000 AXPZ20 KNHC 120332 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Thu Dec 12 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 0000 UTC surface analysis and satellite imagery through 0240 UTC. ...SPECIAL FEATURES... Tehuantepec Storm Warning: The most significant gap wind event thus far of the season has begun this evening across the Gulf of Tehuantepec, and will continue through Fri morning. Strong high pressure across the NW Gulf of Mexico is building southward across the region, behind a cold front stretching across western Cuba to the southern Yucatan Peninsula and into southern Mexico. This pattern is supporting storm-force N winds from the Tehuantepec coast to near 14.5N, with strong to gale-force winds then extending 300 nm offshore of the coast. Seas will quickly build to 18 to 22 ft this evening and tonight. Winds are expected to diminish below storm-force after midnight tonight. Gales are then forecast to persist through late Thu evening. Winds will gradually diminish to strong to near-gale force strength late Thu night and continue to pulse through into the middle of next week. Large swell 8 ft and greater generated from this significant event will spread as far south as 07N by Thu afteroon, extending between the Papagayo region and 105W. Please read the latest High Seas and Offshore Waters Forecasts issued by the National Hurricane Center at website: https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and https://www.nhc.noaa.gov/marine/offshores_eastpac.php for more information. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N75W to 10N85W to 07N89W to 06N100W. The ITCZ then continues from 06N100W to 08.5N115W to beyond 07N140W. Scattered moderate convection is occurring from 06.5N to 09.5N between 97.5W and 122W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the Special Features section for information on the Gulf of Tehuantepec Storm Warning. A strong pressure gradient between a 1031 mb high over the Four Corners region of the western U.S. and troughing along the Sierra Madre Occidentals of northwest Mexico continues to support fresh to strong NW winds through the entire length of the Gulf of California, where seas are now 6 to 9 ft. Fresh N winds are also E through SE of Cabo San Lucas. Moderate to locally fresh NE winds occurring through the gaps of the Baja Peninsula and adjacent waters this afternoon have ended, with gentle to moderate NW to N winds now prevailing across the Baja California offshore waters. Farther south, weak ridging prevails off the coast of southwestern Mexico, leading to light to gentle winds. Seas off the coast of Baja California and southwestern Mexico range from 4 to 7 ft in NW to W swell. For the forecast, aside from the storm-force winds across the Gulf of Tehuantepec, a weakening pressure gradient between high pressure in the Great Basin of the United States and troughing in northwestern Mexico will lead to diminishing winds in the Gulf of California and offshore of Baja tonight into Thu. A cold front moving through the eastern Pacific off the coast of California will lead to moderate to locally fresh NW winds and rough seas north of Punta Eugenia Thu night into Fri, followed by moderate NW swell moving into the Baja waters Fri through Sat. Looking ahead, high pressure building into the region from the NW this weekend will support moderate to locally fresh N to NW winds across the Gulf of California, offshore of Baja California and southwestern Mexico. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... A tightening pressure gradient across Central America is developing as strong high pressure over the Gulf of Mexico is building southward into the region behind a cold front across the northwestern Caribbean that stretches through the southern Yucatan Peninsula and into southern Mexico. Fresh NE winds across the Gulf of Papagayo region are expected to become strong in the next few hours as the front drifts southward. Seas N of 10N are generally 4 to 6 ft. Otherwise, light to moderate S to SW winds and seas of 4 to 5 ft are noted south of the monsoon trough, with gentle to locally moderate winds occurring to the north. For the forecast, fresh NE gap winds across the Gulf of Papagayo will increase to strong this evening through Thu, then pulse to strong at night through Fri night, as strong high pressure behind a cold front across the northwestern Caribbean prevails across the region. Strong winds and very rough seas along the eastern edge of a significant Tehuantepec storm-force wind event will impact the offshore waters of southwestern Guatemala tonight through early Fri, with associated NW swell spreading to offshore of Papagayo by Thu afternoon. Winds offshore of Guatemala will diminish Thu night with seas slowly subsiding through Fri. Moderate N winds will also pulse to locally fresh across the western Gulf of Panama through this weekend. Otherwise, gentle to moderate S to SW winds and moderate seas will prevail south of the monsoon trough, with gentle winds and slight seas occurring north of the trough, away from the gap winds. ...REMAINDER OF THE AREA... A 1024 mb high is centered northwest of the area near 31N148W, and extends a broad ridge south and southeastward to the north of the ITCZ. Moderate to fresh trades are occurring south of 24N and west of 118W, with locally strong NE to E winds occurring between 14N and 20W west of 130W, where seas are 10 to 13 ft. North of 24N, gentle to locally moderate winds are noted, as a dying cold front extends from 30N132W to 27N140W. Fresh NW swell is combining with residual seas north of the ITCZ, to produce a broad swath of seas of 8 to 10 ft north of 08N and west of 120W. South of the ITCZ, moderate to locally fresh SE winds and seas of 4 to 7 ft prevail. For the forecast, the NW swell will propagate southeastward over the next several days, with this swell combining with trade wind swell along and north of the ITCZ. This will maintain seas of 8 ft and higher north of 06N and west of 118W tonight through Fri. Peak seas around 13 ft are expected in the far western waters between 10N and 20N west of 135W in the zone of strongest trade winds. These fresh to strong trades winds will continue from north of the ITCZ to 20N, west of 120W. Farther east, strong NE to E winds and rough to very rough seas will develop downwind of the Gulf of Tehuantepec and Gulf of Papagayo tonight through Thu night, with strong NE to E winds from Tehuantepec extending SW into the waters north of 08N and east of 107W. Rough seas of 8 to 12 will extend well SW of Tehuantepec and reach from 04N to 14N and E of 110W by early Fri. $$ Stripling