000 AXPZ20 KNHC 171520 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Tue Jan 17 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A meandering trough extends from 05N77W to 02N81W to 02N87W to 05N92W to 02N100W. The ITCZ axis extends from 02N102W to 06N115W to 09N123W to 05N140W. Random small areas of moderate convection are located from 12N to 16N between 1120W and 130W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Satellite imagery shows a surface trough from 24N113W to 27N119W west of Baja California drifting southward. Divergent flow aloft is enhancing showers associated with a deep-layer moisture plume spreading northeastward from 13N117W across the Cabo Corrientes region into central Mexico. Gentle to moderate mainly northwest winds prevail off the coast of Baja California and in the Gulf of California. Light to gentle northerly winds prevail south and east of Acapulco. Seas are 5-6 ft west of Baja California, 2 ft or less in the Gulf of California, and 2-5 ft elsewhere. Global models indicate a cold front will move into the waters off Baja California Norte Thursday, then become diffuse ahead of a much stronger cold front that will quickly move across Baja California and the Gulf of California Friday and Saturday. The second front will be accompanied by fresh to strong winds and large northwest swell, expected to build seas to 12-19 ft over the waters off Baja California Norte Saturday, and 8-13 ft seas off Baja California Sur. This could potentially bring hazardous surf conditions to mariners navigating near shore waters. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Northwest winds will pulse to 25 kt late tonight and again late Wednesday night across the Gulf of Papagayo, then diminish by Thursday night. Light to gentle variable winds are expected Friday. Light to gentle easterly winds will prevail elsewhere through Saturday. Seas will be generally 3-5 ft in the forecast waters. REMAINDER OF THE AREA... High pressure centered near 29N136W extends a ridge southeast to the Revillagigedo Islands. The gradient between this high and lower pressure associated with the ITCZ is supporting an area of fresh to strong northeast trade winds from 10N to 14N west of 126W, with 10-11 ft seas. Fresh trades are found elsewhere from 06N to 21N west of 113W, with seas to 10 ft in mixed northwest swell and northeast wind waves. The strongest trade winds will decrease in coverage and shift westward during the next couple of days. Fresh trades will remain from 07N to 20N west of 122W, with 8-10 ft seas in mixed northeast waves and northwest swell. A very active jet stream branch is rounding the base of the trough across northwest Mexico. Strong west to southwest winds are transporting abundant tropical moisture into central Mexico north of 17N. Scattered showers are possible with this moisture plume. Considerable mid-upper level cloudiness is being advected to the northeast with the jet stream. The upper trough will move eastward during the next couple of days as high pressure builds eastward behind the previously mentioned cold fronts. Looking ahead, northwest swell with seas to 8-12 ft associated with a front moving eastward across the waters north of 25N Wednesday and Thursday will be followed by a second front expected to sweep southeastward into northern waters Thursday night and Friday. Wave model guidance shows large northwest swell will propagate southeastward into the waters north of 20N behind the second front, with seas building to 15-20 ft in the far northern waters east of 130W late Friday into Saturday. $$ Mundell