000 AXPZ20 KNHC 140339 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Wed Dec 14 2016 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 0230 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09.5N75W to 09N79W to low pressure near 10N94.5W to 08.5N99W. The ITCZ continues from 08.5N99W to 09.5N119W to 14N131W...then resumes near 10.5N136W to beyond 09.5N140W. Widely scattered moderate convection is from 06N to 12N between 81W and 88W. Scattered moderate to strong convection is from 07N to 11.5N west of 137W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of Tehuantepec: Strong northerly winds across and downstream of the Gulf of Tehuantepec to 14.5N earlier today have become light and variable this evening. A modest high pressure ridge across the SW Gulf of Mexico will maintain enough pressure gradient to produce fresh to strong N to NE nocturnal drainage winds returning late tonight through Wed over the Gulf of Tehuantepec. A new cold front will sink across the northern Gulf of Mexico on Wed with reinforcing high pressure to strengthen the drainage winds over the Gulf of Tehuantepec Wed night through the remainder of the work week. Near gale force winds are possible for Thursday evening through Friday as a result. A stronger cold front could produce a gale wind event beginning on Monday. Moderate northwest winds over the offshore waters north of 20N will become gentle to moderate through Thursday night with 3-5 ft seas prevailing. A cold front will move into the area from the west, and extend from near San Diego, CA to 26N121.5W by Friday evening. The front will then sweep southeastward across the Baja Peninsula and NW Mexico and pass south of the Baja Peninsula by Saturday evening. Model guidance shows strong southwest to west winds ahead of the front and strong to near- gale force west to northwest winds behind the front over the northern Gulf of California on Friday night. Fresh to strong NW winds will affect the offshore zones N of 25N on Saturday and Saturday night, with seas building as high as 11 ft near 30N. Gentle to moderate north to northwest winds will prevail south of Mazatlan through Wednesday, becoming light Thursday through Saturday. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... A weak 1010 mb surface low currently centered south of Tehuantepec near 10N94.5W will move westward away from the forecast area through Thursday night, where global models indicate a gradual opening up of the low to a trough for the next several days. Latest observations and global models suggest easterly winds of 20 to 25 kt and seas to near 8 ft across the northern semicircle of the low this evening, before winds begin to slowly diminish to around 20 kt during the next day or so and seas subside modestly. REMAINDER OF THE AREA... Broad high pressure of 1022 mb near 30N123W continues to reside over the northern waters. Gentle to moderate north-northwest winds are expected east of the high through Wednesday. A trough of low pressure is moving westward across west portions of the trade wind belt, located from 11N133W to 16N132W. The pressure gradient between the high and the north side of the trough is generating NE to E winds of 20 to 25 kt and seas to 8 ft from 14N to 17.5N between 129W and 133W. The trough is expected to gradually weaken as it translates west and then northwestward during the 24 to 36 hours. Associated winds and seas will subside. The remnants of this trough will gradually lift northward Thu through Fri, ahead of low pressure and a trailing frontal boundary currently lurking just northwest of the area. The front will enter the far NW waters on Wed. South to southwest winds of 20 to 25 kt and 8-10 ft seas will precede the boundary tonight through Wed. Reinforcing cold air will push the front east-southeastward across the northern waters Thursday and Friday. NW swell generated behind the front will cause seas north of 25N and west of 120W to build to 8-11 feet by Friday. Seas east of 130W will briefly subside to around 8 ft on Saturday before a round of reinforcing N swell arrives on Sunday. $$ Stripling