Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 352 AM EDT Sat Aug 23 2014 Valid 12Z Sat Aug 23 2014 - 12Z Mon Aug 25 2014 ...There is a slight risk of severe thunderstorms over parts of the Northern Plains and the Upper Mississippi Valley... ...Heavy rain possible over parts of the Northern High Plains eastward to parts of the Upper Mississippi Valley... ...Temperatures will be 10 to 20 degrees below average over parts of the Northern Rockies/Northern High Plains... Developing storm over the Northern Rockies/Northern High Plains will lift northeastward into South-Central Canada by Sunday evening. High moisture content air and strong upper-level dynamics will combine to produce moderate to heavy rain over parts of the Northern Rockies/Northern High Plains on Saturday, waning in intensity on Sunday to light rain over parts of the Northern Plains. Some instability showers and thunderstorms will develop over parts of the Northern Rockies on Sunday evening. In addition, showers and thunderstorms will develop over parts of the Northern Plains with moderate to heavy rain at times also on Saturday. The showers and thunderstorms will move into the Upper Mississippi Valley and parts of the Upper Great Lakes on Sunday. A second area of showers and thunderstorms will develop over parts of the Great Basin/Central Rockies on Saturday moving into the Northern Plains/Upper Mississippi Valley by Sunday morning. Meanwhile, a weak front extending from the Southern Mid-Atlantic roughly westward to the Central Plains will slowly settle southward over the Southeast to the Central Gulf Coast by Sunday. Moisture pooling along the boundary will aid in producing showers and thunderstorms from the Central Plains to the Mid-Atlantic, waning to the Southeast Coast then to the Eastern Gulf Coast by Sunday evening. Additionally, monsoonal moisture and diurnal heating will produce afternoon and evening showers and thunderstorms over parts of the Southern/Central Rockies and parts of the Great Basin on Sunday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php