features' low will slowly propagate SE into the discussion waters by early Tuesday, then merge with an area of 8 ft seas associated with trade-wind waves and swell on Wed. The area will span to the W of 110W from 10N to 20N. $$ ERA