000 AXPZ20 KNHC 030308 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0305 UTC Wed Jan 3 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 0000 UTC surface analysis and satellite imagery through 0130 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: The pressure gradient between high pressure along the eastern coast of Mexico and a surface trough over the eastern north Pacific is supporting a gale force gap wind event over the Gulf of Tehuantepec. This event will be strong and long lived, peaking near 45 kt early Thu morning as seas reach near 18 ft. Swell associated with 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 110W 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 07N77W to 06N90W to 06N100W. The intertropical convergence zone continues from 06N100W to 09N122W, then resumes from 10N127W to 09N140W. No significant convection is currently noted. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see special features section above for more details about the 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 most of the offshore waters, while seas in the 1 to 3 ft range will prevail in the Gulf of California. The only exception is NW swell of 5 to 7 ft that 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. Large NW swell from the Gulf of Tehuantepec gap wind event will reach the western offshore waters of Guatemala throughout the week. REMAINDER OF THE AREA... A deep layered trough is drifting east between 130W and 135W. An associated 1008 mb low pressure area has now moved just north of our area and is centered near 31N133W, with an accompanying cold front reaching from 30N127W to 21N129W. The upper trough continues to support showers and embedded thunderstorms E of the front from 17N to 30N between 122W and 129W. Earlier scatterometer data this afternoon shows winds have decreased to 20 kt or less around the low center, with some rain contaminated 25 kt winds sampled near a surface trough SE of the cold front. The low will continue to move farther north of our area through Wed while weakening. The cold front will dissipate by Wed afternoon. NW swell of 8 to 11 ft is crossing the NW waters N of 17N and W of 125W. This swell will become reinforced by additional swell caused by a cold front approaching the NW corner of 30N140W Wed morning. The result will be seas 8 ft or greater over the NW waters through Fri. By the weekend, forecast models are indicating an area of low pressure may develop roughly near 25N135W with strong winds and seas building to 12 ft. $$ Latto