000 AXPZ20 KNHC 041605 RRA TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Sun Dec 04 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. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The Monsoon Trough axis extends northwest off the Pacific coast of Costa Rica at 10N84W to 08N93W to 09N125W where scatterometer winds indicate the ITCZ begins and continues to 09N134W to 09N140W. Clusters of scattered moderate to isolated strong convection are noted within 120 nm north of the trough axis between 118W and 125W. Scattered moderate convection is within 30nm of a line from 09N103W to 09N108W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of California: Strong northwest winds and 5 to 7 ft seas currently to the north of 27N will diminish/subside to a fresh breeze this afternoon and further diminish to a moderate to fresh breeze tonight, with the associated seas subsiding to 2 to 4 ft. Light to gentle southerly flow is expected north of 29N on Mon, with light and variable winds forecast across the gulf waters south of 29N. The next cold front is expected to pass across the northern gulf on Wednesday, with fresh to locally strong post-frontal flow forecast on Wednesday night. Moderate to fresh northwest to north winds, with combined seas of 5 to 8 ft, are currently observed across the Pacific waters west of 117W. The pressure gradient will gradually slacken through Tuesday allowing for the winds to diminish to a gentle to moderate northerly breeze on Monday, with combined seas in the 4 to 6 ft range, except for higher seas of 7 to 9 ft in northwest swell north of 26N Monday and Tuesday. A low-level trough extends along 102W from 10N to 17N. This trough is under a very active and strong sub-tropical jet stream branch with multiple disturbances riding southwest to northeast along it. Small clusters of scattered moderate convection are observed within 15 nm either side of trough. Similar convection is present west of the trough within 30 nm either side of a line from 11N108W to 14N105W to 16N103.5W to along the coast of Mexico just west of Puerto Vallarta near 19N103W. The trough is forecast to gradually shift east-southeast through the next couple of days while weakening. Gulf of Tehuantepec: The next strong gap wind event is expected to begin beyond 48 hours early on Thursday afternoon. Northerly winds across the Gulf will quickly strengthen to minimal gale force late Thursday afternoon, with the gale conditions possibly increasing to strong gale winds through early on Saturday. Along with these winds, seas are forecast to rapidly build to large heights of around 17 to 21 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Moderate to locally fresh nocturnal northeast to east winds are expected to begin again late Tue night. Light to gentle northerly winds, except for light and variable winds to the east of 97W are present elsewhere north of the monsoon trough, with seas in the 4 to 6 ft range. A gentle to moderate southwest flow is observed to the south of the monsoon trough, with seas in the 5 to 6 ft in long-period southwest. REMAINDER OF THE AREA... Strong high pressure of 1030 mb north of the area at 36N136W extends a ridge southeastward to 32N132W to 24N125W to near 16N115W. High pressure covers the area north of 17N and west of 115W. The pressure gradient between the high and lower pressure near the monsoon trough is producing fresh northeast to east trade winds from 10N to 26N west of 135W, and from 10N to 15N between 115W and 135W with combined seas 8 to 10 ft in a northwest swell. The 1030 mb high is forecast to remain nearly stationary through early on Monday while weakening some, then shift to the southeast to near 32N128W by early on Tuesday as low pressure system and associated frontal system well west of the discussion area tracks to the north-northeast. The current pressure gradient responsible for the aforementioned fresh northeast to east winds will weaken allowing for these winds to become mostly moderate east trades with locally fresh winds. The northwest swell is forecast to gradually decay through Tuesday allowing for the 8 to 10 ft seas to subside to 8 ft in a small area from about 09N to 11N between 114W and 140W by early in Tuesday. $$ Aguirre