000 AXPZ20 KNHC 201532 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1532 UTC Wed Nov 20 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...TROPICAL WAVES... The axis of a tropical wave is near 93W from 04N to 12N, moving west at 10 kt. A few showers are possible where the tropical wave axis intersects the monsoon trough near 10N. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 07N78W to 10N90W to low pressure near 11N110W to 10N120W. The ITCZ continues from 10N120W to 10N140W. Scattered moderate isolated strong convection was noted from 07N to 10N between 95W and 105W. Scattered moderate to isolated strong convection was noted from 12N to 18N between 108W and 112W. Scattered moderate convection also noted from 08N to 10N between 113W and 117W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A cold front is moving into the northern portion of Baja California Norte currently. Strong to near gale force SW winds are ongoing over the northern Gulf of California ahead of the front, and an accompanying pre-frontal trough. An altimeter pass from a few hours ago showed seas reaching possible as high as 8 ft in the far northern Gulf of California. The front will move across much of the region before stalling and weakening over the southern Gulf of California and Baja California Sur Fri. The strong W to SW winds will persist over the northern Gulf of California. Off the Pacific coast of Baja California, mostly moderate to fresh NW winds will follow the front, then diminish through Thu as high pressure builds into the region in the wake of the front. Longer period NW swell is following the front as well. A recent altimeter pass from around 1330 UTC showed 8 to 10 ft seas reaching as far south as Guadalupe Island. The swell will encompass the entire offshore waters of Baja California, with heights of 8 to 10 ft reaching as far south as 20N through late Thu, before starting to subside below 8 ft into Sat. Farther south, clusters of showers and thunderstorms are active in the waters beyond 120 nm off Cabo Corrientes. This is in an area of unstable deep layer tropical moisture, with lift provided on the eastern side of an mid/upper trough well west of the area. Some of this activity may move northward into the Tres Marias area and the entrance to Gulf of California through tonight and Thu as the trough drifts eastward. The showers and thunderstorms will diminish through late Thu as the main moisture is shunted west of the area. Seas are 4 to 6 ft in a mix of NW and SW swell over offshore Mexican waters south of Cabo Corrientes. Winds may briefly increase fresh to strong off Cabo Corrientes late Fri as high pressure builds in the wake of the cold front. Winds are diminishing through the Gulf of Tehuantepec, recovering from a brief pulse of overnight strong gap winds. Looking ahead, another round of strong gap winds can be expected into the Gulf of Tehuantepec by late Sat into early Sun. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to strong NE-E winds are expected across the Gulf of Papagayo through Thu with seas building to around 7 ft. Elsewhere, gentle to moderate southwest monsoonal flow will continue across the offshore waters of Costa Rica, Panama, Colombia, and Ecuador for the next several days, along with light to moderate long period SW swell. REMAINDER OF THE AREA... The remnant low of Tropical Depression Twenty-One-E is near 12N111W, just northwest of Clipperton Island. The low pressure is drifting westward and is interacting with a mid/upper trough west of the area. This interaction is supporting a large area of showers and thunderstorms from near the low pressure northward to just east of the Revillagigedo Islands. This remnant low is forecast to gradually shift west across the tropics for the next few days. Easterly winds to around 20 kt could persist across the N semicircle of this low during this time. A cold front reaches from northern Baja California Norte to westward along roughly 25N/26N to 140W. The front will move as far south as 18N to 20N through late week before stalling and dissipating. The front has temporarily disrupted the subtropical ridge dominance, allowing only moderate trade winds farther south into the deep tropics along the ITCZ. Fresh NE winds are possible west of 130W by late week as high pressure builds behind the front farther east. This will coincide with a push of long period NW swell forecast to reach the forecast waters north of 20N west of 130W by Thu night, with seas peaking near 12 or 13 ft by Fri. Looking ahead, global models are indicating another vigorous deep layer trough digging into the waters north of 20N Sat into Sun. This may re-energize the persistent remnant of Twenty-One-E, allowing it or a remnant trough to deepen along 125W north of 20N with fresh to strong winds and building seas possible between the trough and high pressure farther north. $$ Christensen