000 AXPZ20 KNHC 110938 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Thu Apr 11 2024 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 0900 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: The next gap wind event in the Gulf of Tehunatepec will begin this morning as high pressure surges southward along the eastern slopes of the Sierra Madre Mountains in Mexico. Winds will increase to minimal gale-force speeds in a few hours. North to northeast winds will increase to 40 kt tonight through Fri as seas peak around 17 ft. Winds will drop below gale force by Sat afternoon and diminish to fresh speeds by Sun afternoon. Large seas generated from this strong gap wind event will spread well away from the Tehuantepec area, with seas 8 ft or greater reaching as far west as 104W by Fri night. Seas will subside below 8 ft by Sun. Marine interests transiting across the Gulf of Tehuantepec through the weekend should be aware of this upcoming gap wind event and take the necessary action to avoid hazardous marine conditions over the affected waters. Please read the latest High Seas Forecast at https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more information on this event. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A trough extends from Panama near 08N78W to 07N95W to 07N107W. The ITCZ continues from 07N107W to 04N125W to beyond 04N140W. Scattered moderate convection is noted from 03N to 12N between 80W and 114W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for details on a Gulf of Tehuantepec gale warning. High pressure extends across the Baja California waters. This is leading to gentle to moderate winds across the area. Seas range 5 to 7 ft within NW swell. In the Gulf of California, gentle to moderate NW winds prevail in the central Gulf with light to gentle elsewhere with seas to 3 ft. Fresh to strong winds are likely beginning in the Gulf of Tehuantepec ahead of the gap wind event. Light to gentle winds prevail across the rest of the Mexico offshore waters. Seas are 4 to 6 ft in mixed long period NW and SW swell. Light concentration of smoke is noted along and just offshore the Mexican coast roughly between Manzanillo and the Gulf of Tehuantepec due to agricultural fires. For the forecast, high pressure extending across the Baja California offshore waters will weaken and shift eastward on today through Sat as a cold front approaches the area. Gentle to moderate winds over this region will become light and gentle winds Fri through Sat. The cold front will reach 30N120W by Sat night and continue progressing eastward across the Baja California offshore waters. This front will bring moderate winds and seas to 10 ft through early next week. In the northern Gulf of California, winds will increase fresh to strong ahead of the cold front by Fri through Fri night. The next gale- force gap wind event in the Gulf of Tehuantepec region is forecast to begin this morning and will persist through Sat. Winds will diminish below strong speeds by Sun. Seas are expected to peak to 16 or 17 ft with this upcoming event tonight into Fri, with seas subsiding below 8 ft by Sun. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR Moderate to locally fresh NE to E winds likely prevail in the Gulf of Papagayo downwind to about 88W. Light and variable winds prevail across the rest of the Central and South American waters. Seas range 4 to 6 ft within a long period S to SW swell. Scattered thunderstorms are noted across Costa Rica and Panama. This activity is expected to continue through today. Hazy conditions observed along and just offshore northern Central America are due to mostly smoke produced by agricultural fires. For the forecast, winds will increase fresh to strong across the Gulf of Panama tonight through early next week. Winds could reach near gale force Fri night into Sat with seas building to near 11 ft. Fresh to strong winds will pulse in the Gulf of Panama Fri night and Sat night with seas building to 7 ft. Meanwhile, seas generated in the Gulf of Tehuantepec will propagate across the outer SW offshore waters of Guatemala and El Salvador Fri through Sat. Abundant moisture drawn in by a very moist and unstable southerly wind flow is prevalent across the offshore waters of Costa Rica, Panama and Colombia. Scattered to numerous showers and thunderstorms will persist over these waters through at least today. ...REMAINDER OF THE AREA... High pressure of 1030 mb located well to the north of the forecast region near 35N140W extends a ridge across the waters to beyond the Revillagigedo Islands. This system is the main feature influencing the weather pattern over the waters north of the ITCZ and west of about 105W. The pressure gradient between the high pressure and relatively lower pressure found in the vicinity of the ITCZ is sustaining moderate to fresh trade winds mainly north of the ITCZ to 30N and west 120W. Seas are 8 to 10 ft with these winds. Gentle to moderate winds are noted S of the ITCZ and E of 130W. For the forecast, high pressure north of the area will weaken today as a cold front approaches from the W. The cold front will reach 30N140W on Fri and move across the northern forecast waters on Sat, extending from 30N125W to 25N140W by Sat and gradually weaken through Sun. Fresh to strong northwest to north winds and a new set of northwest swell will follow the front. Seas will peak around 12 or 13 ft in waters N of 29N between 128W and 136W by Sat. This swell will spread southward to 13N through the weekend. $$ AReinhart