Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 348 AM EDT Mon Jul 20 2015 Valid 12Z Mon Jul 20 2015 - 12Z Wed Jul 22 2015 ...There is a slight risk of severe thunderstorms over parts of the Middle Mississippi Valley... ...Heavy rain possible over parts of the Middle Mississippi Valley into the Southern Plains... A front extending from the Northeast to the Central High Plains will move off the Northeast Coast by Tuesday afternoon. A second front over the Upper Midwest will merge with the western parts of the first front over the Ohio Valley on Tuesday. Showers and thunderstorms will develop along and near the boundary from Northern New England to the Mid-Atlantic and westward to the Central High Plains through Tuesday. The second front extending from the Upper Great Lakes to the Northern High Plains will move eastward to the Northeast Coast by Tuesday evening. The boundary will extend from the Southern Mid-Atlantic to the Central High Plains on Tuesday. The system will produce showers and thunderstorms over parts of the Upper Great Lakes that will extend along the front into the Middle Mississippi Valley by Monday evening. Showers and thunderstorms will develop along the front from the Northeast to the Mid-Atlantic to the Tennessee Valley into the Central High Plains by Tuesday evening. A third front will move onshore over the Pacific Northwest by Monday evening and move inland to the Northern Rockies by Tuesday. Showers and thunderstorms will develop along the warm front over the Northern High Plains that will move eastward into the Northern Plains by Tuesday evening. In addition, monsoonal moisture and moisture associated with the remains of T. D. Dolores will aid in producing showers and thunderstorms over parts of Southern California/Great Basin into the Southern/Central Rockies through Tuesday evening. Additionally, moisture pooling over the Southeast and upper-level impulses will trigger showers and thunderstorms over parts of the Southeast/Central Gulf Coast through Tuesday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php