000 AXPZ20 KNHC 260247 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Fri Aug 26 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 0000 UTC surface analysis and satellite imagery through 0215 UTC. ...SPECIAL FEATURES... Tropical Storm Lester is centered near 17.0N 113.8W at 0300 UTC or about 408 nm to the south-southwest of the southern tip of Baja California. Lester is moving W or 270 deg at 5 kt with maximum sustained winds of 50 kt with gusts to 60 kt. The estimated minimum central pressure is 1000 mb. During the course of the day on Thursday Lester exhibited some organization to its overall cloud pattern, and has changed little during the evening hours. Satellite imagery shows numerous strong convection within 45 nm of the center in the northwest quadrant. Scattered moderate/isolated strong convection is elsewhere within 75 nm of the center, except 90 nm in the west quadrant. Lester is forecast to continue moving away from the Mexican offshore waters through tonight, and is forecast to strengthen to a hurricane near 18.0N119.5W by Friday evening. Please read the NHC forecast/advisory under AWIPS/WMO headers MIATCMEP3/WTPZ23 KNHC or the public bulletin under MIATCPEP3/ WTPZ33 KNHC for more details. A broad area of low pressure is located about 1433 nm east- southeast of the Big Island of Hawaii. A 1008 mb low is analyzed within this area of low pressure near 13N132W moving westward about 15 kt. Latest satellite imagery shows that overall cloudiness and convection has increased during the evening hours in association with this area. Numerous convection is within 90 nm of the low in the northwest quadrant. Scattered moderate to isolated strong convection is elsewhere within 120 nm of the low in the northwest quadrant. A tight gradient between this area of low pressure and the sub-tropical ridge to its north is resulting in moderate to fresh northeast winds from 13N to 18N and west of 124W. An Ascat pass from 1804Z Thursday afternoon suggested strong north to northeast winds with the convection located northwest of the low. Strong south-southwest were also indicated by the same Ascat pass to the south of the low from about 08N to 10N between 132W and 136W. Seas with these winds are within the 6 to 9 ft range. Environmental conditions are conducive for continued gradual improvement in organization of this system. It has a high chance for tropical cyclone development during the next 48 hours before crossing 140W by 72 hrs. ...TROPICAL WAVES... No waves at this time. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 11N89W to 09N100W to 11N108W. It resumes at 13N121W to low pressure at 13N132W 1008 mb to beyond 10N140W. Scattered moderate isolated strong strong convection is within 120 nm south of the axis between 93W and 98W, within 120 nm south of the axis between 132W and 138W. Scattered moderate convection is within 120 nm south of the axis between 89W and 93W. Scattered moderate convection is southeast of the monsoon trough within 30 nm of line from 07N85W to 06N89W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A narrow surface ridge extends from the NE Pacific southeastward through 30N129W to north of Lester near 21N113W. This ridge will change little through the upcoming weekend, and combine with the persistent trough meandering along the Baja California peninsula and Gulf of California, to produce mainly light to moderate northerly flow prevailing outside of the Gulf of California. Expect mainly light to gentle southerly flow In the Gulf of California, except for occasionally fresh wind flow in the northern Gulf where the pressure gradient will be slightly tighter. High pressure in the Gulf of Mexico has weakened. The strong gradeint associated with it providing north to northeast winds through the Gulf. These winds are forecast to diminish to 15-20 kt by late tonight, and lower to 10-15 kt on Friday. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to moderate sw winds south of the monsoon trough will continue to spread to the coastal sections through Friday, then a light and variable onshore flow is expected Saturday and Sunday. ELSEWHERE... A broad surface ridge covers the remainder of the area, extending from a large 1036 mb high near 49N145W. The low pressure center that is along 132W will move westward during the next few days. The pressure gradient between this lower pressure and the ridge will yield fresh winds across the trade wind belt, generally from 21N southward to near the trough, from just to the northeast of the low center to beyond 140W. Seas ranging from 6 to 8 feet presently in this area in mixed swell will increase slightly to 7 to 9 feet during this time. A large area of fresh southwesterly monsoonal flow is supporting seas of 6 to 8 feet from 07N northward between 115W and 125W. The strength and areal coverage of these fresh winds will increase to the south and southeast of the low center as it shifts westward during the next few days. $$ Aguirre