Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 234 PM EDT Sun Aug 14 2016 Valid 00Z Mon Aug 15 2016 - 00Z Wed Aug 17 2016 ...Flash flooding possible from the Gulf Coast to the Ohio valley... ...Severe thunderstorms possible across portions of the Northeast this evening... ...Slightly cooler temperatures on the way for the Mid-Atlantic and Northeast... A frontal boundary across the central and eastern U.S. will serve as the primary focus for showers and thunderstorms through the short range forecast period. The front will cross the northeastern U.S. this evening, bringing scattered to numerous showers and thunderstorms. Some of these storms across the Northeast this evening could be severe, and the Storm Prediction Center has placed the area in a slight risk for severe thunderstorms. Farther west, the frontal boundary will remain stationary from Texas to the Ohio valley, and will result in numerous showers and thunderstorms through Monday from the Gulf Coast to the mid-Mississippi and Ohio valleys. As deep, tropical moisture continues to be pulled north into the system, very heavy rainfall will occur, and flash flooding is possible through Monday from the Gulf Coast to the Ohio Valley and southern portions of the Great Lakes. A wave of low pressure forecast to strengthen along the front late on Monday will move east, spreading numerous showers and thunderstorms across the lower Great Lakes and into the Northeast once again by Tuesday. The ridge of high pressure which has led to a period of very hot temperatures across the Mid-Atlantic and Northeast the past several days will remain in place through the short range forecast period, but will weaken slightly. This will allow temperatures to cool a few degrees, but they will remain above average. High temperatures on Monday and Tuesday are forecast to be 5 to 10 degrees above average across much of the Eastern Seaboard. Across the West a series of weak upper-level disturbances will result in isolated to scattered showers and thunderstorms from the Great Basin to the Rockies, primarily during the afternoon and evening. The West Coast will remain dry, however. Temperatures will remain above average across most of the West through Tuesday. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php