Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 423 PM EDT Tue Aug 19 2014 Valid 00Z Wed Aug 20 2014 - 00Z Fri Aug 22 2014 ...Slight risk of severe thunderstorms over parts of the Western Ohio Valley and the Great Lakes... ...Heavy rain possible over parts of the Western Ohio Valley and parts of the Central/Northern Plains... An upper low swinging through the Great Lakes will bring the chance of severe weather to the Western Ohio Valley today. Strong to severe thunderstorms are expected in a hot and humid airmass in place across the region. With above normal moisture being transported by strong southwesterly flow ahead of the cold front, heavy rainfall is expected into the evening associated with the thunderstorms activity. The cold front will sweep across the Ohio Valley tonight before becoming stationary across the region tomorrow afternoon. Precipitation will be focused along and ahead of the occluded boundary as it passes through the Lower Great Lakes and Ohio Valley tonight and tomorrow. With the slow eastward progression of the system flash flooding will be possible tomorrow across Western Pennsylvania and Western New York. A deep upper trough over the western U.S. will bringing heavy rain to the Southwest and Intermountain west this evening. Some of the upper level energy in the Southwest will eject out into the Northern Plains tomorrow, with precipitation breaking out in the afternoon ahead of a cold front dropping out of Western Canada. A warm front pushing northward through the Central Plains will also be a focus for precipitation developing tomorrow afternoon. With the upper level jet strengthening overhead and more shortwave energy crossing the Northern Rockies, the precipitation shield will expand across the Northern Plains tomorrow evening. By Thursday morning, the cold front will be banked up against the Northern Rockies in Montana and precipitation will be enhanced by upslope flow in the region. Krekeler Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php