750 AXPZ20 KNHC 251526 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1526 UTC Tue Sep 25 2018 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 1500 UTC. ...SPECIAL FEATURE... Tropical Storm Rosa centered near 14.7N 108.0W at 25/1500 UTC or 330 nm SW of Manzanillo Mexico moving WNW at 8 kt. Estimated minimum central pressure is 1004 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Numerous moderate and isolated strong convection is within 180 nm in the NE semicircle and within 300 nm in the SW semicircle of Rosa. Rosa is forecast to gradually strengthen, reaching hurricane strength by 36 hours. Associated winds and seas are forecast to spread into the offshore waters of Mexico W of 100W the next couple of days, continuing to spread NW offshore of Baja California through the end of the week into the upcoming weekend. Large swells associated with Rosa are likely to impact the SW coast of Baja California as well as the entrance to the Gulf of California by the end of the week. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCPEP5/WTPZ35 KNHC for more details. ...TROPICAL WAVES... A tropical wave is analyzed from 05N to 17N along 101W moving westward around 10 kt. Scattered moderate and isolated strong convection is from 08N to 15N between 98W and 102W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northern Colombia near 10N75W to 08.5N90W to 12N100W, then resumes from 14N109W to 12N125W to 09N140W. Scattered moderate and isolated strong convection is within an area bounded by a line from 15N102W to 15N94W to 08N91W to 06N76W to 02N78W to 05.5N95W to 10N104W to 15N102W. Scattered moderate convection is from 11N to 13N between 124W and 127W, and also from 05N to 10N between 135W and 140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the special features section for information on Tropical Storm Rosa. A ridge extending from 27N120W to 21N113W will continue to gradually retract NW as Rosa moves NW. Gentle to moderate NW flow is forecast W of the Baja California through Fri, with much uncertainty thereafter due to Rosa. In the Gulf of California, moderate to locally fresh southerly winds across the gulf waters N of 30N will diminish in the next few hours. Otherwise, light to gentle variable winds are expected across the gulf waters through Fri. In the Gulf of Tehuantepec, fresh to strong northerly flow is forecast through the next several days, except briefly diminishing during the mid afternoons. The strongest drainage event is expected on Thu night into early Fri as a tropical low passes to the S. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... In the Gulf of Papagayo, fresh to locally strong east nocturnal drainage flow is expected through early Wed with a surface low developing near 09.5N90.5W Wed morning, moving to near 11N94W Thu morning. Light and variable winds are forecast through Wed morning elsewhere N of the monsoon trough which will meander between 09N and 12N. Moderate SW flow is forecast S of the monsoon trough. The pressure gradient will begin to tighten on Wed night as a surface low develops near 10N93W and moves W of the ares by early Fri. REMAINDER OF THE AREA... Please see the special features section for information on Tropical Storm Rosa. Otherwise, a broad ridge continues across the subtropics accompanied by moderate to locally fresh anticyclonic flow S of 23N W of 120W. $$ Lewitsky