000 AXPZ20 KNHC 170926 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Sun Mar 17 2019 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: High pressure over southern Mexico will continue to support minimal gale force winds in the Gulf of Tehuantepec through early Wed. Brief lulls below gale force are likely during each afternoon starting today. Winds will then pulse to fresh to strong Wed afternoon through Thu night. Large seas up to 12-14 ft will build during the strongest winds, with resultant NE swell propagating well downstream away from the source region to near 100W through Mon. Gale Warning: A strong cold front will reach the NW part of the discussion area later today. Associated NW swell has already moved east of 140W, and fresh to strong southerly winds will spread SE of 30N140W this morning. Gale force winds are possible ahead of the front this evening through early Mon. NW swell will build to 17 ft behind the front by Mon evening, then continue to propagate across the waters W of 120W through early Wed morning while gradually subsiding. 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 extends from 07N78W to 05N87W. ITCZ extends from 05N87W to 03N105W to 05N140W. No significant rain showers are evident near the convergence zone axis. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please read the Special Features section for more details about the Gale Warning in the Gulf of Tehuantepec. Gulf of California: A weak pressure pattern will prevail through Tue with light variable winds, and seas generally 2 ft or less. A decaying front will approach the northern Gulf Tue night with winds becoming SW and increasing to 15-20 kt, and seas building to 4-6 ft in the northern Gulf. Gentle to moderate NW winds off Baja California will persist through Tue night, increasing to moderate to fresh on Wed. NW swell associated with a decaying front will build seas to 8-11 ft in the open offshore waters Wed night and Thu. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: High pres across Central America will continue to support strong winds in the Gulf of Papagayo through Mon. Winds will be greatest during overnight and early morning hours from nocturnal drainage flow. Seas will build to 10-11 ft during the strongest winds. Gulf of Panama: Fresh northerly winds will prevail in the Gulf of Panama, with other pulses of fresh to strong winds possible tonight into early Mon. Maximum seas will build to 6-8 ft the next couple of nights with these winds. Elsewhere, mainly gentle to moderate NE to E winds and 3-5 ft seas will prevail the next several days, except for 5-7 ft SW swell which will affect the waters offshore of Ecuador to the Galapagos Islands through the early part of the week. REMAINDER OF THE AREA... Please read the Special Features section for more details about the gale warning in the Open Pacific NW Waters. A broad ridge extends across the northern waters to just beyond the Revillagigedo Islands. The pressure gradient between the ridge and the ITCZ supports moderate to occasionally fresh trade winds mainly S of 20N to the ITCZ. Altimeter data showed 7 to 8 ft seas across the region. Trades will gradually diminish over the next couple days as the ridge weakens. High pressure will build by the middle of next week in the wake of a cold front, increasing trades S of 20N to the ITCZ, and allowing for seas to build to 8-11 ft combined with long period NW swell. Another cold front will approach 30N140W towards the end of the week with another large long period NW swell event. $$ Mundell