Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 353 AM EDT Thu Jul 25 2013 Valid 12Z Thu Jul 25 2013 - 12Z Sat Jul 27 2013 ...There is a slight risk of severe thunderstorms over Upper Mississippi Valley/Upper Great Lakes and parts of the Central/Southern High Plains... ...Heavy rain possible over parts of eastern Maine and from Arkansas to parts of the Southern/Central Plains... A front extending from the Southern Plains to the Southeast Coast then along the Atlantic Coast will be quasi-stationary through the period. A wave of low pressure will move from the Southeast Coast to Cape Cod by Friday evening. Showers and thunderstorms will develop along the Southeast Coast and likewise move northward to the New England Coast by Friday. A second wave of low pressure will develop over the Central High Plains and move southeastward to the Lower Mississippi Valley/Eastern Texas. Showers and thunderstorms will develop over the Central Plains eastward to the Lower Mississippi Valley by Friday evening. Meanwhile, another front over the Upper Midwest will move eastward to the Great Lakes and southward to the Middle Mississippi Valley/Central Plains into the Central Rockies by the end of the period. Showers and thunderstorms will develop over the Northern Plains that will move eastward to the Great Lakes by Friday evening. Elsewhere, monsoonal moisture and diurnal heating will trigger showers and thunderstorms over portions of the Southwest and the Southern/Central Rockies on Thursday into Friday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php