000 AXPZ20 KNHC 110323 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 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 0000 UTC surface analysis and satellite imagery through 0300 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: High pressure building across the eastern slopes of the Sierra Madre Mountains in Mexico will promote a late season Gulf of Tehuantepec event. Fresh to strong northerly gap winds are already blowing across the Tehuantepec region, and will increase to minimal gale force late tonight through Mon morning. Winds will diminish below gale force by early Mon afternoon with fresh to near gale force winds continuing through Tue morning. Peak seas with this gale event will build to 13 to 14 ft by early Mon 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 a 1008 mb low pressure over northern Colombia to 09N83W to 08N90W to 10N104W. The ITCZ continues from 10N104W to 10N110W to 06N125W to beyond 07N140W. Scattered moderate to strong convection is seen from 07N to 13N between 94W and 112W. Clusters of moderate to strong convection are noted along the coast of Colombia, over the Gulf of Fonseca, and over the eastern part of El Salvador and coastal waters. 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 will continue to impact the offshore waters of Mexico through Monday. Another long period SW swell event is forecast to reach the coast of Mexico between the Tehuantepec region and Cabo Corrientes on Thu. 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 winds are expected in the Papagayo region by Mon 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 before gradually fading. Looking ahead, another impressive SW swell event may approach SW of the Galapagos Islands 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 07 to 10N between 97W and 107W. Peak seas are 8 to 9 ft in this area. This swell will gradually subside through Mon. A cold front has reached the far NW corner of the forecast area. A set of long period NW swell with building seas of 8 to 9 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 while dissipating. A fairly weak pressure pattern will continue to prevail through the week with mainly gentle to moderate trades. $$ GR