000 AXPZ20 KNHC 110856 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Mon May 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 0600 UTC surface analysis and satellite imagery through 0830 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A ridge across the eastern slopes of the Sierra Madre Mountains in Mexico supports a late season Gulf of Tehuantepec event. Around 0400 UTC, a scatterometer pass confirmed the presence of fresh to strong northerly winds across the Tehuantepec region. Winds will increase to minimal gale force late tonight through Mon morning, then diminish below gale force by early Mon afternoon. Fresh to near gale force winds are forecast to persist through Tue morning. Peak seas with this gale event will build to 12 to 13 ft by this morning. Climatologically, the final gale-force event occurs in late March or early April. Only a couple of Tehunatepec events have been detected in May since the 1999-2000 season, one in 2003, and the second one in 2006. Please, see latest NWS High Seas Forecast issued by National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from northern Colombia to 08N83W to 11N95W to 09N110W. The ITCZ continues from 09N110W to 06N125W to beyond 07N140W. Scattered moderate to isolated strong convection is seen from 05N to 12N between 90W and 113W. Clusters of moderate to strong convection are noted from 01N to 08N E of 80W to the coast of Colombia, and N of 11N between 88W and 91W, including most of El Salvador and SE Guatemala. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please read the Special Features section for more details about the Gulf of Tehuantepec Gale Warning. A ridge dominates the offshore forecast waters west of Baja California producing gentle to moderate NW-N winds, with seas of 5 to 7 ft in mixed long period SW and NW swell. Little change in this weather pattern is expected over the next several days. Gentle to moderate southerly winds will prevail across the Gulf of California. Building high pressure over the Pacific waters may strengthen NW winds west of Baja California Wed night into Thu, mainly N of Cabo San Lazaro. These winds may help to build seas to 7 to 9 ft west of Baja California Norte by Thu night. Long period SW swell is forecast to reach the coast of Mexico between the Tehuantepec region and Cabo Corrientes on Thu followed by a stronger one and the end of the week. Haze and areas of smoke from agricultural fires in Mexico may reduce visibilities near the coast from the Tehuantepec region to near Cabo Corrientes. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh NE to E winds are expected in the Papagayo region tonight, and again Tue night as high pressure builds N of area. Elsewhere, a weak pressure gradient will support light to gentle winds during the next several days. Long period SW swell will continue to impact the offshore waters of Central America, Colombia and Ecuador today before gradually fading. Another cross equatorial swell event will reach the waters between Ecuador and the Galapagos Islands on Wed, followed by a second and more impressive SW swell event by the end of the week. The Sangay Volcano located in Ecuador near 02S78W is producing a plume of volcanic ash that extends westward over land reaching the vicinity of the Gulf of Guayaquil. The Satellite Analysis Branch (SAB) in Washington continues to issued Volcanic Ash Advisories. REMAINDER OF THE AREA... A weak 1019 mb high pressure located near 28N127W extends a ridge across the northern waters to near the Revillagigedo Islands. Gentle to moderate trades prevail with a fairly week pressure pattern in place N of the ITCZ. Long period SW swell will continue to impact the waters roughly from 08 to 11N between 98W and 106W. Seas are to 8 ft in this area. This swell will gradually subside today. A cold front is moving across the NW corner of the forecast area. A set of long period NW swell, with building seas of 8 to 10 ft will follow the front. Seas will subside to less than 8 ft on Tue. The front will move eastward across the northern forecast waters over the next couple of days while dissipating. $$ GR