000 AXPZ20 KNHC 221603 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Wed Sep 22 2021 Tropical Weather Discussion for the eastern Pacific Ocean from 03.4S to 30N, east of 120W including the Gulf of California, and from the Equator to 30N, between 120W and 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 1500 UTC. ...SPECIAL FEATURES... A Gale Warning is in effect for the Gulf of Tehuantepec tonight into Thu. High pressure building across the eastern slopes of the Sierra Madre Mountains, in the wake of an early cold front, currently moving across the NW Gulf of Mexico, will support the first gap wind event in the Tehuantepec region this season. Winds are forecast to reach minimal gale force tonight into Thu. Seas are expected to build to 9-11 ft with this event. Please, refer to the latest NWS High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. A broad and elongated area of low pressure located several hundred miles southwest of the southern tip of the Baja California peninsula continues to produce disorganized showers and thunderstorms. A 1011 mb low pressure is analyzed on the 1200 UTC surface map near 15N121W. Scattered moderate to isolates strong convection is noted within about 120 nm NW quadrant of center. Environmental conditions are somewhat conducive for development, and a short- lived tropical depression could form on Thursday or Friday while the low moves generally northwestward at 10 to 15 mph. This system is forecast to move over cooler waters and into an environment of stable air and strong upper- level winds this weekend, which should inhibit further development. The latest Tropical Weather Outlook gives this system a medium chance of tropical cyclone formation through 48 hours. Please, refer to the latest Tropical Weather Outlook, at www.hurricanes.gov for more details. ...TROPICAL WAVES... The axis of a tropical wave is along 110W and from 06N to 18N, moving west at 10 to 15 kt. Convection is limited near the wave axis. The axis of a tropical wave is along 121W from 06N to 20N, moving west at 10 to 15 kt. Please, refer to the Special Features section for more details. The axis of a tropical wave is along 140W from 05N to 18N, moving west at 10 to 15 kt. A 1010 low pressure is along the wave axis near 09N140W. Scattered moderate to isolated strong convection is seen from 08N to 11N W of 137W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N85W to 10N100W to 1011 mb low pressure located near 15N121W. The ITCZ begins near 12N122W and continues to beyond 09N140W. Scattered moderate to isolated strong convection can be found N of 03N E of 84W to the coast of Colombia, including the Gulf of Panama, from 10N to 13N between 100W and 104W, within 120 nm NW quadrant of low pressure located near 15N121W, and from 08N to 11N W of 137W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A ridge will continue to dominate the offshore forecast waters of Baja California producing gentle to moderate NW to N winds. Seas are 4 to 6 ft N of Cabo San Lazaro, and 3 to 5 ft elsewhere. In the Gulf of Tehuantepec N to NE winds of 20-30 kt and seas to 8 ft are now occurring. Gentle to moderate northerly winds prevail in the Gulf of California. For the forecast, please, see the Special Features section for more details on the first Tehuantepec wind event of the season. Surface ridging will continue to dominate the offshore forecast waters of Baja California supporting mainly gentle to moderate NW winds through Sun. Light to gentle winds will prevail over the SW Mexico offshore waters. In the northern Gulf of California, a surface trough will support fresh to locally strong southerly winds Thu night through Fri night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Gentle to moderate southerly winds will prevail across the offshore waters of Costa Rica, Panama, Colombia and Ecuador during the forecast period, with seas of 4-6 ft in SW swell. Mainly light and variable winds are forecast across the offshore waters from Guatemala to northern Costa Rica, with seas of 3-5 ft also in SW swell. REMAINDER OF THE AREA... The northern forecast waters remain under the influence of a surface ridge. The pressure gradient between the ridge and lower pressures near the monsoon trough/ITCZ supports moderate to locally fresh N to NE winds N of 10N and W of 120W, with seas of 5-7 ft, except for 8 ft W of 137W. Winds across this area will diminish over the weekend. $$ GR