000 AXPZ20 KNHC 250318 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 149 UTC Mon Dec 25 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 0000 UTC surface analysis and satellite imagery through 0330 UTC. ..SPECIAL FEATURE... ...Gulf of Tehuantepec Gale-Force Winds... High pressure over the Sierra Madre Oriental range is forcing a gap wind event over the Gulf of Tehuantepec. 30 kt winds are expected to increase to gale force tonight. The gale force winds will persist until Tue morning as a reinforcing shot of cold air enters the Gulf of Mexico. Thereafter, fresh to strong winds are expected to persist over the Gulf through Friday, strongest at night. Seas in the Gulf of Tehuantepec should peak around 13 ft on Monday morning, followed by peak wave heights of 8 ft or greater through Friday. Please refer to the latest high seas forecast issued under AWIPS/WMO headers HSFEP2/FZPN03 for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... An east to west surface trough extends from 05N77W to 07N95W. The ITCZ continues from 07N95W to 09N110W to 09N120W to 07N130W to 10N140W. A surface trough extends from 18N118W to the ITCZ axis near 10N121W. Isolated moderate convection is from 04N to 08N between 77W and 81W. Isolated moderate convection is from 06N to 09N between 100W and 107W. Scattered moderate convection is from 12N to 19N between 117W and 121W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the special features section above for details on the Gulf of Tehuantepec Gale event. Elsewhere, mainly gentle to moderate winds with benign marine conditions are expected through Thu. Late this week, NW swell of 6 to 8 ft may clip the western waters offshore Baja California Norte. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Strong gap winds over the Gulf of Papagayo will continue pulsing through Wednesday night, with the broadest extent of the winds occurring Mon night and Tue 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... A stationary front enters the discussion area near 30N136W and extends to 25N140W. The front supports fresh to strong S winds within about 120 nm east of the front, N of 27N. The front will transition to a surface trough Mon evening. Lingering NW swell of 8 to 14 ft, will slowly propagate SE through Tuesday. By Tuesday, peak wave heights will be 8 to 9 ft mainly N of 15N and W of 122W. Forecast models are also hinting at increasing winds late Tue into Wed between a nearly stationary surface trough currently along about 120W from 09N to 16N, and high pressure building to the north. Winds are currently forecast to peak near 20 kt Tue through Thu, and the combination of the wind waves and NW swell will allow seas to reach near 9 ft over this area. On Thu, a small area of N swell greater than 8 ft will reach the waters N of 28N between 120W and 127W. Elsewhere, moderate to fresh winds will prevail with seas between 6 and 8 ft. $$ Formosa