000 AXPZ20 KNHC 010910 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Mon Jan 1 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 0900 UTC. ...SPECIAL FEATURES... Large Swell Event Across Eastern Pacific: Large NW swell of 12 to 14 ft is occurring from 04N to 20N west of 110W, and with a new swell group impacting waters north of 27N and west of 115W. Seas elsewhere west of 90W are 8 to 12 ft in a mix of swell, to include shorter period swell emerging from persistent gap winds across the Gulf of Tehuantepec and Gulf of Papagayo. Please refer to the High Seas Forecast issued by the National Hurricane Center at https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for details on both special features. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from the coast of Costa Rica near 09N84W to 05N90W to 05N95W. The ITCZ extends from 05N95W to 1012 mb low pressure near 08N117W. Another segment of the ITCZ extends from 05N125W to 04N140W. Scattered moderate convection is noted within 120 nm in the northeastern semicircle of the low pressure near 08N117W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A recent scatterometer satellite pass indicated fresh N winds are pulsing in the Gulf of Tehuantepec. Gentle winds are observed elsewhere. Recent altimeter satellite data from 0440 UTC along with earlier data showed combined seas of 10 to 12 ft along and west of 110W, including the waters offshore of Baja California south of Punta Eugenia, due to long- period NW swell mentioned in the Special Features section. Seas across the waters to the east of 110W are 7 to 10 ft in NW swell. In the Gulf of California, seas are 2 to 3 ft. For the forecast, winds will briefly pulse to minimal gale force across the Gulf of Tehuantepec tonight, related to a cold from moving through the Gulf of Mexico. Farther north, large NW swell off Baja California Sur will subside below 12 ft overnight. New NW swell will accompany and cold front moving into Baja California Norte today. Combined seas off Baja California will subside below 8 ft into mid week. Looking ahead, the next cold front will reach the waters west of Baja California late Wed. Another round of large NW swell will follow in behind this front, affecting the waters west of Baja California Wed night through the end of the week. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to strong NE gap winds persist across the Gulf of Papagayo. Seas are estimated near 8 ft. Farther north, seas of 7 to 9 ft in NW to N swell is noted offshore Guatemala and El Salvador due to a Gulf of Tehuantepec gap wind event. Moderate to fresh N winds continue in the Gulf of Panama. Elsewhere, quiescent marine conditions dominate the waters with gentle to moderate winds and seas of 4 to 6 ft in mixed swell. For the forecast, a building ridge north of the area will support fresh to strong NE gap winds over the Gulf of Papagayo through Wed night, with 6 to 9 ft combined seas. Meanwhile, seas of 6 to 9 ft will also continue offshore Guatemala and El Salvador into mid- week due to continued NW swell over the area. Fresh N winds will pulse at night in the Gulf of Panama through Tue night. Otherwise, a weak pressure gradient will result in moderate or lighter winds across the rest of the area through early next week. ...REMAINDER OF THE AREA... See the Special Features Section above for details on the large NW swell across most of the forecast waters. The pressure gradient between high pressure ridging along 25N and lower pressure associated with the ITCZ is yielding fresh to strong NE trades from 05N to 20N and west of 125W. Moderate to locally fresh trades are noted elsewhere from the ITCZ to 22N, and west of 110W. South of the ITCZ and monsoon trough, winds are moderate or less. A cold front extends from a very weak 1022 mb low pressure area centered near 32N123W to 27N122W to 24N130W with fresh strong winds on both sides of the front, north of 28N between 120W and 125W, north of 25N. Farther east, a 1012 mb low pressure area is analyzed along the ITCZ near 08N117W. A recent scatterometer satellite pass indicated moderate winds near the center, but concurrent altimeter satellite data shows 8 to 10 ft combined seas near the center, likely in NW swell. For the forecast, large swell in excess of 12 ft will persist mainly north of 28N between 125W and 135W in the new group of NW swell accompanying the front move eastward to the north of 25N today. Combined seas of 8 to 11 ft will persist elsewhere mainly west of 90W, and primarily in NW swell although shorter period swell is mixing into the combined seas east of 95W to plumes of gap winds in the Gulf of Tehuantepec and Papagayo. The next cold front will enter the northwest waters tonight, extend from near 30N129W to 26N140W Tue evening, and from near 30N118W to 25N130W by midday Wed. Large NW swell coming in behind this front will build seas to 12 to 15 ft across the waters north of 25N Tue night through Thu. $$ Christensen