Tropical Weather Discussion

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Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Tue Apr 21 2026 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 trough axis extends from near 10N75W to 03.5N79W to 07.5N89W to 04N105W. The ITCZ stretches from 04N105W to 04.5N116W to 01N126W and beyond 06N140W. Scattered moderate isolated strong convection is observed from 02.5N to 08.5N between 85W and 111W, south of 01.5S between 96W and 104W, south of 09N between 112W and 129W, and from 06N to 08.5N between 136W and 140W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weak 1018 mb high is centered well offshore of Cabo San Lazaro and Baja California Sur near 121W this morning, ahead of an approaching cold front. The associated broad ridge is producing gentle to moderate NW to N winds across the Baja waters, with seas of 3-5 ft in S swell, except for locally fresh winds off Cabo San Lucas. Elsewhere W of Puerto Angel, moderate or weaker winds and slight to moderate seas prevail. An elongated middle to upper- level trough extends from central Mexico W-SW into the tropics along 120W, and is supporting continued scattered moderate isolated strong convection from 12N to 16.5N between 109W and the central of Oaxaca. Overnight satellite scatterometer data showed fresh to strong northerly gap winds across the Gulf of Tehuantepec, that should still be prevailing north of 13.5N this morning. Seas in these waters are estimated at 6-9 ft, with recent altimeter data showing seas to 8 ft extending southward to near 09N. For the forecast, high pressure across the Gulf of America will support fresh to strong N winds and rough seas in the Gulf of Tehuantepec through this afternoon. Elsewhere, new NW swell will move through the waters west of Baja California Norte tonight into Wed. Seas are expected to peak to around 8 ft across north and central portions of the Baja waters with this swell. New high pressure will begin to build across the Baja waters late Wed, behind a dissipating cold front expected to die across the area. Fresh to locally strong northwest winds are forecast over the Pacific waters of Baja California beginning late Wed. Northwest winds will pulse to moderate to fresh speeds at night offshore southwestern Mexico today through Fri. Elsewhere, mostly light to gentle west to northwest winds are expected through the end of the week and into the upcoming weekend. ....OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Modest high pressure north of the western Caribbean Sea is forcing fresh to locally strong easterly gap winds and moderate seas across the Gulf of Papagayo region, extending downstream to 90W. Farther east, overnight satellite scatterometer data indicated moderate to locally fresh northerly winds occurring in the Gulf of Panama, that have likely diminished to moderate winds since sunrise. Seas in these waters are 3 to 5 ft in SW swell. Elsewhere, light to gentle variable winds prevail. Cross- equatorial SW swell moving into the area waters is producing seas of 5 to 8 ft. For the forecast, winds will pulse fresh to occasionally strong speeds across the Papagayo region this morning and again late tonight into Wed morning. Similarly, winds will pulse to locally fresh in the Gulf of Panama at night and into the morning hours this morning and tonight into Wed morning. Otherwise, rather tranquil conditions are expected to continue over the Central American and the equatorial waters through the end of the week. SW swell will peak across the area waters today then subside tonight through Wed, with the next significant SW swell expected to reach the area waters Fri night. ...REMAINDER OF THE AREA... A weakening cold front continues to slide southeastward across the northern waters, extending from 30N121W to 25.5N130W, then becomes stationary and stretches to 22N140W. No significant convection is seen near this boundary. Large NW to N swell follows the front, supporting seas of 8-13 ft with the highest seas near 29N137W. High pressure well NW of the front extends weakly into the area and is producing light to gentle anticyclonic winds behind the front to 30N. Weak high pressure SE of the front dominates the remainder of the basin, supporting moderate to locally fresh easterly trade winds and moderate seas in S swell, north of the ITCZ to 18N and west of 110W. Elsewhere, moderate or lighter winds and moderate seas are prevalent. For the forecast, the aforementioned frontal boundary will move east-southeastward, further weakening today and dissipating as it moves into the Baja Norte waters on Wed. The NW swell behind the front will spread southeastward over the next few days, gradually subsiding in the process. Rough seas will reach the western trade waters Wed. Little overall changes are expected with winds and seas elsewhere through Thu.