000 AXPZ20 KNHC 080222 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Sat Apr 08 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 0215 UTC. ...SPECIAL FEATURE... GULF OF TEHUANTEPEC GALE WARNING... Minimal gale force northerly winds currently across the Gulf of Tehuantepec will diminish to near gale force late tonight, and continue to diminish throughout Sat, with one last brief strong surge expected on Sat evening. Seas are expected to build to about 11 ft downstream of the Gulf waters near 15N95W tonight. The resultant 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 late tonight before beginning to subside. Expect all associated seas to subside to less than 8 ft on Sat evening. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 05N83W to 03N92W to 04N111W where scatterometer winds indicate that the ITCZ forms, and continues w to 02N125W to 04N140W. Scattered moderate isolated strong convection is observed within 120 nm either side of a line from 05N82W to 02N98W, within 210 nm of 07.5N108W, and within 60 nm of 08.5N127W. ...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 is expected through Sat afternoon. A tightening pressure gradient will then increase the nw flow to a fresh to locally strong breeze across the waters n of 28N e of 120W, with these conditions forecast to spread se across all waters w of the Baja Peninsula throughout Sat night, with seas building to 6 to 9 ft by Sun morning. The gradient will relax on Sun night, with moderate to locally fresh nw flow expected through the middle of next week as seas gradually subside to less than 8 ft on Wed night. Gulf of California: Light and variable winds expected through late Sat night, except moderate southerly nocturnal winds are forecast across the waters to the n of 30N. The low level winds will gradually shift to the nw and increase to a moderate to fresh breeze across the waters n of 26N on Sun. These nw winds should diminish to a gentle breeze on Mon night. Smoke from agricuture fires over interior Mexico is observed on high resolution satellite imagery across the offshore waters to the n of 10N between 92W and 100W, and is estimated to be locally reducing surface visibility to 3 to 5 nm. Expect improvement in conditions in about 24 hours. 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 expected through Sat night with the resultant ne swell propagating wsw to as far sw as 08N92W on Sat afternoon. Gulf of Panama: Fresh to locally strong nocturnal northerly flow 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... A cold front will sweep e accompanied by a strong sw-w-nw wind shift across the discussion waters n of 30N, and a fresh wind shift across the waters from 28N to 30N. Large post frontal nw swell, in the form of combined seas of 8 to 13 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 w. By Sun night expect 6 to 9 ft seas across the subtropical waters w of 110W. A batch of nw swell, in the form of 7 to 10 ft seas, will propagate into the far nw portion on Sun night ahead of a cold front reaching from 32N138W to 29N140w late Mon night. 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 8 ft combined seas forming across the tropics from 06N to 11N w of 128W this weekend and continuing into early next week. $$ Nelson