000 AXPZ20 KNHC 180316 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 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 0000 UTC surface analysis and satellite imagery through 0240 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: High pressure building across the Gulf of Mexico continues to force northerly gap winds across the Gulf of Tehuantepec this evening, and remain minimal gales north of 15N across Tehuantepec, then become northeasterly at 20-25 kt well downstream to near 12.5N98W. Winds are expected to drop just below gale force by around midnight and persist through sunrise before diminishing to strong winds for Sun and Sun night. Seas downwind are 10 to 12 feet. Seas should fall below 12 ft late tonight, but remain above 8 ft through early next week. ...TROPICAL WAVES... A tropical wave axis extends along 110W-111W from 05N to 16N, moving W at 15 to 20 kt. Associated convection is described below. A tropical wave axis previously analyzed along 137W has become absorbed in a quasi-stationary deep layered trough across that region, extending NNE to SSW. An associated 1007 mb low pressure center is near 15N134W and is weakening. The tropical wave will likely be dropped from the next analysis. Scattered moderate isolated strong convection is observed east of the trough from 09N to 23N between 129W and 136W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from near 10N75W to 07.5N82W to 13N90W to 09N111W to 1007 mb low pressure near 15N134W to beyond 11N140W. Scattered moderate to strong convection is noted from 03.5N to 10N E of 85W, and from 08N to 13.5N between 103W and 111W. Scattered moderate isolated strong convection is noted from 09N to 15.5N between 94W and 101W, and from 07.5N to 14N between 112W and 125W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for more details on the Gale Warning in the Gulf of Tehuantepec. A 1017 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 to the north of Punta Eugenia. Farther south, with exception of strong to gale force winds across the Gulf of Tehuantepec, gentle to moderate breezes persist. Seas are generally in the 4 to 6 ft range in mixed N and SW swell. Winds west of Baja California will diminish some 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 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 1007 mb surface low near 15N135W will weaken and move WNW 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 approach 8 ft into Mon near the monsoon trough east of 110W, 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