000 AXPZ20 KNHC 040331 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Sun Oct 4 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 0000 UTC surface analysis and satellite imagery through 0300 UTC. ...SPECIAL FEATURES... Hurricane Marie is centered near 19.5N 127.9W at 04/0300 UTC moving NW at 7 kt. Estimated minimum central pressure is 960 mb. Maximum sustained wind speed is 100 kt with gusts to 120 kt. Numerous moderate to scattered strong convection is noted within 120 nm NE and 60 nm SW semicircles of center. The hurricane is forecast to move generally northwestward or west-northwestward with little change in forward speed for the next several days. Marie is a category 3 hurricane on the Saffir-Simpson Hurricane Wind Scale. Rapid weakening is anticipated. Marie is forecast to become a tropical storm by Sunday night or early Monday. 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 noe located over the Yucatan Peninsula 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. These gale force gap winds will persist into 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 15-16 ft into Mon 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... A tropical wave extends along 92W N of 03N, moving W at 10 kt. Scattered moderate convection is associated with this wave from 08N to 12N between 91W and 96W. Scattered moderate isolated strong convection is N of 13N to the coast of Guatemala and El Salvador. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 11N86W to 12N92W to 1008 mb low pres near 09.5N102W to 08N112W, then resumes W of Hurricane Marie near 12N126W to beyond 08N140W. Scattered moderate convection is noted within 120 nm NE quadrant of low center, from 07N to 11N between 104W and 112W, and from 10N to 12N between 112W and 118W. 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, mainly offshore Baja California del Norte. Seas generated by Hurricane Marie will continue to spread across the waters W of Baja California into Sun. Light to gentle southerly winds are expected in the Gulf of California into Tue. 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 Tue. Looking ahead, an area of low pressure could form south-southeast of the Gulf of Tehuantepec region early next week. Gradual development of this system is possible thereafter while it drifts northward offshore of the southern coasts of Mexico and Guatemala. There is a low chance of tropical formation in the next 5 days. REMAINDER OF THE AREA... Please see Special Features section above for more information on Major Hurricane Marie. Outside of 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. Currently, seas greater than 8 ft cover most 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 early Mon. An elongated area of low pressure is located several hundred miles south of the southwestern coast of Mexico. A 1008 mb low pressure is analyzed along the monsoon trough near 9.5N102W. Scattered moderate convection is seen within about 120 nm NE quadrant of low center. Additional development of this system is possible and a tropical depression could form by the middle of next week while it moves slowly northwestward. This system has a medium chance of tropical cyclone formation through 5 days. Tropical Storm Gamma located over the northern portion of the Yucatan Peninsula is expected to produce heavy rainfall for several days over portions of southeastern Mexico, the Yucatan Peninsula, Central America, and far western Cuba. This rainfall could result in life-threatening flash flooding and mudslides, particularly in the mountainous regions of southeastern Mexico and Central America. $$ GR