000 AXPZ20 KNHC 282141 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2230 UTC Sun Aug 28 2016 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 2030 UTC. ...SPECIAL FEATURES... Hurricane Lester is centered near 17.8N 124.7W at 28/2100 UTC moving west or 270 degrees at 11 kt. Estimated minimum central pressure is 979 mb. Maximum sustained wind speed is 75 kt with gusts to 90 kt. Little change in strength is expected through the week. Lester is forecast to cross 140W and move into the central Pacific basin by Thursday while continuing on a westward motion. Scattered moderate to strong convection is from 16N to 19N between 123W and 126W. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP3/WTPZ23 KNHC for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N89W to 13N105W to low pressure near 11N112W to 14N119W. Scattered moderate and isolated strong convection is within 60 nm southwest of the axis between 97W and 102W, within 180 nm either side of the axis between 107W and 119W, and also within 150 nm southwest of a line from 11N133W to 15N135W to 15N139W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A ridge dominates the waters off Baja California producing moderate to locally fresh northerly winds and seas generally under 6 ft. Little change in this weather pattern is expected over the next 48 hours. By Tuesday night, marine guidance suggests building seas to 8 to 9 ft in northwest swell across zone PMZ011. Expect light and variable winds in the Gulf of California through the next several days. Farther south, winds will be mainly light to moderate and west-northwest with combined seas of 4 to 6 ft. Active convection in the Gulf of Tehuantepec in the form of scattered moderate and isolated strong, extending within 150 nm northwest of a line from 16N93W to 12N9W, will gradually diminish through the day. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light and moderate winds will continue to prevail on either side of the monsoon trough for the next several days, with combined seas of 4 to 7 ft mainly in cross equatorial southerly swell. ELSEWHERE... Tropical Storm Madeline is west of 140W, however, winds of 20 to 30 kt continue to impact the area from 15N to 20N west of 138W. A large area of mixed swell covers the surrounding waters from roughly 13N to 22N west of 134W. These conditions will gradually diminish and subside through Monday as Madeline continues to move farther west of the area. A broad surface ridge covers most of the northern waters, extending from 1022 mb high pressure near 33N129W. A weak surface trough extends from 30N137W to 25N140W, and will cross 140W by Monday morning. Scattered showers and isolated thunderstorms are occurring in the vicinity of this feature. The pressure gradient between the ridge and Lester will produce a band of moderate to fresh winds roughly from 20N to 25N, with combined seas ranging from 6 to 9 feet. Weak low pressure of 1011 mb remains embedded in the monsoon trough near 11N112W. Associated convection remains disorganized and is described in the monsoon trough section above. Tropical cyclone formation is forecast to remain low through the next several days as it tracks westward along the monsoon trough. Scatterometer data show moderate to fresh southwesterly monsoon flow into the monsoon trough west of the low pressure. Marine guidance suggests fresh to strong southwest to west winds mainly south of the low center from 07N to 13N between 106W and 131W, through early Tuesday, with seas building to 8 to 10 ft on Monday. $$ FORMOSA