Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 406 PM EDT Fri Jun 20 2014 Valid 00Z Sat Jun 21 2014 - 00Z Mon Jun 23 2014 ...Slight risk of severe thunderstorms tonight and Saturday for portions of the Central and Northern Plains, Midwest, Ohio Valley, and central Appalachians... ...Flash flooding possible through Saturday for portions of the Ohio Valley/central Appalachians and the central Plains... A stationary frontal boundary in place this afternoon from the Midwest to the central Appalachians and Mid-Atlantic will largely remain in place through the short range forecast period. A wave of low pressure will develop along the front over the eastern Ohio Valley tonight and will move eastward to the Mid-Atlantic coastline by Saturday evening. Moist southerly flow lifting across the front ahead of the low pressure area will cause an area of widespread showers and thunderstorms to develop this evening, which will move eastward across the Appalachians and Mid-Atlantic ahead of the surface low. The Storm Prediction Center is forecasting a slight risk of severe thunderstorms across portions of the Ohio Valley and central Appalachians through tonight. Please refer to the Convective Outlooks products issued by the Storm Prediction Center for further details on the severe weather threat. Additionally, heavy rain and flash flooding are possible for the Ohio Valley and central Appalachians. A weak surface front across the central Plains will lift slowly northward tonight into Saturday. This boundary will serve to focus shower and thunderstorm development in the vicinity of the frontal boundary. An upper-level disturbance is forecast to trigger an area of more widespread rain and thunderstorms across the central Plains this evening which will move eastward across portions of the Midwest on Saturday. Flash flooding is possible in association with this are of rain and thunderstorms. The Storm Prediction Center is forecasting a slight risk of severe thunderstorms across much of the central and northern Plains on Saturday. Additionally, a slow-moving upper-level disturbance over the southern Plains will provide additional focus for shower and thunderstorm development over western Texas. A frontal system crossing the Rockies today will move into the northern Plains by Saturday afternoon. Moist southerly flow in the Plains ahead of this system will promote shower and thunderstorm development, with the potential for a few areas of more organized and widespread showers and thunderstorms to develop. Temperatures through the short range will be below average across the northern Mid-Atlantic and Northeast beneath an upper-level trough. Above average temperatures are expected across the Southeast and Southwest as with high pressure in place at the upper-levels. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php