000 AXPZ20 KNHC 130349 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 349 UTC Thu Aug 13 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... Gale Warning: Post-Tropical Cyclone Elida is centered near 24.4N 120.2W at 13/0300 UTC moving NW at 8 kt. Estimated minimum central pressure is 1004 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Showers and thunderstorms have largely dissipated, but winds to gale force may linger a few more hours. Therefore a gale warning is in place near the center of the low pressure until it weakens further later in the morning. Large seas will also persist within 60 to 90 nm of the center through much of Thu. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPEP4.shtml and Forecast/ Advisory at https://www.nhc.noaa.gov/text/MIATCMEP4.shtml for more details. Satellite imagery indicates that the area of low pressure near 13N128W, or about 1300 miles southwest of the southern tip of the Baja California peninsula continues to become better defined. The associated shower and thunderstorm activity is also showing some signs of organization. Conditions are expected to remain conducive for additional development, and there is a high chance a tropical depression will form tonight or Thursday while the system moves slowly west-northwestward. A large area of disturbed weather associated with a tropical wave along 102W/10W extends several hundred miles southwest of the southwestern coast of Mexico. Scattered moderate to isolated strong convection is noted from 10N to 12N between 100W and 105W. Environmental conditions appear conducive for development, and a tropical depression is expected to form within the next few days before the system reaches cooler waters later this weekend. This system is forecast to move west- northwestward at about 10 to 15 kt away from the coast of southwestern Mexico. Expect fresh to near gale force winds and building seas to 12 or as high as 15 ft Fri and Sat, though this may need to be boosted significantly if the system does develop into a tropical cyclone. Regardless of tropical development, this system is expected to affect the offshore waters from Acapulco to Cabo Corrientes through tonight, then between Socorro Island and Cabo San Lucas tonight through Sat. ...TROPICAL WAVES... A tropical wave is analyzed along 85W, north of 02N through Costa Rica, moving west at 10 to 15 kt. Scattered moderate convection is noted within 30 nm of the coast of Costa Rica. An area of low pressure is expected to form along the wave axis in a few days over the far eastern portion of the basin to the south of the coast of Central America. Conditions are expected to be conducive for development, and a tropical depression could form this weekend or early next week while it moves generally west- northwestward just offshore the coast of Mexico. At a minimum, heavy rainfall is possible over Costa Rica and Panama into Fri. Please the Special Features section above for more information on the tropical wave along 102W/103W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N78W to 09N90W to 11N113W, and from 16N116W to 1005 mb low pressure near 13N128W to 12N140W. Scattered moderate to isolated strong convection is noted from 10N to 12N between 100W and 105W. Scattered moderate convection is noted from 09N to 11N between 111W and 115W. Scattered moderate to isolated strong convection is observed from 11N to 13N between 127W and 129W, and from 10N to 12N between 135W and 138W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... The impacts of Elida on waters off Baja California are diminishing as the storm gradually dissipates west of the area. However, swell associated with Elida of 6 to 8 ft are likely tonight through the early morning from Cabo San Lazaro to Punta Eugenia beyond 210 nm. Farther south, an earlier ship observation indicated 25 kt winds off the coast of Michoacan. This is evidence fresh to strong winds are developing off the coast between Acapulco and Cabo Corrientes related to the developing area of low pressure farther off the coast. Please see the Special Features section for more on this. Farther south, lower pressures over the eastern Pacific will encourage fresh to strong gap winds to pulse into the Gulf of Tehuantepec into early next week. Seas should peak to near 9 ft in the Gulf of Tehuantepec accordingly. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... A moderate north-south pressure gradient across Central America will promote fresh to strong NE winds across the Gulf of Papagayo during the overnight hours through the end of the week. Moderate to fresh southerly winds will persist south of the monsoon trough through Saturday. An area of low pressure is expected to form in a few days over the far eastern portion of the basin to the south of the coast of Central America. Seas up to 9 feet will be possible west of Panama and Costa Rica. As stated above, environmental conditions appear conducive for development, and a tropical depression is expected to form during the next few days before the system reaches cooler waters over the weekend. This system is forecast to move west-northwestward at about 15 mph away from the coast of southwestern Mexico. Even if this does not occur, expect locally heavy rainfall over portions of Panama and Costa Rica. REMAINDER OF THE AREA... Please see the special features section above for more information about Tropical Storm Elida and two possible developing low pressure systems. The subtropical ridge dominates the waters north of 20N. No significant winds are noted, but NW swell to 8 ft will remain in the area through this evening. Elsewhere moderate north-south pressure gradient between the high and the monsoon trough is promoting generally gentle to moderate NE winds across the waters. Fresh SW flow south of the monsoon trough will increase to fresh to strong through this evening, with seas building to 8 to 9 ft, before diminishing later in the week. $$ Christensen