745 AXPZ20 KNHC 311010 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 843 UTC Sun May 31 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 0930 UTC. ...SPECIAL FEATURES... ...Heavy rainfall in Central America... A Central American Gyre is over the eastern North Pacific, with the broad cyclonic circulation around the gyre encompassing the discussion waters N of the equator and E of 98W, including portions of southern Mexico and Central America. Moderate to strong winds are noted across much of these waters, with seas in the 6-10 ft range. Numerous moderate and scattered strong convection is noted across much of these waters, particularly N of 10N between 86W and 97W. Areas of thunderstorms are impacting portions of Central America from Nicaragua northwestward to Southern Mexico and the Gulf of Tehuantepec. The gyre will move slowly northward, gradually encompassing much of Central America and southern Mexico within the next 24-48 hours. Winds around the gyre will continue to advect abundant moisture into portions of Central America and southeastern Mexico for the next several days. This will create a dangerous situation for these areas with an extended period of active and wet weather, and periods of heavy rainfall, through the weekend and into next week, especially over southern Guatemala, El Salvador, southern Honduras, western Nicaragua, and portions of southern Mexico E of Veracruz and eastern Oaxaca. This will bring the potential for life- threatening flash floods and mudslides for locations that receive the heaviest rainfall, especially in areas of mountainous terrain. Please refer to products issued by your local weather service for more details. ...Tropical Storm Amanda... Tropical Depression Two-E has intensified within the gyre circulation overnight to minimal Tropical Storm Amanda, centered near 13.8N 90.4W at 0900 UTC moving NNE at 8 kt. Amanda will continue to move NNE and inland over Guatemala later today and then gradually dissipate over the mountainous interior Sun night. As this small system is embedded within the larger gyre, the main impacts from Amanda will be to focus locally heavy rains near the center as it moves toward the coast. A cluster of strong convection with Amanda is currently from 12.5N to 14.5N between 89W and 91W, and producing torrential rainfall across Guatemala and western El Salvador. After Amanda moves ashore today, the larger threat will continue to be the Central American Gyre, which will linger across Central America and southern Mexico well after Amanda dissipates. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from the Gulf of Honduras SW across Central America to TS Amanda near 13.8N90.4W to low pres near 07N121W to low pres near 10N130W TO 08N140W. Scattered moderate to strong convection is noted from 05N TO 10N E OF 105W, and from 04N TO 08.5N between 105W AND 127W. Scattered moderate isolated strong convection is from 06.5N TO 10N between 134W AND 140W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for more details on the Central American Gyre, and embedded TS Amanda. The pressure gradient between a ridge of high pressure along the eastern slopes of the Sierra Madre Oriental and the Central American Gyre is producing gap winds to just below gale force across the Gulf of Tehuantepec tonight. These NNW winds will continue in a narrow plume through this morning to near 30 kt. The area of high pressure will weaken enough to allow winds to gradually diminish below 25 kt by early Monday. Outside of the winds and seas associated to those features, fresh to locally strong winds prevail off Baja California Norte while fresh winds turn cyclonically off Cabo San Lucas. Gentle winds prevail elsewhere. Seas are in the 6-8 ft range over the open waters off Mexico, and in the 1-3 ft range over the Gulf of California. The Central American Gyre is progressing across the forecast waters toward the northern portion of Central America and southern Mexico. TS Amanda will move inland over Guatemala today. These features will bring active weather over southern Mexico offshore waters this weekend into early next week. In addition, there will be strong winds over the Gulf of Tehuantepec tonight. Elsewhere, high pressure will build over the northern waters. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please see the Special Features section for more details on the Central American Gyre, and embedded TS Amanda. Outside of winds and seas associated to the Central American Gyre and TS Amanda, moderate to fresh winds prevail N of 02N, and gentle to moderate winds S of 02N. Seas in the 5-8 ft range prevail across the area. The Central American Gyre is progressing across the forecast waters toward the northern portion of Central America and southern Mexico. TS Amanda will move inland over Guatemala today and produce torrential rainfall near the center. Hazardous marine conditions will prevail over the forecast waters west of Costa Rica and northward to Guatemala through early next week, with large clusters of thunderstorms, fresh to strong winds, and building seas. Elsewhere, long-period SW swell will continue propagating across the region through early next week. REMAINDER OF THE AREA... High pressure has started to slowly build across the northern waters. The pressure gradient between the building high pressure and low pressure within the monsoon trough is supporting moderate to locally fresh winds N of the monsoon trough to near 10N and W of 126W. Light to gentle winds prevail elsewhere N of the monsoon trough. Moderate to fresh southerly winds prevail S of the monsoon trough between 103W and 121W, where seas are 7-8 ft. Light to gentle southerly winds prevail elsewhere W of 121W. Seas over the discussion area are in the 5-7 ft range. A high pressure ridge will continue to build across the northern waters this weekend, with little change in marine conditions expected over these outer waters over the next couple days. $$ Stripling