000 AXPZ20 KNHC 310353 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Sun Dec 31 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 0200 UTC. ..SPECIAL FEATURES... Gale Warning: A cold front is moving through the NW corner of the area. This front will move eastward and weaken during the next 24 hours or so. A second cold front will move into the NW corner of the Pacific Ocean on Sunday afternoon. Gale-force NW winds, and sea heights ranging from 17 feet to 22 feet, will be in the NW corner of the area on Monday morning. The front, the gale-force winds, and the 17-to-22 feet of seas will dissipate and disappear by late Tuesday. Please read the latest high seas forecast issued under AWIPS/WMO headers HSFEP2/FZPN03 for more details. GALE WARNING: The Gulf of Tehuantepec: The wind speeds are forecast to slow down during the next 24 hours, to 20 knots or less. The wind speeds are forecast to increase, to 20 to 25 knots early on Monday, until reaching gale-force late on Monday. The sea heights are forecast to range from 9 feet to 12 feet at their highest, late on Monday. Strong gap winds will pulse again tonight due to overnight drainage flow, with seas nearly reaching 8 feet. A strong cold front will push into the Gulf of Mexico late on Sunday, reaching the Bay of Campeche on Monday. Strong high pressure behind the cold front is expected to induce the next gale-force gap wind event in the Gulf of Tehuantepec. This next gale-force gap winds event has the potential to be a strong and long-lasting event, persisting for much of the next week. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... SURFACE TROUGH FROM 09N83W TO 09N86W TO 06N96W. ITCZ CONTINUES FROM 06N96W TO 08N108W TO 09N120W...AND FROM 08N132W BEYOND 09N140W. NO SIGNIFICANT CONVECTION. Precipitation: widely scattered moderate to isolated strong rainshowers are N of 05N from 83W eastward, and from 05N to 10N between 100W and 112W. isolated moderate to locally strong rainshowers are from the ITCZ to 16N between 113W and 122W. Isolated moderate to locally strong rainshowers are within 360 nm to the W of the line that passes through 30N128W, to 19N132W, and 10N136W. This precipitation is to the east of the cold front, that passes through 30N135W to 25N138W to 21N140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please read the SPECIAL FEATURES section, for more details about the gale-force winds for the Gulf of Tehuantepec. Elsewhere: tranquil marine conditions are expected with light to gentle winds prevailing across the forecast waters. Seas in the range of 3 to 5 ft will continue in the offshore waters, while seas in the 1 to 3 ft range will prevail in the Gulf of California. A sharp upper trough, that is parallel to the Baja California peninsula, is supporting widespread cloudiness and possible rainshowers, from 16N to 27N from 120W eastward. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... NE winds will pulse to fresh to strong in the Gulf of Papagayo through the middle of next week. Light to gentle NE to E winds will prevail elsewhere N of 09N, with gentle to moderate S to SW winds expected S of 09N. REMAINDER OF THE AREA... Please read the SPECIAL FEATURES section, for more details about the gale-force winds in the NW corner of the forecast area, and the associated swell. One surface trough is along 124W/126W from 14N to 20N. A second surface trough is along 130W from 10N to 16N. A surface trough will persist and shift northward through Tue ahead of the advancing frontal boundaries. The surface trough is supported by a broad middle level-to-upper level trough, that is moving into the area slowly from the west, and persisting in the region, to the west of 130W, through at least mid week. Strong winds and seas to 8 ft are expected from 22N to 24N between 124W and 125W. The surface trough will move WNW during the next few days. Long period northwest swell in excess of 8 ft will cover most of the area that is to the north of 10N and to the west of 125W through the middle of the week. $$ mt