000 AXPZ20 KNHC 310306 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Sat Oct 31 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 0200 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: High pressure and cooler, denser air behind a cold front that moved across the southwest Gulf of Mexico and is currently located over the Yucatan Peninsula continues to spill through the isthmus of Tehuantepec. Recent scatterometer data confirmed gale force winds which are peaking around 45 kt. Large fresh seas have built due to these winds, near 17 to 18 ft. Winds will diminish slightly to minimal gale force through Sat night with resultant peak seas also subsiding to 13 to 14 ft. A reinforcing cold front is expected to move into the southwest Gulf by early Sun allowing for gale force winds to increase back to near 45 kt Sun night through early next week. Northerly swell will mix with longer period southerly swell to support seas in excess of 8 ft well downstream of the Gulf of Tehuantepec, with peak seas building back to near 20 ft early next week. Please refer to the latest High Seas Forecast issued by the National Hurricane Center at: https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for further details. Potential Heavy Rainfall event: A heavy rainfall event is possible across portions of Central America late this weekend into early next week, particularly western Panama and Costa Rica to begin with, then spreading northwestward early next week. If heavy rainfall occurs, flash flooding and mudslides may be possible. Refer to statements provided by your national meteorological service for more details. ...TROPICAL WAVES... A tropical wave axis is along 89W/90W from N of 05N to across El Salvador, moving W at around 10 kt. Associated convection is described below. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 11N85W to 08N93W to 13N110W to 1014 mb low pressure near 12N123W to beyond 10N140W. Scattered moderate convection is noted from 07N to 09N between 90W and 93W, from 13N to 15N between 97W and 100W, and from 12N to 14N between 107W and 110W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the special features section for details on the Gulf of Tehuantepec Gale Warning. High pressure west of Baja California is supporting gentle to moderate northerly breezes across the Mexican offshore waters off Baja California and the Gulf of California. Seas are mostly 2 to 4 ft in both the open waters and in the Gulf of California. Seas will build to 4 to 6 ft in the waters of Baja California by early next week. Elsewhere, little change is expected through the next several days. Gentle winds persist south of Cabo Corrientes outside of the Gulf of Tehuantepec plume, but seas are likely 4 to 6 ft in mostly southerly swell, and increased southerly swell is expected to move into the area, reaching up to 8 ft off Michoacan and Guerrero by late Sat, then subsiding into early next week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Moderate south to southwest winds will prevail south of the monsoon trough through Sun, with isolated areas of fresh winds ahead of a tropical wave. Seas are expected to increase offshore of Guatemala and El Salvador through Sat night due to gale force winds in the Gulf of Tehuantepec pushing northerly waves into the area. Larger seas are expected early next week across this same area due to greater coverage and strength of the Tehuantepec gap winds NW of the area. Elsewhere seas are mainly 4 to 7 ft in mainly long period southerly swell. Seas will build slightly to the south and east of the Galapagos Islands late this weekend into early next week due to reinforcing southerly swell. Moderate offshore gap winds are expected across the Papagayo region through Sun before turning onshore Mon through Tue. REMAINDER OF THE AREA... High pressure dominates the waters north of 20N. The gradient between the high pressure and lower pressures associated with the monsoon trough will support moderate to locally fresh NE trade winds over an area roughly from the monsoon trough to 20N, west of 115W, for the next several days. Seas are 5 to 7 ft across this region, in a mix of swell and easterly wind waves. Little change is expected through the weekend. A complex low pressure system north of the Hawaiian Islands is forecast to move NE through the weekend. A weak trailing cold front may slip southeast of 30N140W early next week with winds remaining 20 kt or less. Associated seas will build to 8 to 9 ft behind this boundary Sun night through Mon night. South of the monsoon trough, moderate to fresh S to SW winds prevail between 100W and 140W, where seas are 5 to 8 ft. Minor fluctuations in winds and seas are expected across this area through the weekend. Looking ahead, computer models suggest that a tropical wave moving offshore of SW Mexico Sun and Mon could spawn a low pressure center forming west of the offshore waters in the vicinity of 10N110W by Mon morning, and move WNW through mid week. $$ Christensen