000 AXPZ20 KNHC 270925 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 711 UTC Thu Aug 27 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... Tropical Storm Hernan is centered near 18.6N 106.0W at 27/0900 UTC moving N at 4 kt. Estimated minimum central pressure is 1001 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Numerous moderate and scattered strong convection is noted within 120 nm in the SW semicircle. Scattered moderate isolated strong convection is elsewhere from 15N to 19N between 105W and 111W. Hernan will move slowly northward this morning, followed by a turn toward the northwest by this afternoon, with a west- northwestward motion expected on Friday. By Saturday, Hernan is forecast to degenerate into a remnant low pressure system. 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 16.6N 116.2W at 27/0900 UTC moving NNE at 4 kt. Estimated minimum central pressure is 1001 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Numerous moderate and scattered strong convection is noted within 150 nm in the SW semicircle. Iselle is moving toward the NE and this motion is expected to continue through Sat. Little change in strength is forecast during the next few days. 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 week across these areas with the heaviest amounts expected across southern Mexico. 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 85W, moving westward at around 15 kt. Associated convection is described in the section below. A tropical wave axis is near 100W, moving westward at around 15 kt. Associated convection is described in the section below. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from near 14N88W to 16N100W. It resumes west of Iselle near 14N122W to 11N140W. Other than the convection associated with Tropical Storm Hernan and Tropical Storm Iselle, numerous moderate and scattered strong convection is noted N of 08N between 85W and 105W, including portions of Central America and southern Mexico. Scattered moderate isolated strong convection is noted from 08N to 11N between 128W and 140W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for details on Tropical Storm Hernan, Tropical Storm Iselle and 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. 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 S-SW swell will propagate into the waters offshore of Ecuador by early today, decaying by the end of the week. Another set of southerly swell will approach the waters W of Ecuador Mon night. 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. 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. $$ AL