Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 403 PM EDT Tue Apr 16 2013 Valid 00Z Wed Apr 17 2013 - 00Z Fri Apr 19 2013 ...Severe Thunderstorms are possible over parts of the Ohio Valley/Tennessee Valley and parts of the Central and Southern Plains... ...Heavy snow is possible over parts of the Northern/Central High Plains... ...Heavy rain is possible over parts of the Middle Mississippi Valley... A front extending from the Northern Appalachians southwestward to the Southern Plains will move off the Northeast coast by Wednesday morning and become quasi-stationary from the Southern Plains to Southern New England. A developing wave of low pressure over the Southern Rockies will lift northward to the Middle Mississippi Valley by Thursday. The wave will pull a warm front northward into the Great Lakes, while part of the front hangs up over the northern Mid-Atlantic coast. Likewise, the storm will pull the cold front out of the Southwest eastward into the Southern Plains. Moderate to heavy rain will move eastward along the front across the Northeast out over the Western Atlantic by Tuesday evening. Moisture from the Gulf of Mexico will overrun the boundary producing showers and thunderstorms along and north of the front from the Central Plains eastward to the Ohio Valley/Central Appalachians through Wednesday evening. In addition, some of the areas of showers and thunderstorms will have moderate to heavy rain over parts of the Ohio Valley on Tuesday evening and over parts of the Central Plains/Middle Mississippi Valley on Wednesday. Upper-level energy over the West Coast will move eastward to the Southern Rockies by Thursday. The energy will aid in producing snow over parts of the Northern/Central Rockies and the Great Basin through Tuesday afternoon. Some pockets of moderate snow will develop over parts of the Northern/Central High Plains Tuesday evening into Wednesday afternoon. On Wednesday evening, the snow will move onto parts of the Northern/Central Plains and parts of the Upper Mississippi Valley by Thursday morning. As some of the upper-level energy moves onto the High Plains, showers and thunderstorms with heavy rain will develop along and ahead of the cold front from the Southern Plains to the Middle Mississippi Valley and parts of the Upper Great Lakes on Thursday morning. Elsewhere, weak upper-level energy will move over parts of the Pacific Northwest that will produce light rain over parts of the coastal region Wednesday night into Thursday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php