Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 401 AM EDT Mon Jul 22 2013 Valid 12Z Mon Jul 22 2013 - 12Z Wed Jul 24 2013 ...There is a slight risk of severe thunderstorms from parts of the Central Plains to the Upper Great Lakes... ...Heavy rain possible over parts of the Middle Mississippi Valley and parts of the Central Gulf Coast... ...Temperatures will 10 to 15 degrees below average over parts of the Upper Midwest... A front extending from the Great Lakes to the Northern Rockies/Northern High Plains will move eastward to the Lower Great Lakes southward to the Central Plains then northwestward to the Northern High Plains by Tuesday evening. Showers and thunderstorms will develop along and ahead of the boundary over the Upper Great Lakes to the Middle Mississippi Valley that will move eastward to the Northeast/Central Appalachians/Mid-Atlantic to parts of the Tennessee Valley by Tuesday. In addition, showers and thunderstorms will develop over parts of the Central Plains/Middle Mississippi Valley along the western end of the front on Tuesday. Meanwhile, upper-level energy over the Southern Ohio Valley/Tennessee Valley will move eastward to the Mid-Atlantic/Southeast Coast by Tuesday evening. The energy will produce showers and thunderstorms over the region on Monday, moving off the Mid-Atlantic coast by Tuesday morning. Another area of upper-level energy will move over the Northern High Plains on Monday evening advancing to parts of the Upper Mississippi Valley/Northern Plains by Tuesday evening. A third area of upper-level energy will move from Northwest Mexico to off the Central California Coast also by Tuesday. This area of energy will trigger showers and thunderstorms over parts of the Southwest/Southern California. Additionally, monsoonal moisture and diurnal heating will produce showers and thunderstorms over parts of the Southern Rockies and the Lower Rio Grande Valley through Tuesday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php