000 AXPZ20 KNHC 280352 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0351 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 0000 UTC surface analysis and satellite imagery through 0330 UTC. ...SPECIAL FEATURES... Tropical Storm Hernan is centered near 20.5N 107.0W at 28/0300 UTC moving NNW at 7 kt. Estimated minimum central pressure is 1004 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Numerous moderate to strong convection is noted within 300 nm in the SW semicircle and 90 nm in the NE semicircle. Scattered moderate convection is noted from 14N to 24N between 103W and 113W. On the forecast track, the center of Hernan, along with the strongest winds and heaviest rains, is expected to remain offshore of the southwestern coast of Mexico and the southern Baja California peninsula. Little change in strength is forecast through Fri night, before Hernan is forecast to weaken into a remnant low Sat and become absorbed by Tropical Storm Iselle, described below, Sat night. 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. Tropical Storm Iselle is centered near 17.6N 115.5W at 28/0300 UTC moving NNE at 3 kt. Estimated minimum central pressure is 999 mb. Maximum sustained wind speed is 45 kt with gusts to 55 kt. Numerous moderate to strong convection is noted from 15N to 19N between 114W and 119W. A northwestward motion of the system is expected during the weekend. Iselle is expected to begin to gradually weaken by late Friday. 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. A very active monsoon trough extends across southern Mexico and Central America. Heavy rainfall will continue through the weekend across these areas with the heaviest amounts expected across southern Mexico, where widespread 5 to 10 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 90W, moving westward at 10 to 15 kt. Scattered moderate convection is noted from 14N to 19N between 90W and 95W. A tropical wave axis is near 105W, moving westward at 10 to 15 kt. Scattered moderate convection is noted from 10N to 17N between 100W and 107W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough over Central America, then resumes west of T.S. Iselle from 15N118W to 11N140W. Other than the convection associated with Tropical Storm Hernan, Tropical Storm Iselle, and the tropical waves all described above, scattered moderate convection is noted within 90 nm on either side of the monsoon trough. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for details on Tropical Storm Hernan, Tropical Storm Iselle, and the heavy rain potential over southern Mexico. Elsewhere, high pressure prevails over the waters W of Baja California. More tranquil weather conditions will likely return across the majority of the offshore waters by early next week. 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 Central America. To the south of the Monsoon Trough, moderate to fresh S-SW winds will prevail S of Costa Rica and Panama through the next several days, with gentle to occassionally moderate winds elsewhere. Long-period mainly southerly swell will continue to propagate into the waters offshore Ecuador through Fri, bringing seas of 8 to 10 ft. Another set of southerly swell will approach the waters W of Ecuador by late Mon. Locally higher winds and rough seas are possible near scattered to numerous showers and thunderstorms that will prevail over the forecast waters the next couple of days, especially N of 09N. REMAINDER OF THE AREA... Please see Special Features section for details on Tropical Storm Iselle. Elsewhere, a ridge dominates the northern forecast waters N of 20N. N of the monsoon trough, gentle to moderate winds prevail. Fresh to locally strong SW winds prevail S of the two tropical cyclones, between 100W and 120W, along with seas of 8 to 11 ft. Northerly swell, with seas of 8 ft or greater, are forecast to reach S of 30N by Sun night into early next week, before starting to decay late Mon night. $$ ERA