000 AXPZ20 KNHC 080302 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 302 UTC Sat Oct 8 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 0000 UTC surface analysis and satellite imagery through 0245 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning...high pressure building southward over eastern Mexico and the Gulf of Mexico will tighten the pressure gradient across the isthmus of Tehuantepec, allowing fresh gap winds which combined with overnight drainage effects will result in string to near-gale force winds overnight. The gradient will tighten even more through Saturday with minimal gale force winds expected Saturday night into Sunday. A cold front will move across the Gulf of Mexico late this weekend which will allow dense, cooler, and drier air to push into the Gulf of Tehuantepec, increasing the winds to 30 to 40 kt Sunday night. Gap winds will diminish slightly thereafter as the airmass to the north modifies and shifts east. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N86W to 11N91W, then resumes from 13N105W to 13N115W TO 12N125W to 1011 MB low near 11N136W to 10N140W. Scattered moderate to strong convection was noted from 10N to 13N between 100W and 105W and within 120 NM of the coast of Costa Rica. Scattered moderate isolated strong convection was noted within 240 NM south of axis between 105W and 122W and from 09N to 12N between 93W and 97W. Scattered moderate convection was noted elsewhere within 180 NM south of the axis between 128W and 135W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A sub-tropical ridge axis extends from northwest to southeast across the Pacific waters to the Revillagigedo Islands. Strong northerly winds off the coast of California to the north of the region had supported a surge of northerly swell to 8 ft as far south as 27N between 121W and 125W, impacting the offshore zones off of Baja California Norte. This swell has decayed to less than 8 ft and swell of 5 to 7 ft will persist through Saturday. Otherwise, gentle to moderate northwest to north flow is observed elsewhere across the open Pacific waters west of 110W. The pressure gradient will relax late through today, with the northwest flow diminishing to 5 to 10 kt, and associated seas forecast at 3 to 6 ft everywhere west of 105W by late today. Little change then expected through next Tuesday. Moderate to occasionally fresh northwest winds expected across the Gulf of California north of 30N through early Saturday with seas building to 5 ft. Winds will diminish to a gentle northwest flow by late Saturday and persisting through early next week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to gentle westerly winds are expected through tonight north of the monsoon trough which is meandering east to west along about 11N, while moderate southwest flow is expected south of the monsoon trough through the upcoming weekend. Winds will become light and variable across the waters north of 11N on Saturday, with little change except moderate easterly flow possible across the Gulf of Papagayo on Sunday night. Combined seas of 3 to 6 ft, primarily in long-period southwest swell, is expected across the offshore waters later in the period from the early to middle part of next week. Fresh trade wind flow is likely between 10N and 15N between the low pressure areas, and the mostly stationary ridge to the north early next week. REMAINDER OF THE AREA... High pressure 1021 mb was centered north of the area near 35N132W will shift southeastward through the next couple of days, ahead of a cold front moving into the forecast area by 48 hours. Areas of moderate to fresh trade winds persist north of the monsoon trough to near 20N, with seas of 5 to 7 ft. Global models are in good agreement showing a series of weak low pressure areas forming along the monsoon trough. Although the model depictions differ somewhat in precise locations, there is some general agreement of low pressure forming between 115W and 120W through late Sunday. and there is a moderate chance of tropical cyclone development with this low early next week as it tracks westward along the monsoon trough west of 125W. Have depicted a low near 12N118W by 48 hours in the High Seas with an area of 20 to 25 kt winds and seas to 8 ft within 150 NM of the low in the southeast semicircle. $$ COBB