Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 458 AM EDT Fri May 19 2017 Valid 12Z Fri May 19 2017 - 12Z Sun May 21 2017 ...There is a slight risk of severe thunderstorms from Southern High Plains/Middle Mississippi Valley to Western Ohio Valley... ...Heavy rain possible from the Southern Plains/Middle Mississippi Valley to the Western Ohio Valley... ...Temperatures will be 15 to 30 degrees below average over the Central Rockies/Central High Plains... Low pressure over the Central Plains will lift northward to the Upper Mississippi Valley by Saturday evening. A front extending from the Northeast to the Ohio and Middle Mississippi Valleys will be quasi-stationary until Saturday morning when the boundary will begin to lift northward as a warm front. Showers and thunderstorms will develop along and near the front from the Central Plains to the Ohio Valley that will expand into the Mid-Atlantic by Friday afternoon ending over most of the Mid-Atlantic by Saturday evening. On Saturday morning, the showers and thunderstorms will lift northward into Middle Mississippi Valley/Great Lakes into Saturday evening. In addition, snow and lower elevation rain will develop over parts of the Central Rockies that will slowly come to an end by Saturday morning. Showers and thunderstorms will also develop along and ahead of the associated cold front over the Central/Southern Plains that will move eastward to Lower/Middle Mississippi Valley and the Tennessee Valley into parts of the Western Gulf Coast by Saturday evening. Meanwhile, upper-level energy over the Pacific Northwest will move southeastward to the Northern Intermountain Region by Saturday. The energy will aid in producing rain over parts of the Northern Rockies by Saturday morning that will expand into parts of the Northern High Plains and parts of the Central Rockies by Saturday evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php