000 AXPZ20 KNHC 071500 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1500 UTC Wed Dec 7 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 1415 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Winds will be light and variable through Thursday afternoon, with northerly winds at night with nocturnal drainage flow. A strong cold front will charge through the Gulf of Mexico north of the area by the end of the week with high pressure ridging surging down eastern Mexico. Northerly winds will rapidly increase to fresh to strong in the Gulf of Tehuantepec by Thursday evening, then increasing to minimal gale force by early Friday. Gale force winds will persist through Saturday night. Winds will peak around 40 kt Friday night. Seas will build to up to 18 ft by Friday night. Gale force winds will diminish by early Sunday, however, another gale force wind event is possible early next week. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 09N77W to 07N98W to low pressure near 10N107W to 10N120W. The intertropical convergence zone axis extends from 10N120W to 08N140W. Scattered moderate from 07N to 08N between 78W and 81W, from 08N to 11N between 94W and 97W, from 11N to 13N between 107W and 113W, from 07N to 10N between 113W and 120W, and from 08N to 10N between 128W and 131W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of California: Broad and weak low pressure is in the northern gulf near 30.5N114W with troughing reaching to the southwest across Baja California norte. A small area of fresh southwest winds is possible from 29.5N to 30.5N to the east of the trough. A weak cold front will clip by the northern gulf through the day today causing winds to become northerly across the basin. A tight pressure gradient will then setup Thursday through Friday night with northerly flow increasing to fresh to strong across the central and southern gulf. Seas will build to 5 to 7 ft as a result. A ridge will meander across the area from 23N116W to 18N107W today, then shift southwest some tonight. Gentle to moderate anticyclonic flow is forecast around the ridge through the end of the week. Combined seas, mainly northwest swell, of 4 to 7 ft will subside from northwest to southeast today. Winds offshore of Baja California norte will increase to fresh to strong north of 27N Friday night through the weekend as the gradient tightens. Fresh seas will build to 7 to 9 ft as a result. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Moderate to locally fresh nocturnal east- northeast winds are expected the next couple of nights, increasing to fresh to strong Friday night and Saturday night as the gradient across the region tightens. Seas will build to up to 8 ft just downwind of the gulf with the strongest winds. Mostly light to gentle northerly winds, and combined seas of 2 to 4 ft, are occurring elsewhere north of the monsoon trough which is meandering along about 10N. Light to moderate southwest flow is observed to the south of 10N, where combined seas of 3 to 5 ft in long period southwest swell are expected this week. REMAINDER OF THE AREA... A 1022 mb surface high is analyzed near 28N128W with a ridge extending southeast to near 18N107W. The surface high will shift southeast to near 30N124W later today, and will strengthen some blocking the southern advance of a cold front, causing it to stall from 32N137W to 31N140W on Thursday, and then further weaken as it drifts west on Thursday night. Gentle to moderate northwest to north flow is expected northeast of the ridge today and on Thursday. Moderate to locally fresh northeast trades are forecast south of the ridge, with the fresh winds mainly just to the north of the ITCZ. Seas of 5 to 7 ft today will build to 7 to 9 ft late this week across the deep tropics north of the ITCZ. $$ LEWITSKY