000 AXPZ20 KNHC 201458 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1458 UTC Mon Mar 20 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... An overnight scatterometer pass confirmed winds to minimal gale force in the Gulf of Tehuantepec. These winds likely increased slightly early this morning due to local overnight coastal drainage effects, but should be diminishing below gale through early afternoon. Another pulse of gales is likely tonight, but the overall pressure gradient is starting to weaken as high pressure over the western Gulf of Mexico deceases and shifts east. 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. Northerly swell generated by this gap wind event will continue to propagate southward and mix with swell generated in the Gulf of Papagayo region as well as with cross equatorial southwest swell. This will result in combined seas of up to 10 ft in waters from 04N to 12N between 95W and 115W today and between 90W and 120W Tuesday. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A trough stretches from 03N90W to 02N90W. The ITCZ starts near 02N105W and reaches to 03N140W. A surface trough embedded in the ITCZ reaches from 03N112W to 09N112W. Scattered moderate convection is noted from 04N to 10N between 110W and 115W. ...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 24N120W will maintain gentle to moderate northwest winds across the offshore waters west of Baja California through Wednesday evening with seas of 4 to 6 ft. On Wednesday night, a cold front will start to push into northern Baja California while strong high pressure builds behind it. This will result in northwest winds around 20 to 25 kt off the coast of Baja California Wednesday night through early Friday morning as the pressure gradient increases in that zone. Seas off Baja California will build to 8 to 10 ft during that period. Winds will also increase to fresh to strong across the Gulf of California with the frontal passage over the northern and central basin Wednesday night through Thursday, and across the southern gulf Thursday afternoon through Thursday night. 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 most of the forecast period with seas 8 to 9 ft. Fresh to strong north to northeast winds are also in the Gulf of Panama and downwind to about 05N through later this morning with seas building up to 8 ft. 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 24N120W will remain nearly stationary over the next 24 hours. A cold front reaching from 30N128W to 22N140W will dissipate through late today, ahead of another cold front moving into the region. The second front will reach from 30N127W to 23N140W in 24 hours, and from 30N120W to 22N130W in 48 hours, then continue eastward into the Baja California peninsula through 72 hours. Seas will build to 11 ft across the NW waters in the wake of this front. A third cold front is forecast to reach the northwest forecast waters early Friday morning, briefly producing fresh to strong winds N of 29N and building seas of 8-10 ft. $$ CHRISTENSEN