000 AXPZ20 KNHC 150836 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Wed Nov 15 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 0600 UTC surface analysis and satellite imagery through 0830 UTC. ...SPECIAL FEATURES... A gale warning will remain in effect for a few more hours this morning in the Gulf of Tehuantepec. A scatterometer pass at 0400 UTC showed 30 kt winds within about 60 nm of the coast. A ridge north of the area will weaken slightly today, allowing winds to diminish below gale force, but strong gap winds will persist into Sat night. Winds are forecast to increase again to gale force Sun 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 Sun afternoon. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A monsoon trough extends from 09N84W TO 08N125W then transitions to the intertropical convergence zone extending to 11N140W. Scattered moderate isolated strong convection is north of 06N between 75W and 80W. Scattered moderate convection is noted within 60 nm of the axis between 89W and 121W. ...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. Weak ridging west of the area is supporting moderate to fresh winds and 5 to 7 ft seas off Baja California, with the help of residual northwesterly swell. The ridge will weaken and shift closer to the coast today, allowing winds to diminish through Fri. Winds increase again to 15-20 kt off Baja California Norte by late Fri as stronger ridging builds north of the area, then shifts eastward through Sun allowing the winds to diminish again. Light northwest winds will persist across the Gulf of California through Fri in a weak pressure pattern. A cold front will move across Baja California Norte and northern Gulf of California late Fri and Sat. Strong high pressure building behind the front N of the area over the Great Basin will allow strong winds in the northern Gulf Sat, reaching the central Gulf of California Sun. These winds will diminish late Sun as the front dissipates and the high pressure north of the area shifts east. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Earlier ship observations show fresh to strong southwest to west winds to the south of western Panama. These winds are expected to persist with seas building to 9 ft near the Azuero peninsula through late Thu. The winds and seas are the result of a tight pressure gradient related to 1007 mb low pressure centered over the southwest Caribbean. The fresh to strong winds and seas to 9 ft will persist off western Panama through Thu, when the low pressure weakens and starts drifting farther north. 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 centered near 21N133W has a small area of 8-9 ft seas N of the low center. A passing short wave trough and dry air aloft will cause the low to weaken into a trough during the next 24 hours. Winds and seas north of low will continue to diminish today. A cold front is approaching the discussion area, ahead of a 1012 mb low pressure area. Scatterometer and ship observations show fresh to strong southwest winds ahead of the front. Long period swell is also propagating into the region, allowing combined seas to reach 8-10 ft north of 26N and west of 135W. The front will stall and start to dissipate from southern California to 25N140W later today. Residual northerly swell to 8 ft will persist north of 26N and west of 135W through late Fri. $$ Mundell