566 AXPZ20 KNHC 280241 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Mon Sep 28 2020 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 0240 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec gale warning: A strong gale force gap wind event is expected across the Gulf of Tehuantepec Tue night through Fri as cold front moves across the Gulf of Mexico. Marine guidance suggests N winds blasting across the Tehuantepec waters late Tue afternoon and quickly increasing to 30 to 45 kt Tue night with seas building up to 16 or 17 ft. Of note, the 20-year climatology of the Tehuantepec gap wind events indicates that on average 16 gale-force events and 5 storm force-events occur in the Gulf of Tehuantepec each cold season. Most gale-force events occurred during November and December, while most storm-force winds occurred in January. Based on latest model trends and the present evolving synoptic scale setup, it appears that the forecast gale to near strong force wind event may supersede the previously recorded earliest start date of October 3rd. Tropical cyclone potential: Low pressure centered near 12.5N104W is producing a large area of disorganized cloudiness and thunderstorms. The disturbance is forecast to move generally westward for the next several days, and environmental conditions are expected to gradually become more conducive for a tropical depression to form around midweek. There is currently a medium probability of tropical cyclone development in the next 48 hours, and a high chance for formation in the next 5 days. Please see the latest eastern north Pacific Tropical Weather Outlook for more information. ...TROPICAL WAVES... The axis of a tropical wave is near 99W N of 03N, moving westward at 5 to 10 kt. Associated convection is described below. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N85W to low pres near 12.5N104W to 11N140W. Scattered moderate isolated strong convection is noted from 09N to 17N between 94W and 107W, and from 08N to 11N between 110W and 140W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see above for more on the Gulf of Tehuantepec gale force gap wind event. A weak ridge west of Baja California will maintain gentle to moderate NW to N winds across the region for the next few days. Northwesterly swell propagating through the waters off Baja California the past 48 hours has peaked and has started to subside this afternoon. However, new north swell has moved into the northern waters this afternoon, maintaining seas of 7-9 ft. Light to gentle southerly winds will prevail across the Gulf of California through Mon afternoon before shifting to the north. Elsewhere, light to gentle winds are generally expected across the waters from Las Tres Marias to Puerto Angel for the next several days. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Moderate southerly flow prevails S of the monsoon trough, with gentle winds north of the monsoon trough. Combined seas are currently 5 to 7 ft in a mix of wind waves and southerly swell. Long period SW swell is moving over the waters between Ecuador and the Galapagos Islands, with seas to 8 ft. This swell will continue to propagate northward and reach the offshore waters of Central America tonight through Mon, where seas will build to 6 to 8 ft. REMAINDER OF THE AREA... Please see Special Features section above for tropical cyclone potential. West of 120W, moderate N to NE winds prevail with seas 7-9 ft in NW to N swell. Southerly swell has propagated N of the equator, where seas of 8-10 ft will prevail between 100W and 120W through Mon. Seas will gradually subside across the waters S of 20N and E of 120W by the middle of the week. $$ AL