000 AXPZ20 KNHC 070951 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Wed Dec 07 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 0945 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends off the n coast of Costa Rica at 11N85W to 08N93W to 10N106W where scatterometer winds indicate a transition to an ITCZ which continues wsw to beyond 08N140W. Scattered moderate isolated strong convection is noted sw of the Gulf of Panama within 30 nm either side of a line from 09N79W to 06N82W. Similar convection is observed within 30 nm either side of a line from 14N93W to 09N95W, and along the ITCZ within 180 nm either side of a line from 13N108W to 10N120W to 08N126W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of California: Moderate to fresh sw flow is expected along 30N this morning just ahead of a weak cold front that will sweep se across the northern gulf waters today. Light and variable winds forecast across the gulf waters s of 29N early today, becoming a moderate to fresh nw breeze behind the front. Fresh nw flow is forecast across the entire gulf early Thu, and increasing to a strong breeze across the central gulf waters on Thu afternoon, and across the southern half on Thu evening. The pressure gradient will relax late Thu night into Fri, with fresh nw flow expected across the southern gulf from late Fri into late Fri night. A ridge will meander across the area from 23N116W to 15N101W today, then shift sw some tonight. Gentle to moderate anticyclonic flow is forecast around the ridge as long period nw swell continues to subside. The highest seas of 5 to 8 ft observed n of 29N seaward of 120 nm are expected to subside to less than 8 ft this afternoon. Gulf of Tehuantepec: Moderate to locally fresh n winds expected late tonight. A strong n surge is expected to begin late Thu afternoon and gradually strengthen to minimal gale force late Thu night, with the gale conditions continuing through sunrise on Sat. Combined seas are expected to build to near 18 ft downstream of the gulf waters near 14.5N95.5W late Fri. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Moderate to locally fresh nocturnal ene winds are expected late tonight. Fresh drainage flow is forecast on Thu night. A strong gap event is expected on Fri and Sat nights. Mostly light to gentle northerly winds, and combined seas of 2 to 4 ft, are occurring elsewhere n of the monsoon trough which is meandering e to w along about 10N. Light to moderate sw flow is observed to the s of 10N where combined seas of 3 to 5 ft in long-period sw swell are expected this week. REMAINDER OF THE AREA... A 1022 mb surface high is analyzed near 32N128W with a ridge extending se to near 16N102W. The surface high will shift se to near 30N124W later today, and will strengthen some blocking the eastward advance of a cold front, causing it to stall from 32N137W to 31N140W on Thu, and then further weaken as it drifts w on Thu night. Gentle to moderate nw to n flow is expected ne of the ridge today and on Thu. Moderate to locally fresh ne trades are forecast s of the ridge, with the fresh winds mainly just to the n of the ITCZ. Seas of 5 to 7 ft today will build to 7 to 9 ft late this week across the deep tropics n of the ITCZ. $$ Nelson