000 AXPZ20 KNHC 110356 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 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 0000 UTC surface analysis and satellite imagery through 0330 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: The next gap wind event is expected in the Gulf of Tehunatepec starting early on Thu. This is due to high pressure surging southward along the eastern slopes of the Sierra Madre Mountains in Mexico in the wake of a cold front that will be moving across the Gulf of Mexico. Winds are forecast to increase to minimal gale-force speeds by Thu morning. North to northeast winds will increase further to a maximum speed of 40 kt Thu night into Fri along with building seas expected to peak to around 16 or 17 ft. Winds then will diminish to minimal gale- force by Sat morning, and below gale force by Sat 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. Marine interests transiting across the Gulf of Tehuantepec Fri night into Sat 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 09N78W to 06N93W to 07N110W. The ITCZ continues from 07N110W to 04N125W to beyond 04N140W. Scattered moderate to isolated strong convection is noted from 02N to 10N between 80W and 97W. Scattered moderate convection is noted from 06N to 12N between 105W and 112W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for details on a Gulf of Tehuantepec gale warning. High pressure is the main feature controlling the wind regime across the offshore forecast waters of Baja California. Gentle to moderate northwest to north winds are over the offshore waters of Baja California. Seas with these winds are 5 to 7 ft. In the Gulf of California, gentle to moderate northwest winds are over the central and southern sections while light and variable winds are over the northern Gulf. Seas are 2 to 4 ft with the strongest winds and 1 to 3 ft elsewhere. Gentle to moderate winds prevail over the southwest Mexico offshore waters, with light to gentle west to northwest winds dominate the remainder of the Mexican offshore waters. Seas range 4 to 6 ft in mixed long period northwest and southwest 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 over the offshore forecast waters of Baja California will begin to weaken and shift eastward on Thu in response to a cold front that will be approaching from the W. Winds offshore Baja California will diminish to gentle to moderate speeds through Thu. Winds will then become light and gentle winds Fri through Sat ahead of the aforementioned cold front forecast to reach 30N120W by Sat night. In the Gulf of California, winds will generally become light and variable on Thu. By Fri, winds over the northern part of the Gulf are forecast to become fresh in speeds, south to southwest in direction, then increase to fresh to strong speeds Fri night prior to the approach of the cold front. Gentle to locally moderate winds will prevail elsewhere with slight to moderate seas. The next gale- force gap wind event in the Gulf of Tehuantepec region is forecast to begin Thu morning, and will likely persist through Sat. Winds then will diminish to fresh to strong speeds Sat night into Sun. Seas are expected to peak to 16 or 17 ft with this upcoming event Thu night into Fri. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR Mainly gentle to moderate NE to E winds are noted in the Gulf of Papagayo and downwind to about 88W. Light and variable winds and seas of 2 to 3 ft are in the Gulf of Panama. Generally gentle to moderate southerly winds are north of the Equator while light to gentle southeast winds are present between Ecuador and the Galapagos Islands. Seas are 4 to 6 ft due to a long-period south to southwest swell. Scattered to numerous showers with embedded thunderstorms are still noted across the offshore forecast waters of Costa Rica and Panama. Winds and seas may be higher in and near this convective activity as it is expected to stay active through at least Thu. 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 in the Papagayo region to fresh to strong speeds Thu night along with seas building to 8 to 9 ft on Fri. There is a possibility for these winds to reach near gale-force Fri night into Sat with seas building to 8 to 11 ft. Fresh to locally strong northerly winds will develop in the Gulf of Panama Fri night, then pulse through Sun night. Seas with these winds will build up to 7 ft. Seas generated in the Gulf of Tehuantepec will propagate across the outer SW offshore waters of Guatemala and El Salvador on Fri. 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. It is expected to favor the development of scattered to numerous showers and thunderstorms over these waters through at least Thu. ...REMAINDER OF THE AREA... High pressure of 1029 mb located well to the north of the forecast region near 37N137W extends a ridge across the discussion 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 110W. The pressure gradient between the high pressure and relatively lower pressure found in the vicinity of the ITCZ is sustaining a rather large area of fresh trade winds mainly from 07N to 22N west of about 125W. Seas are 8 to 11 ft with these winds based on altimeter data. Light to gentle N to NE winds along with moderate seas are present elsewhere under the influence of the ridge. For the forecast, the aforementioned high pressure will weaken on Thu 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 30N120W to 24N130W by Sat evening while gradually weakening. Fresh to strong northwest to north winds and a new set of northwest swell will follow the front. Seas peaking 12 or 13 ft are currently forecast for the waters N of 29N between 128W and 136W by Sat evening. $$ AReinhart