000 AXPZ20 KNHC 110953 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 655 UTC Sun Dec 11 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: High pressure over southern and eastern Mexico has begun to weaken. Latest satellite-derived wind data indicate the pressure gradient over the Isthmus of Tehuantepec is slackening. Highest sustained winds over the Gulf are now 30 to 35 kt. Winds will continue to diminish below gale force by this afternoon as high pressure over the western Gulf of Mexico weakens and shifts eastward. Max seas will be around 13 ft this morning, becoming 10-12 ft by this evening then subsiding to below 8 ft Monday. North winds are still expected to pulse to around 25 kt over the Gulf of Tehuantepec in response to nocturnal drainage flow during the overnight hours each night Monday through Friday. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 08N78W to 08N85W to 05N95W. The ITCZ continues from 05N95W to 09N109W to 05N133W to beyond 06N140W. Scattered moderate isolated strong convection is evident from 06N to 08N between 80W and 83W and from 08N to 15N between 106W and 126W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... High pressure centered west of the area is maintaining moderate to fresh NW winds over the forecast zones. Seas range between 4 and 6 ft in NW swell. Other from the Tehuantepec high wind event, light to gentle winds will prevail S of 17N through Wednesday, then winds will increase on Thursday and Friday in response to low pressure passing to the south. Fresh to locally strong NW winds north of 28N along the west coast of Baja California will continue through tonight, then diminish Monday as the ridge weakens in response to an area of low pressure approaching from the NW. Between 17N and Mazatlan moderate to fresh northwest winds will prevail through Tuesday night, then become light to moderate on Wednesday and Thursday. 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 92W will continue to pulse mainly during the overnight hours this weekend. Max seas during this event will be 8-9 ft. An easterly wave over the western Caribbean will cross Central America early Monday. GFS model guidance indicates low pressure development along the wave axis as it moves westward away from Costa Rica on Tuesday and Wednesday. Model consensus and climatology suggest this system will proceed as a trough or as modest low pressure. Associated winds should remain 25 kt or less. Fresh to strong winds north of the monsoon trough in the vicinity of the Gulf of papagayo will subside to light to moderate NE to E winds on Wednesday and Thursday. The monsoon trough is expected to remain between 08N and 10N through Thursday. South of the monsoon trough, light to moderate southwest to west winds are expected to prevail from 05N to 09N through Thursday. Combined seas will range between 3 and 5 ft in southwest swell. Moderate to fresh southerly flow is expected south of 05N through Thursday. REMAINDER OF THE AREA... High pressure centered near 28N129W ridges southeast to 15N105W. Gentle to moderate north-northwest flow is expected northeast of the ridge axis through Wednesday. Moderate to fresh trades will predominate south of the ridge axis and north of the ITCZ. An area of fresh to occasionally strong NE winds and combined seas of 8-9 ft is currently evident from 07N to 17N W of 125W. This area will shift westward and diminish in size until it disappears on Monday evening. Low pressure approaching the far northwestern waters is weakening the ridge, and will help maintain a relatively light wind regime in this area Tuesday through Friday. A cold front will enter the far northwest waters Tue night, then weaken as it proceeds eastward toward Baja California Norte Wednesday through Thursday night. NW swell generated to the N of the front will cause seas N of 26N and W of 127W to build to between 8 and 10 feet by Friday morning. $$ cam