Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 351 PM EDT Wed Jun 05 2013 Valid 00Z Thu Jun 06 2013 - 00Z Sat Jun 08 2013 ...There is a slight risk of severe thunderstorms over parts of the Lower Mississippi Valley, Southern Plains, and Southern High Plains... ...Heavy rain is possible over Western Pennsylvania... ...Heavy rain is possible from the west coast of Florida to the Carolinas Coast... ...Temperatures will be 10 to 15 degrees below average over parts of the Upper Midwest... A front extending from the Upper Mississippi Valley southwestward to the Southern Plains/Southwest will move eastward to the Northern/Central Appalachians to the Central Gulf Coast by Friday morning. Showers and thunderstorms, some with moderate rain, will develop along and ahead of the boundary over parts of the Upper Great Lakes to the Middle Mississippi Valley/Southern Plains that will move eastward to the Central Plains/Tennessee Valley. A warm front will develop over the Carolinas and will lift northward to the Mid-Atlantic and join the storm moving eastward by Thursday morning. Showers and thunderstorms will develop over parts of the Southern/Central Appalachians and lift into parts of the Mid-Atlantic by Friday. Areas of rain will develop over parts of the Upper Mississippi Valley and move eastward to the Northeast. During the overnight into the early morning on Thursday and Friday, the rain will become light to moderate over parts of the Lower Great Lakes and the Mid-Atlantic, respectively. A broad are of low pressure developing over the Gulf of Mexico will move northeasterly to the Southeast Coast by Friday. The disturbance will produce showers and thunderstorms, some with moderate rain over the southwestern portion of Florida and move northward into the Southeast and Southern Mid-Atlantic by Friday morning. Elsewhere, a weakening front over the Northern Rockies will slowly dissipate by Thursday evening. A new boundary will begin to move into the Pacific Northwest by Friday morning producing light rain over parts of the Northwest Coast. In addition, upslope flow around high pressure over the Northern Plains and diurnal heating will produce showers and thunderstorms over parts of the Southern/Central High Plains that will sink southeastward to Southern Texas by Friday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php