000 AXPZ20 KNHC 110955 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 909 UTC Sat Jan 11 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: The next gap wind event over the Gulf of Tehunatepec is expected to commence Sat evening as a cold front moving across the Gulf of Mexico reaches the Isthmus of Tehuantepec. High pressure building in the wake of the front will provide a tight pressure gradient over the area and produce an increase in northerly winds funneling across the Gulf of Tehuantepec. Winds will rapidly increase to 30 to 40 kt early Sun morning, with seas forecast to peak near 13 ft by sunrise Sun morning. Winds will diminish below gale force by Sun night as the area of high pressure shifts eastward, and the pressure gradient 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 on this gale warning. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from northern Colombia near 09N75W to 04N80W TO 07N86W TO 04N91.5W. The ITCZ continues from 04N91.5W to 03.5N108W to beyond 07.5N140W. Scattered moderate convection is noted from 06N to 10N between 120W and 135W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A broad surface ridge extends SE across the offshore forecast waters W of Baja California to just SE of the Revillagigedo Islands. The pressure gradient between this ridge and a trough over the Gulf of California will support moderate to fresh northerly winds W of Baja California through the forecast period. Seas in the 6-8 ft range will prevail overnight before new NW swell propagate through the waters off Baja California Norte Sun. Seas associated to this swell event will peak near 14 ft W of Baja California Norte late Sun through Mon. The swell will spread southward, with seas greater than 8 ft prevailing W of the entire Baja California peninsula by Tue. The current pressure gradient is also supporting fresh to strong northerly winds across the southern Gulf of California, and also across the waters between Cabo Corrientes and Los Cabos, but will begin to diminish Sat night. Seas across the southern Gulf of California and waters just south of Cabo San Lucas are running 7-9 ft tonight and will gradually subside to 5-7 ft Sat afternoon through night as winds diminish. Fresh N to NW winds also prevail offshore or Cabo Corrientes and Las Tres Marias tonight, with strong NW winds along the coast of Cabo Corrientes. Elsewhere to the E, moderate westerly winds prevail across the near shore waters to Acapulco, and then become 10 kt or less to Puerto Angel. Light offshore winds are expected overnight across the Gulf of Tehuantepec, but will increase on Sat as a cold front moves across the western Gulf of Mexico. Please see the Special Features section above for more details on the upcoming gale force gap wind event in the Gulf of Tehuantepec. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... A tight N to S pressure gradient between a 1042 mb high pressure system across the western Atlantic and the equatorial trough is supporting strong to near gale force NE to E winds across and downstream of the Gulf of Papagayo region. Seas are currently running 6-8 ft across the area. This pattern will continue across Central America through Tue, which will continue to support fresh to strong daytime winds pulsing to near gale force each night. Seas will build to 8-10 ft each late night following the pulse of peak winds. Northerly swell generated from the upcoming gale force gap wind event in the Tehuantepec region will move SE into the Guatemala and El Salvador offshore waters on Sun. REMAINDER OF THE AREA... A surface ridge extends across the northern forecast waters from a 1039 mb high pressure located near 40N149W. The pressure gradient between the ridge and lower pressure in the vicinity of the ITCZ to the south of the ridge is producing a large area of fresh to strong trade winds that covers the waters N of the ITCZ to about 27N W of 120W. Seas are in the 9 to 13 ft range within this area of winds based on overnight altimeter data. These marine conditions are forecast to persist through the upcoming weekend as the strong high pressure prevails NW of the forecast region. New long-period NW swell will reach the NW waters late Sat, spreading SE across the forecast area through early next week. Seas are forecast to peak 14 or 15 ft roughly N of 27N between 118W and 130W by Sun evening. $$ Stripling