000 AXPZ20 KNHC 101641 AAA TWDEP Tropical Weather Discussion...Updated NWS National Hurricane Center Miami FL 1605 UTC Sun May 10 2020 Updated for Sangay Volcano over Ecuador 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 1445 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. Northerly gap winds have increased to fresh to near gale force this morning, 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 12 to 13 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. Volcanic Ash Advisory: Sangay Volcano located in Ecuador near 02S78W is in a state of unrest and producing volcanic ash per the Satellite Analysis Branch in Washington, D.C. and per latest high resolution satellite imagery. The plume is extending offshore of Ecuador, including in the vicinity of the Gulf of Guayaquil. While there have been no reports of volcanic ash reaching the surface or reduced visibilities, mariners are still urged to exercise caution and report any observations to the National Hurricane Center by calling 305-229-4424. 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 1010 mb low pressure over northern Colombia near 10N76W to 09N90W to 09N100W. The ITCZ continues from 09N100W to 07N120W to beyond 06N140W. Scattered moderate to strong convection is noted along and offshore of the Pacific coast of Colombia from 02N to 09N between 77W and 80W including the Gulf of Panama, within 11N93W to 05N92W to 02N96W to 06N100W to 02N107W to 09N113W to 11N93W, and from 11N to 13N between 98W and 107W. Scattered moderate and isolated strong convection is noted from 03N to 07N between 113W and 120W, from 04N to 07N between 123W and 129W, and from 10N to 13N between 120W and 127W. Isolated moderate to strong convection is within 180 nm SW of Central America from western Panama to Nicaragua. 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. Seas of 8 ft in SW swell are noted between the Revillagigedo and Clarion Islands per altimeter data. Seas will subside to less than 8 ft later today. Gentle to moderate southerly winds will prevail across the Gulf of California. On Thu, building high pressure over the Pacific may strengthen NW winds west of Baja California. 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... Please read the Special Features section for more details about the Volcanic Ash Advisory for offshore 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 today before gradually fading. Looking ahead, another impressive SW swell event may approach SW of the Galapagos Islands by the end of the week. REMAINDER OF THE AREA... A weak 1018 mb high pressure located near 30N129W 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 roughly the waters from 03N to 15N between 95W and 115W, and from 15N to 20N between 100W and 110W, including near cabo Corrientes. Peak seas are 8 to 9 ft in this area per earlier altimeter data. This swell will gradually subside through Mon. A complex low pressure system north of the area extends a weak cold front through 32N137W to 29N140W, with a second trailing front NW of the area. The fronts will merge SE of 30N140W by late tonight, then will gradually weaken through the middle of the week. A set of long period NW swell will follow the merged fronts, building seas subside to less than 8 ft during the day Tue. A fairly weak pressure pattern will continue to prevail through the week with mainly gentle to moderate trades. $$ Lewitsky