000 AXPZ20 KNHC 052158 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Fri May 5 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 1800 UTC surface analysis and satellite imagery through 2115 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning...A cold front is shifting quickly SE across the eastern Gulf of Mexico this afternoon. High pressure has built along the east coast of Mexico in the wake of the front, which has tightened the pressure gradient between this area of high pressure and a surface trough extending across the eastern north Pacific. This tight gradient is supporting gale force winds over the Gulf of Tehuantepec mainly N of 14N, with peak seas 10-12 ft. The area of high pressure will start shifting eastward into the northern Gulf of Mexico tonight through Saturday. This will veer winds over the southwest Gulf and start to diminish winds over the Gulf of Tehuantepec. Winds will diminish below gale force early Saturday morning, and to 20 kt or less by early Sunday. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 07N72W TO 10N85W TO 11N93W TO 09.5N97W TO 09.5N104W TO 06N114W, then quickly transitions to ITCZ, continuing on to 06N130W TO 04.5N140W. Scattered moderate to strong convection is occurring from 02.5N TO 11N E of 89W, and from 05N TO 12N between 90W AND 104W. Scattered moderate to strong convection was noted within 120 nm of the axis between 104W and 126W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See the special features section for more information on the latest Gulf of Tehuantepec gale force gap wind event. Outside of the Gulf of Tehuantepec area, light to gentle winds prevail over the Gulf of California with seas in the 1-3 ft range while gentle to moderate NW to W winds and seas in the 4-6 ft range over the remainder of the forecast waters. A cold front will approach the SW United States and NW Mexico this evening, then move across NW Mexico tonight through Sunday. Winds will increase across the Pacific waters of Baja California through Saturday night ahead of the front, then become fresh to near gale force in the northern Gulf of California ahead of the front late tonight into early Saturday. Behind the front, fresh to strong winds are forecast offshore of Baja California Norte and in the northern Gulf of California. Seas will build to 8-15 ft in N swell in Pacific waters north of 22N west of the front through early next week. Seas will build to 5-8 ft north of 29N in the Gulf of California tonight through Saturday night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gentle to moderate winds prevail over the forecast waters with seas in the 5-7 ft range. Only minor fluctuations in winds are expected across the area through Saturday, before some uncertainty in the forecast arises Sunday through the middle of next week. Looking ahead, global models continue to indicate an elongated cyclonic circulation is likely to develop and extend across the region. Upper atmospheric conditions will be conducive for sustained deep convection this weekend through the middle of next week across central America and the adjacent offshore waters to portions of far southeastern Mexico. The models are not in good agreement in the development of a low pressure system within the larger elongated gyre, but do suggest that a surface low or two will eventually develop across the tropical eastern Pacific between Central America and 95W by the middle of next week. Slow movement of this low pressure area could lead to periods of very heavy rainfall across portions of the region from Costa Rica NW toward SW Guatemala. REMAINDER OF THE AREA... A cold front moving through the NW part of the discussion area extends from 30N129W TO 25N140W. Fresh to strong winds prevail northwest of the front with seas in the 8-11 ft range. The front will shift across the northern forecast waters, with the fresh to strong winds spreading eastward in its wake. Large NW swell, with seas to 12 ft, will also accompany the front with 8 ft or greater seas likely to cover much of the area of north of 20N this weekend. $$ Stripling