000 AXPZ20 KNHC 010912 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 615 UTC Mon Jan 1 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ..SPECIAL FEATURES... Gale Warning: Overnight ASCAT pass indicates a large area of winds to just below gale force over the far NW waters and beyond to the west, between low pressure centered near 29N138W and high pressure to its west centered near 33N149W. The overnight ASCAT pass suggests winds have diminished west of the low since Sunday afternoon. Will keep the gale warning up for the next 6 hours as it is likely there will be frequent gusts to gale force over this area. High pressure west of the low will continue to weaken, further diminishing winds this morning. A fresh set of NW swell is propagating into the area, with seas near 15 ft over the far NW waters near 30N140W. Seas will peak near 17 ft over this area this morning, and will slowly subside afterwards while propagating southeast across the forecast waters. By midweek, seas 8 ft or greater associated to this swell will cover much of the forecast waters north of 10N and west of 120W. Refer to the latest high seas forecast issued under AWIPS/WMO headers HSFEP2/FZPN03 for more details. Gulf of Tehuantepec Gale Warning: Winds and seas will increase over the Gulf of Tehuantepec today as strong high pressure building behind a cold front moving across the Gulf of Mexico helps tighten the pressure gradient over the forecast area. Winds will increase to gale force over the Gulf of Tehuantepec by late today. This gale event is expected to be strong and long- lasting, with gale force winds persisting for much of the week, and peaking near 45 kt. Swell associated to this event will push downstream of the Gulf of Tehuantepec, with seas 8 ft or greater reaching as far south as 05N and west to 105W by midweek. 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 08N78W to 06N97W. The ITCZ extends from 06N97W to 11N122W. It resumes from 11N130W to 08N140W. Scattered moderate convection was noted from 08N to 10N between 118W and 124W. Scattered moderate isolated strong convection was noted from 08N to 12N between 128W and 133W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see special features section above for more details about the upcoming gale force gap wind event in the Gulf of Tehuantepec. Relatively tranquil marine conditions will persist through the week 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. NW swell of 6 to 8 ft will propagate into the waters off Baja California Norte later in the week. 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 the week. Winds will further increase to near gale force Thursday as high pressure builds north of the area. 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 see special features section above for more details about gale force winds in the NW corner of the forecast area, and associated swell. Overnight ASCAT pass indicates fresh to strong winds associated to a surface trough that extends from 24N125W to 19N127W. Winds associated to this trough will diminish to 20 kt or less Tuesday, while seas to 8 ft merge with NW swell propagating across the area. $$ AL