811 AXPZ20 KNHC 110901 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Wed Jul 11 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...TROPICAL WAVES... A tropical wave is analyzed north of 10N along 101W moving W at 15 to 20 kt. Scattered moderate convection is observed S of 13N within 60 nm either side of the wave axis. A tropical wave is analyzed from 08N to 18N along 122W moving W at 15 kt. Scattered moderate convection is observed from 11N to 15.5N within 120 nm either side of the wave axis. A tropical wave is analyzed from 08N to 18N along 130W moving W at 10 to 15 kt. Scattered moderate convection is observed well east of the wave axis. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends westward from 08N77W to 09N97W. The ITCZ continues from 10N103W to 09N118W. Except for convection associated with tropical waves, scattered moderate convection is within 180 nm S of the convergence zone between 97W and 108W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of Tehuantepec: High pressure in the Gulf of Mexico and northerly winds east of a trough in the Bay of Campeche will enhance the nocturnal drainage flow in the Gulf of Tehuantepec, with peak winds around 30 kt each night through Sun night. Surface troughing west of Baja California is supporting a weak pressure pattern N of 15N W of 96W across the offshore waters, promoting mainly gentle winds. The trough will meander between 115W and 120W the next couple of days, which will help maintain weak flow over the region into the weekend. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Strong nocturnal NE to E winds, with seas to 10 ft, are expected in the Gulf of Papagayo Fri night and Sat. Gentle to moderate easterly winds are expected elsewhere north of the monsoon trough, with gentle southerly winds forecast south of the trough axis. REMAINDER OF THE AREA... What remains of a surface trough that extended from 26N126W to 21N128W will drift westward the next few days. The pressure gradient NW of the remnant trough axis with support fresh NE trade winds, and enhance residual mixed swell in the region to produce an area of 8 ft seas from 22N to 26N W of 135W during the next 24-48 hours, then shift west of 140W on Thu. GFS model guidance indicates a sharp surface trough or possibly a low will develop along the convergence zone boundary in association with the tropical wave along 122W in the next 24 hours. The pressure gradient between the developing trough and higher pressure N of 30N should induce an area of strong NE winds N-NW of the trough axis. The GFS model shows winds in excess of 30 kt in this area Thu and Fri, with seas building to 10-12 ft by Sat. Cross-equatorial southerly swell of 7-8 ft will affect southern waters mainly south of 02S between 100W and 115W during the next 24 hours, then subside by Wed night. $$ Mundell