000 AXPZ20 KNHC 180241 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Thu Nov 18 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 0000 UTC surface analysis and satellite imagery through 0200 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A cold front is forecast to move through the Gulf of Mexico Thu into Fri with high pressure building behind it across eastern Mexico. The building high combined with lower pressure south of southern Mexico will support a gale-force northerly gap wind event from early Fri through Sat morning. Seas will build to around 12 ft during the event. Please see the latest NWS High Seas Forecast issued by the National Hurricane Center at website://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more information. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N85W to 1010 mb low pres near 10N120W to 09N124W. The ITCZ extends from 09N124W to 09N127W, then resumes W of a trough near 07N131W to 07N138W. Scattered moderate convection is noted from 09N to 12N between 114W and 120W. Scattered showers prevail along the monsoon trough between 95W and 111W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section above for details on a Gulf of Tehuantepec Gale Warning. Fresh N-NE winds are across the Gulf of Tehuantepec with seas to 6 ft. A surface ridge extends across the offshore waters with mainly gentle to moderate winds across the waters outside of the Tehuantepec region. Seas are in the 4 to 6 ft range across the open waters. Seas are 2 to 4 ft in the southern Gulf of California, and 3 ft or less in the central and northern Gulf of California. For the forecast, moderate to fresh winds will prevail across the Tehuantepec area tonight. A gale force northerly gap wind event is forecast in the Gulf of Tehuantepec early Fri through Sat morning. Fairly tranquil conditions are forecast elsewhere through the upcoming weekend. Gap winds may approach gale-force again in the Gulf of Tehuantepec early next week. Fresh to strong NW-N winds may develop in the northern Gulf of California early next week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR Moderate to fresh winds prevail across the Papagayo region. Otherwise, light to gentle winds are noted north of the monsoon trough. Gentle to moderate southerly winds prevail south of the monsoon trough. Seas are in the 4 to 7 ft range across the majority of the offshore waters, highest south of Panama and west of Colombia and Ecuador. Scattered showers and thunderstorms are noted south of Panama and Costa Rica, and west of Colombia. For the forecast, moderate to fresh winds will prevail in the Papagayo region through Fri. Fresh to strong winds will return Fri night through Sat, then moderate to fresh thereafter. Gentle to moderate winds will prevail across the rest of the area through the next several days. REMAINDER OF THE AREA... A broad and weak ridge extends from a 1020 mb surface high centered near 28N137W to near 18N110W. A weak surface low is embedded in the monsoon trough, with a 1010 mb low pressure area near 09N119W. Associated convection with this low has diminished. A pair of surface troughs are west of the low extending along 129W and 138W. No significant convection is noted near the troughs. Moderate to locally fresh trades are noted north of the convergence zone to 21N, with gentle to moderate winds north of there under the ridge. Gentle to moderate southerly flow prevails south of the monsoon trough. Seas of 5 to 7 ft prevail south of 21N, locally to 7 ft near 12N118W, with 4 to 6 ft north of 22N, highest along 30N between 120W and 130W. For the forecast, little change is expected through the end of the week. A cold front may drop south into the far northern waters Fri night. High pressure may build behind the front with freshening winds for the end of the weekend into early next week. Seas may build to around 8 ft in the west-central waters north of the ITCZ early next week with the freshening winds and lengthening fetch. $$ ERA