000 AXPZ20 KNHC 180910 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Sun Oct 18 2020 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... Gulf of Tehuantepec: High pressure building across the Gulf of Mexico continues to force northerly gap winds across the Gulf of Tehuantepec tonight. Recent ASCAT data shows that winds have diminished to 30 kt across Tehuantepec, and gale warnings has been discontinued. Northeasterly winds at 20-25 kt continue well downstream to near 13.5N98W. These winds are expected to persist around 30 kt through sunrise before diminishing to strong winds Sun and Sun night. Peak seas are currently 10 to 11 feet, and will begin to subside by morning, but remain above 8 ft through early next week. ...TROPICAL WAVES... A tropical wave axis extends along 111W-112W from 05N to 16N, moving W at 15 to 20 kt. Associated convection is described below. A tropical wave axis previously analyzed along 138W has become absorbed in a quasi-stationary deep layered trough across that region, extending NNE to SSW. An associated 1010 mb low pressure center is near 15.5N135W and is weakening. The tropical wave has been dropped from the latest surface analysis. Scattered moderate isolated strong convection is observed east of the trough from 09N to 20N between 130W and 137.5W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from near 11N75W to 07.5N80W to 13N91W to 10N111W to 1010 mb low pressure near 15.5N135W to beyond 11N140W. Scattered moderate to strong convection is noted from 05N to 10N E of 84W, and from 07.5N to 13.5N between 94W and 114W. Scattered moderate isolated strong convection is noted from 08.5N to 14N between 114W and 126W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for more details on the recently discontinued Gale Warning in the Gulf of Tehuantepec. A 1019 mb high pressure is centered west of Baja California near 24N126W. The pressure gradient between the high pressure and lower pressure over the Sonoran desert is supporting moderate to fresh NW winds across the offshore waters of northern and central Baja California from Punta Eugenia northward. Farther south, with exception of strong winds across the Gulf of Tehuantepec, gentle to moderate breezes persist. Seas are generally in the 4 to 7 ft range in mixed N and SW swell. Winds west of Baja California will diminish some on Sun, but winds and seas will increase off Baja California Norte by early next week as high pressure strengthens and low pressure deepens over the southwest U.S. Mostly gentle to moderate breezes and slight seas will persist elsewhere. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Moderate to fresh SW winds prevail south of the monsoon trough along about 10N-11N and east of 90W. Seas are 5 to 7 ft primarily in SW swell. Moderate to fresh NE winds prevail tonight across and downstream of the Gulf of Papagayo region to 88W. The pressure gradient is subtly tightening across the southwest Caribbean, southern Central America and the tropical eastern Pacific as high pressure builds north of the area. This will support moderate to fresh gap winds across the Gulf of Papagayo region through Mon morning. Meanwhile, SW winds will increase slightly off Panama as pressure lowers over the southwest Caribbean. These increased winds will coincide with the arrival of new longer period SW swell into the waters off Central America, allowing combined seas to reach 8-9 ft between Panama and the Galapagos Islands by Mon afternoon. REMAINDER OF THE AREA... The 1010 mb surface low near 15.5N135W will weaken and move NW through Sun, then move west of the region by Mon. High pressure will then build north of 20N, supporting fresh trade winds early next week from roughly 15N to 25N mainly west of 125W. Farther east, seas will build to 8 ft into Mon near the monsoon trough between 110W and 120W, due in part to fresh northerly swell emerging out of the Gulf of Tehuantepec and new longer period SW swell moving into the area. $$ Stripling