000 AXPZ20 KNHC 170152 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 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 0000 UTC surface analysis and satellite imagery through 0215 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Sharp high pressure behind a strong front in the Gulf of Mexico will continue to support gale force winds in the Gulf of Tehuantepec through early Wed. Winds will peak at 40 kt overnight tonight. Brief lulls below gale force are likely during the afternoon hours starting Sun. 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 on Sun. Associated NW swell has already arrived SE of 30N140W, and fresh to strong southerly winds will spread SE of 30N140W later tonight into Sun morning. The front will be near 30N140W by Sun evening. Gale force winds are possible ahead of the front Sun evening through early Mon morning. NW swell will build to 17 ft in the wake of 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 low pressure over northern Colombia near 09N75W to 05N87W. The ITCZ continues from 05N87W to 02N94W to 05N100W to 03N109W to 06N125W to 06N140W. Scattered moderate and isolated strong convection is from 07N to 09N between 127W and 130W. A second and active ITCZ persists S of 03.4S. Scattered moderate and isolated strong convection is S of 01S and W of 109W. ...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 relatively loose pressure pattern will prevail through Tue with light and variable winds, and seas of 2 ft or less, except higher near the entrance of the Gulf. A decaying frontal boundary will approach the northern Gulf Tue night with winds becoming SW and increasing to at least fresh. Seas will build to 4-6 ft in the northern Gulf with the increasing winds. Winds and seas will diminish and subside on Thu as the boundary washes out in the area. Gentle to moderate NW winds off Baja California will persist through Tue night, increasing to moderate to fresh thereafter as high pressure builds in behind a decaying frontal boundary. A set of NW swell will accompany the boundary, building seas to 8-11 ft in the open offshore waters. 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 to near gale force winds in the Gulf of Papagayo through Mon, with fresh to strong thereafter. Winds will be greatest during the overnight and early morning hours with the assistance of the nocturnal drainage flow. Seas will build to up 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 anticipated tonight and again Sun night into early Mon. Seas will build to 6-8 ft during the next couple of nights with these winds. Elsewhere, mainly gentle to moderate NE to E winds along with 3-5 ft seas will prevail through the next several days, except for 5-7 ft SW swell which will continue to propagate through the waters offshore of Ecuador to the Galapagos Islands region through the early part of next 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 from 32N129W SE to just beyond the Revillagigedo Islands. The pressure gradient between the ridge and the ITCZ supports moderate to locally fresh trade winds mainly S of 20N to the ITCZ. Altimeter data showed 8 to 9 ft seas across this same area. Trades will gradually diminish over the next couple days as the ridge weakens. The swell event will gradually decay through Mon. 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 next week with another large, long period NW swell event. $$ Lewitsky