Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 414 AM EDT Sun Aug 09 2015 Valid 12Z Sun Aug 09 2015 - 12Z Tue Aug 11 2015 ...There is a slight risk of severe thunderstorms over parts of the Central High Plains to the Middle Mississippi Valley and over parts of the Northern High Plains... ...Heavy rain possible over parts of the Middle Mississippi Valley... A slow moving front over the Upper Midwest will merge with a quasi-stationary front extending from the Southeast to the Central Plains by Monday morning. Showers and thunderstorms will develop along and ahead of the boundary over the Upper Midwest and parts of the Northern High Plains through Sunday morning. The showers and thunderstorms will move into the Great Lakes to parts of the Middle Mississippi Valley by Monday. Meanwhile, the quasi-stationary front from the Southeast to the Central Plains will develop a wave of low pressure over the Central Plains that will move northeastward to the Middle Mississippi Valley by Sunday evening. By Monday morning the wave of low pressure will link up with the front moving across the Upper Midwest. Showers and thunderstorms will develop over parts of Central Plains and move into the Ohio Valley by Sunday morning. On Sunday, the showers and thunderstorms will expand into parts of the Central Appalachians/Mid-Atlantic by Monday morning, while continuing along the boundary into the Southern Plains. In addition, showers and thunderstorms will develop over parts of the Southeast/Eastern Gulf Coast through Monday. Elsewhere, monsoonal moisture and daytime heating will aid in the development of showers and thunderstorms over parts of the Southern/Central Rockies during the late afternoon and evening hours through Monday. Also, upper-level troughing over the Pacific Northwest Coast will produce light rain along the Northwest Coast Saturday evening into early Sunday morning. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php