Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 527 PM EDT Mon Aug 25 2014 Valid 00Z Tue Aug 26 2014 - 00Z Thu Aug 28 2014 ...Cooler air to push across the Midwest on Tuesday and Wednesday while temperatures will warm across the East... ...Heat and humidity will continue across the Southern Plains into the lower Mississippi Valley... ...Scattered showers and thunderstorms will persist across the Southwest and Southern Rockies and expand eastward across the Central Plains with localized flash flooding possible... Cooler air across the northern Rockies and Northern Plains will continue moving eastward towards the Midwest over the next couple days. Along the leading edge of the accompanying cold front, some scattered showers and thunderstorms will fire up along the Mid Mississippi Valley across the Midwest and approach the Northeast on Wednesday. Out ahead of the front, the high pressure area that brought comfortable temperatures to much of the East will weaken and stagnate over the next couple days allowing temperatures to warm up and temperatures could become relatively hot by Wednesday out ahead of the approaching cold front with temperatures likely to rise above 90 degrees from the Mid Atlantic states into New England. While the heat and humidity of late will break across the Mid to Upper Mississippi Valley, cooler air will remain mostly north of Kansas and Missouri southward across the Southern Plains and lower Mississippi Valley where heat and high humidity will continue through Wednesday with temperatures in the 90s to near 100 degrees. An upper level disturbance will cross the Great Basin on Tuesday and cross the Rockies on Wednesday bringing diurnally enhanced showers and thunderstorms to those regions. As this system approaches the Central Plains, it will interact with the frontal boundary separating the hot and humid air across the Southern Plains from the cooler air to the north and will focus the threat of showers and thunderstorms especially across the Central Plains toward the mid and upper Mississippi Valley on Tuesday into Wednesday. In these areas, the possibility that some of the rainfall could be quite heavy could also bring the threat of flash flooding in some places. Kocin Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php