230 AXPZ20 KNHC 162139 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Sat Dec 16 2023 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 1800 UTC surface analysis and satellite imagery through 2030 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Gale force north to northeast winds are presently occurring in the Gulf of Tehuantepec, with rough seas. These conditions will intensity through the weekend with winds peaking to 40 kt, then pulsing gales will prevail through Fri. Seas will peak to 14 ft on Tue. NW Eastern Pacific Gale Warning and Significant Swell event: A deep extratropical low pressure system is located N of the area near 33N138W. A cold front extends from 30N127W to 23N130W, then becomes stationary to 14N140W. Gale force winds are already occurring N of 28N and W of 137W. These winds will prevail S of the low as it drifts east just N of the forecast area through tonight. An extensive set of northwest swell will continue to follow the low/front over the NW section of the area and spread across most of our forecast waters through Tue. Seas are currently peaking to 25 ft within the area of gale winds, 12 to 15 ft N of 17N and W of 127W, and 8 to 12 ft N of 13N and W of 125W. Seas of 8 ft or greater will extend as S as 05N by early next week. Please read the latest NWS High Seas Forecast issued by the National Hurricane Center at https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N86W to 06N99W. The ITCZ continues from 06N99W to 08N140W. Scattered moderate convection is within 120 nm either side of the boundaries and E of 107W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the Special Features section for details on an ongoing Gulf of Tehuantepec Gale Warning. The combination of high pressure over the U.S. Great Basin and relatively lower pressure over northwest Mexico and the Gulf of California area is allowing for fresh northwest to north winds over the Gulf of California with seas to 5 ft. These winds are spilling out of the Gulf reaching as far south as the waters between Cabo Corriente and 109W. Meanwhile, weak pressure gradient dominates the Mexican offshore waters, outside of the Gulf of Tehuantepec. Moderate or weaker winds and slight to moderate seas continue across the rest of the offshore waters. Seas across the Baja California offshore waters and over the southern Mexico offshore waters are in the 4-6 ft range due to long-period west to northwest swell. No significant convection is presently noted over these waters. For the forecast, gale force winds are occurring over the gulf of Tehuantepec, with seas peaking to 10 ft. These conditions will prevail through Mon, then pulse through the week. Seas to 14 ft are expected on Tue in this area. Meanwhile, high pressure will continue to build over the Great Basin in the western United States tonight. The associated gradient will maintain fresh northwest winds over the Gulf of California through tonight, then diminish to moderate speeds through Sun and to gentle speeds Mon. Seas to around 8 ft associated with a large swell event will reach the outer offshore forecast waters of Baja California between Cabo San Lazaro and Punta Eugenia by Sun night. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate NE winds are in the Gulf of Papagayo region, including the coast of southern Nicaragua. Seas with these winds are in the range of 3-5 ft. To the northwest of the Gulf of Papagayo region, seas of 5-8 ft in a northwest swell generated by the Gulf of Tehuantepec gap wind event are over the outer offshore waters of Guatemala and El Salvador. Gentle north winds and seas of 3-4 ft are in the Gulf of Panama. Scattered showers and thunderstorms are along and just inland the coast of Colombia from 04N to 08N. For the forecast, the moderate NE winds in the Gulf of Papagayo will increase to fresh to strong beginning Mon, and continue through the middle of next week while expanding to the southwest. These winds are expected to reach near-gale force Tue and Wed. Rough seas are expected over the Guatemala and El Salvador offshore waters Sun due to the Gulf of Tehuantepec gap wind event. Elsewhere, winds are moderate or weaker for the next several days. ...REMAINDER OF THE AREA... Refer to the section above for details on the Gale Warning and significant swell event for the western portion of the basin. A deep extratropical low pressure system is located N of the area near 33N138W. A cold front extends from 30N127W to 23N130W, then becomes stationary to 14N140W. A tight pressure gradient associated with this system will remain in place over the northwest corner of the forecast area through Sun. Outside of the warning area described above, a N to S high pressure ridge offshore southern California and northern Baja California controls the gradient across the remainder of the forecast waters north of the ITCZ and west of 110W. Gentle to moderate winds are on either side of the ITCZ/Monsoon Trough with seas of 5-7 ft in mixed swell. For the forecast, gale force winds will prevail across the NW portion of the basin through tonight. The trade winds north of the ITCZ to near 13N will increase slightly to fresh speeds through Sun. Winds south of the ITCZ will be in the moderate to fresh range through Mon. Fresh to strong winds from the gap wind event of Tehuantepec will merge into the trade winds between 100W-104W by late Sun. Swell from the Tehuantepec gap wind event will spread southwest and west reaching to near 104W by late Sun, with generated seas of 8-9 ft. $$ ERA