000 AXPZ20 KNHC 252148 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Wed Oct 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 1800 UTC surface analysis and satellite imagery through 2145 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Strong gale force northerly drainage winds, with seas to 23 ft, are forecast to gradually diminish overnight to below gale force around midday Thu, and gradually diminish to 20 kt or less early Fri. The resultant large NE swell continues to mix with long period cross- equatorial southerly swell, with a plume of seas 12 ft or greater reaching as far S as 06N between 93W and 101W overnight, with these seas gradually subsiding thereafter. Strong N winds will resume in the Gulf of Tehuantepec on Fri night, and increase to minimal gale force around sunrise on Sat, with gale conditions persisting through late Sun night. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 12N86W to 08N98W to 11N108W to 07N140W. Scattered moderate isolated strong convection is observed within 150 nm either side of a line from 06N83W to 10N88W to 11N108W to 08N120W to 09N130W to 07N140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of Tehuantepec: please see the special features section above for information on a strong gale event. Gulf of California: Light and variable winds expected through midday Fri, then a moderate NW breeze is forecast through the upcoming weekend. A surface ridge extends into the area along 22N116W to 22N110W. Light to gentle anticyclonic winds will accompany the ridge through the weekend. Mixing long period NW swell and cross- equatorial southerly swell results in 5 to 8 ft seas elsewhere across the open waters W of the Gulf of Tehuantpec event, or W of about 98W. These seas will gradually to less than 8 ft tonight. The next batch of long-period NW swell, in the form of 8 ft seas or greater, will arrive at 30N120W late Sat and reach the Pacific coast of the Baja Peninsula on Sat night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gentle N winds and 5 to 8 ft seas will continue N of 09N tonight, then increase to a moderate NE breeze on Thu as a tropical low develops off the Pacific coast of Costa Rica. Fresh to locally strong southerly winds, and 7 to 10 ft seas, are expected S of 09N tonight, with these conditions expected within about 180 nm of the developing low pressure on Thu. The low is forecast to move northwestward through the upcoming weekend, with the possibility of tropical cyclone formation in a couple of days. REMAINDER OF THE AREA... A broad ridge dominates the EPAC waters N of 15N W of 115W accompanied by gentle to moderate anticyclonic flow and combined seas of 6 to 9 ft in mixing cross-equatorial southerly swell and long period NW swell. These seas will gradually subside t o less than 8 ft on Thu. A new batch of long-period NW swell in the form of 8 ft seas will arrive at 32N140W early Fri. Expect seas of 8 to 13 ft W of a line from 32N125W to 14N140W early Sat, before beginning to subside. However, seas of 8 to 9 ft are expected W of a line from 32N116W to 05N140W early Sun. $$ Nelson