000 AXPZ20 KNHC 170925 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Tue Sep 17 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 0830 UTC. ...TROPICAL WAVES... The southern portion of a tropical wave is along 90W extending from Guatemala southward over the eastern Pacific to near 07N, moving westward at 10 kt. isolated moderate convection is occurring over the Pacific waters within 180 nm of this wave. A tropical wave is along 107W from offshore of Cabo Corrientes to near 07N, moving westward at about 10 kt. A lone cluster of moderate convection is occurring along the base of the wave where it intersects with the monsoon trough. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 11.5N73.5W to 10.5N86W to 08N93W to 11N102W to 10N120W. The ITCZ extends from 10N120W to 11N130W to beyond 09N140W. Scattered moderate to strong convection is seen N of 03N and E of 83W, within 60 nm of the Mexican coast from 94W to 101W, from 8.5N to 11.5N between 98W and 106W, within 75 nm N of a line from 15N109W to 12N120W to 10N122W, and from 08N to 12N between 125W and 136W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gentle to moderate S to SW winds prevail across the central Gulf of California, in the wake of Ileana, whose remnants are now across northern Sonora. Seas there are 3 ft or less. A narrow plume of fresh to strong SW gap winds extends northeastward across the northern Gulf from the coast along Campo Huerfanito to near La Choya, where recent scatterometer data showed winds 20 to 30 kt. Seas there are 4 to 7 ft, while winds and seas are lower on either side. Elsewhere, light and variable winds prevail across the southern Gulf south of 24.5N, where seas are 2 to 3 ft. A persistent broad and weak ridge extends southeastward into the area waters tonight. The resultant pressure gradient is producing gentle to moderate NW winds across the near and offshore waters of Baja California, and extend to Cabo Corrientes and the Revillagigedo Islands. Winds have increased to fresh tonight along the coast of Baja Norte. Seas across these area waters are generally 4 to 5 ft except to 6 ft across the waters NW of Isla Guadalupe. Generally, light NW to W 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. Scattered moderate to strong thunderstorms continue across the nearshore waters within 75 nm of the coast from Tehuantepec to Zihauntanejo. For the forecast, fresh to strong SW gap winds will weaken through morning as a dying cold front moves into the far northern Gulf, allowing fresh to strong N winds to briefly spill into the northern basin. Elsewhere, broad high pressure northwest of the area supporting gentle to moderate northerly winds across the Baja offshore waters will strengthen slightly tonight through Wed morning, leading to a slight increase in seas. Winds will pulse to fresh during the afternoons and evenings off the Baja California coast through Wed. A dying cold front will sink into the northern waters Thu and early Fri and act to weaken the ridge ahead of it. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh NE gap winds prevail across the Papagayo region tonight, where seas are 4 to 5 ft. Elsewhere Light and variable winds prevail across the regional waters north of 09N. Seas there range 4 to 5 ft in south swell. S of 09N, 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. Thunderstorms across Colombia have shifted into the adjacent waters tonight, and cover the Colombian waters N of 03N extending into the Gulf of Panama, and the coastal waters of western Panama. For the forecast, gentle to moderate southwest to west winds will continue south of the monsoon trough through Tue, then freshen modestly Wed through Fri, leading to a modest increase in seas. 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 today before shifting SE tonight. 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 153W, extending a broad ridge southward into the region, dominating the area north of the ITCZ and west of about 115W. The related pressure gradient is producing generally moderate northeast trades W of 128W, except W of 135W where fresh trades are occurring due to a weak low level trough shifting westward across that area. Seas there are 7 to 8 ft in NE swell west of 136W, while seas over the rest of the area are 5 to 7 ft in mixed swell. 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 W through Wed, then reorganize to the NE Thu and Fri, 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 S of 23N 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. $$ Stripling