Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 334 PM EDT Fri May 17 2013 Valid 00Z Sat May 18 2013 - 00Z Mon May 20 2013 ...Severe thunderstorms are possible over parts of Central Texas, Central Gulf Coast, and Northern Plains... ...Heavy rain possible for parts of the Central Appalachians and the Upper Midwest... A quasi-stationary east-west front extends from the Mid-Atlantic to the Central Rockies/High Plains. In addition to the boundary, upper-level energy over the Tennessee Valley will drift eastward to the Central Appalachians by Sunday. The energy will aid in the developing of showers and thunderstorms from the parts of the Ohio Valley to the Mid-Atlantic as well as the Central Gulf Coast/Tennessee Valley to the Central Appalachians. The showers and thunderstorms will move into parts of the Southeast by Saturday evening/Sunday morning as well as remaining in the Mid-Atlantic. Along the west end of the front, showers and thunderstorms will develop over parts of the Upper Midwest through Saturday afternoon. The showers and thunderstorms will retreat to the Northern/Central Plains by Saturday evening before moving eastward to the Upper Mississippi Valley/Middle Missouri Valley by Sunday morning. Upper-level trough over the West Coast will move eastward to the Rockies by Sunday. The instability associated with the upper-level trough and elevated heat source will aid in producing showers and thunderstorms over parts of the Northern Rockies/Great Basin expanding into the Central Rockies by Sunday. Additionally, onshore flow will produce rain along parts of the pacific Northwest through Sunday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php