000 AXPZ20 KNHC 110903 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0902 UTC Sun Sep 11 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 0900 UTC. ...SPECIAL FEATURES... Tropical Storm Orlene centered near 14.8N 115.9W or about 595 nm southwest of the southern tip of the Baja California Peninsula moving northwest at 11 kt. Estimated minimum central pressure is 1006 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Numerous moderate and isolated strong convection is within 240 nm in the northwest semicircle and 180 nm in the east quadrant. Orlene is forecast to move to the west-northwest strengthening to a minimal hurricane by Monday afternoon, with a significant decrease in forward speed through the early part of the week. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP1/WTPZ21 KNHC for more details. ...TROPICAL WAVES... A tropical wave extends from the far southwest Gulf of Mexico southward across southeast Mexico to southwest of the Gulf of Tehuantepec near 11N97W, moving west at around 10 to 15 kt. Associated convection is lagging behind the wave axis with scattered moderate and isolated convection within from 06N to 14N between 93W and 99W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N83W to 10N96W to 11N107W, then resumes from near 11N124W to 12N140W. Scattered moderate convection is north of 02N east of 80W including the Gulf of Panama, and also within 120 nm south of the axis between 103W and 106W. ...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 develop along the central Baja Peninsula briefly on Monday evening. 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 through today. Guidance is suggesting moderate south to southwest flow over the northern gulf waters along 30N/31N tonight, and fresh to moderate southerly flow in the same area on Monday night into Tuesday. The low level flow will veer to the northwest across the entire Gulf of California on Wednesday. Model guidance indicates a fresh to strong northerly surge will develop across, and just downstream of the Gulf of Tehuantepec tonight with seas building briefly to 6 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light and variable 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 are forecast to be 4 to 7 ft 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 Orlene, a weak trough analyzed from 15N to 22N along 130W will continue to drift west across the waters and gradually fill through Monday. A 1021 mb surface high pressure east of the trough near 29N125W will lose identity as the sub-tropical ridge rebuild from west to east along 26N early next week after the trough dissipates. $$ LEWITSKY