000 AXPZ20 KNHC 200840 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Wed Nov 20 2024 Tropical Weather Discussion for the eastern Pacific Ocean from 03.4S to 30N, east of 120W including the Gulf of California, and from the Equator to 30N, between 120W and 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 Gale Warning: A gap wind event will develop in the Gulf of Tehuantepec today following a strong cold front that will progress southeastward through central Mexico. The tightening pressure gradient between building high pressure over Mexico and low pressure off the southwestern coast of Mexico will support strong N winds later this morning or afternoon with gale force winds quickly following this evening. Severe gales will be possible early Thu through Thu night. Rough seas will occur across the Gulf of Tehuantepec this evening through this weekend, with very rough seas likely in the area of strongest wind. Seas will peak around 15 ft Thu through Thu night. Gale force winds will end early Sat morning with strong winds ending by early Sun morning. Seas will fall below 12 ft by Fri night and below 8 ft by Sat night. For more details, please read the latest NWS High Seas Forecast issued by the National Hurricane Center at website https//www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 15N93W to a 1009 mb low centered near 15N102W to a 1009 mb low centered near 10N115W to 09N121W. The ITCZ then extends from 09N121W to beyond 08N140W. Scattered moderate to strong convection is occurring from 11N to 17N between 91W and 106W. Scattered moderate to locally strong convection is noted from 08N to 12N between 112W and 118W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the Special Features section for information on the upcoming Gulf of Tehuantepec Gale event. A 1022 mb high is centered near 30N124W, and ridging extends across the Baja California offshore waters. This pattern supports gentle to moderate NW winds across the Baja California waters and areas offshore of southwestern Mexico. A long-period N to NW swell continues to produce rough seas north of 23N and west of 115W, with peak seas to 11 ft north of Punta Eugenia. Meanwhile, the pressure gradient between the ridge of high pressure and troughing over NW Mexico is supporting moderate to fresh NW winds in the Gulf of California, and locally strong winds in the central Gulf, as confirmed by recent scatterometer satellite data. Seas of 3 to 5 ft are noted in this area. Elsewhere, fresh to locally strong SW winds are occurring surrounding a 1009 mb low centered near 15N102W offshore of Oaxaca. Rough seas of 8 to 11 ft are ongoing in this region. For the forecast, strong N winds will develop in the Gulf of Tehuantepec later this morning or afternoon, with gale-force winds occurring this evening through Sat. Severe gales will be possible early Thu through Thu night. Rough to very rough seas will accompany the winds, with the highest seas occurring near the strongest winds. Peak seas to 15 ft are expected Thu and Thu night. Winds and seas will slowly diminish for the second half of the weekend. Elsewhere, moderate to fresh SW winds and locally rough seas occurring offshore of Oaxaca will diminish through today. Rough seas offshore of Baja California Norte will expand southward to 22N this morning and to 19N by tonight. Another long-period N swell will reinforce rough seas offshore of Baja California Norte on Thu before seas subside on Fri. Fresh to locally strong NW winds will pulse in the central and southern Gulf of California through Thu. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate SW winds are occurring offshore of Guatemala and El Salvador, where seas of 5 to 7 ft are noted. Gentle to locally moderate S to SW winds and seas of 4 to 6 ft prevail across the remainder of the Central and South American offshore waters. For the forecast, fresh to strong N to NE winds and very rough seas associated with a Gulf of Tehuantepec gap wind event are forecast to affect the far western Guatemala offshore waters early Thu through Fri. Fresh to strong E to NE winds will then pulse in the Gulf of Papagayo Fri night into early next week. Elsewhere, moderate to locally fresh SW winds will occur offshore of Colombia and Ecuador, mainly east of 86W, on Thu and Fri as low pressure in the southwestern Caribbean strengthens. Looking ahead, a long-period S to SW swell will promote rough seas offshore of Ecuador early next week. ...REMAINDER OF THE AREA... A 1022 mb high is centered near 30N124W, and ridging extends across the waters north of the monsoon trough. Moderate to locally fresh E to NE winds are occurring along the periphery of the ridge north of the trough to 23N. A residual N swell is leading to seas of 8 to 9 ft from 07N to 18N west of 112W. Another N swell is producing seas of 8 to 11 ft north of 24N, with the highest seas occurring north of 28N and east of 121W. South of the monsoon trough, fresh to locally strong SW winds are occurring surrounding 1009 mb low centered near 15N102W, with moderate to locally fresh winds near a 1009 mb low near 10N115W. Seas of 8 to 10 ft prevail in the aforementioned areas. Otherwise, gentle to moderate SE to SW winds and seas of 5 to 7 ft prevail south of the trough. For the forecast, rough seas associated with a long-period N swell will propagate to 22N this morning and to 19N by tonight before merging with the swell along the monsoon trough. These seas will subside completely by Sat. Another long-period N swell will reinforce rough seas north of 25N later today into this weekend. Elsewhere, rough seas generated by the Gulf of Tehuantepec gap wind event will move across the high seas waters W of 97W Thu night into Sun. Looking ahead, a long-period S to SW swell will promote rough seas south of 05N Sun into early next week. $$ ADAMS