000 AXPZ20 KNHC 312133 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Sun Jul 31 2016 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 1800 UTC surface analysis and satellite imagery through 2130 UTC. ...SPECIAL FEATURES... Tropical Depression Nine-E centered near 15.4N 121.2W at 2100 UTC July 31 or 785 nm west-southwest of the southern tip of Baja California moving west-northwest at 8 kt. Estimated minimum central pressure 1006 mb. Maximum sustained wind speed is 30 kt with gusts to 35 kt. Scattered moderate to strong convection is within 180 nm in the south and 90 nm in the northwest semicircles of the depression. Associated seas are 8 to 11 ft. The depression is forecast to continue to move west-northwest today while strengthening to a tropical storm tonight, and then more northwesterly. The system is forecast to move west of 140W by early Thursday while weakening and becoming a post- tropical/remnant low. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP4/WTPZ24 KNHC for more details. ...TROPICAL WAVES... A tropical wave along 106W from 05N to 14N is moving west at 10 to 15 kt. A 1009 mb area of low pressure trails the wave and is located near 11N103W. Scattered moderate to strong convection in association with both features is from 10N to 13N between 102W and 106W. Scattered moderate convection was noted elsewhere from 07N to 15N between 98W and 110W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 09N84W to 08N90W to 1009mb low pressure near 11N103W and trails off to 10N113W. Scattered moderate convection was noted in an area from 08N to 11N between122W and 138W. ...DISCUSSION... N of 15N E of 120W: In the Gulf of California, weak surface troughing will linger along the Baja California peninsula for the next several days. Light to moderate southerly flow will prevail across the northern Gulf, with northerly flow across the southern Gulf. Across the Gulf of Tehuantepec, nocturnal northerly flow will pulse to fresh to strong during the overnight and early morning hours starting late tonight, and occurring each night through Thursday morning. Seas will build to up to 8 to 10 ft by early Monday. Elsewhere, a weak surface ridge extends into the area from the northwest. This ridging will support mainly gentle west to northwest flow across the open Pacific waters, occasionally pulsing to moderate just offshore of the Baja California peninsula. Seas will remain in the 4 to 6 ft range. S of 15N E of 120W: Across the Gulf of Papagayo, fresh easterly drainage flow is expected through Monday during the overnight hours helping to build fresh seas to 7 to 9 ft. Weaker winds are expected through the rest of the next week as the monsoon trough drifts slightly northward and a strong tropical wave approaches the western Caribbean. Otherwise, light to moderate flow is anticipated on either side of the monsoon trough. Long-period, cross-equatorial southwesterly swell producing seas of 4 to 7 ft will linger through most of the week. W of 120W: Ridging extending from northwest of the area is partially disrupted by the remnant trough of former tropical cyclone Frank, currently along 133W. Fresh to strong northerly winds offshore of California will generate fresh northerly swells. Seas of 8 ft will propagate down to 29N by late tonight into early Monday, decaying to less than 8 ft by the middle of the week. $$ COBB