000 AXPZ20 KNHC 220409 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Fri Oct 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 0000 UTC surface analysis and satellite imagery through 0300 UTC. ...SPECIAL FEATURES... Gale warning: Shower activity associated with a low pressure area located a few hundred miles southwest of the Gulf of Tehuantepec has become better organized during the last 24 hours. Environmental conditions are expected to be conducive for additional development of this system during the next several days, and a tropical depression is likely to form during the next couple of days while the system moves slowly west-northwestward to northwestward near or just offshore the southern coast of Mexico. A gale warning has been issued accordingly for the waters off western Oaxaca, Guerrero, and Michoacan. Regardless of development, this system could bring an increase in winds and seas across the southern coast of Mexico from Oaxaca to Michoacan over the next 48-72 hours. Currently, this system has a high chance of tropical cyclone formation through 48 hours. Please see latest Tropical Weather Outlook at www.hurricanes.gov. ...TROPICAL WAVES... A tropical wave is along 140W extending from 05N to 16N, moving westward at 10 to 15 kt. No significant convection is observed near this tropical wave. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N79W to 1009 mb low pressure near 13N98W to 09N105W to 1011 mb low pressure near 13N117W to 08N131W to 10N140W. Scattered moderate convection is observed in the Gulf of Panama. Numerous moderate to isolated strong convection is noted from 10N to 16N between 92W and 101W. Scattered moderate to isolated strong convection is evident from 13N to 15N between 115W and 117W, and from 09N to 12N between 117W and 112W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A surface ridge extends from 1021 mb high pressure centered near 28N125W to south of Los Cabos. Moderate to occasionally fresh NW winds persist between the ridge axis and lower pressure over north central Mexico. A pair of afternoon radar altimeter satellite passes indicated moderate seas off Baja California. NW swell in excess of 8 ft has started entering the waters off Baja California Norte since those passes. Farther south, fresh to strong winds are likely off western Oaxaca and eastern Guerrero in thunderstorms associated with 1009 mb low pressure developing about 210 nm SSW of Puerto Angel. Seas are building in this area to near 8 ft, due to local winds and longer period SW swell. For the forecast, in additional the high likelihood of a tropical depression forming off southern Mexico over the next couple of days, NW swell in excess of 8 ft moving into the offshore waters of Baja California Norte will subside through Fri. Another set of large NW swell will follow Fri night, reach as far south as Socorro Island by Sun, then subside Mon and Tue. Looking ahead, a third round of NW swell may reach Baja California Norte waters Mon night into Tue. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Mainly gentle to moderate S to SW will follow the monsoon trough as it lifts north of the area over the next couple of days. By Sat night into Sun, expect building seas in SW swell between Ecuador and the Galapagos Islands. This swell event is forecast to reach the offshore forecast waters of western Panama on Sun, supporting seas to 8 ft. Seas will subside thereafter across the region. REMAINDER OF THE AREA... 1021 mb high pressure centered near 28N125W is shifting east and weakening ahead of a cold front moving across waters north of 25N over the next couple of days. Large, long period NW swells follow the front forecast to reach 30N128W to 27N140W on Fri, and from 30N119W to 26N140W on Sat while weakening. Moderate to fresh SW winds are between the front and the high. Currently, seas of 8 to 11 ft in NW swell cover the area northwest of a line from Guadalupe Island to 14N140W. Highest seas of 12 to 15 ft are expected in the wake of the front by Fri morning. This swell event will continue to propagate across the forecast region through at least Sat, with seas in excess of 8 ft covering much of the waters N of 20N W of 120W. $$ Christensen