Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 432 AM EDT Sun Aug 25 2013 Valid 12Z Sun Aug 25 2013 - 12Z Tue Aug 27 2013 ...Heavy rains and flash flooding expected across the Southwest... ...Late summer heatwave in store for the Dakotas and Upper Midwest... ...Severe weather possible over portions of Minnesota and Wisconsin... Widespread showers and thunderstorms will continue to fire up across the southwestern corner of the country on Sunday. Moisture from Tropical Depression Ivo getting pulled northeastward...in-between a trough digging into the West and an upper ridge building in over the central U.S....will fuel moderate to locally heavy rains across the Southwest and into the southern Great Basin. Flash flooding will remain a concern across the region...but by Monday...Ivo is expected to weaken and shower and thunderstorm activity should become less intense across the Southwest. Temperatures will be on the rise across the Upper Midwest on Sunday as an upper ridge builds in over the Central U.S.. The expanding ridge is expected to remain anchored over the Middle Mississippi Valley the next few days...leading to a late summer heatwave across the north central U.S.. Heat advisories are already in effect for portions of the Dakotas and Upper Midwest...where heat indices will climb into triple digits. In addition to the heat...impulses of energy streaking through the northern periphery of the upper ridge should help trigger scattered convection across the northern tier of the Nation. Some of these storms will have the potential to produce severe weather...especially across portions of Minnesota and Wisconsin. A strong surface high over the Eastern U.S. will keep conditions pleasantly dry across New England and the Mid-Atlantic states on Sunday. However...by Monday...upper energy making its way over the top of the central U.S. ridge will help ignite scattered showers and thunderstorms across the Northeast. Farther south...showers and thunderstorms will remain in the forecast across the Gulf Coast states. The heaviest precipitation should stay just off shore...but some storms containing moderate to heavy rains could make their way inland. Gerhardt Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php