000 AXPZ20 KNHC 311542 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1302 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: The next gap wind event over the Gulf of Tehuantepec is expected to commence Sat afternoon 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 area, 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 will 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. Marine interests transiting the Gulf of Tehuantepec Sat night into Sun should be aware of this upcoming gap wind event, and take necessary action to avoid hazardous marine conditions over the affected waters. 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 06N77W to 05N100W. The ITCZ continues from 05N100W to 07N116W, then resumes west of a surface trough from 05N123W to 05N140W. Scattered moderate isolated strong convection is noted north of the ITCZ from 10N to 18N between 112W and 120W. This convective activity is mainly associated with the surface trough that extends from 11N115W to 07N122W. 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 central and southern Gulf of California. Fresh to locally strong winds are expected across the Gulf of California later today through Sat morning, particularly S of 29N as the high pressure located NW of Baja California remains nearly stationary over the next 24 hours. 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 in late night and early morning hours Sat night through Mon night. Large NW swell will affect the waters off Guatemala and El Salvador from gale force winds in the Gulf of Tehuantepec on Sun and Mon. REMAINDER OF THE AREA... A ridge extends from a 1029 mb high near 35N130W to near the Revillagigedo Islands. The pressure gradient south of the ridge is supporting fresh to strong NE trades from 08N to 20N 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 1200 UTC surface map and extends from 11N115W to 07N122W. 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. $$ GR