000 AXPZ20 KNHC 202207 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2140 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...TROPICAL WAVES... A tropical wave is along 94W south of 12N, moving west at 10 kt. A few clusters of scattered moderate to strong thunderstorms are from 07.5N to 10N between 91W and 97W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N74W TO 06.5N80W TO low pres 1010 MB near 08.5N85W TO 09N100W TO low pres 1010 MB near 11.5N111W 08N119W TO 11.5N127W. The ITCZ continues from 11.5N127W TO beyond 10.5N140W. Scattered moderate to strong convection is noted from 07N to 10N between 91W and 101W, and from 10.5N to 16N between 105W and 114W. Scattered moderate isolated strong convection is noted from 08N to 13N W of 134W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A cold front is moving southeastward across northern portions 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 several hours ago showed seas reaching as high as 8 ft in the far northern Gulf of California, as are expected to have reached as high as 10 ft in far NE portions this afternoon. The front will move across much of the region before stalling and weakening over the southern Gulf of California and Baja California Sur on 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 cloud cover and convection aloft will move northeastward across Las 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. Looking ahead, another round of strong gap winds can be expected across 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 each night. 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 has moved WNW and merged with a broader area of weak low pressure, now centered near 11.5N111W, to the 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 merged area of low pressure 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 25.5N120W to 24.5N127W to 28N140W. 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 north of 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. A broad surface trough may form between 120W and 125W north of 20N related to the upper feature. Fresh to strong winds and building seas are possible between the trough and high pressure north of the area. $$ Stripling