000 AXPZ20 KNHC 221546 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Sun Dec 22 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 1500 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: The pressure gradient between persistent high pressure over eastern Mexico and low pressure within the eastern north Pacific monsoon trough will continue to support gale-force gap winds in the Gulf of Tehuantepec N of 14N through tonight. Presently, strong N to NE winds extend beyond the Gulf coast to near 300 nm offshore. Seas within and just downwind of the gale force winds at expected to peak 12 to 14 ft. The high pressure will shift east by early Mon, with the pressure gradient loosening. This will diminish winds below gale force early Mon with fresh to strong northerly pulses thereafter into mid-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 large, complex, and powerful low pressure system north of the area will move NE through Mon, followed by another similar low pressure system sweeping just north of the area waters. These systems have generated several rounds of large NW swell that will propagate into the area through next week. This morning, seas greater than 12 ft cover the waters NW of a line from 30N119W to 15N130W to 09N140W, with seas peaking at 18-19 ft north of 28N between 125W and 134W. This large NW swell will continue to spread SE, covering the waters from west of Baja California near Punta Eugenia to 08N132W early this evening, when a reinforcing pulse of new NW swell will enter the NW waters, with peak seas of 20-24 ft near 30N140W. 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 11N73.5W to 09N84W to 05N92.5W to 06N104W. The ITCZ extends from 06N104W to 07.5N125W to beyond 07N140W. Scattered moderate isolated strong convection is noted from 03.5N to 09N east of 99W to the coast of Colombia. ...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 significant NW swell that will impact the waters offshore Baja California through next week. Aside from those conditions, a 1024 mb high pressure center is located near 27N129W, with an associated ridge extending southeastward to offshore of Cabo Corrientes. The pressure gradient between this area of high pressure and a trough over NW Mexico is supporting with moderate to locally fresh northerly winds across the Baja California waters, and inside the Gulf of California, while gentle to moderate winds prevail south of 20N to offshore of Manzanillo. Seas are in the 5 to 7 ft over the open waters off Mexico, except are quickly building to 7 to 12 ft well offshore Baja California. Seas are 2 to 4 ft over the Gulf of California, except 2 ft or less over the northern Gulf. For the forecast, other than the aforementioned Gale Warning in the Tehuantepec region and significant NW swell, high pressure will generally remain in place to the west of Baja California through Tue, before a weakening cold front moves into the area Tue night through Wed. Moderate northerly winds across the Baja waters will pulse to fresh at times through Tue, then increase to fresh to strong from Cabo San Lazaro northward starting Tue night, as high pressure strengthen across the region behind the dissipating cold front. Gentle to moderate winds will prevail across the remaining waters to the east. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The pressure gradient between a surface ridge extending southward 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 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, with similar winds near the Gulf of Fonseca. South of the monsoon trough and 06N, gentle to moderate S to SW winds and 3 to 5 ft seas in moderate S to SW swell prevail. Except for seas of 6 to 8 ft well offshore of western Guatemala, where NW swell from the Gulf of Tehuantepec gap wind event prevails. Active convection is present S of 09N from the coast of Colombia westward across the near and offshore waters of Panama and Costa Rica, and extends beyond 90W. For the forecast, the pressure gradient between high pressure over 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, then moderate to fresh thereafter. Gales in the Tehuantepec region will continue to generate northwesterly swell and rough seas well offshore Guatemala through early Mon. Elsewhere, winds will be moderate or weaker with moderate seas through mid-week, pulsing to moderate to fresh in the Gulf of Panama at times. Seas will build by mid-week in W-NW swell. ...REMAINDER OF THE AREA... Please read the Special Features section about large NW swell over the waters north of the ITCZ/monsoon trough through the next several days. A cold front is just north of the NW waters with moderate to fresh SW winds beginning to creep into the northwest waters N of 27N and W of 131W. High pressure at 1024 mb is ahead of the front near 27N129W. Light to gentle anticyclonic winds are elsewhere north of 22N and east of the front to 120W. The pressure gradient between the high pressure and lower pressure in the vicinity of the ITCZ is supporting moderate to fresh winds north of the ITCZ to 21N and west of 118W per overnight satellite scatterometer data, and locally to strong within 120 nm of the ITCZ west of 120W. Across the remainder of the open waters, including south of the ITCZ, gentle to moderate trades prevail. Aside from the large swell discussed above, seas are mainly in the 5 to 8 ft range except 7 to 10 ft S of 10N and W of 120W with the arrival of the NW swell. For the forecast, other than the large NW swell discussed in detail in the Special Features sections, little change in winds are forecast over the next several days, while a front manages to push SE of 30N140W by early Mon, decaying over the northern waters into mid-week. New high pressure will build into the region behind this front. Meanwhile, seas of 8 ft or greater will cover most of the waters west of 110W by early next week, and then west of 95W by mid-week. $$ Stripling