000 AXPZ20 KNHC 192123 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Sun Mar 19 2017 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... A gale warning remains in effect for the Gulf of Tehuantepec through Monday night. Winds are forecast to remain up to 40 kt through early Monday morning, with seas building up to 14 ft. Winds will diminish to near gale force afterwards, however will briefly increase again to minimal gale force Monday night. Northerly swell generated by this gap wind event will continue to propagate southward and mix with swell generated in the Gulf of Papagayo region. This will result in combined seas of up to 10 ft in waters from 04N to 11N between 90W and 110W, and from 06N to 12N between 110W and 121W on Monday. Strong winds and high seas will persist through Thursday morning as high pressure in the Gulf of Mexico enhances drainage flow across the Isthmus of Tehuantepec into the eastern Pacific Ocean. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... No ITCZ or Monsoon Trough is discernible at this time. A trough stretches from 13N124W to 05N125W. A second trough extends from 10N107W to 04N108W. Scattered moderate convection is from 06N to 09N between 112W and 120W...and from 09N to 11N between 122W and 125W. A diffluent pattern aloft is enhancing this convective activity. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See the Special Features section for information on the Gulf of Tehuantepec gap wind event. A 1022 mb high pressure centered near 24N122W will maintain gentle to locally moderate northwest winds across the offshore waters west of Baja California through Monday with seas of 4 to 6 ft. By late Monday into Tuesday, expect NW winds in the 15-20 kt range within about 75 nm of the coast of Baja California as the pressure gradient slightly tightens there. A weakening cold front is expected to push into northern Baja California by late Wednesday. A tight pressure gradient will result between the front and high pressure building behind it. This will support fresh to strong NW winds off the Baja California coast Wednesday night through Thursday night. Seas off Baja California will build to 8-9 ft during that period. Winds are forecast to also increase across the north and central Gulf of California or Sea of Cortez with the frontal passage Wednesday evening through Thursday, and across the southern Gulf of California Thursday afternoon through Thursday night. Currently, marine guidance shows SW winds of 20-25 kt and building seas of 6-7 ft ahead of the front and W-NW winds of 20-30 kt behind the front. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... High pressure will prevail over the northwest Caribbean and Gulf of Mexico, which will allow for the continuation of fresh to strong gap winds across the Gulf of Papagayo through early Thursday with seas 8 to 9 ft. Fresh to strong north to northeast winds are also forecast in the Gulf of Panama and downwind to about 05N at night through Monday night with seas building up to 8 ft near 5.5N81W by eraly Monday morning. Otherwise, light to gentle winds and combined seas of 3-5 ft are expected to continue the next several days elsewhere. REMAINDER OF THE AREA... High pressure of 1022 mb located near 24N122W will remain nearly stationary over the next 24 hours. A cold front is moving across the NW waters and extends from a weak 1013 mb low pressure near 31N132W to 22N140W. A recent altimeter pass indicated seas of 8-11 ft in NW swell in the wake of the front. The low will continue to move NE and away from the forecast area, dragging the cold front across the north waters through Monday. A reinforcing cold front will enter the NW forecast waters Monday morning and is expected to reach northern Baja California by late Wednesday. Moderate to locally fresh trades will persist elsewhere across the tropical Pacific with combined seas of 5-7 ft through Monday. Another cold front is forecast to reach the NW forecast waters late on Thursday, accompanied by fresh to strong winds and building seas of 13-14 ft. $$ GR