000 AXPZ20 KNHC 160236 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Fri Sep 16 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 0000 UTC surface analysis and satellite imagery through 0200 UTC. ...SPECIAL FEATURES... Tropical Storm Orlene centered near 19.7N 123.8W at 0300 UTC moving west at 11 kt. Estimated minimum central pressure 998 mb. Maximum sustained winds are 65 kt with gusts to 80 kt. Numerous moderate isolated strong convection is within 60 nm of the center. It is expected to move west and continue to weaken through Sun. See latest NHC forecast/ advisory under AWIPS/WMO headers MIATCMEP1/WTPZ21 KNHC for more details. A broad and disorganized area of low pressure centered about 400 nm southwest of Acapulco embedded within the monsoon trough is expected to deepen this weekend. Global models show it becoming better organized as it moves to the north-northwest in the next three days...and could become a tropical depression by Sunday. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N85W to a 1007 mb low pressure centered near 12N106W to 10N130W. Scattered moderate isolated strong convection is within 180 nm south of the trough axis between 89W and 105W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Surface ridging reaches from 1026 mb high pressure near 37N140W through Baja California Sur, supporting moderate to locally fresh northerly flow off the Pacific coast of Baja California with 4 to 6 ft seas. Winds will diminish tonight and Friday, with gentle to moderate winds persisting into Sunday west of Baja California, and light winds in the Gulf of California. The tropical disturbance southwest of Acapulco expected to develop this weekend will approach the Revillagigedo Islands Sunday. Even if it does not develop into a tropical cyclone, there is good potential for strong southerly winds between Revillagigedo and Cabo Corrientes and Cabo San Lucas Sunday into Monday with seas to 11-12 ft. In the Gulf of Tehuantepec, northerly winds will occasionally pulse to moderate to fresh during overnight and early morning hours through the weekend. Strong northerly flow is expected late Monday night into early Tuesday from the development of another low pressure area farther south. 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 early next week. 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 next week from long-period southwesterly swell. Scattered showers and isolated thunderstorms are possible at night in offshore waters. REMAINDER OF THE AREA... A subtropical 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 ft from 12N to 20N west of 135W. 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 Friday morning from 07N to 11N between 90W and 100W, south of the developing low pressure area, then diminish through Sunday as the low pressure moves north. $$ Mundell