000 AXPZ20 KNHC 160224 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 215 UTC Mon Dec 16 2019 Tropical Weather Discussion for the eastern Pacific Ocean from the Equator to 32N, east of 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 0300 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N86W to 07N100W. A segment of the ITCZ continues from 07N100W to 09N125W, with another extending from 11N133W to beyond 11N140W. Scattered moderate convection is noted from 06N to 08N between 112W and 115W, and from 13N to 15N between 123W and 125W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... In the Gulf of Tehuantepec: a strong cold front will move across the western Gulf of Mexico through Tue. High pressure will build southward across the Sierra Madre Oriental in the wake of the front. The pressure gradient between this building high pressure, and the equatorial trough in the eastern north Pacific will usher in the next gale force gap wind event Tue night. This will be a strong gap wind event, with wind speeds possibly reaching minimal storm force, and seas building in excess of 20 ft on Wed. Gale conditions are forecast to prevail through Fri. A ridge extends from high pressure centered near 35N134W to near the Revillagigedo Islands. The pressure gradient between this ridge and a surface trough across the Gulf of California is supporting fresh winds off the coast of Baja California Norte. Northerly swell continues to propagate across the forecast area, with seas near 13 ft off the coast of northern Baja California Norte, and seas greater than 8 ft covering the offshore waters W of 105W. The area of high pressure will weaken over the next 24 hours. This will loosen the pressure gradient and diminish winds off the coast of Baja California. The NW swell will slowly subside, and fall below 8 ft by Tue. A fresh set of NW swell will propagate into the waters off Baja California Norte Wed evening, with seas building to near 11 ft Thu. High pressure building over the Great Basin region will support fresh to strong NW winds across the Gulf of California late Mon through early Wed. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh winds are expected across the Gulf of Papagayo, increasing to fresh to strong Wed, and continuing through Fri. Elsewhere, gentle to moderate south to southwest monsoon flow will persist across the offshore waters of Costa Rica, Panama, Colombia, and Ecuador, while light to gentle flow will dominate across the Gulf of Panama. REMAINDER OF THE AREA... Ridging extends across the waters north of 20N. Scatterometer satellite data from earlier today showed moderate to fresh trade winds south of the ridge to the ITCZ, particularly within 120 nm near a surface trough centered along 130W. NW swell continues across the forecast waters, with seas 8 ft or greater covering much of the waters W of 105W. The NW swell will gradually subside over the next couple of days, and areal coverage of seas 8 ft or greater will decrease. A cold front will move from the north central Pacific into the region by late Mon, reaching from 30N125W to 24N140W by late Tue, before starting to weaken from near Guadalupe Island to near 22N140W by late Wed. While the front will initially weaken the subtropical ridge as it moves into the area, high pressure building behind the front will allow trade winds to increase west of 120W by mid week. A new round of long-period NW swell in excess of 8 ft will accompany the front, spreading across the region north of 10N and west of 120W. $$ Christensen