000 AXPZ20 KNHC 272118 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Thu Oct 27 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Tropical Storm Seymour continues to rapidly weaken, and is located near 21.2N 123.1W at 2100 UTC, moving north-northwest at 10 kt. Estimated minimum central pressure is 992 mb. Maximum sustained winds are 55 kt with gusts to 65 kt. Numerous moderate isolated strong convection is within 150 nm northeast of the center. It will continue to rapidly weaken tonight, becoming a post-tropical cyclone by Friday afternoon, and dissipate Sunday. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP5/WTPZ25. Gulf of Tehuantepec Gale Warning...a high pressure ridge across eastern Mexico continues to produce a tight pressure gradient across southeast Mexico. As a result, strong northerly winds will continue to blow across the Gulf of Tehuantepec and spill downstream for the next two days, pulsing to minimal gale force, with the strongest winds occurring during the overnight and early morning hours. Seas will build to 12 or 13 ft during the periods of gale force winds. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N85W to 08N101W to 11N118W, then resumes from low15N130W to 10N140W. Minimal convection is associated with the convergence zone. Small areas of active convection are centered near 08N108W and 13N132.5W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See special features section for details on a persistent Gulf of Tehuantepec high wind event. Gentle to moderate anticyclonic winds prevail across waters offshore of the Baja California peninsula. Winds will slowly diminish this weekend, as a dying cold front moves east and the pressure gradient weakens. 5 to 8 ft seas in NW swell will subside to 4 to 6 ft this weekend, then build to 6 to 9 ft by Sunday as another cold front and a new pulse of northwest swell moves across the northern waters. In the Gulf of California, gentle to moderate northerly flow will prevail today, with winds becoming light and variable by early Friday as an elongated northwest to southeast trough sets up across the gulf. Low pressure is forecast to develop in the far northern Gulf of California by early Sunday. Winds southeast of the low are forecast to increase to fresh to strong Sunday, pulsing through early next week. Seas will be 2 ft or less across the northern gulf through the weekend, building to 4 to 7 ft as the winds increase, with 2 to 4 ft seas expected over the southern half. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gentle to moderate west to southwest winds are found south of the monsoon trough, while gentle west to northwest winds prevail north of the trough. Latest altimeter data shows seas ranging between 4 to 6 ft, primarily in long period southwest swell. Seas will decay to 3 to 4 ft this weekend. REMAINDER OF THE AREA... Please refer to the Special Features section for details on Tropical Storm Seymour. A 1012 mb surface low is located near 30N130W, with a cold front extending south-southwest from the low to 27N129W to 18N140W. Moderate to fresh northwest winds behind the front and northwest swell supporting seas to 10 ft. Gentle to moderate southwest winds prevail ahead of the front. The front will weaken as the low moves north of the area Friday. Its swell will continue to propagate southeastward, and mix with seas generated by Seymour, resulting in a large area of confused seas between 118W and 126W through Friday night. Another cold front will reach the area late Friday, bringing a reinforcing pulse of large northwest swell. Moderate to fresh trades will prevail outside of the influences of the front and Seymour, with combined seas of 4 to 6 ft. $$ Mundell