Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 422 PM EDT Tue Aug 20 2013 Valid 00Z Wed Aug 21 2013 - 00Z Fri Aug 23 2013 ...Scattered showers and thunderstorms will affect the southwest and southeast through Thursday... ...Severe weather possible across portions of the Upper Midwest tomorrow... A quasi-stationary boundary in place across portions of the southeast will be the focus for showers and thunderstorms through Wednesday. This boundary will begin to dissipate late Wednesday as the upper level forcing begins lifting out of the region. Precipitation will become increasingly scattered across the southeast as the front dissipates, but upslope flow in the Appalachians should allow for continued convection across the higher terrain. An upper level low off the California coast and associated jet streak entering the desert southwest will produce widespread showers and thunderstorms across the west. Diurnally driven convection is expected to continue through the forecast period. A cold front pushing southeastward across the Upper Midwest will displace a warm and humid airmass. The front combined with a strengthening upper level jet to the north and an approaching mid level shortwave should spark convection tomorrow afternoon. Some thunderstorms are expected to be severe. Krekeler Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php