Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 444 AM EDT Fri Jul 25 2014 Valid 12Z Fri Jul 25 2014 - 12Z Sun Jul 27 2014 ...A surge in heat and humidity expected for the Middle Mississippi and Ohio Valleys... ...Flash flooding and severe weather possible across portions of the Midwest on Saturday... Heat and humidity will make a return to the Middle Mississippi and Ohio Valleys late this week as a frontal boundary stretched from the Central Plains to the Lower Mississippi Valley begins to surge northeastward as a warm front. Meanwhile...showers and thunderstorms will continue to ignite ahead of a seasonably strong cold front pushing through the north central U.S. on Friday. These storms will be capable of producing heavy downpours and severe weather...especially as they propagate southeastward into a moist and unstable airmass setting up across the Midwest on Saturday. A plume of moisture streaming off the Eastern Pacific will fuel additional days of scattered afternoon convection across the Southwest and Central Rockies Friday and Saturday. Elsewhere in the West...temperatures will be on the rise over the Northern Rockies and Intermountain West this weekend as an upper ridge sprawled across the south central U.S. builds northward into the region. Pleasant conditions will prevail in the wake of a cold front pushed well off the New England and northern Mid-Atlantic coasts on Friday. However...the tail end of the boundary will linger over the Southeast and Gulf Coast states...helping to foster shower and thunderstorm activity Friday and Saturday. Gerhardt Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php