Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 357 AM EDT Mon Sep 12 2016 Valid 12Z Mon Sep 12 2016 - 12Z Wed Sep 14 2016 ...There is a slight risk of severe thunderstorms over parts of the Middle Mississippi Valley and Central Plains... ...Temperatures will be 10 to 25 degrees below average over parts of the Northern Rockies/High Plains... A front extending from the Upper Mississippi Valley southwestward to the Central High Plains will move eastward to the Great Lakes to the Southern High Plains by Tuesday into Wednesday. Rain will develop over parts of the Upper Mississippi Valley into the Northern High Plains/Rockies on Monday morning through Monday evening. Wet snow will also develop over parts of the highest elevations of the Northern Rockies through Tuesday morning. As the precipitation moves farther out into the Plains, showers and thunderstorms will develop along the boundary from parts of the Upper Great Lakes/Upper Mississippi Valley into the Central Plains and parts of the Northern/Central High Plains on Monday evening moving to Great Lakes to the Central/Southern Plains on Tuesday. In addition, monsoonal moisture and daytime heating will aid in producing showers and thunderstorms over parts of the Southwest/Eastern Great Basin and the Central/Southern Rockies on Monday afternoon into late evening. On Tuesday, an upper-level low will develop over parts of California into parts of the Great Basin. The cold pool of air aloft will aid in producing showers and thunderstorms over parts of California into parts of the Southwest/Great Basin on Tuesday. A weakening front over parts of the Southeast along with tropical moisture over the Gulf Coast States will aid in the development of showers and thunderstorms from parts of the Southern Mid-Atlantic/Southeast into the Eastern to Western Gulf Coast through Tuesday evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php