000 AXPZ20 KNHC 160914 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Mon Sep 16 2024 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 0600 UTC surface analysis and satellite imagery through 0800 UTC. ...TROPICAL WAVES... A tropical wave is along 104W from southwest Mexico to 08N, moving W at 10 kt. Widely scattered small clusters of moderate convection are noted along the Mexican coast and along the monsoon trough between 98W and 105W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 11N73.5W to 10.5N87W to 09N94W to 11N101W to 08.5N120W, where it transitions to ITCZ continuing on to 06N131W. Another segment of ITCZ extends from low pressure 1011 mb near 15.5N127W to 12N133W to beyond 12N140W. Scattered moderate to strong convection is noted from 06N to beyond 10N and into the Caribbean between 78W to 85W. Scattered moderate convection is noted from 09N northward to the coasts between 86W and 94W. Scattered moderate isolated strong convection is noted within 90 nm of the trough between 98W and 118W. Scattered moderate to strong convection is seen from 06N to 09N between 120W and 133W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Post-Tropical Cyclone Ileana continues to move slowly northwestward across the Gulf of California, and is located near 26.5N110.5W in the central Gulf of California. Scattered showers are noted within 30 nm north and 90 nm south of the center, while a lone thunderstorm has recently develop within 15 nm south of center. Peak winds of 15 to 20 kt are assumed to still be occurring within 60 nm across the eastern semicircle, where maximum seas are to 5 ft. This system will continue to move slowly NW and weaken then dissipate by Mon. Elsewhere inside the Gulf of California, moderate S to SW winds generally prevail north of Ileana, and are strong SW across NW portions north of 30N. Seas across the area are 2-3 ft except 4 to 6 ft NW portions. 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. 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, 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. For the forecast, Post-Tropical Cyclone Ileana will continue to weaken as it moves northwestward and dissipates today. Fresh to strong SW winds will continue over portions of the northern Gulf of California through early Tue morning, where seas will build to 5 to 6 ft. Elsewhere, broad high pressure will remain northwest of the area and maintain gentle to moderate northerly winds across the Baja offshore waters today before winds increase slightly Mon night through Wed morning. Winds will pulse to fresh during the afternoon and evenings off the Baja California coast Mon through Fri. Expect seas of 3 to 6 ft to persist through Tue morning. New northerly swell will move into the regional waters Tue through Wed, bringing seas to 5 to 7 ft before slowly subsiding Thu and Fri. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Winds have shifted offshore around 15 kt tonight across the Papagayo region. 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. Scattered thunderstorms continue within 150 nm of the coasts from Guatemala to Costa Rica. Scattered to numerous strong thunderstorms have developed recently across the waters of Panama extending to 06N. 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. Moderate offshore gap winds will continue across the Papagayo region and persist through Tue night before shifting SE. Moderate seas in primarily southwest swell will continue through Wed before increasing Wed night through Fri. ...REMAINDER OF THE AREA... A 1031 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 23N and W of 123W per recent scatterometer data. Fresh to locally strong winds are noted north of the ITCZ to 20N and W of 135W where seas are 8 to 9 ft. Seas across 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 south to southeast 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 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 by Wed through Fri. Moderate to fresh southwest to west 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. $$ Stripling