000 AXPZ20 KNHC 270312 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 021 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 0000 UTC surface analysis and satellite imagery through 0300 UTC. ...SPECIAL FEATURES... Tropical Storm Hernan is centered near 18.3N 105.8W at 27/0300 UTC moving N at 5 kt. Estimated minimum central pressure is 1004 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Numerous moderate and isolated strong convection is noted within 90 nm in the SW semicircle. Scattered moderate isolated strong convection is elsewhere from 13N to 18N between 104W and 113W. Hernan will maintain a slow northward motion tonight, followed by a turn toward the northwest on Thursday, and a west- northwestward motion on Friday. On this track, most of Hernan's significant winds should remain just offshore the southwestern coast of Mexico tonight and Thursday, and pass near or just south of the southern tip of Baja California Sur on Friday and Saturday. A weakening trend is expected to begin late Thu night, and Hernan is forecast to become a remnant low Fri 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 16.2N 116.2W at 27/0300 UTC moving NE at 5 kt. Estimated minimum central pressure is 1001 mb. Maximum sustained wind speed is 35 kt with gusts to 45 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 Fri. 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 83/84W, moving westward at around 15 kt. Associated convection is described in the section below. A tropical wave axis is near 99W, 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 E of 104W, including portions of Central America and southern Mexico. Scattered moderate isolated strong convection is noted from 05N to 11N between 130W 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 a heavy rainfall event 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 a heavy rainfall event 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 with seas of 7-9 ft will propagate into the waters offshore of Ecuador by early Thu, 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, 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. No significant wind or swell events are anticipated through Sun, with the potential for a northerly swell event with seas of 8 ft or greater reaching S of 30N by Sun night into early next week, decaying beginning late Mon night. $$ AL