000 AXPZ20 KNHC 030916 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Sat Oct 3 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... Powerful Hurricane Marie is centered near 17.9N 126.4W at 03/0900 UTC moving NW at 8 kt, and this motion is expected to continue through the weekend. A turn to the west-northwest is expected by Monday. Estimated minimum central pressure is 948 mb. Maximum sustained wind speed is 115 kt with gusts to 140 kt. Marie is a category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale. The hurricane is forecast to begin weakening later today, and this weakening trend should continue into early next week. Marie is expected to be a tropical storm by Sun night. 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: A ridge across the western Gulf of Mexico and eastern slopes of the Sierra Madre Mountains in Mexico combined with Tropical Storm Gamma in the NW Caribbean will continue to support fresh to strong northerly winds over the Bay of Campeche. These winds are funneling through the Chivela Pass into the Gulf of Tehuantepec, producing gale force winds in the Tehuantepec region. A recent scatterometer pass provided observations of minimal gale force winds across the area, with fresh to strong N-NE winds extending farther S to near 12N97W. This gap wind event will persist through Mon night as T.S. Gamma moves just N of the Yucatan Peninsula. Expect the strongest winds of 35-40 kt during the overnight and early morning hours. Seas will peak near 16-17 ft early this morning, then will gradually subside to 8-10 ft by Tue night. 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. ...TROPICAL WAVES... The tropical wave that spawned T.S. Gamma now extends along 89W N of 03N. The wave is helping to induce some convective activity over the regional waters of Nicaragua and El Salvador, mainly N of 12N between 87W and 91W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 13N87W to 10N95W to 1009 mb low pres near 08N102W to 11N108W, then resumes W of Hurricane Marie near 13N125W to 09N136W. The ITCZ is from 09N136W to beyond 10N140W. Scattered moderate convection isolated strong convection is noted from 04N to 08N E of 80W, from 08N to 12N between 85W and 89W, from 06N to 10N between 100W and 111W, and from 12N to 15N between 98W and 103W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see above for more on the ongoing Gulf of Tehuantepec Gale Warning. Elsewhere, mainly light to gentle winds will dominate the offshore forecast waters of Baja California under a weak pressure gradient. By Mon night, a ridge will establish again over the area, bringing gentle to moderate NW winds. Seas generated by Hurricane Marie will continue to spread across the waters W of Baja California through early Sun. Light to gentle southerly winds are expected in the Gulf of California into the start of next week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Moderate to locally fresh southwesterly winds are expected S of the monsoon trough with mainly light to gentle winds N of it. Seas generated by the gale-force gap winds in the Tehuantepec region will continue to propagate across the offshore waters of Guatemala and El Salvador into the beginning of next week. REMAINDER OF THE AREA... Please see Special Features section above for more information on Category Four Hurricane Marie. Outside of Major Hurricane Marie, a weak ridge prevails over the NW corner of the forecast area. The pressure gradient between this ridge and Marie is maintaining gentle to moderate winds N of the monsoon trough to about 28N, and gentle to moderate winds S of the monsoon trough. The large size of Hurricane Marie will generate a large area of seas greater than 8 ft which will spread well away from the cyclone center. By this afternoon, seas greater than 8 ft will cover much of the waters N of 10N and W of 115W. Long period SE swell from the Southern Hemisphere is forecast to reach the equator by Mon. An area of low pressure is expected to form within the next couple of days several hundred miles southwest of the coast of southwestern Mexico. Some development of this system is possible through the middle of next week while it moves slowly northwestward. Another area of low pressure could form south or southeast of the Gulf of Tehuantepec early next week. Gradual development of this system will be possible thereafter while it drifts near or south of southern coasts of Mexico and Guatemala. Currently, marine guidance suggests increasing winds across the offshore waters of Guatemala and El Salvador early next week. The latest Tropical Weather Outlook states that these systems have a low chance of tropical cyclone formation through 5 days. $$ GR