Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 358 PM EDT Sun Aug 13 2017 Valid 00Z Mon Aug 14 2017 - 00Z Wed Aug 16 2017 ...Flash flooding possible across the Lower Mississippi Valley... ...Heavy rainfall and severe thunderstorms will be possible in the Plains over the next few days... ...Continuous showers and thunderstorms expected in the Southeast... The heavy rainfall that impacted Oklahoma and northern Texas shifted to the lower Mississippi Valley today as a strong upper level disturbance moved over this region. Precipitation will remain over Arkansas and Louisiana overnight and drift into the Southeast by Monday. As a result, flash flooding will remain a threat for the lower Mississippi Valley overnight. Meanwhile, farther north, another upper level disturbance will swing across the northern Plains overnight and move into the Upper Midwest by Monday night. A surface front will also follow this path--with a low moving into western Minnesota by Monday morning. Showers and thunderstorms ahead of this low will spread across the Upper Great Lakes, middle Mississippi Valley, and parts of the central Plains on Monday. Finally, more thunderstorms will fire off in the south/central High Plains late tonight and will move along the Red River Valley. These thunderstorms will bring heavy rainfall and possibility of severe thunderstorms across the southern Plains. Meanwhile, a wavy front will stretch from the southern Plains to the Carolinas--along with a moist and unstable airmass. This boundary will act as an anchor for showers and thunderstorms across the southern U.S. Expect the most coverage for thunderstorms in the late afternoon and evening throughout the short term period. Localized flooding is possible as some of these thunderstorms could produce heavy downpours. Monsoonal moisture across the Southwest will lead to late afternoon/early evening thunderstorms across the region this evening and Monday. By Tuesday, limited moisture will lead to dry conditions and limited coverage of thunderstorms. Expect no extreme temperatures across the U.S. over the next few days; below average temperatures will especially be prominent over the western U.S. on Monday and Tuesday. Reinhart Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php