Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 456 AM EDT Thu Aug 01 2013 Valid 12Z Thu Aug 01 2013 - 12Z Sat Aug 03 2013 ...Unsettled weather expected along the Eastern Seaboard... ...Thunderstorms developing over the Central Plains and Middle Mississippi Valley will carry a risk of severe weather and flash flooding... ...Flash flooding possible across the Northern Rockies... Showers and thunderstorms will continue to break out ahead of a cold front approaching the Eastern Seaboard on Thursday. The best chance for any organized areas of storms and heavy rains will be near a surface low along the front tracking from the northern Mid-Atlantic states into southern New England. An abundance of moisture in place could also lead to some higher precipitation totals along the Florida Panhandle and up into the coast of North Carolina. On Friday...the front will push offshore and conditions should begin to improve across the Mid-Atlantic and New England states. However...the southern portion of the boundary will linger across the Southeast...leading to an additional day of showers and thunderstorms. A frontal boundary stretched through the Central U.S. will serve as a focal point for convection the next few days from the Northern High Plains into Midwest. Much of the activity should be scattered in nature...but a piece of energy embedded in the flow aloft should help fire up an organized area of thunderstorms across the Central Plains on Thursday...which should progress into the Middle Mississippi Valley by Friday. Given the amount of moisture/instability available...these storms will pose a threat for both flash flooding and severe weather. The northwestern corner of the country will see a decrease in temperatures and an increase in shower activity while a closed upper vortex gradually moves inland from the Pacific Coast. By late Thursday into Friday...low level easterly/southeasterly flow will strengthen ahead of the closed low...and the combination of upslope flow against the terrain and moisture being drawn up from the Central Plains should lead to some moderate to heavy rains developing across the Northern Rockies and Northern Great Basin. These organized areas of rain with embedded thunderstorms will have the potential to cause flash flooding across the region. Gerhardt Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php