000 AXPZ20 KNHC 170935 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Fri Jan 17 2020 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 0900 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: High pressure across the southern Gulf of Mexico continues to support strong to minimal gale force northerly winds across the Tehuantepec region. Winds are greatest during the overnight and early morning hours, from nocturnal drainage flow. Highest seas will reach 11-12 ft during the periods of gales. Seas in excess of 8 ft continue to reach several hundred miles downstream, mixing with longer period NW swell. Looking ahead, a cold front will move across the Gulf of Mexico this weekend and induce a stronger and much broader gale wind event across Tehuantepec Mon night and Tue, with northerly winds reaching 35 to 40 kt, and seas to 16-17 ft. Papagayo region Gale Warning: A broad persistent ridge across the Caribbean and Central America is supporting strong to near gale force NE to E winds across and downstream of the Papagayo region, extending downstream to 240 nm. Winds will briefly pulse to minimal gale force late tonight and Sat morning. The synoptic pattern will persist through the weekend. Seas will build to 10 to 11 ft each night during the period of peak winds. Please see the latest High Seas Forecast issued by the National Hurricane Center under AWIPS/WMO headers FZPN03 KNHC/HSFEP2 or at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for further details on these two Gale Warnings. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from near 06N78W to 05N97W. The ITCZ continues from 05N97W to 08N140W. No significant convection is observed. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see above for more on the latest gale force gap wind event in the Gulf of Tehuantepec. A ridge extends from a 1021 mb high pressure located near 29N121W to Cabo San Lucas. Ship observations show an area of fresh winds off Baja California Sur. This is part of a larger plume of anticyclonic winds east of the peninsula, with a relatively tight pressure gradient. Seas are estimated to be 7 to 9 ft in the area of highest winds. An upper trough moving across Baja California is producing unsettled weather over Baja California Sur and the central and southern Gulf of California. Winds will diminish today as the high weakens ahead of a weak cold front approaching Baja California Norte. High pressure building behind this front through today will support fresh NW winds north of Punta Eugenia, and fresh to strong NW winds over the central Gulf of California late tonight through Sat night. Winds will diminish Sun and Mon, although winds may increase to 20-25 kt farther south off Cabo Corrientes. Looking ahead, a new cold front will approach Baja California Norte and Guadalupe Island Tue and Tue night, accompanied by NW swell of 8-10 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please see above for more on the latest gale force gap wind event in the Papagayo region. The pressure gradient responsible for the gap winds in southern Mexico and Central America is also supporting fresh to strong NE to E winds across the waters of northern Nicaragua and offshore of the Gulf of Fonseca, as well as fresh northerly winds in the Gulf of Panama. Winds across the Gulf of Panama and downstream to near 04N will increase each night this week, with downstream seas building to 6-7 ft by sunrise. REMAINDER OF THE AREA... Scatterometer data shows a large area of fresh to strong trade winds between 10N and 18N. Earlier altimeter passes showed seas reaching 11-12 ft in this area, likely due to NW swell mixing with shorter period wind waves. Winds will diminish today as high pressure weakens ahead of a cold front entering the area N of 28N. The front will stall then dissipate later today. High pressure building behind the front will support a large area of fresh to strong trade winds south of 20N west of 120W through Sat. Seas in this area will be 8-10 ft. Farther east, 8-9 ft seas persist between 06N-12N between 95W and 120W, due to swell originating from ongoing gap winds farther east in the Gulf of Tehuantepec and off the Nicaraguan coast. The synoptic pattern will change significantly early Sun, as a deep layer trough north of Hawaii shifts eastward. An associated surface low will drift eastward along roughly 25N, reaching 135W by late Sat into early Sun. Strong to near gale force SW winds, with seas to at least 12 ft may accompany this low within 360 nm radius on its southeast semicircle as it moves to the northeast. The low and associated weather is expected to move north of 30N by late Mon, leaving a trailing trough toward roughly 10N140W. $$ Mundell