000 AXPZ20 KNHC 291447 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1447 UTC Tue Aug 29 2017 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... Weak low pressure embedded in the monsoon trough is centered near 16.5N 105W, around 150 nm southwest of Manzanillo Mexico. The low pressure is moving slowly to the west-northwest. A large area of scattered showers and thunderstorms is active east of the low pressure along the monsoon trough, enhanced in part by nocturnal coastal effects. A large area of strong southwest winds are converging into the low pressure, covering much of the area between 10N to 15N between 100W and 120W. Earlier altimeter satellite passes indicated these winds are supporting seas of 8 to 10 ft. Global models continue to show the low pressure becoming better organized over the next 48 hours, and there is still a high chance the low will develop into a tropical cyclone. A gale warning has been issued in anticipation of further development, covering the area between Cabo Corrientes to Cabo San Lucas, including the southern Gulf of California from Thu through the end of the week, with seas building as high as 14 ft. The low is expected to move west of Los Cabos late week, with gale or tropical storm warnings possible in the southern Gulf. For more information, see hurricanes.gov. ...TROPICAL WAVES... A tropical wave is analyzed N of 10N along 112W moving W at 10 to 15 kt. No significant convection noted along the tropical wave. A tropical wave is analyzed from 10N to 18N along 121W moving W at around 10 kt. No significant convection is noted. ..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N85W to low pressure near 16.5N105W 1006 mb to 10N140W. Scattered moderate to isolated strong convection within 90 nm either side of axis between 95W and 105W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the special features section for developing low pressure SW of Mexico near 16.5N105W. Otherwise, a ridge axis extends toward the northern offshore waters just W of 120W supporting gentle to moderate NW flow across the open waters W of the Baja California Peninsula. Winds in the Gulf of California are light and variable with seas 2 ft or less, except 3 to 5 ft near the entrance. In the Gulf of Tehuantepec, light offshore nocturnal flow is expected this week into the upcoming weekend, with light to gentle onshore flow during the day. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Weak and transient low pressure is near 10N89W. This low will move W of the area by mid-week. In the Gulf of Papagayo, gentle offshore nocturnal flow is expected this week into the upcoming weekend. Otherwise, light and variable flow is expected N of the monsoon trough through the week and into the upcoming weekend, while moderate to locally fresh southerly winds are expected S of the monsoon trough axis. Long period southerly cross-equatorial swell, in the form of 5 to 7 ft seas will gradually subside through mid-week. REMAINDER OF THE AREA... Ridging dominating the waters W of 120W will support moderate to locally fresh trades and 4 to 7 ft seas through the week and into the upcoming weekend. The pressure gradient will tighten offshore of central California later in the week which may build and send down fresh 8 ft seas into the area N of 25N between 125W and 135W. $$ Christensen