000 AXPZ20 KNHC 302104 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Wed Aug 30 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 2050 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from Panama near 09N79W to Costa Rica near 10N86W to 12N119W. The monsoon trough resumes from 13N134W to 11N140W. Scattered moderate convection is noted from 09N to 12N between 88W and 90W, and from 06N to 15N between 99W and 114W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Surface high pressure ridging extends southeastward from strong high pressure of 1032 mb north of the area near 36N144W toward the waters west of the Baja California peninsula. The pressure gradient between this ridge and lower pressure over Mexico is supporting gentle NW to N winds within 120 nm west of the coast of Baja California, and moderate winds between 120 nm and 250 nm west of Baja California. Moderate SE to S winds are in the northern Gulf of California. Light to moderate winds prevail elsewhere. Seas of 6-9 ft prevail west of Baja California Norte with 4-7 ft west of Baja California Sur. Seas are 2-4 ft in the northern Gulf of California and 1-3 ft elsewhere in the Gulf. Seas elsewhere offshore of Mexico are generally 4-5 ft. For the forecast, northerly swell producing seas to 7 to 9 ft offshore Baja California Norte will subside to 5 to 7 ft by Thu. SE to S winds in the far northern Gulf of California will briefly increase to fresh to strong this evening before diminishing later overnight. Fresh to locally strong S winds over the northern Gulf of California will then return again late Thu morning and persist through Fri night. Fresh N winds are possible in the Gulf of Tehuantepec over the upcoming weekend. Looking ahead, the gradient is likely to increase a bit near Baja California late in the weekend or early next week as high pressure strengthens west of the area, leading to a larger area of fresh NW to NNW winds to the west of Baja California. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to gentle southwest winds prevail across the offshore waters N of 04N along with seas of 4-5 ft, except 4-6 ft offshore Panama and Colombia in long-period south to southwest swell. To the south of 04N, including the waters offshore southern Colombia and in between Ecuador and the Galapagos Islands, moderate to locally fresh S winds with seas of 7-9 ft are present due to long-period S to SW swell. For the forecast, moderate 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 to 9 ft there through late tonight before subsiding late Thu. Renewed long period S to SW swell will move through those waters late Fri, increasing seas again to 7 to 9 ft through Sat and subsiding by the end of the weekend. Swell of 6 to 8 ft will reach the waters offshore Panama and Costa Rica. Elsewhere, light to gentle variable winds will prevail through most of the week 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 19N 134.5W with an estimated central pressure of 1007 mb. It is moving westward at 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 northern semicircle from the low to 25N between 132W and 140W. Seas are 10 to 14 ft in this area. Scattered moderate convection is present from 19N to 22N between 133W and 135W. Elsewhere north of 21N and west of 120W, fresh N to NE winds and 7 to 10 ft seas prevail. Mostly gentle winds are east of 130W from 07N to 20N with seas 5-7 ft. Moderate SE to S winds are south of 07N. Long-period S swell has raised seas to the range of 8-9 ft over the southern part of the area, to the south of 07N. For the forecast, the post-tropical remnant low of Irwin will continue moving westward, with a slightly slower motion expected later this week. The low should gradually weaken and cross 140W by Fri evening. As it does, the fresh to strong winds to its north will translate to west of the discussion area. Elsewhere, northerly swell will propagate through the open waters well W of Baja California through at least Thu night, keeping seas of 6-10 ft N of 22N and between 121W-137W. Southerly swell in the far southern waters to the south of 07N will keep seas 8-9 ft through tonight. This swell area will subside Thu. Another long period S swell event will push northward across the Equator on Fri, with seas of 8-9 ft south of 05N and east of 120W into Sat before subsiding late in the weekend. A broad north-south oriented surface trough is expected to set up to the SW of Baja California along 112W from north of the monsoon trough to 30N starting tonight, and drift westward to near 119W by Sat. $$ Hagen