000 AXPZ20 KNHC 302114 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Wed Sep 30 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 1800 UTC surface analysis and satellite imagery through 2120 UTC. ...SPECIAL FEATURES... Newly upgraded Hurricane Marie is centered near 14.3N 115.1W at 30/2100 UTC moving W at 14 kt. Estimated minimum central pressure is 988 mb. Maximum sustained wind speed is 65 kt with gusts to 80 kt. Numerous moderate to strong convection is noted within 250 nm W semicircle. Marie is expected to turn westward to west- northwestward through Friday. Rapid strengthening is forecast, and Marie is expected to become a hurricane this evening or tonight. Marie could then become a major hurricane by late Thursday. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPEP3.shtml and Forecast/ Advisory at https://www.nhc.noaa.gov/text/MIATCMEP3.shtml for more details. Gulf of Tehuantepec gale warning: The pressure gradient between high pressure building in the wake of a cold front in the Gulf of Mexico and the eastern Pacific monsoon trough has tightened over the area. This has increased winds funneling through the Chivela Pass into the Gulf of Tehuantepec and gale force gap winds are underway across the Gulf of Tehuantepec. Gale force winds will continue through early Sat with seas building to 15-18 ft. Swell is forecast to reach 100W by tonight. Please read 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. Of note, the 20-year climatology of the Tehuantepec gap wind events indicates that on average 16 gale-force events and 5 storm force-events occur in the Gulf of Tehuantepec each cold season. Most gale-force events occurred during November and December, while most storm-force winds occurred in January. Based on latest model trends and the present evolving synoptic scale setup, these gales most likely will supersede the previously recorded earliest start date of October 3rd. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N86W to 14N107W, then resumes W of Hurricane Marie near 12N121W to 10N140W. Scattered moderate to isolated strong convection is noted from 08N to 19N between 95W and 108W. Scattered moderate convection is also located from 09N to 13N between 128W and 140W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see above for more on the Gulf of Tehuantepec gales. Gentle to moderate N to NW winds off the coast of Baja California will continue through the next few days. As Marie continues to move farther away into the Pacific, swell from this system will generate a large area of seas greater than 8 ft off the coasts of the Revillagigedo Islands today. This swell will continue to spread across the offshore waters west of Baja California and the Revillagigedo Islands through Friday morning. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Moderate southerly flow prevails S of the monsoon trough with gentle winds north of the monsoon trough. Fresh southerly winds S of the monsoon trough are expected to develop by this weekend. Seas are ranging from 5 to 7 ft. Some higher seas from gales in the Tehuantepec region will spread into offshore waters of Guatemala over the next few days. REMAINDER OF THE AREA... Please see Special Features section above for more information on T.S. Marie. Outside of Hurricane Marie, a weak pressure gradient prevails west of 120W which is maintaining gentle to moderate winds N of the monsoon trough to 20N and gentle to moderate winds S of the monsoon trough. As a cold front approaches the forecast waters, NW swell will approach the NW forecast waters by tonight with seas building to 9 ft. The swell will stay west of 131W and is expected to subside by early Friday morning. As Hurricane Marie strengthens into a major hurricane, the size of the system will generate a large area of seas greater than 8 ft spreading well away from the cyclone center. By Saturday, seas greater than 8 ft will cover much of the waters N of 08N and W of 115W. $$ AReinhart/Konarik