000 AXPZ20 KNHC 130915 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Tue Nov 13 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... Gulf of Tehuantepec Storm Warning: A strong cold front will move across the western Gulf of Mexico today, followed by a strong high pressure system. Winds are forecast to reach minimal gale force across the Gulf of Tehuantepec by early afternoon today, then quickly increase to storm force by late afternoon or early evening. Seas downstream of the Gulf of Tehuantepec are expected to build to 13-22 ft by late tonight and early Wed. Storm force winds are expected to continue through late Wed night, with gale force winds likely lasting into early Sat morning. A large swath of high seas from this event will propagate south and southwest of the Gulf of Tehuantepec region, with the leading edge of the 8 ft seas forecast to reach near 108W by Fri. Gale Warning west of northern Baja California: Strong high pressure building across the southwestern United States and northern Mexico will bring strong to near gale force northerly winds over the Gulf of California. These winds will funnel through mountain passages across Baja California Norte with minimal gale force northeast winds over regional waters from 28N to 30N E of 115W this morning. Strong to near gale force northeast winds and building seas of 8 to 10 ft are also expected across the offshore forecast waters west of Baja California, mainly N of Cabo San Lazaro through late tonight. ...TROPICAL WAVES... The axis of a tropical wave extends from 15N118W to 05N121W, moving westward at 10 to 15 kt. Scattered moderate convection is noted within 90 nm of the wave axis. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northern Colombia near 08N76W to 07N85W to 09N100W to 09N120W to 07N124W. The ITCZ axis extends from 07N124W to 08N140W. Scattered moderate convection is seen within 45 nm of the trough axis between 93W and 98W, and east of 85W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for an upcoming Gulf of Tehuantepec storm event and a gale event off the west coast of Baja California Norte. Gulf of California: The pressure gradient associated with strong high pressure north of the area is bringing strong to near gale force northwest winds over the northern and central Gulf. These winds will spread southward across the entire length of the Gulf of California and across the waters between Las Marias Islands and Los Cabos later this morning. Seas are forecast to build to 8 to 10 ft, then subside in the afternoon as the high north of the area moves northward and weakens. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh northeast winds will pulse over the Gulf of Papagayo today, then diminish to moderate to fresh tonight. Winds will become fresh to strong by late Wed night as a tight pressure gradient develops over northern Central America behind a strong cold front that will move across the northwestern Caribbean Sea. Seas are forecast to build to 9 ft by Thu morning. This gap wind event will expand and continue through the upcoming weekend. A strong Tehunatepec gap wind event west of the area is forecast to spread strong to near gale force winds and building seas of 12 to 18 ft into the Guatemala and El Salvador offshore waters, mainly to the west of 92W, tonight through Thu morning. Otherwise, light to gentle winds are forecast N of the monsoon trough, with gentle to moderate SW winds S of the trough for the next several days. Cross-equatorial long period SW swell will keep seas around 6-7 ft from Ecuador and the Galapagos Islands to near the Azuero Peninsula through Wed. REMAINDER OF THE AREA... High pressure centered W of California near 34N130W has a ridge extending southeastward to near the Revillagigedo Islands. The pressure gradient will tighten between the high and low pressure in the vicinity of the ITCZ today, resulting in fresh to locally strong trades just north of the ITCZ. Seas of 8 to 9 ft will be associated with these winds covering roughly the waters from 10N to 16N W of 119W today, shifting to 10N-15N between 122W and 126W. These conditions are forecast to last through Thu, while they shift westward and decrease in coverage. A stationary front is dissipating near 30N140W. Model guidance depicts a cold front approaching the far northwest corner of the area on Fri. NW swell associated with the dissipating stationary front is forecast late tonight and early Wed, with seas of 8-10 ft covering much of the waters north of 07N and west of 130W by early Thu as the swell merges with waves generated by the area of fresh to strong trades. Cross equatorial SW swell of 7 to 9 ft will propagate across the waters south of 06N between 100W and 116W through tonight, then shrink south of 01N between 113W and 121W by Wed night. $$ Mundell