Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 335 AM EDT Fri Sep 18 2015 Valid 12Z Fri Sep 18 2015 - 12Z Sun Sep 20 2015 ...There is a slight risk of severe thunderstorms today and tonight across portions of the southern/central plains and Midwest... ...Flash flooding is possible today and tonight for portions of the Midwest... A cold front will move across the central U.S. today as a vigorous upper-level disturbance moves from the Rockies into the central and northern plains. In response to this disturbance, a wave of low pressure will develop along the front across the central plains today, which is forecast to then move across the Great Lakes Friday night into Saturday morning as it deepens. Scattered to numerous showers and thunderstorms are expected today along and ahead of the cold front from the southern plains into the Midwest and Upper Great Lakes. The Storm Prediction Center is forecasting a slight risk of severe thunderstorms today and tonight from portions of the southern/central plains into parts of the Midwest. Please refer to products issued by SPC for further details on the severe weather threat. In addition to the severe weather, heavy rain and flash flooding will be possible across portions of the Midwest as well, as new showers and thunderstorms may move across areas where the ground is already saturated from previous rains. On Saturday, the cold front will move eastward into the Lower Great Lakes and the Appalachians, with showers and thunderstorms again possible along the front. The front will move across the Northeast Saturday night and will generally be off the Northeast/Mid-Atlantic coastline by Sunday morning. Behind the front, another area of high pressure originating in Canada will bring cool, fall-like temperatures to much of the central and eastern U.S. The frontal boundary will stall across the southern plains Saturday night and will eventually begin to move north as a warm front. Thus, showers and thunderstorms will remain a possibility across the southern plains into Sunday. Conditions will remain dry across most of the western U.S and temperatures will gradually warm through the weekend. A Pacific cold front will approach the Northwest by Saturday night/early Sunday, bringing some showers to coastal portions of Washington. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php