000 AXPZ20 KNHC 150852 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 852 UTC Thu Sep 15 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 0600 UTC surface analysis and satellite imagery through 0845 UTC. ...SPECIAL FEATURES... Tropical Storm Orlene centered near 20.1N 121.2W at 15/0900 UTC or about 652 nm west-southwest of the southern tip of the Baja California Peninsula moving west at 6 kt. Estimated minimum central pressure is 991 mb. Maximum sustained wind speed is 60 kt with gusts to 75 kt. Scattered moderate and isolated strong convection is within 45 nm of the center, except 60 nm in the northwest quadrant. Orlene is forecast to move west while accelerating and gradually weakening. See latest NHC forecast/ advisory under AWIPS/WMO headers MIATCMEP1/WTPZ21 KNHC for more details. ...TROPICAL WAVES... A tropical wave is analyzed along 97W north of 08N moving west at 5 to 10 kt. Scattered moderate convection is from 07N to 14N between 94W and 97W, and also from 14N to 16.5N between 97W and 100W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N75W to low pressure near 12.5N103.5W to 11N120W to 10N130W to 11N140W. Scattered moderate convection is from 12N to 14N between 111W and 113W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Surface ridging will continue to extend into the western portion of the area. This will support mainly moderate northwest to north flow offshore of the Pacific coast of the Baja California peninsula, diminishing to gentle late in the weekend into early next week. Winds will be mainly light and variable across the Gulf of California through the next several days as elongated troughing continues to stretch across the waters from northwest-north to the southeast-south. The one caveat to these conditions is the potential for developing low pressure to move into the area from the southeast Saturday night through early next week. Model disparities currently exist with this low, however, if it does manage to develop then conditions will deteriorate during this time period. In the Gulf of Tehuantepec, northerly winds will occasionally pulse to moderate to fresh during the overnight and early morning hours through the weekend, however, strong northerly flow is forecast late Monday night into early Tuesday. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to gentle winds are expected south of 07N through Monday. Mainly moderate southwest to west low level flow is expected across the waters southward. Combined seas of 4 to 6 ft are likely across the entire area through the weekend into early next week, in long-period southwest swell. Scattered showers and isolated thunderstorms are possible each night in the offshore waters. REMAINDER OF THE AREA... A sub-tropical ridge building from west to east across northern waters will support fresh trades through the end of the week which will build seas to 8 to 9 ft from 12N to 21N west of 136W. Winds and seas will diminish this weekend as the ridge weakens and Orlene moves west. Southwest winds feeding into the monsoon trough are expected to increase later this morning from 06N to 09N between 92W and 109W, south of the developing low pressure area near 12.5N103.5W. $$ LEWITSKY