000 AXPZ20 KNHC 202205 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Mon Mar 20 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 1800 UTC surface analysis and satellite imagery through 2145 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A tight pressure gradient in southeastern Mexico resulting from high pressure that is building southward along the Sierra Madre Oriental Mountains of Mexico is causing a gap wind gale event in the Gulf of Tehuantepec. Winds will diminish below gale late tonight as the high pressure north of the area shifts eastward and the present tight gradient that is over southeastern Mexico slackens. Fresh to strong gap winds will continue in the Gulf of Tehuantepec into Tue. Wave heights currently peaking to 14 ft are forecast to subside to 10 ft late tonight. Wave heights will subside below 8 ft across the area early Tue. Pacific Gale Warning for far northern waters behind a Cold Front: A cold front over the northwest part of the area is analyzed from near 30N134W to west of the area at 26N140W. Strong high pressure building in behind the front with cold-air advection will lead to gale-force W to NW winds by late tonight and into early on Tue north of about 29N and between 130W-135W, with strong to near- gale force winds north of 25N into Wed. Winds to gale-force will reach as far south as 29N Tue. These winds will diminish below gale- force late Tue, but strong to near-gale force winds will persist north of 28N east of 125W through Tue night. Pacific Significant Swell Event: The other hazard from the aforementioned cold front will be large NW swell following the front, with seas reaching to about 18 ft late Tue into early on Wed north of 27N. Wave heights in excess of 12 ft will reach as far south as 23N Wed into Wed night before subsiding. Looking ahead, even as the NW swell decays Thu into Fri, it will mix with increasing shorter-period waves associated with northeast trade winds along with combined significant wave heights reaching 12 ft mainly from 05N to 25N and west of 110W. Please read the latest High Seas Forecast at https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and Offshore Waters Forecast at www.nhc.noaa.gov/marine/offshores.php for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The ITCZ extends from 03N111W to 03N124W and to below the Equator at 130W. Scattered moderate to isolated strong convection is seen within 60 nm north of the ITCZ between 123W-126W. Scattered moderate convection is within 120 nm north of the ITCZ between 119W-123W and within 60 nm north of the ITCZ between 116W-119W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see Special Features section for details on an ongoing gale warning in the Gulf of Tehuantepec region. Elsewhere off Mexico, weak high pressure dominates most of the waters. Light to gentle winds are present over most of these waters along with seas of 3-4 ft, except less than 2 ft in the Gulf of California. For the forecast, a weak cold front that extends from the northern Baja California to 27N116W and to near 23N121W will dissipate as it moves east across the northern and central Gulf of California through late Tue. A stronger cold front will cross the same area Tue night into Wed. Fresh to locally strong southwest to west gap winds will develop in the northern Gulf behind the first front and continue until the second front passes. Fresh to locally strong west to northwest winds can be expected offshore Baja California Tue into Thu night, along with seas of 8-12 ft due to long-period NW swell. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh gap winds are occurring across the Gulf of Papagayo due to high pressure building north of the area. Elsewhere, light to gentle variable winds prevail over the offshore waters of Central America and South America along with seas of 3-5 ft due to a long-period south to southwest swell. For the forecast, fresh to locally strong gap winds will pulse in the Gulf of Papagayo and the coast of Nicaragua tonight, before a more sustained gap wind sets up Tue night with winds to 30 kt into Wed. Moderate to fresh north to northeast winds can be expected over the Gulf of Panama as well starting tonight. Large long-period swell associated with an ongoing gale event in the Gulf of Tehuantepec will be well off the coast of Guatemala through tonight. Gentle to moderate winds and slight seas will prevail elsewhere. REMAINDER OF THE AREA... Please see Special Features section above for details on a gale warning well west of Baja California Norte Tue as well as significant seas over the northern waters into mid-week. A cold front extends from northern Baja California to 27N118W and to near 23N124W. Another cold front over the northwest part of the area is analyzed along a position from near 30N134W to 27N140W. Weak high pressure ridging is the main feature over the area to the south of these fronts. Moderate to fresh trade winds mainly from 02N to 15N west of 118W are supporting combined seas of 4-6 ft in that area. Generally slight seas are noted elsewhere. For the forecast, the first front will dissipate as it moves east across the northern and central Gulf of California through late Tue. The next cold front will move east across the northern and central waters through Wed as its southern part weakens and dissipates. Farther east, northeast swell generated from the ongoing Gulf of Tehuantepec gale event will reach into Pacific waters as far west at 104W through tonight, then subside. Mainly gentle winds and slight seas will persist elsewhere east of 110W through Wed night. $$ Aguirre