000 AXPZ20 KNHC 160951 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 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 0600 UTC surface analysis and satellite imagery through 0830 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N85W to 07N90W to 08N100W. The ITCZ continues from 08N100W to 07N110W to 06N120W to 09N133W to 11N140W. Scattered moderate convection is from 06N to 10N between 101W and 117W. 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. Storm force conditions are forecast through early Thu, however gale conditions are forecast to prevail through the upcoming weekend. A ridge extends from high pressure centered near 35N128W to near the Revillagigedo Islands. The pressure gradient between this ridge and a surface trough across the Gulf of California is supporting moderate to fresh winds off the coast of Baja California Norte. Northerly swell continues to propagate across the forecast area, with seas near 12 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 Tue and will loosen the pressure gradient, thus diminishing winds off most of Baja California offshores. High pressure building over the Great Basin region will support fresh to near gale force NW winds across the Gulf of California Mon night through early Wed. Strong winds will move across the mountain passages of Baja California Norte into the Sebastian Vizcaino Bay Mon night through Tue night. 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 and propagate SE to near the Revillagigedo Islands through the upcoming weekend. Seas will build to near 11 ft off Baja California Norte with this new set of NW swell. 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 the upcoming weekend. 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 15N. Latest scatterometer satellite data show moderate to fresh trade winds south of the ridge to the ITCZ and W of 120W. 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 this afternoon, reaching from 30N125W to 26N133W by late Tue, before starting to weaken from near 31N117W to near 25N124W 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 130W by mid week. A new round of long-period NW swell in excess of 8 ft will accompany the front with seas building to 12 ft N of 25N W of 125W. $$ NR