000 AXPZ20 KNHC 080845 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Tue Dec 8 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 0840 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: The pressure gradient between high pressure along the eastern slopes of the Sierra Madre in eastern Mexico and the eastern north Pacific monsoon trough is supporting gale force winds in the Gulf of Tehuantepec. Winds are forecast to remain in the 35 to 40 kt range through Wed before diminishing below gale force Wed night. Seas are peaking near 17 ft early this morning. Swell from these gales will spread well away from the Tehuantepec region, with seas 8 ft or greater reaching as far west as 110W by Wed. Please read the latest NWS High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFEP2.html for more details. Of note: Based on the last 20 years, 329 gale and 106 storm- force gap wind events have been observed in the Tehuantepec region, an average of 16 gale and 5 storm events per cold season. The average starting date for Tehuantepec gale events is around October 25th, and the average date of the last event is around April 9th. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N84W to 08N104W to 11N120W to 09N128W. The ITCZ continues from 09N128W to beyond 08N140W. Scattered moderate convection is noted from 07N to 09N between 100W and 102W, and from 08N to 10N between 120W and 140W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for more on the Gulf of Tehuantepec gale force gap wind. NW swell has propagated into the waters west of Baja California Norte, with seas in the 7-10 ft range. The swell will continue to propagate southward across the waters west of Baja California, peaking near 14 or 15 ft N of Punta Eugenia today. Seas greater than 8 ft will prevail through the week, then subside below 8 ft Sat. Elsewhere, over the waters off SW Mexico, seas are in the 4-5 ft range. Seas will build to 7-9 ft Wed through Thursday in a mix of large NW swell, and NE swell generated by the Gulf of Tehuantepec gale force gap wind event. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh to strong winds will prevail through early Fri as high pressure builds over the western Caribbean. Winds may reach near gale- force Wed. Seas will build to near 10-11 ft Thu, with seas greater than 8 ft extending well downwind of the Papagayo region by the end of the week. Elsewhwere, gentle to moderate S to SW winds will prevail south of the monsoon trough through the next several days. Swell generated in the Tehuantepec region will propagate over the waters off Guatemala and El Salvador, building seas of up to 10 ft through the middle of the week. Seas in the 4-6 ft range will prevail elsewhere. REMAINDER OF THE AREA... The pressure gradient between high pressure north of the area near 34N134W and lower pressure in the vicinity of the ITCZ, and within the monsoon trough, is supporting an area of moderate to fresh trade winds roughly from 10N to 20N west of 125W. Low pressure is centered near 30N122W. The pressure gradient between the area of high pressure and this low is supporting fresh to strong winds west of the low. The low will gradually weaken and dissipate by Wed night. Winds will decrease Wed as the low weakens. Long period NW swell is propagating over the NW portion of the forecast region, and will continue to spread SE across the forecast waters. Seas greater than 8 ft currently cover the waters NW of a line from 30N117W to 08N140W, with seas peaking near 17 ft over the far N waters. This swell will bring seas greater than 12 ft over much of the waters north of 20N today. Seas greater than 8 ft with this swell will cover much of the waters west of 105W by Wed night. Seas will slowly subside, and fall below 8 ft over much of this area by Sat. $$ AL