000 AXPZ20 KNHC 210117 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Sat Dec 21 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 0040 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: The pressure gradient between high pressure over the western Gulf of Mexico and adjacent eastern Mexico and lower pressure within the EPAC monsoon trough will support continuing gale-force gap winds in the Gulf of Tehuantepec through Sun night. Seas during this time will peak at 12 to 18 ft. The high pressure will shift east by early Mon, with the pressure gradient loosening. This will diminish winds below gale force early next week. Please see the latest NWS 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 details. Significant NW swell: A complex and powerful low pressure well north of the area will generate several rounds of large NW swell that will propagate into the area through the weekend and early next week. The first significant set will lead to seas of 12 to 20 ft west of a line from 30N132W to 23N140W early this evening, peaking at around 23 ft near 30N140W late tonight. Seas greater than 12 ft will continue to spread SE, covering the waters west of 30N124W to 16N140W early Sat evening, then from west of Baja California near Punta Eugenia to 08N132W early Mon evening. NW swell will be reinforced into the middle of next week. Please see the latest NWS High Seas Forecast issued by the National Hurricane Center at website: https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from The ITCZ extends from Scattered moderate convection is noted from 04N to 09N between 78W and 83W, and from 06N to 09N between 134W and 138W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please read the Special Features Section for information on a Gale Warning in the Gulf of Tehuantepec, and on a significant NW swell event that will impact the waters offshore Baja California. Aside from the gale warning area, high pressure prevails over the waters offshore Baja California peninsula. The pressure gradient between this area of high pressure and a trough over western Mexico is supporting gentle to locally moderate winds over the Gulf of California southeastward to near Cabo Corrientes. Light to gentle winds prevail elsewhere over the open waters off Mexico. Seas are in the 5 to7 ft over the open waters off Mexico, and 1 to 3 ft over the Gulf of California. For the forecast, other than the aforementioned Gale Warning in the Tehuantepec region and significant incoming NW swell, gentle to moderate mainly N winds will increase slightly this weekend as a NE Pacific high pressure ridge builds toward the region. Winds will pulse to moderate to fresh at times offshore Baja California. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The pressure gradient between a surface ridge over the northwestern Caribbean Sea and the EPAC monsoon trough is supporting fresh to strong NE gap winds and seas of 5 to 6 ft in the Gulf of Papagayo region. Light to gentle winds prevail elsewhere N of the monsoon trough, except well offshore Guatemala where they are moderate to fresh downwind from a Gulf of Tehuantepec gap wind event. South of the monsoon trough, gentle to moderate southerly winds and 4 to 6 ft seas in moderate S to SW swell prevail, mixed with some NW swell from the Gulf of Tehuantepec gap wind event. For the forecast, the pressure gradient between high pressure building toward the western Caribbean and the eastern north Pacific monsoon trough will support pulsing fresh to strong NE gap winds in the Papagayo region into early Wed. Gales in the Tehuantepec region will support northerly swell and rough seas well offshore Guatemala through the weekend. Elsewhere, winds will be moderate or weaker with moderate seas through early next week, pulsing to moderate to fresh in the Gulf of Panama at times. Seas may build mid-week in NW swell. ...REMAINDER OF THE AREA... Please read the Special Features section about very rough seas expected over NW waters through the weekend and into early next week. A frontal boundary is NW of the area. Ahead of the front, fresh to strong SW winds are noted north of about 28N between 132W and 140W. A 1022 mb high is centered near 24N124W. Light winds are found elsewhere across the open waters north of 20N, with seas of 6 to 8 ft. Moderate to locally fresh trades prevail on either side of the ITCZ, south of 15N, where seas are in the 5 to 9 ft range. For the forecast, other than the NW swell and very rough seas mentioned in the Special Features sections, little change in winds are forecast over the next several days while seas of 8 ft or greater will cover most of the waters west of 110W by early next week, and then west of 100W by mid-week. $$ Lewitsky