000 AXPZ20 KNHC 070957 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Fri Apr 07 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. ...SPECIAL FEATURE... GULF OF TEHUANTEPEC GALE WARNING... Post-frontal high pressure over the SW Gulf of Mexico will continue to support gale force winds of 30 to 40 kt across the Gulf of Tehuantepec through this morning, with maximum seas of 15 ft developing downstream of the Gulf waters near 14.5N95.5W. These winds will diminish to just below gale force briefly late in the morning, then increase again to minimal gale force this evening, and continue to around sunrise on Sat. Expect only fresh N winds by late Sat afternoon with these conditions continuing through sunrise on Sun. The resultant N to NE swell, in the form of 8 ft seas or greater, will propagate SW mixing with long period cross-equatorial SW swell, reaching as far s as 08N between 98W and 104w tonight before beginning to subside. Expect all associated seas to subside to less than 8 ft on Sat night. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A 1009 mb surface low is over NW Colombia near 10N75W with a surface trough extending sw along 06N77.5W TO 05.5N88W TO 06N100W, where scatterometer winds indicate that the ITCZ forms and continues WSW to 02.5N117W TO 03N130W TO 01N140W. Scattered moderate to strong convection is observed within 60 nm N and 270 nm S of the trough between 86W and 100W, and within 270 nm N of the ITCZ between 100W and 124W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See special features above for on the ongoing Gulf of Tehuantepec gale force gap wind event. Broad surfacing ridging extends e across the offshore waters w of the Baja Peninsula, with gentle to moderate n flow expected through Sat afternoon. A dissipating cold front sweeping east across the northern waters to the west will move through the area, with high pressure behind the dying front to gradually tighten the pressure gradient Saturday through early Monday. This will increase the nw flow to a fresh to locally strong breeze which will spread se across all waters w of the Baja Peninsula throughout Sat night, with seas building to 6 to 9 ft. The gradient will slowly relax Sun night through Monday, with moderate to locally fresh nw flow expected early next week. Gulf of California: Light and variable winds are expected through early Saturday until the pressure gradient W of the peninsula tightens over weekend, and fresh to strong NW to W winds begin to spill into the Gulf through gaps in the hills of the peninsula. Fresh to strong NNW winds are expected across N portions of the Gulf by early Sunday and will spread S during the day Sunday to near 26N before diminishing by late evening. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh to locally strong nocturnal drainage winds are expected through Sat night with the resultant NE swell propagating WSW to as far SW as 08N92W on Sat. Gulf of Panama: Moderate to fresh northerly nocturnal flow is expected during the overnight hours through the middle of next week. Light to gentle winds, and combined seas of 3 to 5 ft, are occurring elsewhere outside of the swells originating near the gap events. REMAINDER OF THE AREA... Moderate to locally fresh ne trades expected across the tropics from 05N to 15N w of 110W with the NE wind waves resulting in an area of 6 to 9 ft combined seas forming across the tropics from 06N to 15N W of 122W over the upcoming weekend. A series of weak colds fronts will dip into the nw waters and sweep eastward across the northern waters, accompanied by a strong sw-w-nw wind shift across the discussion waters n of 30N. Large post frontal nw swell in the form of combined seas of 8 to 12 ft to the S of 30N, and 10 to 14 ft between 30N and 32N, will propagate E and cross 120W tonight as the seas subside from the west. By Sun night expect 6 to 9 ft seas across the entire area waters w of 110W. $$ Stripling