000 AXPZ20 KNHC 181530 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Tue Apr 18 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 1200 UTC surface analysis and satellite imagery through 1520 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 07N78W to 04N105W. The ITCZ continues to 02N115W, and again from 01N130W to beyond 01N140W. Another ITCZ segment is farther south, extending from 01S90W to 03.4S115W. Scattered convection from 04N to 07N between 85W and 90W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Winds diminished across the Tehuantepec last night, as high pressure north of the area weakened and shifted eastward. Winds were likely 15 to 20 kt starting this morning, but are diminishing to 10 to 15 kt. Combined seas will take a little longer to subside across the Gulf of Tehuantepec, with maximum wave heights to 8 ft possible today. Farther north, a broad surface ridge extends from 1026 mb high pressure centered near 35N145W southeastward to near the Revillagigedo Islands. Earlier scatterometer satellite data and ship observations indicate moderate to locally fresh NW winds winds off Baja California, between the ridge and lower pressure over north-central Mexico. Seas are 5 to 8 ft in fresh NW swell across this area, except 8 to 9 ft across the NW waters north of Guadalupe Island. Gentle to moderate winds persist elsewhere off Mexico to Puerto Angel. Combined seas are 4 to 6 ft elsewhere in open waters. Inside the Gulf of California, winds have shifted to SW to W and are producing areas of fresh gap winds across several sections of the Gulf. Seas are 2 to 3 ft except to 4 ft downstream of the gap winds. For the forecast, the high pressure west of Baja California will support fresh to occasionally strong NW winds off Baja California north of Cabo San Lazaro through late Thu. Combined seas are expected to peak near 12 ft offshore Baja Norte Wed morning. The high pressure will weaken and drift northwest Fri through Sat leading to a dimishing trend in winds and seas across the regional waters. Farther south, lingering rough seas over the Gulf of Tehuantepec will subside through late today. Looking ahead, fresh or possibly strong gap winds may return to the Tehuantepec region Sat night. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Recent scatterometer wind data showed moderate to fresh gap winds across the Papagayo region extending offshore to 90W. Seas are 4 to 6 ft there. Moderate to locally fresh N winds are across the Gulf of Panama, and extend southward to 06N, where seas are 2 to 4 ft. Elsewhere, light to gentle variable winds and seas 4-6 ft prevail. Fuego Volcano in Guatemala has been emitting ash overnight, which has moved due southward to near the coast. This small ash plume is expected to disperse before reaching to the local coastal waters, but may be seen along the coast early this morning. For the forecast, high pressure north of the area will support fresh to occasionally strong gap winds pulses through mid week across the Gulf of Papagayo and the coast of Nicaragua. Moderate winds in the Gulf of Panama will briefly pulse to fresh Tue night and Wed night. Elsewhere, light to gentle variable winds and moderate seas in SW swell will prevail. ...REMAINDER OF THE AREA... Recent buoy data and earlier scatterometer satellite data showed fresh to strong NE trade winds from 05N to 15N west of 120W, between a trough in the deep tropics between 120W and 130W and the subtropical ridge north of 20N. Recent altimeter satellite data confirmed combined seas in this area are 7 to 9 ft mixed NE and NW swell. Scattered thunderstorms near the surface trough have diminished significantly in recent hours. Gentle to moderate winds are noted elsewhere to the north, where seas of 5 to 7 ft prevail. For the forecast, winds and seas over the tropical Pacific west of 125W will gradually diminish through mid week as high pressure weakens north of the area. New longer period NW swell in excess of 8 ft will move into the waters north of 20N through Wed, with highest seas reaching 12 ft along 30N120W. For Thu through Sat, combined seas of 8 to 9 ft will persist north of 25N and east of 125W to near the Baja California coast. Seas associated with fresh trade winds in NW swell will persist from 05N to 20N west of 125W. $$ Christensen