000 AXPZ20 KNHC 220800 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Fri Jun 22 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 0800 UTC. ...TROPICAL WAVES... A tropical wave axis extending from 17N100W to 04N102W is moving west at 15 kt. Scattered moderate isolated strong convection in an area bounded by 12N98W to 07N107W to 14N105W back to 12N98W. An area of low pressure is expected to develop from this wave by early next week, and a tropical cyclone may eventually develop as the tropical low becomes better organized south of Mexico. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from coast of Costa Rica near 10N86W to 14N107W to 1011 mb low pressure near 13N106W to 08N122W. The ITCZ continues from 08N122W to 10N138W. Scattered moderate convection is within 120 nm either side of the convergence zone axis west of 114W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Moderate NW winds west of Baja California will diminish through Sat night, and a broad surface trough will prevail along the length of the peninsula through Sun morning. Southerly winds will increase east of the trough axis in the Gulf of California this weekend, becoming fresh to strong southeasterly N of 29N Sat afternoon, continuing into early Sun morning. Seas in the northern Gulf of California will build to 6-8 ft by Sat night, then subside Sun along with a decrease in surface winds. Long period cross-equatorial SW swell will reach the waters off Southern Mexico this afternoon, and build seas to near 7 ft in offshore waters by Sat. Seas will subside there Sun and Mon. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The monsoon trough will meander between 09N and 11N the next several days. Light to gentle winds will prevail north of the monsoon trough, with gentle to moderate S to SW winds expected south of the trough axis. Long period cross-equatorial SW swell will spread across southern forecast waters, with seas building to around 8 ft S of 08N by early Sat, then gradually subside on Sun and Mon. REMAINDER OF THE AREA... Low pressure centered near 14N116W is embedded in the monsoon trough with an estimated pressure of 1011 mb. Model guidance shows this low emerging from the trough and drifting northward with a gradual increase in intensity through the weekend. The GFS forecast is much more aggressive with this low than other global models, and considered an outlier at this point. However, this low merits close observation over the next few days for signs of increased organization. A trough is analyzed from 14N137W to 07N140W. Scattered moderate convection is associated with this feature. Seas to 8 ft are evident near the trough axis in latest altimeter sea state data. The trough will drift westward, and move west of 140W tonight. Elsewhere, high pressure centered well north of the area extends a ridge SE to near the Revillagigedo Islands. Gentle to moderate trades prevail west of 120W, and light to gentle winds dominate the remainder of the basin, based on latest ASCAT data. A pulse of northerly swell will propagate into the northern waters with seas building to 6 to 9 ft north of 25N between 120W and 130W early Sat. Cross-equatorial southerly swell will build seas to 6 to 9 ft south of 10N and west of 90W late tonight. $$ Mundell