000 AXPZ20 KNHC 210228 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Tue Mar 21 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 0000 UTC surface analysis and satellite imagery through 0200 UTC. ...SPECIAL FEATURES... The latest scatterometer pass provided observations of minimal gale force winds in the Gulf of Tehuantepec while an altimeter pass indicated seas to near 12 ft. Another pulse of minimal gale force winds is likely tonight with the assistance of the nocturnal drainage flow. 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 continues to propagate southward mixing with swell generated in the Gulf of Papagayo region as well as with cross equatorial southwest swell. This is resulting in combined seas of up to 10 ft in waters from from 10N to 13N between 95W and 102W, and from 03N to 10N between 90W and 110W. Seas will begin to gradually susbside on Tuesday. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The ITCZ extends from 07N86W to 03N100W to 04N110W, then resumes at 07N125W to 04N140W. Scattered moderate convection is noted within 60 nm north of axis between 91W and 100W. A trough stretches from 09N112W to 03N113W. Scattered moderate convection is on either side of the trough from 04N to 09N 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 1020 mb high pressure centered near 23N120W will maintain gentle to moderate northwest winds across the offshore waters west of Baja California through Wednesday with seas of 4 to 6 ft. A weakening cold front is expected to push into northern Baja California by Wednesday evening. 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 8-10 ft during that period. Winds are forecast to also increase across the north and central Gulf of California with the frontal passage Wednesday evening through Thursday, and across the southern Gulf of California Thursday afternoon through Thursday night. Currently, marine guidance suggests SW-W winds of 20-30 kt and building seas of 5-6 ft across the northern Gulf of California, and NW winds of 20-25 kt and seas of 6-7 ft across the remainder of the Gulf. 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 northerly winds are also expected tonight in the Gulf of Panama and downwind to about 05N with seas less than 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 1020 mb located near 23N120W will remain nearly stationary over the next 24 hours. A cold front extends from 30N130W to beyond 25N140W. This front will reach from 30N121W TO 21N140W Tuesday evening, and from 30N116W to 19N130W Wednesday evening, then continue eastward into the northern Baja California peninsula and the northern Gulf of California. Seas will build to 11-12 ft across the NW waters in the wake of this front by Tuesday evening. 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 12-13 ft. $$ GR