000 AXPZ20 KNHC 141523 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Tue Nov 14 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... A gale warning remains in effect for the Gulf of Tehuantepec. An earlier scatterometer pass showed 35-40 kt winds within about 60 nm of the coast in the Gulf of Tehuantepec, and another small area of similar wind speeds near 13.5N96W. A ridge along the eastern slopes of the Sierra Madre Mountains combined with low pressure in the SW Caribbean is maintaining a tight pressure gradient across the Isthmus of Tehuantepec. Model guidance suggests that the current synoptic pattern will remain favorable for gale force winds through early Wed morning. Seas will begin to slowly subside later today and Wed. Winds will diminish below gale force on Wed as the ridge weakens some, but northerly winds in the 20 to 30 kt range will continue to blow across the Tehuantepec region through Sat. Winds are forecast to increase again to gale force by Sat night as a strong cold front moves into the western Gulf of Mexico. Marine guidance suggests winds of 30-40 kt and building seas of 14-15 ft by early Sun morning. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N84W to 08N100W to 08N120W to 09N125W to 12N130W 12N140W. Scattered moderate convection is from 05N to 08N E of 82W to the coast of Colombia. Similar convection is within 30 nm N and 60 nm S of trough between 92W and 110W, and from 05N to 10N between 110W and 130W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the Special Features section for information regarding the ongoing Gulf of Tehuantepec gale warning. A ridge will dominate the waters W of Baja California the next several days. The pressure gradient W of Baja California will tighten slightly as high pressure shifts closer to the coast, resulting in fresh NW winds N of 28N between 116W and 120W today with seas building to 7 ft. Gentle to moderate NW winds are expected to persist across the Gulf of California. Elsewhere, mainly light to gentle winds and seas of 4 to 5 ft will prevail through Wed night. A weakening cold front will move across the northern Baja California peninsula on Fri. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... A pair of ship observations near the Azuero peninsula indicated SW to W winds of 20 kt, while an earlier ASCAT pass showed moderate to locally fresh monsoonal flow over the same area. Winds are forecast to further increase to 20-25 kt south of Panama later today through Thursday, with seas building up to 9 or 10 ft in the Gulf of Panama on Wed. These marine conditions will be associated with a broad area of low pressure forecast to persist over the SW Caribbean over the next few days. Elsewhere, gentle to moderate winds and seas of 4 to 6 ft are expected N of the monsoon trough, which will fluctuate between 08N and 10N, with moderate to locally fresh S to SW winds and seas of 5 to 7 ft S of the monsoon trough through Thu. REMAINDER OF THE AREA... A 1012 mb low pressure area is centered near 19N131.5W moving NW at 10 kt. An area of fresh to strong winds and seas to 10 ft is noted within about 180 nm N semicircle of low center. A swirl of low clouds is associated with this low. A passing short wave trough and dry air aloft is expected to cause the low to weaken into a trough during the next 24 hours. Winds and seas N of low will continue to diminish today, and early on Wed winds will be less than 20 kt with seas less than 8 ft. An altimeter pass provided observations of 8-11 ft across the NW waters, mainly N of 26N and W OF 133W. Fresh to locally strong southerly winds are also seen by scatterometer data over this area. A developing low pressure system located west of area supports these marine conditions. The low pressure will move NE and the associated cold front will enter the far NW corner of the forecast area early on Wed. Fresh winds and seas of 8 to 9 ft will follow the front forecast to reach from 30N134W to 26N140W by Wed night. $$ GR