000 AXPZ20 KNHC 170023 CCA TWDEP Tropical Weather Discussion...Corrected NWS National Hurricane Center Miami FL 2205 UTC Mon Sep 16 2024 Corrected ITCZ/Monsoon Trough section 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 2145 UTC. ...TROPICAL WAVES... The southern portion of a tropical wave is along 86W extending from Belize to western Honduras and continuing southward over the eastern Pacific to near 09N. It is moving westward at 5-10 kt. Scattered moderate convection is noted within 120 nm either side of the wave where it just crosses the monsoon trough. Otherwise, no significant convection is occurring with this wave. A tropical wave is along 105W from southwestern Mexico to near 08N, moving westward at about 10 kt. Scattered moderate convection is within 120 nm east of the wave from 09N to 10N. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...Corrected The monsoon trough extends from along the coast of northwest Colombia, westward to across northern Costa Rica, and to 10N85W to 08N92W to 10N98W to 11N105W to 10N114W. The ITCZ extends from 12N116W to 09N130W to beyond 09N140W. Scattered moderate to isolated strong convection is seen from 05N to 10N between 77W and 85W. Numerous moderate convection is within 180 nm south of the iTCZ between 126W and 131W, and also within 60 nm north of the trough between 88W and 92W and within 60 nm south of the ITCZ between 131W and 135W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... The remnant low of former tropical cyclone Ileana is over the central Gulf of California near 28N111W with a pressure of 1008 mb. It is moving slowly in a general northward motion. Latest visible satellite imagery shows that is it just about to move inland the NW part of Mexico. Isolated small showers are within 60 nm inland the coast of Sonora 27N to 29N. Mostly moderate southerly winds are east of the low, and light to gentle NW to N winds are elsewhere over the central section of the Gulf from 17N to 28N W of 111W. Seas are 3 to 4 ft over the central section of the Gulf, 4 to 5 ft over the northern section and 2 to 3 ft over the southern section. A persistent broad and weak ridge extends southeastward into the area waters tonight. The resultant pressure gradient is producing gentle to moderate NW winds prevail across the near and offshore waters of Baja California, and extend to Cabo Corrientes and the Revillagigedo Islands. Seas across these area waters are generally 3 to 5 ft except to 6 ft across the waters NW of Isla Guadalupe. Generally, light and variable winds dominate the waters from Manzanillo to the Tehuantepec region where seas are 4 to 5 ft in southerly swell east of 103W, and with mixed NW and S swell west of 103W. Widely scattered thunderstorms have shifted off the coast and into the nearshore waters of Michoacan and Colima as this activity is being driven by strong east flow around the southern periphery of a large mid to upper-level anticyclone that is centered near 23N106W For the forecast, the remnant low former of tropical Cyclone Ileana will continue to weaken as it drifts in a general northward direction inland NW Mexico, dissipating tonight. Fresh to strong SW winds will continue over portions of the northern Gulf of California through early Tue morning. A brief instance of fresh to strong N winds is expected N of 30N late tonight into early Tue morning as the tail-end of a weak cold front sweeps eastward across the far northern Gulf of California. Elsewhere, broad high pressure northwest of the area is supporting gentle to moderate northerly winds across the Baja offshore waters. These winds are expected to increase slightly tonight Mon night through Wed morning. Winds will pulse to fresh during the afternoons and evenings off the Baja California coast through Fri. New northerly swell will move into the regional waters Tue through Wed, raising seas slightly before slowly subsiding Thu and Fri. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Recently, winds have become moderate to fresh NE in direction across the Papagayo region. Seas there are 3 to 5 ft. Elsewhere Light and variable winds prevail across the regional waters north of 10N. Seas there range 4 to 5 ft in south swell. S of 10N, gentle to moderate southwest to west winds prevail. Seas are 4 to 6 ft in south to southwest swell there, except 2 to 3 ft inside the Gulf of Panama. A very moist and unstable atmospheric environment is sustaining numerous showers and thunderstorms along the Central America coast from Costa Rica to Panama, with similar activity present along the coast of Colombia. All of this activity extends well offshore to 90W, and inland the aforementioned geographic locations. Scattered showers and thunderstorms are just along the coast of Guatemala and well inland from there. For the forecast, gentle to moderate southwest to west winds will continue south of the monsoon trough through Tue, then freshen modestly Wed and Fri. North of the trough, light to gentle winds are expected through Thu. The moderate to fresh gap winds across the Papagayo region will become gentle to moderate east winds on Tue before shifting SE. Moderate seas in primarily southwest swell will continue through Wed before increasing Wed night through Fri, with little change expected afterward. ...REMAINDER OF THE AREA... A 1030 mb high continues across the NE Pacific along 145W, extending a broad ridge southward into the region, dominating the area north of the ITCZ and west of about 122W. The related pressure gradient is producing generally moderate to fresh northeast trades S of about 20N and W of 123W, except W of 135W where locally strong trades are likely due to a stronger gradient between a weak trough that is along 129W and the broad ridge mentioned earlier. Seas are 7 to 8 ft in NE swell are west 135W, and seas over the rest of the area are 5 to 7 ft in mixed swell. Gentle to moderate winds and seas 4 to 5 ft are noted N of 27N. Moderate to fresh S to SE winds continue south of the ITCZ W of 130W, with gentle to moderate winds elsewhere south of the monsoon trough. Seas are 5 to 7 ft south of the monsoon trough, and 4 to 7 ft east of 120W. For the forecast, the aforementioned high pressure will drift SW through the rest of the week, with the associated ridge changing little. This will result in moderate to fresh trades south of 20N and west of 130W, and seas 6 to 8 ft in NE swell through Wed morning. Winds will become moderate to locally fresh Wed through Fri. Moderate to fresh SW to W winds and mostly seas of 4 to 7 ft are expected elsewhere south of the monsoon trough through Wed night before a modest increase E of 110W Thu and Fri. $$ Aguirre