000 AXPZ20 KNHC 062106 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Sun Dec 6 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Low pressure over the SW Gulf of Mexico will move rapidly northeastward dragging a cold front across the Gulf of Mexico. The pressure gradient between high pressure building in the wake of the front and the eastern north Pacific monsoon trough will support another round of gale force gap winds in the Gulf of Tehuantepec late tonight through Wed night. Winds are forecast to increase to 30-40 kt Mon night through Wed with building seas to 15-17 ft during this period of strongest winds. 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 the coast of Colombia near 06N77W to 09N86W to a 1010 mb low pressure near 08N98W to 09N110W to 1012 mb low pressure near 13N113W to 08N130W. The ITCZ continues from 08N130W to beyond 07N140W. Scattered moderate isolated strong convection is noted from 08N to 10N between 92W and 97W, from 07N to 15N between 105W and 110W, from 10N to 13N between 110W and 153W, and from 06N to 09N W of 130W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for more on the Gulf of Tehuantepec gale force gap wind event. Elsewhere, moderate to locally fresh NW-N winds will prevail over the Gulf of California tonight, with mainly gentle to moderate winds the remainder of the forecast period. Seas will be in the 3-5 ft range. Seas continue to subside across the offshore waters of Baja California, falling below 8 ft tonight. Another set of NW swell will enter the waters off Baja California on Mon. Seas will peak near 14 or 15 ft N of Punta Eugenia on Tue. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Moderate to fresh NE to E winds are expected in the Papagayo region through Mon. Winds will increase to fresh to strong Mon night through Fri as high pressure builds over the western Caribbean. Winds may reach near gale-force Wed night and Thu. Elsewhwere, light to gentle winds are expected north of the monsoon trough, with gentle to moderate S to SW winds 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 on Mon, building seas of up to 10 or 11 ft mainly Mon night through Wed. Seas in the 4-5 ft range will prevail elsewhere. REMAINDER OF THE AREA... High pressure of 1032 mb is centered near 36N129W. The pressure gradient between this area of high pressure and lower pressure in the vicinity of the ITCZ, and within the monsoon trough, is supporting an area of fresh to locally strong trade winds roughly from 13N to 21N west of 125W. Seas are 8 to 9 ft in subsiding NW swell and NE wind waves across this area. Another area of similar wind speeds is noted between the ridge to the N and a weak low along the monsoon trough covering the waters from 15N to 19N between 112W and 120W. A ridge will persist across the northern forecast waters over the next several days, keeping a large area of fresh trade winds. A weak low pressure from southern California will reach the waters N of Punta Eugenia on Tue. The pressure gradient between the low and high pressure to the west will bring fresh to strong northerly winds over the waters N of 25N between 122W and 133W on Tue. The low will drift eastward and dissipate by late Wed. Subsiding NW swell prevails across most of the waters N of the equator and W of 110W, with seas of 7-9 ft. Another set of long period NW swell is now propagating over the NW corner of the forecast region and will spread SE across the forecast waters. This swell will bring seas greater than 12 ft over much of the waters north of 20N on Tue. Seas will peak near 15-17 ft Tue before starting to subside. Seas greater than 8 ft with this swell event will cover much of the waters west of 105W by Wed night. $$ GR