000 AXPZ20 KNHC 282138 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2126 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Tropical Storm Iselle is centered near 18.8N 115.2W at 28/2100 UTC moving NNE at 6 kt. Estimated minimum central pressure is 999 mb. Maximum sustained wind speed is 45 kt with gusts to 55 kt. Scattered moderate and isolated strong convection is present within 150 nm in the W semicircle. A northward turn is expected by Saturday morning followed by a north-northwestward motion on Sunday morning. Afterward, Remnant Low Iselle is forecast to turn northwestward in the low- level flow. Weakening is forecast and Iselle should become a tropical depression Saturday night, degenerate to a remnant low on Sunday and dissipate early next week.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. Post-Tropical Cyclone Hernan is centered near 23.2N 110.1W at 28/2100 UTC moving W at 12 kt. Estimated minimum central pressure is 1008 mb. Maximum sustained wind speed is 25 kt with gusts to 35 kt. Scattered moderate convection is noted from 18N to 21N between 117W and 123W. Hernan's motion toward the west is expected to continue until the system dissipates west of the southern portion of the Baja California peninsula tonight or 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 96W, 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 12N86W to 17100W. It resumes at 13N124W to beyond 13N140W. Scattered moderate convection is noted from 07N to 12N west of 135W and north of 07N east of 87W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for details on Tropical Storm Iselle, Post-Tropical Hernan, and the heavy rain potential over southern Mexico. Elsewhere, a 1025 mb high prevails at 39N137W well north of the waters west of Baja California. Indirectly related to Post- Tropical Hernan, moderate SE winds are expected in the central and N Gulf of California tonight and Sat. Seas should peak near 7 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 moderate S swell event should impact the equatorial zones on Tue and Wed. REMAINDER OF THE AREA... A 1025 mb high prevails at 39N137W well 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 southeast 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 Sun night 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