000 AXPZ20 KNHC 311600 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Thu Aug 31 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 1200 UTC surface analysis and satellite imagery through 1540 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from Panama near 09N79W to Costa Rica near 09N84W to 12N94W to 12N103W to 07N119W to 08N132W. Scattered moderate isolated strong convection is evident from 02N to 09N between 77W and 83W, including Panama and western Colombia. Similar convection is also noted from 03N to 07N between 86W and 99W, from 12N to 17N between 99W and 104W, and from 05N to 09N between 107W and 118W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Upper-level diffluence is enhancing scattered moderate convection from 20N to 26N between 106W and 114W, including both sides of Baja California Sur and near the entrance to the Gulf of California. Scattered moderate isolated strong convection is also noted offshore of Guerrero, from 12N to 17N between 99W and 104W. Broad surface troughing extends from near Punta Eugenia to 1007 mb low pressure near 17N115W. Mainly gentle winds dominate the offshore waters of Mexico, except in the northern Gulf of California where fresh to locally strong SE to S winds are likely occurring. Seas are 4-6 ft in mainly long period S-SW swell from Cabo San Lazaro southward, and 5-7 ft in NW swell from Cabo San Lazaro northward. Seas are 2-4 ft in the Gulf of California, except up to 5 ft in the northern part. Offshore the remainder of Mexico, seas are 5 to 6 ft in S swell. For the forecast, pulsing fresh to strong S winds will continue in the northern Gulf of California today through Fri night. Fresh to strong northerly winds will pulse in the Gulf of Tehuantepec Fri night through Sat night. Winds will be moderate or weaker elsewhere through Sat. Winds will increase to moderate to fresh nearshore Baja California Sun night through Mon as the pressure gradient tightens along the peninsula. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to gentle winds prevail across the offshore waters N of 05N, except for moderate NE to E winds in the Papagayo region. Seas north of 05N are 5-6 ft in long-period south to southwest swell. To the south of 05N, including the waters offshore southern Colombia and in between Ecuador and the Galapagos Islands, moderate S winds with seas of 7-9 ft are present due to long-period S to SW swell. Scattered tstms are noted off Colombia and Panama ahead of a tropical wave currently over the S-central Caribbean Sea and central Colombia. For the forecast, moderate to locally fresh south to southwest winds will continue between the coast of Ecuador and the Galapagos Islands most of the time through the weekend. Southerly swell will keep seas around 7-9 ft there through today before subsiding slightly, then renewed long period S to SW swell will move through those waters Fri, increasing seas back to 7-9 ft through early Sun. Swell of 6-8 ft will reach the waters offshore Panama and Costa Rica. Elsewhere, light to gentle variable winds will prevail through most of the the forecast, locally and occasionally moderate to fresh near Gulfs of Papagayo and Fonseca, along with slight to moderate seas in long-period SW swell. ...REMAINDER OF THE AREA... The post-tropical remnant low of former Tropical Cyclone Irwin is centered near 19N137W with an estimated central pressure of 1008 mb. It is moving westward at around 10 kt. A tight pressure gradient between the low and strong high pressure to its north is keeping strong to near gale force winds in the northwest semicircle from the low to 26N between 135W and 140W. Seas are 10-13 ft in this area. Scattered moderate convection is present within 90 nm in the N semicircle. Elsewhere north of 20N and west of 122W, fresh N to NE winds and 7 to 10 ft seas prevail. Winds are mainly moderate or weaker across the remainder of the open waters, with seas 6-8 ft. A surface trough extends from 27N115W to 1007 mb low pres near 17N115W to 15N116W. Upper-level diffluence is enhancing showers and tstorms east of the trough axis. For the forecast, the post-tropical remnant low of Irwin will continue moving westward, with a slightly slower motion expected, reaching 140W on Fri. Fresh to strong winds and elevated seas will continue to accompany the low, mainly in the NW semicircle. Elsewhere, northerly swell will propagate through the open waters well W of Baja California through early Fri, keeping seas of 6-10 ft N of 20N and W of 120W. Southerly swell in the far southern waters to the south of 06N will keep seas 7-9 ft through this morning before subsiding slightly late today. Another long period S swell event will push northward across the Equator late tonight and Fri with seas of 8-9 ft south of 05N and east of 120W into Sat before subsiding late in the weekend. The broad north-south oriented surface trough with accompanying low pressure is expected to move from along 114W to 120W by the weekend, resulting in shifting winds. $$ Hagen