199 AXPZ20 KNHC 290847 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Sat Apr 29 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 0600 UTC surface analysis and satellite imagery through 0830 UTC. ...SPECIAL FEATURES... Gale Warning in the Gulf of Tehunatepec: A brief gap wind event is expected in the Tehuantepec region tonight into Sun as a ridge builds across the eastern slopes of the Sierra Madre Mountains in Mexico behind a cold front moving through the Gulf of Mexico. Winds are forecast to suddenly increase to 30 to 35 kt tonight, with seas building to 12 ft by early Sun morning. Fresh to strong northerly winds will persist on Sun afternoon, with seas in the 8 to 11 ft range. Winds will further diminish to 20 kt and combined seas will subside below 8 ft through Sun night. Please see the latest NWS High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. Climatologically, the first gale-force event of the season occurs in mid-October, with the final gale-force event occurring in lat March or early April. Occasionally, gale-force events may occur as early as September, and as late as May. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N79W to 05N115W. The ITCZ continues from 05N115W to beyond 02N140W. Scattered moderate convection is observed from 08N to 10N east of 85W, and from 04N to 08N between 95W and 115W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A Gale Warning is in effect for the Gulf of Tehuantepec. Please, see the Special Features section for details. A weak ridge extends from 1022 mb high pressure located near 28N135W southeastward toward the Revillagigedo Islands. This pattern is supporting gentle to moderate NW to N winds across the offshore waters of Baja California. Recent satellite derived data indicates wave heights are 4 to 6 ft in open waters, likely in moderate S to SW swell. Light and variable winds are noted per overnight scatterometer satellite data in the Gulf of California where seas are in the 1 to 3 ft range. Light W to NW winds dominate the remainder of the Mexican offshore waters, with seas generally in the 4 to 5 ft range in S to SW swell. Areas of smoke from agricultural fires are still noted on visible satellite imagery off southern Mexico. For the forecast, other than the Gulf of Tehuantepec, the relatively weak pressure pattern will continue to support gentle to moderate NW winds across most of the Mexican offshore waters through early Sun. SW gap winds will briefly pulse over the northern Gulf of California Sun night ahead of a weak cold front moving into the waters off Baja California Norte late Sun. NW swell following the front will persist north of Punta Eugenia through mid week. Looking ahead, SW gap winds may pulse again over the northern Gulf of California Wed night ahead of another weak cold front approaching the region. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to gentle winds and slight to moderate combined seas in SW swell dominate the forecast area. For the forecast, the weak pressure gradient will support light to gentle winds across the region through early next week. Expect slight to moderate combined seas primarily in S to SW swell. Also, areas of smoke from agricultural fires may persist over the offshore waters from northern Costa Rica to Guatemala. Looking, ahead, fresh to possibly strong gap winds may pulse across the Gulf of Papagayo and the coast of Nicaragua mainly at night by mid week. ...REMAINDER OF THE AREA... A weak surface ridge, anchored by 1022 mb high pressure situated near 28N135W, dominates waters north of 15N and west of 110W. Moderate trades are noted along the southern periphery of the ridge. Mainly gentle winds are evident over the remainder of the area. Combined seas are generally 4 to 6 ft in mixed NW and SW swell. Scatterometer data indicate stronger winds associated with the convection along the monsoon trough/ITCZ, particularly near 10N105W. For the forecast, the ridge will continue to dominate the waters north of 15N through today, maintaining moderate trade winds farther south. High pressure will strenghten north of the area on Sun bringing moderate to fresh trades along the ITCZ and west of 130W, and producing fresh to locally strong N to NE winds to the north of 25N by late Sun, and north of 20N by late Mon. In addition, a weak cold front will move across the waters north of 25N and east of 125W Sun through Mon while dissipating. High pressure will build north of 20N in the wake of the front north of 20N through mid week. $$ Christensen