Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 401 AM EDT Mon May 27 2013 Valid 12Z Mon May 27 2013 - 12Z Wed May 29 2013 ...There is a slight risk of severe thunderstorms over the Plains and the Middle Mississippi Valley... ...Heavy rain possible from the Middle Mississippi Valley to the Great Lakes... A slow moving warm front extending from the Northern Plains southeastward to the Southern Appalachians will lift northeastward into the Great Lakes to the Central Appalachians/Mid-Atlantic by Tuesday evening. The system will also have a trailing quasi-stationary front extending from parts of the Upper Midwest southwestward to the Great Basin/Southwest. Showers and thunderstorms will develop near the warm front from parts of the Northern Plains into the Middle Mississippi Valley/Ohio Valley moving into the Great Lakes to the Mid-Atlantic over the next two days. Additionally, upper-level energy over the Northern Rockies will move northeastward into South-Central Canada by Tuesday. The impulse will develop showers and thunderstorms over parts of the Northern Rockies/High Plains moving into parts of the Northern Plains/Upper Mississippi Valley by Tuesday morning before entering Canada by Tuesday evening. Meanwhile, a new front will move onshore over the Pacific Northwest on Monday, advancing inland to Northern Rockies before dissipating on Tuesday morning. The energy will reinforce a deep upper-level trough over the western portion of the country. The system will produce rain over the Northwest Coast into Northern California, with moderate rain at times. The rain will spread eastward into the Northern Intermountain Region/Great Basin by Monday evening. By Tuesday evening, the energy will ignite showers and thunderstorms over parts of the Northern/Central Rockies/Eastern Great Basin. Also, weak onshore flow will produce light rain along parts of the Pacific Northwest Coast on Tuesday evening. Southern stream energy will move over moisture streaming northward over the Southern/Central Plains producing showers and thunderstorms over the region on Tuesday evening. In addition, easterly flow off the Atlantic will aid in triggering showers and thunderstorms over the southern tip of Florida through Tuesday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php