Tropical Weather Discussion

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Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Mon Jun 5 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 1800 UTC surface analysis and satellite imagery through 2030 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from northern Nicaragua near 12.5N87W to 10N97W to 10N120W to 1012 mb low pres near 06N138W to beyond 05N140W. Numerous moderate to strong convection is seen from 05N to 10.5N between 99W and 112W. Scattered moderate to strong convection is noted from 03N to 15.5N between 85W and 95W. Scattered moderate isolated strong convection is occurring near the 1012 mb low pres from 05N to 08N between 133W and 140W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A NW-SE oriented surface ridge is located to the west of the Mexico offshore waters. Its associated gradient is allowing for mostly moderate NW winds to the west of Baja California Sur, where seas are 6 to 7 ft in mixed S and NW swell. Offshore Baja California Norte, recent ASCAT satellite wind data indicate mainly gentle W winds, where seas are 5-8 ft in primarily NW swell. Recent ASCAT data from 05/1704 UTC show moderate to fresh S winds in the northern Gulf of California, where seas have recently built to 3 to 5 ft. Gentle winds are in the southern and central Gulf of California, with 1-2 ft seas, except at the entrance to the Gulf, where seas are 3-5 ft. Gentle to moderate NW winds are west of Cabo Corrientes, with 6-7 ft seas. Gentle winds prevail elsewhere off S and SW Mexico, from Manzanillo eastward to the Guatemala border, but seas are 6 to 8 ft in this area due to southerly swell. Scattered thunderstorms have been occurring near the Gulf of Tehuantepec during the last few hours. For the forecast, the high pressure ridging west of the area will build slightly eastward tonight into Tue. The gradient between the high pressure ridge and low pressure over the northern Gulf of California will support strong to near- gale force S to SW winds over the northern Gulf of California beginning late this afternoon and lasting through the overnight hours tonight. Fresh to strong winds will pulse again there Tue night. Fresh to locally strong NW winds are expected near Cabo San Lucas at night through the forecast period. Gentle to moderate W to NW winds across the SW Mexican offshore waters will change little through the period. Offshore S and SW Mexico, large long-period S swell, with seas 7 to 8 ft, will continue through early Tue before subsiding late Tue into Tue night. Looking ahead, fresh to strong winds may return to the northern Gulf of California this weekend. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Recent ASCAT satellite wind data shows moderate SE winds within 120 nm of the coast of Guatemala. Moderate SW winds are likely occurring off Nicaragua and El Salvador. Recent ASCAT data indicates mostly gentle wind speeds off Costa Rica and western Panama, while moderate S winds prevail in between Ecuador and the Galapagos Islands. Long period S to SW swell is occurring across the entire area. From Ecuador and the Galapagos Islands northward to Panama and eastern Costa Rica, seas are 8 to 10 ft. Seas are 6 to 9 ft elsewhere offshore Central America. Scattered moderate to strong convection is noted offshore of Costa Rica through Guatemala, mainly from 07N to 13.5N between 85W and 94.5W. For the forecast, scattered thunderstorms will continue during the next several days in the waters offshore from Colombia to Nicaragua, as the monsoon trough will remain north of its climatological position during at least the next few days. Outside of any strong thunderstorms, winds across the offshore waters should remain moderate or weaker through the forecast period. Large, long-period cross equatorial S to SW swell will continue to spread across all the Central America and South America waters through this evening, peaking at 8-9 ft late this afternoon through this evening off most of Central America. Between Ecuador and the Galapagos Islands, seas of 8 to 10 ft now will begin subsiding this evening, and continue subsiding into early Tue. ...REMAINDER OF THE AREA... A high pressure ridge, anchored by a 1032 mb high pressure center offshore of Oregon and Washington near 47N135W, dominates the forecast waters N of 15N and W of 110W, generating a moderate anticyclonic flow. However, ASCAT shows fresh N winds occurring N of 29N between 124W and 131W. Moderate to fresh NE to E trade winds are N of the aforementioned low that is along the monsoon trough. Seas are generally 5-7 ft due to a mix of N and S swell with a few exceptions. Seas are 7-9 ft S of 14N and E of 114W due to a long-period S to SW swell. Seas are 7 to 10 ft in N swell N of 26N and E of 135W. For the forecast, the high pressure ridge will begin to shift eastward Tue in response to a cold front that is expected to approach the northwest corner of the area late in the week. The low along the monsoon trough will weaken to a trough as it crosses 140W on Tue afternoon. Long-period cross equatorial S to SW swell from the Southern Hemisphere S of 15N and E of 110W will decay tonight into early Tue. The northerly swell over the N waters will continue to propagate S through early Tue, spreading seas of 8 to 10 ft N of 25N and E of 135W. That swell will subside late Tue night into Wed. The aforementioned cold front is forecast to enter the NW corner of the forecast area by late Fri, reaching from 30N130W to 27N140W by early Sat.