000 AXPZ20 KNHC 101553 CCB TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1536 UTC Thu Aug 10 2017 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. ...TROPICAL WAVES... A poorly defined tropical wave is along 86W/87W from central Honduras southward, moving westward 10 knots. This is related to an upper low centered north of Honduras, and will lose definition into Fri as the upper low weakens. Scattered moderate convection lingering off the coast from western Panama to northwest Costa Rica will diminish later this afternoon. A tropical wave along 93W/94W north of 08N is well defined on satellite imagery and satellite derived winds, moving west at 10 to 15 kt. Scattered moderate convection is noted where the tropical wave and the monsoon trough intersect, from 05N to 10N between 90W and 100W. Global models indicate low pressure will form over the next couple of days at the intersection of the tropical wave and monsoon trough, near 11N97W. .INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A segment of the monsoon trough extends from 09N84W to 09N90W. Another segment of the monsoon trough extends from 1010 mb low pres near 14N106W to 1011 mb low pressure near 10N125W, then onward to beyond 12N140W. Except for otherwise noted in tropical wave section above, scattered moderate convection within 120 nm south of monsoon trough axis between 120W and 135W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Thunderstorms off the Mexican coast between Acapulco and Manzanillo are related to the approaching remnants of tropical cyclone Franklin, moving westward across the high terrain of central Mexico. A weak remnant is expected to emerge into the Pacific off Cabo Corrientes. While tropical cyclone development is not anticipated, fresh to strong winds, building seas and scattered showers and thunderstorms will accompany the low pressure as it moves west-northwest to the north of the Revillagigedo Islands through Sunday. Farther north, an upper trough is drifting northwest high above Baja California Sur. Associated divergence aloft was responsible for clusters of showers and thunderstorms that moved off the eastern coast of the Gulf of California last night, then dissipated over the Gulf through this morning. Overnight gap winds through the Gulf of Tehuantepec will increase to moderate to fresh by Fri night in the immediate wake of the tropical wave passing through the region, increasing to a fresh to strong pulse by Sat night as high pressure builds north of the region in the wake of the tropical wave. Long period southerly swell will propagate into the coast of southern Mexico by early Mon with seas to 8 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate southerly winds are expected south of the monsoon trough, with gentle and variable winds north of the monsoon trough through Saturday. A new and extensive set of cross-equatorial swell is forecast by wave model guidance to cross the equator by late Fri, bringing seas to 9 ft to the Central American coast by early Monday. REMAINDER OF THE AREA... A weak and broad ridge dominates the waters north of the monsoon trough. Moderate to fresh winds are within 120 nm of 1011 mb low pressure centered near 10N125W. Elsewhere, gentle to moderate northeast winds persist north of the monsoon trough, with moderate flow converging into the monsoon trough from the south and southwest, supporting scattered showers and a few thunderstorms. No major changes are anticipated through Sun. $$ Christensen