Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 500 AM EDT Thu Jun 13 2013 Valid 12Z Thu Jun 13 2013 - 12Z Sat Jun 15 2013 ...The threat for severe weather and flash flooding will shift into the Mid-Atlantic states on Thursday... After intense thunderstorms rocked portions of the Midwest on Wednesday...the threat for severe weather and flash flooding will shift into the northern Mid-Atlantic states. Energy amplifying aloft will continue to ignite storms along a frontal boundary stretched from Ohio to the Delmarva Peninsula. These developing storms will likely become organized and capable of producing heavy downpours...damaging winds...large hail...and isolated tornadoes...as they propagate into a warm and juicy airmass to the south of the boundary. In addition...while the main surface low along the boundary races towards the Mid-Atlantic coast on Thursday...showers and thunderstorms should fire up ahead of the trailing cold front crossing the southern and central Appalachians. The low will push offshore late Thursday...clipping southern New England with some heavy rains and storms as it exits farther out into the Atlantic. Behind this system...much cooler and drier air will fill in across the Ohio Valley and Mid-Atlantic regions. An upper trough carving out over the Western U.S. will bring increased precipitation from the Pacific Northwest to the Northern Rockies on Thursday. Once the associated surface front pushes east of the Rockies on Friday...some showers and thunderstorms will develop over the Northern Plains and eventually Upper Midwest. With increasing amounts of moisture and instability across the region...some of these storms could produce severe weather. Elsewhere across the Nation...warm and above normal temperatures will persist underneath an upper ridge centered over the south central U.S.. Weak energy aloft combined with an abundance of Gulf Moisture should help trigger and fuel showers and thunderstorms from south Texas into eastern Colorado. Gerhardt Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php