000 AXPZ20 KNHC 170310 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Mon Apr 17 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 0000 UTC surface analysis and satellite imagery through 0220 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: High pressure is building behind a cold front that is over the central and western Gulf of Mexico. The high pressure will continue to build southward across eastern Mexico and the Gulf of Mexico in the wake of the front through Mon night. The pressure gradient associated to the high pressure will support strong northerly winds across the Gulf of Tehuantepec beginning late tonight through Mon, with winds briefly increasing to gale-force early Mon morning through late morning. This will be a short-lived gale event as the high pressure will weaken as it shifts eastward allowing for winds to diminish Mon afternoon. Seas are expected to peak to near 11 ft during Mon morning before subsiding to 8 ft during Mon afternoon and to below 8 ft early Mon night. Please refer to latest High Seas Forecast issued by National Hurricane Center at website: https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from low pressure 1009 mb over NW Colombia near 10N75W southwestward to 06N82W to 07N88W to 02N100W, where it transitions to the ITCZ and continues to 02.5N109W to 06.5N118W to 04N134W and to beyond 05N140W. Scattered moderate to strong convection is noted E of a line from 08.5N84W to 05.5N90W to 03.4S98W to the coastline. Scattered to numerous moderate to strong convection is noted from 04N to 10N W of 112W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the Special Features section above for details on an upcoming Gulf of Tehuantepec gap wind gale-force event. A broad surface ridge extends from high pressure NW of the area to near 14N106W. The associated pressure gradient is producing moderate to locally fresh northerly winds across the Baja California offshore waters and fresh to locally strong winds near the coast from Las Tres Marias to Lazaro Cardenas. Seas are 5-6 ft, except for slightly lower seas of 3-5 ft from from the Gulf of Tehuantepec region to Lazaro Cardenas. Elsewhere, gentle to moderate west to northwest winds prevail. For the forecast, The next gap wind event in the Tehuantepec region is expected to begin late tonight, with brief gale-force winds expected early Mon morning through late Mon morning. Gentle S to SW winds over the northern Gulf of California will briefly become fresh S to SW winds Mon night. NW to N winds are expected to increase to strong N of 29N starting Mon night, becoming fresh to strong across all Baja waters Wed and Wed night as the high pressure shifts eastward, then diminish to fresh speeds Thu and Thu night. New NW swell will build across the Baja waters Mon night through Tue, then become reinforced by NW swell Tue night through Thu, then begin to subside late Thu through Fri. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate east winds prevail across the waters of the Gulf of Papagayo region, with these winds are 4-5 ft. Moderate N to NE winds are over the Gulf of Panama, where seas are 3 ft. Elsewhere, light to gentle variable winds and slight seas prevail. For the forecast, weak high pressure is expected to persist N of the region through tonight, then strengthen modestly Mon night through Fri. This pattern will produce fresh easterly winds in the Gulf of Papagayo pulsing to strong at night and into the early morning hours through Wed night. However, seas are expected to remain below 8 ft. Moderate winds in the Gulf of Panama will briefly pulse to fresh at night Tue, Wed and Thu. Elsewhere, light to gentle variable winds and moderate seas in SW swell will prevail. ...REMAINDER OF THE AREA... High pressure ridging stretches southeastward, from a 1029 mb high center that is near 34N144W, and extends to near 14N106W. The ridge dominates most of the forecast waters north of 12N and west of about 108W. Afternoon ASCAT data showed moderate to fresh NE winds S of 20N and W of 110W. Seas in this area of trade winds are 6 to 9 ft. Light to gentle winds are present south of the ITCZ. For the forecast, high pressure will dominate the northern forecast waters over the next several days, strengthening modestly Tue through Wed. The associated pressure gradient will support moderate to fresh trade winds over the west-central waters. An elongated zone of seas 8 to 9 ft in mixed N and E swell exists W of 114W from about 06N to 15N. NE trade winds within this area are at fresh speeds, but are expected to increase to fresh to strong starting tonight and into early Mon as the high pressure ridge strengthens some. Seas with these winds will build to 8-10 ft by early on Mon. By Mon afternoon the high pressure ridge will weaken some allowing for these winds to diminish back to fresh speeds. Seas will subside slightly to 8-9 ft in N to NE swell, and continue to further subside through Tue as the N to NE swell over this area decays. A weakening cold front will push southward across the far northern waters Tue and Tue night. New NW swell will follow the front reaching south of 30N and to near 26N by late Tue night. Seas of 8-9 ft are expected with this NW swell. The swell will propagate farther S into Thu, then begin to subside to 8 ft later on Thu. $$ Stripling