140 AXPZ20 KNHC 140920 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0920 UTC Wed Aug 14 2019 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... Recent scatterometer data revealed broad low pressure is centered near 15N127.5W along a tropical wave extending from near 18N127W to 05N129W. Scattered moderate convection is noted within 120 nm west semicircle of the low. Environmental conditions are expected to be somewhat conducive for some development during the next few days, and a tropical depression could form later this week before upper-level winds become unfavorable. This system has a medium chance of tropical cyclone formation during the next 48 hours. Refer to the latest NHC Tropical Weather Outlook under AWIPS/WMO headers MIATWOET/ABPZ20 KNHC for more information. ...TROPICAL WAVES... A tropical wave is along 83W north of 05N, moving west around 15 kt. Scattered moderate and isolated strong convection is noted from 06N to 09N between 79W and 85W. A tropical wave is along 96W north of 04N, moving west around 10-15 kt. Scattered moderate and isolated strong convection is noted from 06N to 13N between 95W and 100W, and within 120 nm east of the wave axis north of 14N. A tropical wave is along 104W north of 04N, moving west around 10-15 kt. This wave was evident in local wave diagnostic tools and supported by the latest total precipitable water composite imagery. No significant convection is noted with the wave at this time. A tropical wave is along 115W north of 04N, moving west around 15-20 kt. Scattered moderate convection is noted from 11N to 15N between 110W and 115W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N76W to 09N95W to 12N104W to 11N114W, then resumes from 16N120W to 1010 mb low pressure near 15N127.5W to 10N136W. Scattered moderate convection is noted within 240 nm south of the monsoon trough between 88W and 93W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A broad high pressure ridge is gradually building toward the Baja California offshore waters as the remnants of Henriette continue weakening. Recent scatterometer data showed gentle to moderate NW winds off the Baja California coast north of Cabo San Lazaro. Several overnight altimeter passes indicated seas were generally running 4-6 ft off Baja California Sur. The ridge will support mainly gentle to moderate W-NW flow through the weekend, except occasional fresh winds offshore of Baja California Norte. Strengthening northerly winds off the California coast will produce a set of NW swell that will reach the Baja California Norte waters Fri into Sat. This will build seas to near 8 ft west of Guadalupe Island this weekend. In the Gulf of California, mainly gentle winds and seas of 3 ft or less will prevail through Thu. A deepening low pressure trough along the Baja California peninsula will support fresh to strong SE winds over the northern Gulf Fri and Sat, with seas building to 6 ft. Fresh northerly winds will pulse across the Gulf of Tehuantepec early this morning, and again tonight into early Thu. Looking ahead, a broad area of low pressure is forecast to form south or southeast of the southeastern coast of Mexico late this week. Environmental conditions are expected to be conducive for gradual development of the system over the weekend while the system moves generally westward. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to occasionally strong NE to E winds will pulse across the Gulf of Papagayo early this morning and again on Wed night, building seas to 6-8 ft during the strongest winds. Freshening SW monsoon flow will cause seas to build to 8 ft off the coast of Central America today through Thu, with lower winds and seas thereafter. Looking ahead, broad low pressure is expected to form offshore of Central America late this week, then shift W-NW this weekend. REMAINDER OF THE AREA... Please see the Special Features section for more information on the potential for tropical cyclone development associated with broad low pressure near 15N127.5W. The remnant low of Henriette is analyzed near 22N117W and will continue moving W-NW today while dissipating. No convection is associated with the system at this time. Recent scatterometer data highlights a large area of moderate to fresh trade winds roughly north of a line from 16N125W to 12N140W. Associated seas in this region are generally 7-9 ft per available altimeter data. Moderate to occasionally fresh NE trades will prevail north of the monsoon trough, with mainly moderate SE-S winds south of the monsoon trough for the next several days. Elsewhere, a set of northerly swell will spread S of 32N Fri through Sat, building seas to 8-9 ft north of 28N between 123W and 132W this weekend. $$ Reinhart