000 AXPZ20 KNHC 140925 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Thu Dec 14 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 0600 UTC surface analysis and satellite imagery through 0915 UTC. ...SPECIAL FEATURES... Tehuantepec Gale Warning: An expansive 1041 mb high pressure system over the eastern United States continues to force gale-force gap winds over the Gulf of Tehuantepec. A recent scatterometer satellite pass captured a broad area of 34-38 kt winds. The fresh to strong winds extend south to near 10N and west to 100W. Peak seas are around 15 ft. The 8 ft seas extend west- southwestward to 05N107W. The gale-force winds will end tonight into early Fri morning as a low pressure develops in the Gulf of Mexico. Strong winds will persist through the weekend. Seas will subside below 12 ft by Fri morning. NW Eastern Pacific Gale Warning: A weak 1012 mb low pressure is analyzed at 31N140W and forecast to strengthen over the next few days as it gradually moves northward. Strong to gale S-SW winds are expected ahead of its associated cold front. After the front reaches the NW corner on Thu night, near gale to gale W to NW winds behind the front should occur north of 25N and west of 125W through Fri night into early Sat. Very large NW swell will be accompanying this system with seas over 20 ft through Sun. The 12 ft seas will through the weekend, extending as far south as 16N and as far east as 125W. Please read the latest High Seas Forecast and the Offshore Waters Forecast issued by the National Hurricane Center at https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and www.nhc.noaa.gov/marine/offshores.php for details on the special feature. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from the coast of Panama near 08N78W to 05N97W and to 06N112W. The ITCZ extends from 06N112W to 07N117W. A surface trough is analyzed from 12N117W to 05N125W. The ITCZ then continues from 07N127W to beyond 08N140W. Scattered moderate to isolated strong convection is noted from 03N to 09N and between 87W and 103W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the Special Features section for details on a Gale Warning for the Tehuantepec region. A weak pressure gradient dominates the Mexican offshore waters, outside of the Gulf of Tehuantepec. Moderate or weaker winds and slight to moderate seas prevail across the offshore waters. No significant convection is noted at this time. For the forecast, ridging will build over the Great Basin in the western United States late this week. This will sustain fresh to strong NW winds over the Gulf of California starting tonight through Fri night or early Sat. Looking ahead, a new gale-force gap wind event over the Gulf of Tehuantepec is expected to begin on late Sat and continue into early next week. Rough to possibly very rough seas can be expected with these winds. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... An expansive and strong ridge centered over the eastern United States and lower pressures in the deep tropics sustain persistent fresh to strong easterly trade winds across the Gulf of Papagayo region, including the coast of southern Nicaragua. Wave heights in these waters range from 6 to 9 ft. Seas to 9 ft generated by the Gulf of Tehuantepec gap wind event continue to impact the offshore waters of Guatemala and El Salvador. The aforementioned strong pressure gradient is also supporting moderate to fresh northerly winds in the Gulf of Panama, extending south to 05N. Seas in these waters are 2-4 ft. Farther south, a recent scatterometer satellite pass captured moderate southerly winds south of 03N. Seas in these waters are 4-6. Elsewhere, light to gentle winds and slight to moderate seas prevail. For the forecast, the strong NE-E gap winds in the Gulf of Papagayo are expected through Fri, diminishing to moderate to fresh this weekend. Winds will surge again to strong speeds by Mon. The large NW swell over the Guatemala and El Salvador offshore waters will gradually diminish through tonight. Expect another round of rough seas in this area due to another Gulf of Tehuantepec gap wind event on Sun. Elsewhere, winds are moderate or weaker for the next several days. ...REMAINDER OF THE AREA... Please see the Special Features section for more information on the gale warning for the northwest waters of the area. A 1020 mb high pressure system is located to the west of California and dominates most of the tropical eastern Pacific. Moderate to fresh easterly easterly trade winds are prevalent from the deep tropics to 21N. This was confirmed by a the latest satellite-derived wind data. Seas in these waters are 6-9 ft. Meanwhile, moderate southerly winds are found south of 03N. Seas in these waters are 6-8 ft. Elsewhere, light to gentle winds and moderate seas are prevalent. For the forecast, trade winds will slowly diminish to be moderate or weaker by Fri and continue through the weekend as the extratropical low moves across the area. Large swell from the extratropical low will impact most of the waters, with the 8 ft seas extending as far south as the equator and as far east as 100W. A new gale event across the Gulf of Tehuantepec will bring rough waters to the high seas later on Sun and into Mon, extending towards 10N100W. $$ Delgado