000 AXPZ20 KNHC 120853 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0845 UTC Mon Sep 12 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 0830 UTC. ...SPECIAL FEATURES... Hurricane Orlene centered near 17.1N 119.1W or about 626 nm west- southwest of the southern tip of the Baja California peninsula moving northwest at 8 kt. Estimated minimum central pressure is 990 mb. Maximum sustained wind speed is 70 kt with gusts to 85 kt. Numerous moderate and isolated strong convection is within 120 nm of the center. Scattered moderate convection is elsewhere within 240 nm in the east semicircle. Orlene is forecast to make a turn to the north-northwest and then north with a significant decrease in forward speed during the next couple of days. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP1/WTPZ21 KNHC for more details. ...TROPICAL WAVES... A tropical wave is along 86W and north of 08N extending northward across Nicaragua and Honduras to the northwest Caribbean Sea, moving west at around 10 kt. Isolated to widely scattered convection is in the vicinity of the wave axis. A tropical wave is along 100W from 07N to 16N moving west at 10 to 15 kt. Isolated to widely scattered convection is in the vicinity of the wave axis. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 09N78W to 12N90W to low pressure near 11N106W. A trough axis extends from 12N121W to 09N140W. Scattered moderate convection is within 120 nm south of the trough axis between 120W and 128W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A sub-tropical ridge axis extends from northwest to southeast across the western portion of the offshore zones west of the Baja Peninsula. Gentle to moderate northwest flow is expected through the period, except moderate to fresh northwest flow will pulse occasionally just offshore of the central and northern Baja California Peninsula. A thermal trough will meander over the Baja Peninsula and across the northern Gulf of California through the period. This will maintain light, mostly southerly, flow across the Gulf of California for the next few days. The exception is in the northern Gulf of California where moderate south to southwest flow will increase to fresh to strong north of 30N late tonight through Tuesday night. The surface winds will veer to the northwest across the entire Gulf of California on Wednesday and continue through Friday. Fresh northerly drainage flow is expected through the morning with seas briefly building to 6 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to gentle winds are forecast to the north of about 08N through the period, while moderate southwest to west low level flow is expected across the discussion waters generally to the south of 08N. Combined seas of 4 to 7 ft are forecast across the entire area through the period, primarily in long-period southwest swell. REMAINDER OF THE AREA... Except as previously mentioned in the special features section concerning Hurricane Orlene, weak and broad troughing covers the waters north of 27N between 125W and 135W. The sub-tropical ridge will rebuild from west to east along 26N/27N during the middle of the week. $$ LEWITSKY