Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 358 PM EDT Tue Jun 14 2016 Valid 00Z Wed Jun 15 2016 - 00Z Fri Jun 17 2016 ...Flash flooding and severe weather to impact the central and eastern portions of the U.S. over the next few days... Showers and thunderstorms firing off in the upper and middle Mississippi Valleys will continue to move eastward over the next few days. An upper level low will move across the Great Lakes on Wednesday and toward the Mid-Atlantic by Thursday. Ahead of it, warm, moist and unstable air will allow for the development and continuation of convection throughout the short term period. At the surface, a warm front that is already the focal point for this convection will lift north and east over the Great Lakes on Wednesday. This will shift the precipitation over this region along with the existing flash flooding and severe weather threat. During the afternoon on Wednesday, thunderstorms are also expected to break out across the eastern Tennessee Valley some of which could also be severe. By Thursday, showers and thunderstorms will continue its eastward trek across the Northeast and Mid-Atlantic as the front moves over these regions. Both the flash flooding and severe weather threats can also be expected. Farther west, an upper level low will very slowly move south and east, over the Pacific Northwest which will promote onshore flow over this area. This will generate light to moderate rainfall across both the Pacific Northwest and into the Intermountain West throughout Wednesday and Thursday. Fanning Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php