000 AXPZ20 KNHC 291602 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1230 UTC Mon Aug 29 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 1200 UTC surface analysis and satellite imagery through 1430 UTC. ...SPECIAL FEATURES... Lester is already a major hurricane and continues to intensify. At 29/1500 UTC, it is centered about 1120 NM W of the southern tip of Baja California near 18.1N 129.2W moving W or 270 degrees at 13 kt. Estimated minimum central pressure is 957 mb. Maximum sustained winds are 110 kt with gusts to 130 kt. Lester is now a strong category 3 hurricane on the Saffir-Simpson Hurricane Wind Scale. Some additional increase in strength is expected today. A slow but steady weakening trend is then expected to begin by Tuesday. Lester is forecast to cross 140W and move into the central Pacific basin by Wednesday night while continuing on a westward motion. Numerous moderate and scattered strong convection is seen within 75 NM of the center. Scattered moderate and isolated strong convection is present elsewhere within 120 nm of the center. 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 11N90W to 11N97W to 13N105W to low pres near 13N115W 1010 MB to 13N120W. Scattered moderate and isolated strong convection exists within 240 nm either side of the monsoon trough axis E of 104W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A ridge extending from 32N130W to 16N110W dominates the waters off Baja California. The ridge is producing moderate to locally fresh northerly winds and seas generally under 6 ft. Little change in this weather pattern is expected through the end of the week. Marine guidance suggests seas will build close to 8 ft in NW swell across the western part of zone PMZ011 on Tuesday night and Wednesday, then subside. Surface troughing over the Baja peninsula will maintain a light and variable wind regime in the Gulf of California through the end of the week with seas generally 2 ft or less. Farther south, winds will be mainly gentle to moderate and WNW with combined seas of 4 to 6 ft. A light and variable wind pattern is expected across the Gulf of Tehuantepec through Thursday. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gentle to moderate SW winds will prevail S of the monsoon trough with mainly light to gentle winds N of it through Friday. Long period cross equatorial SW swell will continue to dominate the area with seas ranging between 4 and 7 ft. REMAINDER OF THE AREA... Hurricane Madeline is W of 140W. However, mixed swell on the E side of Madeline will maintain seas at 8 ft from 18N to 23N W of 139W. These marine conditions will merge with those produced by hurricane Lester in about 12 hours. Hurricane Lester will reach the W central waters this afternoon. A broad surface ridge covers most of the northern waters, extending from 1023 mb high pressure near 33N130W. A weak surface trough crosses the NW part of the forecast area from 27N140W to 32N137W. Ascat satellite imagery continues depicting the wind shift associated with this trough. Scattered low-topped showers are occurring in the vicinity of this feature. The pressure gradient between the ridge and Lester will produce a band of fresh to occasionally strong winds from 20N to 25N between 125W and 135W, with combined seas ranging from 9 to 12 feet. Weak low pres of 1010 mb remains embedded in the monsoon trough near 13N115W. Convection associated with this system has gradually increased in both areal coverage and intensity over the past 24 hours. Satellite imagery shows scattered moderate to isolated strong convection from 11N to 15N between 111W and 120W. Chances for tropical cyclone formation for this system are forecast to remain low through the next several days as it tracks slowly westward along the monsoon trough. Scatterometer imagery shows moderate to fresh SW winds feeding into the monsoon trough S of the low. Marine guidance suggests that an area of fresh SW to W winds will persist S of the low center during the next 48 hours, with seas building to 8 ft in the vicinity of the low during this time frame. SW swell crossing the equator will produce and area of seas S of Mexico between 8 and 10 ft generally from 06N to 13N between 94W and 112W during the next couple of days. $$ cam