000 AXPZ20 KNHC 281601 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1526 UTC Fri Aug 28 2020 Tropical Weather Discussion for the eastern Pacific Ocean from the Equator to 32N, east of 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 1500 UTC. ...SPECIAL FEATURES... Tropical Storm Iselle is centered near 18.3N 115.3W at 28/1500 UTC moving NNE at 6 kt. Estimated minimum central pressure is 997 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. Scattered moderate and isolated strong convection is present within 180 nm in the W semicircle. A northward turn is expected by Saturday morning followed by a northwestward motion on Sunday evening. Afterward, Remnant Low Iselle is forecast to turn west- northwestward in the low-level easterly flow. A gradual weakening trend should commence later tonight. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPEP4.shtml and Forecast/ Advisory at https://www.nhc.noaa.gov/text/MIATCMEP4.shtml for more details. Tropical Depression Hernan is centered near 23.4N 109.1W at 28/1500 UTC moving WNW at 18 kt. Estimated minimum central pressure is 1006 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Scattered moderate convection is present within 120 nm of the center. Hernan is forecast to move over the southern portion of the Baja California peninsula this afternoon or tonight. Hernan is expected to degenerate to a remnant low pressure area tonight. The remnants are expected to dissipate on Saturday. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPEP3.shtml and Forecast/ Advisory at https://www.nhc.noaa.gov/text/MIATCMEP3.shtml for more details. A very active monsoon trough extends across southern Mexico. Heavy rainfall will continue through the weekend across these areas with widespread 4 to 6 inches of additional rainfall is forecast. This rainfall may cause dangerous and life-threatening flash flooding and mudslides, and river flooding. Refer to information issued by your local or national meteorological agency for details. ...TROPICAL WAVES... A tropical wave axis is near 95W, moving westward around 15 kt. Scattered moderate convection is noted from 14N to 17N between 95W and 98W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough emerges off of Central America near 08N82W to 16N97W. It resumes at 12N125W to beyond 13N140W. Scattered moderate convection is noted from 08N to 13N west of 135W and from 06N to 08N east of 85W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for details on Tropical Storm Iselle, Tropical Depression Hernan, and the heavy rain potential over southern Mexico. Elsewhere, a 1025 mb high prevails at 39N137W north of the waters west of Baja California. Indirectly related to Tropical Depression Hernan, moderate SE winds are expected in the central and N Gulf of California tonight and Sat. Seas should peak near 6 ft. Elsewhere, tranquil weather conditions will likely return across the offshore waters from Mon through at least Wed. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Please see the Special Features section for details on heavy rain potential over southern Mexico. In general, quiescent conditions should prevail for the next several days. North of the monsoon trough along 08-10N winds should be moderate or weaker, while moderate to fresh S winds will prevail south of the monsoon trough. A S swell is boosting seas to 8 ft in the equatorial zones today, before relaxing on Sat. A new, moderate S swell event should the equatorial zones on Tue and Wed. REMAINDER OF THE AREA... A 1025 mb high prevails at 39N137W north of the waters west of Baja California. The weak pressure gradient between the high and the monsoon trough to the south is promoting moderate to fresh NE trades. Moderate to fresh S winds will prevail south of the monsoon trough. The exception is SW moderate winds between 12N- 18N between 110W and 120W south of Tropical Storm Iselle. These enhanced monsoonal SW winds should diminish on Sat. A N swell event will cross the 30N border near 130W boosting combined seas to 8-9 ft through Tue night. A S swell event should cross our 03.4S border east of 120W on Tue and Wed increasing seas to around 8 ft. $$ Landsea