000 AXPZ20 KNHC 100914 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 917 UTC Mon Apr 10 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... Northeast Pacific Gale Warning...Low pressure north of the discussion waters will drag a cold front into the northern portion. Winds ahead of the front north of 30N will increase to gale force later today continuing through late tonight. Seas will build to greater than 12 ft later today and tonight. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough axis extends from 10N86W to 05N91W to 03N100W. The intertropical convergence zone axis extends from 05N107W to 06N114W to 02N133W. Scattered moderate and isolated strong convection is from 02N to 07N between 86W and 98W. Scattered moderate convection is within 90 nm north of the ITCZ between 127W and 132W. A surface trough is analyzed N of the ITCZ from 10N117W to 05N117W. Scattered moderate and isolated strong convection is from 05N to 10N between 114W and 123W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A ridge extends into the area from the NW to the Revillagigedo Islands. Northwest winds are moderate to fresh W of the Baja California Peninsula where seas are 8-10 ft. The seas will subside to less than 8 ft through early Tue with winds diminishing to mainly moderate as the local pressure gradient relaxes. A pulse of fresh NW swell will move back into the area with seas building to 7-10 ft Tue afternoon through mid-week. The pressure gradient will tighten supporting fresh to strong NW winds Wed through Fri helping to keep seas up. In the Gulf of California, moderate NW flow prevails along with 2-4 ft seas. Winds will become light and variable across the northern half of the Gulf tonight through the end of the week, with similar conditions spreading to the southern half of the Gulf by mid-week. Seas will subside to 2 ft or less with the diminishing winds. In the Gulf of Tehuantepec, light and variable flow will prevail through Tue night. The local pressure gradient will tighten thereafter and northerly surges of fresh to near gale force will commence early Wed through early Thu. Model guidance indicates winds potentially reaching minimal Gale force early Thu. Seas will build to 12 ft each morning during the strongest winds. Nocturnal winds will pulse to fresh to strong Thu night and Fri night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... In the Gulf of Papagayo, fresh to locally strong nocturnal drainage winds are expected this week with seas up to 5-7 ft. In the Gulf of Panama, moderate to fresh nocturnal northerly flow is expected during the overnight hours this week. Elsewhere, light to gentle winds, and combined seas of 3 to 6 ft are expected to prevail. REMAINDER OF THE AREA... Long-period 6-9 ft NW swell will decay through tonight from NW to SE, however, a new set of NW swell will quickly breach 30N140W as early as later this morning ahead of an approaching cold front. That front will slip SE of 30N140W this evening with winds just ahead of it briefly increasing to fresh to strong until around midnight tonight. The front will extend from 30N133W to 26N140W by late Tue morning, then will weaken as it approaches 120W through Thu. A reinforcing front will arrive into the northern waters Wed night ushering in another and larger set of NW swell with seas building to 12 ft near 30N by late Wed night into early Thu. The front and the associated swell will decay as they reach 120W by early Fri. Elsewhere, recent scatterometer data showed fresh to locally strong trades SW of a ridge axis that extends from 1026 mb high pressure near 30N129W to 18N110W where combined seas are 8-10 ft. Mainly moderate to fresh trades will prevail across the waters N of the ITCZ to 20N and W of 120W through the week with persistent 8-10 ft combined seas. $$ LEWITSKY