000 AXPZ20 KNHC 210324 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 323 UTC Tue Nov 21 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 0000 UTC surface analysis and satellite imagery through 0300 UTC. ....SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: The latest observations from Salina Cruz, on the southern coast of the isthmus of Tehuantepec indicated 20 kt northerly winds, hinting of stronger gap winds over the adjacent Gulf of Tehuantepec. The winds and seas over the Gulf will diminish through early Tue as high pressure north of the area weakens. Seas to 8 ft will linger well offshore with the assistance of long period southwest swell. These seas will subside through late Tue as the swell decays. The window of relative diminished winds and seas will be short however, as another front moving through the Gulf of Mexico will initiate a new round of strong winds into the Gulf of Tehuantepec late Wed, reaching gale force Wed night with seas building 12 to 17 ft, and may persist into Fri. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 08N78W to 06N105W. Intertropical convergence zone extends from 06N105W to 12N140W. Scattered moderate convection is observed within 60 nm of the intertropical convergence zone between 125W and 140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Features paragraph for Gulf of Tehuantepec Gale Warning. A ridge reaching from 1021 mb high pressure centered near 31N125W through the Revillagigedo Islands will maintain light to gentle breezes over the waters within 250 NM off the Baja California peninsula to the coast of central Mexico, with 3 to 5 ft seas over the next several days. Light to gentle NW winds over the Gulf of California will increase to 15 to 20 kt by late Tue as high pressure builds over the Great Basin, then diminishing by Thu. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Moderate to locally fresh NE drainage winds are forecast during the overnight hours tonight, then light drainage flow expected during the overnight hours through Thu night, with fresh to locally strong nocturnal drainage possible on Fri and Sat nights. Light and variable winds, and 3 to 5 ft seas, are expected elsewhere to the N of the monsoon trough which has been meandering from 09N to 11N, while moderate to locally fresh southerly winds, and 4 to 7 ft seas, are forecast south of the monsoon trough this week. REMAINDER OF THE AREA... A sharp deep layer trough northwest of the discussion area along 145W will make slow progress eastward against a large blocking ridge currently along 120W that will gradually deamplify as it drifts slowly eastward over the next several days. This pattern will support a persistent area of fresh to occasionally strong southerly winds in the far northwest corner of the discussion area, north of 28N and west of 135W. A strong and mostly stationary upper jet will support scattered showers and a few thunderstorms over the next couple of day north of 20N and west of 135W. Farther south, modest trade wind convergence in conjunction with upper divergence between the upper ridge to the north and an upper cyclone farther south near the equator is supporting a surface trough with a few showers and thunderstorms from 07N to 17N between 125W and 130W, and expected to drift westward through 135W over the next couple of days. Long period NW swell will propagate E across the discussion waters W of 120W from mid to late week, and subside during the upcoming weekend. $$ Christensen