Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 451 PM EDT Tue Jul 14 2015 Valid 00Z Wed Jul 15 2015 - 00Z Fri Jul 17 2015 ...Severe thunderstorms and flash flooding possible for a good portion of the eastern U.S. through tonight, followed by cooler and drier conditions over the Midwest and Northeast... A dome of cool air from eastern Canada is forecast to advance into much of the eastern U.S. over the next couple of days. Before the arrival of the cool air however, very warm and moist air lifted ahead of a cold front will give rise to strong to severe thunderstorms this afternoon and tonight from the Tennessee Valley, eastward across the Ohio Valley, the Appalachians, into the Mid-Atlantic, and the northern part of the Southeast. By tomorrow, Wednesday, showers and thunderstorms will be pushed southward into the Southeast as the cool Canadian air overspreads the northeastern part of the U.S. Meanwhile, return flow from the Gulf of Mexico will push northward through the Plains and result in showers and thunderstorms in the northern Plains through Thursday. Temperatures are expected to be sightly warmer than normal over the Plains and through the Deep South while the cool air from Canada could drop temperatures to more than 10 degrees below normal in the Midwest. Out West, monsoonal moisture will bring scattered afternoon and evening thunderstorms across much of the Rockies through Wednesday. Meanwhile, dry conditions are expected to continue farther westward across the Great Basin and into all of the West Coast. Kong Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php