000 AXPZ20 KNHC 010347 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Wed Mar 1 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 0000 UTC surface analysis and satellite imagery through 0330 UTC. ...Special Features... Gulf of Tehuantepec Gale Warning: Very strong high pressure will build southward in the wake of a strong cold front that will move across the Gulf of Mexico and reach the southwest Bay of Campeche by Thursday. A very tight pressure gradient will set up between the front and the high leading to minimal gale force north winds to funnel through the Chivela pass into the Gulf of Tehuantepec beginning on Thursday night and through Saturday morning. Seas are expected to build to around 13 ft Thursday night, and possibly to 16 ft on Friday. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The ITCZ/Monsoon Trough is not presently identifiable. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... The fresh to locally southwest winds earlier over the far northern Gulf of California have diminished to moderate to fresh winds as indicated by the 1654Z Ascat pass from Tuesday afternoon. These winds are ahead of a weakening cold front that extends from far northwestern Mexico southwest to across Baja California Norte and continues southwest to 28N111W and to 26N115W. The cold front will begin to dissipate from near Cabo Corrientes to 18N115W by early Wednesday afternoon and become diffuse by early Wednesday evening. Wave model guidance suggests that northwest swell producing seas to 8-9 ft will begin to propagate through the waters off Baja California Norte, primarily in the northwest portion of zone PMZ011 beginning late tonight and through Wednesday afternoon before subsiding Wednesday night as swell energy decays. Strong high pressure building north of the area over the Great Basin will induce strong northwest winds along the length of the Gulf of California from late Wednesday afternoon into early Friday morning, with seas reaching 8 ft in the southern Gulf of California Thursday. The pressure gradient will weaken across the region later this week, with winds and seas diminishing Friday and Saturday. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo...Winds will pulse over the area the next couple of days. Winds will peak near 25 kt during the late night and early morning hours, and will diminish to 20 kt or less during the early evening hours. These winds are expected to expand northward to near 12N, southward to 10N and westward to near 91W. Seas with these winds will build to around 9 ft per Wave model guidance. Gulf of Panama...Winds will freshen each night before diminishing during the late afternoon hours. Elsewhere, light to gentle breezes will persist through Thursday. REMAINDER OF THE AREA... A cold front extends from Baja California Norte southwest to 28N111W to 26N115W and to 22N125W where it becomes a dissipating stationary front to 19N120W to 18N140W. A broad area of mainly northwest swell, with seas in the 7-9 ft range is present throughout much of the northern and central forecast waters. High pressure builds is building north of the region. The associated pressure gradient between it and lower pressure in the tropics is forecast to increase the trade winds from 21N to 23N between 126W and 135W beginning early Wednesday afternoon, with winds there reaching the strong range and combined seas building up to 10 ft. By Thursday afternoon, these winds are expected to be confined over an area from 20N to 24N west of 132W. The combination of northeast wind waves with persistent long-period northwest swell will support combined seas of 8 to 10 ft over much of the region north of about 04N and west of 118W Wednesday and Thursday. The northwest swell will begin to mix with a north component on Wednesday over the western section of the area. Winds will diminish slightly across the region by Friday, allowing seas to subside from east to west below 8 ft through Saturday. $$ Aguirre