000 AXPZ20 KNHC 312201 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Fri Jan 31 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: The next gap wind event over the Gulf of Tehuantepec is expected to commence tonight as a strong cold front moves across the Gulf of Mexico. High pressure building behind the front will provide a very tight pressure gradient over the Tehuantepec region, and bring an increase in winds funneling into the Gulf of Tehuantepec. Winds will rapidly increase to gale force early Sat afternoon, and reach near storm force Sat night into Sun. Seas are expected to peak near 22 ft by Sun morning. Winds of 20 to 30 kt and seas of 8 ft or greater will extend downstream of the Tehuantepec region to beyond 100W by Sun morning. Winds will diminish rapidly late Sun night and Mon as the high shifts eastward and weakens. Please read 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. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A trough axis extends from 10N74W TO 04.5N78W TO 04N94W. The ITCZ continues from 04N94W TO 08N109W, then resumes from 06N122W TO 04.5N137W TO beyond 05N140W. Scattered moderate isolated strong convection is noted within 90 nm either side of a surface trough from 14.5N107.5W TO 10N112W TO 07N121W. Scattered moderate convection is noted within 150 NM N of the ITCZ between 126W AND 140W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Large, long-period northwest swell will continue to dominate the forecast waters west of Baja California through Sat, with seas in the 8 to 10 ft range. Seas are forecast to subside to 5 to 7 ft by Sat night. A ridge dominates the offshore forecast waters W of Baja California producing mainly gentle to moderate NW to N winds W of Baja California, and moderate to locally fresh northerly winds across the Gulf of California. Fresh to locally strong winds are expected across the Gulf of California this evening through midday Sat as high pressure across the Great Plains builds southward into northern Mexico. Seas are expected to peak around 7 ft through central portions of the Gulf during this time. A cold front will sweep southeastward across the northern half of the Baja California Peninsula Sun and Mon, to significantly increase the winds and seas west of Baja California Norte. A 1042 mb high pressure will follow the front, bringing a very tight pressure gradient just off the coast of southern California. Fresh to strong NW winds and seas in the 12 to 18 ft range are expected just off Baja California Norte Sun night into Mon. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... A weak pressure pattern will prevail through Sat, with tranquil winds across offshore waters, except for moderate to fresh gap winds over the Papagayo and Gulf of Panama regions. A tightening pressure gradient over Central America will induce strong winds in the Gulf of Papagayo region and fresh northerly winds across the Gulf of Panama during the late night and early morning hours Sat night through Mon night. Large NW swell will affect the waters off Guatemala and El Salvador on Sun and Mon generated from gale force winds in the Gulf of Tehuantepec. REMAINDER OF THE AREA... A ridge extends from a 1032 mb high near 34N131W to near the Revillagigedo Islands. The pressure gradient south of the ridge is supporting fresh to strong NE trades from 06N to 23N W of 125W, with seas of 9 to 12 ft in mixed NE and NW swell. The ridge will weaken tonight through Sun, and the trades will diminish. A dying cold front will reach the far northwest part of the area near 30N140W Sat, then stall and dissipate through Mon. A surface trough is analyzed on the 1800 UTC surface map and extends from 14.5N107.5W TO 10N112W TO 07N121W. Fresh to strong northerly winds and seas to 9 ft are noted within about 120 nm W of the trough axis. The trough is forecast to move eastward extending from 14N110W to 07N114W by Sat morning, with fresh to strong winds and seas 8 to 10 ft within about 210 nm W of the trough axis. Winds will diminish to 20 kt or less in association with this trough by Sun morning, but seas to 8 ft will persist on the E side of the trough roughly from 13N to 16N between 110W and 113W. On Sun morning, also expect fresh to strong northerly winds and seas to 8 ft near Cabo Corrientes. Long period NW swell dominates the rest of the forecast waters, with seas 8 ft or greater covering much of the area north of 05N and west of 115W. Swell will gradually diminish the next few days, with the areal coverage of 8 ft or greater seas shrinking this weekend. Significant long period NW swell will sweep into the waters north of 20N Mon and Tue. $$ Stripling