000 AXPZ20 KNHC 092140 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Fri Dec 9 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... Gulf of Tehuantepec Gale Warning: Scatterometer data at 1630 UTC showed gale force winds north of 15N in the Gulf of Tehuantepec. The pressure gradient will continue to tighten this evening and sustained winds are expected to increase to around 45 kt. Max seas will build to 16-18 ft by early Saturday. Gale conditions will persist until Sunday morning, then pulse to 25-30 kt each night from Sunday night through Tuesday night. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 08N82W to 07N98W. The ITCZ continues from 07N98W to 09N118W to 07N127W to 08N140W. Scattered moderate convection is within 90 nm north of the axis between 111W and 122W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of California: The pressure gradient between surface troughing along the Mexico coast and high pressure over the east Pacific will continue to support fresh to strong northwest winds over the Gulf of California south of 27N through tonight. The pressure gradient will relax somewhat late tonight, with winds becoming moderate to fresh. An area of high pressure northwest of the area will weaken late Saturday, allowing for gentle to moderate winds to prevail Saturday night through Thursday. Ridging dominates elsewhere in offshore waters of Mexico with a high centered near 29N125W. Aside from the Tehuantepec event, light to gentle winds will prevail south of 17N through the forecast period. Fresh to occasionally strong northwest winds west of Baja California will continue through Sunday night, then become moderate to fresh as the ridge weakens slightly. From 17N north to Mazatlan moderate to fresh northwest winds will prevail. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh to strong offshore winds east of 90W will continue to pulse mainly during the overnight hours this weekend. Max seas will be around 8 ft during the event. An easterly wave in the central Caribbean will cross Central America Monday. Some model guidance indicates low pressure development along the wave axis as it moves west of the coast Tuesday through Wednesday. Light to gentle north to northeast winds and combined seas of 3 to 5 ft are occurring north of the monsoon trough, which is expected to meander between 08N and 10N through Wednesday. Light to moderate southwest flow is observed from 05N to 09N, with combined seas of 3 to 5 ft in southwest swell. Moderate to fresh southerly flow is expected south of 05N through Wednesday. REMAINDER OF THE AREA... High pressure centered near 29N125W extends with a ridge axis southeast to near 15N105W. Gentle to moderate north-northwest flow is expected northeast of the ridge axis this weekend and moderate to fresh trades will prevail south of the ridge axis, north of the ITCZ. Fresh to occasionally strong NE winds and combined seas of 8 to 9 ft will generally prevail from 07N to 15N W of 120W through Sunday. Low pressure approaching the far northwest waters will weaken the ridge on Tuesday and Wednesday, allowing winds and seas in this area to subside. $$ Mundell