Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 402 PM EDT Sat Aug 30 2014 Valid 00Z Sun Aug 31 2014 - 00Z Tue Sep 02 2014 ...Central and Northern Plains and the Upper Mississippi Valley will have a threat of severe weather on Sunday... ...Heavy showers and thundershowers will affect the Gulf Coast and Lower Mississippi Valley through tonight before reaching the Ohio and Tennessee Valleys on Sunday... ...Warmer and more humid conditions will spread eastward across much of the East while cooler temperatures cover much of the West on Sunday and Monday, except for hot and dry conditions for the Southwest... A cold front currently advancing eastward from the Northwest is expected to reach the Northern Plains on Sunday. Southerly winds ahead of the front will be transporting warmer temperatures and moisture northward and this will lead to a favorable set-up for severe thunderstorms, including large hail and a few tornadoes later on Sunday. the main threat area is expected to be from Kansas and Nebraska northeast into Iowa and Minnesota. Meanwhile, a weak upper trough moving gradually east into the Lower and Middle Mississippi Valley coupled with a surge of deep tropical moisture advancing inland off the Gulf of Mexico will continue to produce an area of heavy showers and thundershowers across the central Gulf Coast states through tonight. This deep moisture and expansive area of showers and thunderstorms will lift into the Ohio and Tennessee Valleys on Sunday and portions of the central Appalachians and Northeast on Monday. A separate area of showers and thunderstorms should impact the Great Lakes region as well through Sunday. As high pressure moves eastward off the Northeast coast, warmer and more humid conditions will return across much of the East and will continue through Labor Day with scattered thundershowers and temperatures approaching or exceeding 90 degrees. Meanwhile, cooler conditions will cover much of the Northwest and Northern Rockies and then move eastward toward the Midwest by Monday. Hot and dry conditions will continue though over the Desert Southwest where temperatures will exceed 100 degrees. Orrison Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php