Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 419 AM EDT Sat Jul 11 2015 Valid 12Z Sat Jul 11 2015 - 12Z Mon Jul 13 2015 ...Severe thunderstorms and flash flooding possible for portions of the Mid-Atlantic... ...Flash flooding possible for portions of the northwestern U.S and central Mississippi Valley... Low pressure along a surface frontal boundary will move across the central Appalachians and into the Mid-Atlantic states this morning. showers and thunderstorms are expected to develop near the Central Appalachians as the warm front lifts north. The Storm Prediction Center is forecasting a slight risk of severe thunderstorms today across eastern North Carolina and extreme southeast Virginia. Flash flooding will be possible as any thunderstorms could produce locally heavy rainfall. This area of low pressure and the area of most widespread shower and thunderstorm activity will move southeastward to the southern Mid-Atlantic coastline by early Saturday evening, before moving offshore. A warm front across central portions of the U.S. will push northeast through the weekend, reaching the Northern Plains and Midwest by Sunday. This warm front will be the focus for a few potential areas of showers and thunderstorms, generally along and north of the frontal boundary. Iowa, Missouri and Illinois may receive excessive rain with these thunderstorms. Flash flooding will be possible today for this region. The upper-level trough that has sat up over the West will not progress quickly over the next couple of days. Impulses of energy moving through the flow aloft will trigger more widespread convection today for much of the Inter-mountain West and along and east of the Rockies. Localized heavy rainfall may raise the possibility of flash flooding for some areas. The northwestern U.S. will remain the focus for daily shower and thunderstorm activity through the weekend as the aforementioned trough remains in place. High pressure will build in at the mid and upper-levels through the weekend across the southwestern U.S., keeping afternoon and evening thunderstorm activity a little more sparse relative to the Northwest. Campbell/Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php