000 AXPZ20 KNHC 120958 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 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 0600 UTC surface analysis and satellite imagery through 0800 UTC. ...SPECIAL FEATURES... Tehuantepec Storm Warning: The most significant gap wind event thus far of the season continues tonight 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 northern Honduras. This pattern is supporting storm- force N winds from the Tehuantepec coast to near 14N, with strong to gale-force winds then extending 300 nm offshore of the coast. Evening satellite altimeter data measured high seas of 14 to 18 ft downwind of Tehuantepec, and seas are likely peaking at 18 to 21 ft tonight. Winds are expected to diminish below storm- force within the next few hours. Strong gales will then continue Thu and very slowly diminish below gale-force near sunrise on Fri. Strong to near- gale force strength winds are then expected to continue Fri through Mon morning as strong high pressure persists across the Gulf of Mexico and the NW Caribbean. Large swell of 8 ft and greater generated from this significant event will spread as far south as 06N by Thu evening, extending between the Papagayo region and 105W. Significant winds and seas occurring this weekend across Tehuantepec are only expected to extend to around 240 nm offshore. 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 09N76W to 10N85W to 06.5N92W to 07N102W. The ITCZ then continues from 07N102W to 09N118W to beyond 06.5N140W. Scattered moderate isolated strong convection is noted from 05N to 07.5N E of 80W and from 06N to 10N between 96W and 125W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the Special Features section for information on the Gulf of Tehuantepec Storm Warning. Strong high pressure over the Four Corners region of the western U.S. extending southward into the Gulf of California, to the west of troughing along the Sierra Madre Occidentals of northwest Mexico, has weakened and begun to shift eastward tonight. Strong winds across the Gulf of California and extending to offshore of Cabo Corrientes this past afternoon are steadily weakening to moderate to locally fresh tonight, with seas subsiding to 4 to 7 ft. Elsewhere a broad high pressure ridge extends southeastward into Baja California and southwestern Mexico. This pattern is producing gentle to moderate NW to N winds across the Baja offshore waters, where seas are 5 to 7 ft in NW swell, except to 8 ft NW of Isla Guadalupe. Farther south, weak ridging prevails off the coast of southwestern Mexico, leading to light to gentle winds. Seas off the coast of southwestern Mexico range from 4 to 6 ft in NW to W swell. For the forecast, winds and seas will slowly diminish across the Tehuantepec region this afternoon through Thu night with gales forecast to end near sunrise on Fri. Winds are expected to remain strong to near gale-force strength Fri through Mon morning there as a strong high pressure ridge persists across the Gulf of Mexico and the NW Caribbean. Elsewhere, moderate to locally fresh NW winds and rough seas will build across the waters north of Punta Eugenia Thu night into Fri, as a weakening cold front moves into the Baja Norte waters. High pressure will build modestly across the area waters Sat afternoon through Mon behind this dying front to bring a return to moderate to locally fresh NW to N winds across all waters W of Manzanillo. ...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 from western Cuba to northern Honduras. Fresh to strong NE winds are across the Gulf of Papagayo region, where seas are 6 to 7 ft. Elsewhere N of 10N winds are light to gentle with seas generally 4 to 6 ft. S of 10N light to moderate S to SW winds and seas of 4 to 5 ft are noted south of the monsoon trough, with moderate N winds occurring across the western Gulf of Panama. For the forecast, fresh to strong NE gap winds are expected across the Gulf of Papagayo region through Fri morning as strong high pressure persists across the NW Caribbean behind a cold front. Winds across the Papagayo region will then pulse to strong at night through Sun morning. Strong northerly winds and very rough seas occurring along the eastern edge of a strong Tehuantepec gale-force wind event will impact the offshore waters of southwestern Guatemala through 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 afternoon. Moderate N winds across the western Gulf of Panama will pulse to fresh at night 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 1027 mb high is centered northwest of the area near 38N140W, and extends a broad ridge south and southeastward to the north of the ITCZ. Moderate to fresh trades are occurring south of 25N and west of 120W, with locally strong NE to E winds occurring between 08N and 20W west of 136W, where seas are 10 to 13 ft in NW swell. North of 25N, gentle to locally moderate anticyclonic winds are noted, ahead of an approaching cold front along 32N Fresh NW swell is combining with residual seas north of the ITCZ, to produce a broad swath of seas of 8 to 11 ft north of 05N and west of 120W. South of the ITCZ, moderate to locally fresh SE winds and seas of 5 to 8 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, moderate to locally fresh trade winds will continue north of the ITCZ to around 15N between 105W and 120W. Moderate NW swell moving through the regional waters will merge with NE swell generated downwind of the Gulf of Tehuantepec to produce rough seas of 8 to 12 ft across these waters through Sun before conditions improve. An E to W ridge will move into the area waters along about 27N over the weekend to maintain fresh trade winds from 20N to the ITCZ into early next week. $$ Stripling