371 AXPZ20 KNHC 291005 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Tue Aug 29 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 0600 UTC surface analysis and satellite imagery through 0945 UTC. ...SPECIAL FEATURES... Tropical Storm Irwin is centered near 19.5N 127.1W at 29/0900 UTC, moving west at 14 kt. Estimated minimum central pressure is 1001 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Peak seas to 16 ft are within 90 nm of the center in the NE quadrant, 30 nm in the SE quadrant, 0 nm in the SW quadrant and 60 nm in the NW quadrants. Latest satellite imagery shows that the earlier observed convection has dissipated quite significantly. Presently, scattered moderate convection is within 150 nm of the center in the W quadrant. An overnight ASCAT pass nicely highlighted the elsewhere peripheral 20-33 kt winds around Irwin, with the largest radii of these winds extending 240 nm of the center in the SE quadrant and up to about 420 nm of the center in the NW quadrant. Irwin is forecast to continue in a westward motion, with a slower motion expected later this week. Small fluctuations in intensity are possible overnight. Slow weakening is likely and Irwin could become post- tropical as soon as tomorrow or on Wed. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and the latest Irwin NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northwest Colombia to 11N86W to 14N94W to 15N105W to 18N114W. It resumes south of Irwin near 11N126W to 07N132W. The ITCZ extends from 07N132W to 08N140W. Scattered moderate convection is seen from 08N to 12N between 134W-137W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Surface high pressure ridging extends toward the Baja California Peninsula anchored by a 1027 mb high pressure center that is north- northwest of the area near 35N142W. The pressure gradient between this high and lower pressure over Mexico is supporting mostly gentle to moderate northwest to north winds, with fresh winds near the coast north of Punta Eugenia. Gentle to moderate winds prevail elsewhere. Seas of 4-6 ft prevail across the Mexican offshore waters. Winds in the Gulf of California are light to gentle along with seas to 3 ft, except for slighter higher seas of 3-5 ft from the long-period south swell are near the southern tip of Baja California. For the forecast, moderate to fresh NW winds off Baja California north of Cabo San Lazaro will persist through Wed. Northerly swell will raise seas to 8 ft north of Punta Eugenia today, then subside by Thu evening. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to gentle south to southwest winds prevail across most of the offshore waters N of 02N along with seas to 4 ft in long- period south to southwest swell. In the Ecuador and Galapagos Islands offshore waters, moderate to fresh south winds with seas of 4-5 ft due to long-period south swell are noted. For the forecast, gentle to moderate south to southwest winds and moderate seas will continue between the coast of Ecuador and the Galapagos Islands through Thu night. By Wed, an increase of southerly swell and seas to 7 ft could impact the Galapagos Island offshore waters. Elsewhere, light to gentle variable winds will prevail through most of the week with slight to moderate seas in southwest long-period swell. ...REMAINDER OF THE AREA... Please see the Special Features section for details on Tropical Storm Irwin. The pressure gradient between surface ridging north of about 20N and lower pressures associated to Tropical Storm Irwin and low pressure embedded in the monsoon trough west of 140W is maintaining moderate to fresh north to northeast winds mainly north of the monsoon trough to 23N and west of 120W. Seas are 5-7 ft. Gentle to moderate northeast to east winds and slight to moderate seas remain north of 15N and west of 125W. Gentle to moderate southwest winds are elsewhere south of the monsoon trough with seas of 5-7 ft. For the forecast, Tropical Storm Irwin will maintain intensity as it moves to near 19.5N 129.4W this afternoon, weaken to a tropical depression near 19.1N 134.4W Wed afternoon, become a remnant low and reach near 19.2N 136.3W late Wed night, move to near 19.4N 137.9W Thu afternoon and to near 19.5N 139.2W late Thu night. The remnant low will change little in intensity as it moves to just west of the area near 19.6N 141.4W by late Fri night. Northerly swell will propagate through the open waters W of the Baja California offshore through at least Thu night. Southerly swell in the far southern waters could see 8 ft seas starting tonight. This swell area could travel as far north as 05N between 92W-120W through late Thu. $$ Aguirre