427 AXPZ20 KNHC 120321 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 321 UTC Fri Jun 12 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 0300 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A Tehuantepec gap wind event is starting 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 farther to the south, which will support strengthening northerly gap winds. Expect strong to near gale- force winds to prevail in the Tehuantepec region to persist through early next week, with a brief period of marginal gale- force winds expected late tonight. Combined seas will build to 8-12 ft by 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 north of 03N along 80W across central Panama into the southwest Caribbean Sea, moving west at 10 to 15 kt. No significant convection is noted with this tropical wave. A tropical wave extends along 95W, moving west around 10 to 15 kt. Scattered moderate convection is from 07N to 10N between 88W and 94W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from near 11N86W to 11N120W. The ITCZ continues from 11N120W to 1011 mb low pressure near 11N130W to beyond 11N140W. Scattered moderate and isolated strong convection is noted within 60 nm off the coast from central Nicaragua to central El Salvador. Scattered moderate convection is from 07N to 10N between 88W and 94W. 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 waters north of 20N. Earlier scatterometer data shows 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 per earlier altimeter data and ship observations, and 3 ft or less inside the Gulf of California. Hazy conditions may linger offshore of Baja California Norte this evening due to smoke from nearby inland fires. Winds off Baja California will strengthen Fri night into this weekend as a reinforcing 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... Moderate to locally fresh S to SW flow prevails south of the monsoon trough per recent scatterometer data. Long-period southerly swell persists across the offshore waters this afternoon with wave heights of 7-9 ft between the Galapagos Islands and Ecuador. North of the monsoon trough, winds remain mainly 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, then decaying Tue before the next set arrives later in the week. REMAINDER OF THE AREA... A broad high pressure ridge remains across the forecast waters roughly north of 20N and west of 100W. Moderate to fresh trades are occurring west of 130W between the ridge and the ITCZ. A mix of NE wind waves and SE to S swell is likely maintaining 7-9 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. Farther east, moderate to locally fresh 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 8-10 ft seas south of the monsoon trough between 90W and 105W. This swell will gradually decay over the next couple days, allowing wave heights to subside below 8 ft by Fri night. Looking ahead, a broad 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 only marginally conducive, and any development should be slow to occur through early next week while the system moves west-northwestward. There is a low chance of tropical cyclone formation within the next five days. $$ Christensen