000 AXPZ20 KNHC 191512 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Sun Mar 19 2023 Tropical Weather Discussion for the eastern Pacific Ocean from 03.4S to 30N, east of 120W including the Gulf of California, and from the Equator to 30N, between 120W and 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... Gulf of Tehuantepec Gale Warning: A strong cold front is moving through the Gulf of Mexico. Cool, dense air behind the front along with a tight pressure gradient associated with high pressure building in the wake of the front will together support northerly gap winds to gale force into the Gulf of Tehuantepec today and tonight. Winds will diminish below gale by early Mon as the high pressure north of the area shifts eastward. Fresh to strong gap winds will persist over the Gulf of Tehuantepec through Mon night. Wave heights may reach as high as 14 ft, with rough seas reaching as far as 420 nm downstream through Mon. Wave heights will subside below 8 ft across the area early Tue. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The ITCZ extends from 03N115W to 00N128W. Scattered moderate convection has developed from 04N to 06N between 112W and 120W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see Special Features section for details on the gale warning in the Gulf of Tehuantepec region. In addition to the gale force winds and rough seas, scattered showers and thunderstorms are noted off western Oaxaca, from 90 to 240 nm offshore. This activity is on the northern end of a surface trough extending to the southwest of the area. Elsewhere off Mexico, weak high pressure dominates most of the waters. Light to gentle winds are present most areas, with seas of 2 to 4 ft, except less than 2 ft in the Gulf of California. For the forecast, a cold front and strong high pressure in the Gulf of Mexico will support gale force gap winds in the Gulf of Tehuantepec through tonight. A weak cold front will approach the waters offshore Baja California Norte Mon, then dissipate as it moves E across the northern Gulf of California Mon night into Tue. Another stronger cold front will cross the same area Tue night into Wed. Fresh SW to W gap winds will develop in the northern Gulf behind the first front and continue until the second front passes. Fresh to locally strong W to NW winds can be expected offshore Baja California Tue into Thu night, along with seas of 8 to 12 ft in NW swell. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to gentle variable winds prevail over the offshore waters of Central America and South America along with seas of 3 to 5 ft in SW swell. Moderate gap winds persist in the Papagayo Region. For the forecast, fresh to locally strong gap winds will pulse across the Gulf of Papagayo and the coast of Nicaragua tonight and Mon night, before a more sustained gap wind event sets up Wed. Moderate to fresh N to NE winds can be expected over the Gulf of Panama as well by mid week. Large northerly swell associated with a gale event in the Gulf of Tehuantepec can be expected well off the coast of Guatemala tonight into Tue. Gentle to moderate winds and slight seas can be expected elsewhere. REMAINDER OF THE AREA... A cold front is passing south of 30N near 125W, with a second reinforcing front following behind it to its northwest. A 1022 mb high pressure area is centered near 28N141W, with a surface ridge extending toward Clarion Island. Farther to the northwest, a third front is starting to form over the north- central Pacific well north of Hawaii. Trade wind convergence south of the ridge is supporting clusters of showers and thunderstorms along the ITCZ between 110W and 120W. Moderate to fresh trade winds mainly from 05N to 15N west of 125W are supporting 5 to 7 ft combined seas in that area. Generally slight seas are noted elsewhere. For the forecast, the first two fronts will merge later today and continue eastward north of 27N, reaching Guadalupe Island overnight and the northern coast of Baja California Norte Mon morning, before continuing southeastward and dissipating into Tue. The developing front to the northwest will move south of 30N and west of 140W tonight, then continue eastward toward Baja California through mid week. Cold air and strong high pressure building behind this front will likely support winds to gale force mainly north of the area by Tue. Strong to near-gale force winds are likely north of 25N Mon into Wed. Winds to gale force may reach as far south as 29N Tue, and a gale warning may be required. The other impact will be large NW swell following the front, with seas reaching as high as 15 to 17 ft Tue and Wed north of 27N. Wave heights in excess of 12 ft will reach as far south as 23N Wed into Thu before subsiding. Looking ahead, even as the NW swell decays Thu, it will mix with increasing shorter-period waves associated with NE trade winds, with combined significant wave heights reaching 12 ft mainly from 05N to 25N, west of 110W. Farther east, NE swell generated from the Tehuantepec gale will reach into Pacific waters as far west at 105W through Tue, before subsiding. Gentle breezes and slight seas will persist elsewhere east of 110W through mid week. $$ Christensen