000 AXPZ20 KNHC 111552 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Thu Jun 11 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A Tehuantepec gap wind event is expected to begin this afternoon as a cold front crosses the western Gulf of Mexico. An enhanced pressure gradient will develop between building high pressure across eastern Mexico and lower pressures associated with the monsoon trough, which will support strengthening northerly gap winds. Expect strong to near gale-force winds to prevail in the Tehuantepec region tonight through early next week, with a brief period of marginal gale- force winds expected late tonight. Combined seas will build to 8-12 ft early Fri in mixed northerly wind waves and southerly swell. Please see the latest NWS High Seas Forecast at https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for details. ...TROPICAL WAVES... A tropical wave extends along 92W/93W, moving west around 10-15 kt. Scattered moderate and isolated strong convection is noted from 10N to 14N between 90W and 95W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from northern Colombia near 11N74W to 11N100W to 10N116W. The ITCZ extends from 10N116W to 10N120W, then resumes from 10N125W to 10N140W. Scattered moderate and isolated strong convection is noted from 10N to 12N between 85W and 90W, from 08N to 11N between 94W and 98W, from 05N to 08N between 97W and 100W, from 08N to 11N between 106W and 111W, and from 07N to 12N between 124W and 140W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for more details about the Gulf of Tehuantepec Gale Warning. A weak high pressure ridge persists across the northern waters. Light to gentle winds prevail across the forecast waters under a weak pressure pattern. Wave heights are generally 4-7 ft over the offshore waters, and 3 ft or less inside the Gulf of California. Hazy conditions may linger offshore of Baja California Norte today due to smoke from nearby inland fires. Winds off Baja California will strengthen Fri night into this weekend as a high pressure ridge builds eastward over the region. A brief period of fresh SW gap winds is expected Fri night over the northern Gulf of California. Increasing NW swell will build wave heights to 8-9 ft in the Baja California Norte waters this weekend. Marine conditions will improve early next week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Volcanic Ash from the Sangay Volcano in Ecuador may impact the area around the Gulf of Guayaquil today. Mariners in the vicinity are urged to exercise caution. Gentle to locally moderate S to SW flow prevails south of the monsoon trough. Long-period southerly swell persists across the offshore waters this morning with wave heights of 7-9 ft between the Galapagos Islands and Ecuador. North of the monsoon trough, winds remain light and variable and seas are running 5-7 ft in southerly swell. Cross-equatorial S to SW swell will continue impacting the region while gradually decaying through Fri. Fresh winds will pulse across the Papagayo region tonight and Fri night. Wave heights will briefly subside this weekend, before another set of southerly swell crosses the region late Sun through Mon. REMAINDER OF THE AREA... A broad high pressure ridge remains across the forecast waters roughly north of 15N and west of 100W. Moderate to fresh trades are occurring west of 130W between the ridge and the ITCZ, except locally strong near 13N138W. A mix of NE wind waves and SE to S swell is likely maintaining 7-10 ft seas in this region. Little change is expected over the next couple days as a weak low pressure or a trough moves along the ITCZ and supports fresh winds and locally higher seas west of 135W. Elsewhere, moderate southerly flow prevails south of the monsoon trough/ITCZ. Long-period southerly swell still dominates the waters south of 15N and east of 110W, with 8-9 ft seas south of the monsoon trough between 90W and 100W. This swell will gradually decay over the next couple days, allowing wave heights to subside below 8 ft by Fri night. Looking ahead, an area of low pressure is forecast to form well south or south-southwest of the southern tip of Baja California Sur this weekend. Environmental conditions are expected to be conducive for some gradual development of this system early next week while it moves west-northwestward away from Mexico. There is a medium chance of tropical cyclone formation within the next five days. $$ Lewitsky