000 AXPZ20 KNHC 081455 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Fri Oct 8 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 1440 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: The pressure gradient between high pressure across eastern Mexico and lower pressure within the monsoon trough south of the Gulf of Tehuantepec and a tropical wave SE of the Gulf of Tehuantepec will support gale force northerly winds through today. Fresh to strong northerly winds will then pulse through Sat night before diminishing. Please read the latest High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml. Low pressure has developed along a tropical wave near 10N89W. Environmental conditions are forecast to be conducive for development of this low, and a tropical depression is likely to form late this weekend or early next week while the system moves westward to west-northwestward at about 15 mph south of the coast of Mexico. Please see the latest eastern north Pacific Tropical Weather Outlook for more information. ...TROPICAL WAVES... The axis of a tropical wave is near 89W and N of 01N, moving W at around 10 to 15 kt. Low pressure has developed along the wave, and is being monitored for potential tropical cyclone development. Scattered moderate isolated strong convection is noted from 08N to 13N between 87W and 92W. Please see SPECIAL FEATURES section above for more on the possibility of TC development. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N85W to 10N110W to 13N128W to 10N134W to 13N140W. Aside from convection discussed in association to the low and tropical wave above, scattered moderate convection is noted from 03N to 08N E of 82W. Scattered moderate isolated strong convection is noted from 07N to 15N between 93W and 104W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please read the Special Features section for details on a Gulf of Tehuantepec Gale Warning currently in effect, as well as the potential for tropical cyclone development south of southern Mexico. Aside from the Gulf of Tehuantepec, moderate to locally fresh winds prevail west of Baja California. Gentle to moderate winds are noted in the central Gulf of California. Light to gentle winds prevail elsewhere. Seas are in the 4 to 6 ft range over the open waters off Mexico, and 1 to 3 ft over the Gulf of California. For the forecast, gale force northerly winds will prevail in the Gulf of Tehuantepec today before diminishing. High pressure will build west of the Baja California peninsula which will strengthen winds for the remainder of the week into the weekend. NW swell will propagate into the waters west of Baja California bringing building seas this weekend. Low pressure has developed association with a tropical wave. The low will move south of southern Mexico this weekend, and environmental conditions are conducive for tropical cyclone development offshore southern Mexico late this weekend or early next week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Fresh winds prevail over the Gulf of Papagayo, with light to gentle winds elsewhere north of the monsoon trough. Mainly moderate winds are noted south of the monsoon trough. Seas are in the 5 to 7 ft range across the area. For the forecast, fresh to locally strong winds will pulse nightly into the weekend, with light to gentle winds elsewhere north of the monsoon trough through early next week. Mainly moderate southwest winds will prevail south of the monsoon trough. A moderate southwest swell will propagate through the regional waters during the next several days. Low pressure along a tropical wave offshore Central America from El Salvador to Costa Rica is being monitored for tropical cyclone development. The low will move W or WNW offshore and away from Guatemala this weekend. REMAINDER OF THE AREA... High pressure is building north of the area. This is supporting fresh to strong N-NE winds and seas of 8 to 11 ft over the NW waters. A trough extends from near 19N136W to 16N140W. The pressure gradient between the trough and area of high pressure to the north is supporting fresh to strong winds, and seas to 8 ft, west of the trough. Another surface trough extends from 28N121W to 16N128W. A couple of low pressure areas are embedded within the monsoon trough, one near 13N128W and another one near 12N118W. Aside from the areas mentioned above, gentle to moderate winds, and seas in the 5 to 7 ft range, prevail. For the forecast, high pressure will continue to build north of the area, strengthening trade- winds north of the monsoon trough and west of 120W this weekend into early next week. Southerly swell will maintain seas greater than 8 ft south of the equator and west of 90W. Seas greater than 8 ft will spread north of the equator and west of 95W into the weekend. A cold front may move south across the waters west of Baja California Norte to 130W early next week, with fresh to strong northerly winds and large NW swell behind it. $$ AL