Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 348 AM EDT Sun Aug 24 2014 Valid 12Z Sun Aug 24 2014 - 12Z Tue Aug 26 2014 ...There is a slight risk of severe thunderstorms over parts of the Upper Mississippi Valley... ...Temperatures will be 10 to 20 degrees below average over parts of the Northern High Plains ... A storm over the Upper Midwest will move northward into South-Central Canada on Monday. The strong dynamics and ample moisture supply will aid in producing moderate to heavy rain over parts of the Northern High Plains on Sunday that will lift into Southern Canada by Monday morning. The system will also produce showers and thunderstorms over parts of the Upper Mississippi Valley and the Northern Plains on Sunday. The showers and thunderstorms will move into the Great Lakes on Monday. In addition, upper-level energy over the West Coast of Canada will move southeastward to the Northern Rockies/Northern Intermountain Region by Monday evening. The energy will produce showers and thunderstorms over parts of the Northern Intermountain Region/Northern Rockies by Sunday evening that will move into parts of the Central Rockies/Central Plains by Monday morning. By Monday evening the area of showers and thunderstorms will extend from the Northern Rockies to the Central Plains and into parts of the Middle Mississippi Valley. Meanwhile, an old boundary extending from the Southeast to the Middle Mississippi Valley will aid in triggering showers and thunderstorms over parts of the Southeast into parts of the Middle Mississippi Valley on Sunday. The showers and thunderstorms will move into Florida and the Eastern Gulf Coast by Sunday evening. The convection will expand westward into the Central Gulf Coast by Monday evening as weak upper-level energy moves over the Central Gulf Coast. Additionally, easterly flow off the Atlantic will aid in producing rain over parts of the Central Appalachians on Sunday. Rain will also develop over parts of the Southeast Coast on Sunday evening into Monday evening. Elsewhere, monsoonal moisture and diurnal heating will produce showers and thunderstorms over parts of the Southern Rockies on Sunday and Monday afternoon/evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php