975 AXPZ20 KNHC 211502 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 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 1200 UTC surface analysis and satellite imagery through 1430 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 gale-force gap winds in the Gulf of Tehuantepec through Sun night. Seas during the warning event will peak at 12 to 14 ft. The high pressure will shift east by early Mon, with the pressure gradient loosening. Winds will diminish winds below gale force early Mon. 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 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. This morning, seas greater than 12 ft cover the waters NW of a line from 30N130W to 18N140W, with seas peaking in excess of 20 ft over the far NW waters. The rough to very rough seas will spread SE, covering the waters from west of Baja California near Punta Eugenia to 08N133W early Mon evening when a reinforcing set of NW swell arrives with peak seas of 21 ft near 30N140W. NW swell will continue to 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 10N85W to 07N104W. The ITCZ extends from 07N104W to 08N114W to beyond 08N140W. Scattered moderate convection is noted from 05N to 09N E of 80W, and from 04N to 07N between 92W and 100W. ...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 west of the Baja California peninsula. The pressure gradient between this area of high pressure and a trough over Mexico is supporting with gentle to moderate winds across much of the forecast waters. Seas are in the 5 to 7 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 NW swell, gentle to moderate mainly N winds will increase slightly this weekend as a NE Pacific high pressure ridge builds toward the region, and 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 7 ft in the Gulf of Papagayo region. Light to gentle winds prevail elsewhere N of the monsoon trough, except well offshore Guatemala where moderate to fresh winds are 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 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 extends over the far NW waters from 30N132W to 28N140W. High pressure of 1022 mb is centered near 25N125W. The pressure gradient between these features is supporting moderate SW winds within 120 nm E of the cold front. Light to gentle winds are in the vicinity of the high center. Gentle to moderate winds prevail elsewhere N of 20N. The pressure gradient between the area of high pressure and lower pressure in the vicinity of the ITCZ is supporting moderate to fresh winds N of the ITCZ to 19N and W of 118W. S of the ITCZ, gentle to moderate trades prevail. Aside from the large swell discussed above, seas are mainly in the 6-9 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. $$ AL