000 AXPZ20 KNHC 101606 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Mon Oct 10 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 1200 UTC surface analysis and satellite imagery through 1545 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning...High pressure building southward over eastern Mexico and the western Gulf of Mexico will tighten the pressure gradient across the Isthmus of Tehuantepec over the next several days. This will allow the strong northerly gap winds currently spilling across the Gulf of Tehuantepec this morning to combine with nocturnal drainage effects to result in gale force into Tuesday morning. Winds will briefly diminish to just below gale force on Tuesday afternoon before increasing to minimal gale force Tuesday night, and diminishing to 25 to 30 kt on Wednesday as the high pressure north of the area weakens and shifts east. Beyond Wednesday, strong to near gale force winds will persist through mid week, with strongest winds during the overnight hours. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N85W to 11N91W to low pressure near 10N96W 1009 mb to 12N105W to 14N112W to low pressure near 12N119W 1007 mb to 11N121W to 10N140W. Scattered strong convection is seen from 10N to 14N between 93W and 96W. Scattered moderate to isolated strong convection is within 120 nm either side of the the trough between 116W and 127W. Scattered moderate convection is within 120 nm south of the trough between 85W and 87W, and also between 107W and 110W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weak sub-tropical ridge axis extends northwest to southeast across the Pacific waters near the southern tip of Baja California Sur. Light to gentle northerly breezes will persist across the region north of 20N through Tuesday, including the Gulf of California on the eastern periphery of the weak ridge. Winds off the coast of the Baja California peninsula will increase to 15 to 20 kt by Wednesday north of Cabo San Lazaro between high pressure to the northwest and troughing over northwest Mexico. Elsewhere a light to gentle breeze, and 3 to 5 ft seas will persist. Scattered thunderstorms within about 150 nm offshore the coast of Mexico between 101W and Cabo Corrientes will gradually weaken through the afternoon, then materialize again mainly during the night time hours through Wednesday. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate southwest winds persist from 05N to the monsoon trough which is meandering east to west along roughly 10N to 11N, with a light to gentle southwest breeze farther south toward the Galapagos Islands. Seas are 4 to 6 ft south of the monsoon trough largely in long period southwest swell. Little change is expected with these observations through Wednesday Farther north, clusters of strong thunderstorms that moved offshore the coast of Guatemala during the overnight hours are presently noted from 10N to 14N between 93W and 96W. This activity is being driven westward under strong easterly flow aloft between a ridge axis that extends from a large anticyclone anchored just to the east of the Bahamas and an inverted mid-level trough that stretches from southeastern Mexico to within 180 nm southwest of the Gulf of Tehuantepec. Small clusters of scattered showers and thunderstorms are elsewhere offshore Central America. A 1009 mb low pressure area along the monsoon near 10N96W will support moderate to fresh easterly flow off the Guatemala and El Salvador coasts beyond 150 nm through late today with 6 to 8 ft seas. The low pressure will also enhance easterly flow through the Gulf of Papagayo and within 150 of the Nicaragua coast. Winds and seas will gradually diminish through late Tuesday as the low pressure area moves farther to the west allowing for the gradient to relax. REMAINDER OF THE AREA... High pressure of 1020 mb centered near 27N131W will weaken as it shifts to near 30N129W by early on Tuesday. A weakening cold front has moved into the northwest portion of the area, and extends from a 1012 mb low at 32N138W to 29N136W and to southwest of the area at 26N140W. The front will stall and start to dissipate from near 32N134W to 24N140W by Tuesday. The leading edge of a large area of NW swell begins 120 nm to the east of the front, and covers the entire area behind the front. Seas in the range of 8 to 10 ft are being produced by this swell. The swell area will diminish in size through Tuesday, and decay to less than 8 ft by early on Wednesday. Areas of moderate to fresh trade winds persist north of the monsoon trough to near 20N, with seas of 5 to 7 ft. Increasingly favorable conditions aloft is expected to provide weak low pressure systems currently along the monsoon trough, one near 12N119W and the other one near 12N125w with pressures of 1007 mb, more conducive environmental conditions for them to develop beyond 48 hours. Winds and seas will gradually increase near and roughly within 180 nm of mainly the low near 12N119W. $$ AGUIRRE