000 AXPZ20 KNHC 251002 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 733 UTC Wed Jan 25 2017 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 0900 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The ITCZ extends from 05N102W to 08N110W to 04N132W to 04N140W, but lacks significant convection. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Long period NW swell continue propagating SE across the open waters W of 100W. Latest satellite-derived sea height data indicate seas in this area range between 8 and 14 ft, with the highest seas between the Baja peninsula and 125W. These large seas are forecast to subside to 7 to 9 ft by Thursday morning. Hazardous near shore marine conditions and the associated dangerous surf are both expected to continue until the seas subside. Mixing SW and NW swell resulting in seas of 7 to 10 ft are expected between 96W and 110W early tonight, and then expected to subside to 4 to 7 ft on Wed. Gulf of California: moderate NW to N winds this morning are expected to increase to a fresh this afternoon, and further increase to locally strong NW winds across the central gulf waters tonight. Strong high pressure is beginning to build across the western United States. The pressure gradient between the high and the Gulf of California will continue tightening throughout Thu with strong NW flow expected across the entire Gulf on Thu night, with embedded swaths of near gale force winds by late Thu night. Latest model guidance continues to suggest minimal gale conditions over the northern and central gulf waters on Sat evening. Have gone with gales for zone PMZ017 for now, but extent of the gales may need to be extended to include zone PMZ019 as well during this time frame if the aggressive trend for winds in the models continues. Seas are forecast to build to 11 ft in the open fetch waters along 26N on Fri night and Sat. The pressure gradient will relax on Sun and Mon, allowing winds and seas to subside. Gulf of Tehuantepec: strong northerly winds are expected to begin on Thu evening and rapidly increase to near gale force late Thu night, with seas building to 10 ft downstream of the gulf near 15N95W. The north winds will diminish to a fresh breeze by mid day on Fri, then briefly increase to locally strong on Fri and Sat evenings. Guidance is beginning to suggest minimal gale conditions beginning late Sat night, then continuing through Sun. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh ENE winds expected tonight and Wed night, then increasing a little with brief strong winds forecast on Thu night, with seas building to about 6 ft. Fresh to strong ENE winds may visit this area Sat night and Sun night. Gulf of Panama: Fresh N winds expected tonight and Wed with guidance suggesting very brief strong winds on Wed night. Then fresh nocturnal northerly flow is forecast on Thu night. Light to gentle winds, and combined seas of 3 to 4 ft, are generally occurring elsewhere. REMAINDER OF THE AREA... A ridge extends SE from 1029 mb high pressure centered near 32N138W to the vicinity of the Revillagigedo Islands at 18N111W. Large NW swell and combined seas to 14 ft are spreading SE across the discussion waters W of 92W. A surface trough is expected to begin developing across the tropics S of the ridge tonight and extend from 09N140W to 16N133W on Thu morning. An area of strong winds will develop on the N side of the trough, and gradually spread outward out to about 840 nm on Thu night. A surface low is expected to develop along the trough near 12N135W on Thu as well. The associated pressure gradient will support strong to near gale force winds across the waters from 11N to 24N between 124W and 140W, with seas building to about 18 ft on Fri. $$ cam