Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 329 AM EST Sat Dec 12 2015 Valid 12Z Sat Dec 12 2015 - 12Z Mon Dec 14 2015 ...There is a slight risk of severe thunderstorms over parts of the Southern Plains... ...Heavy rain over parts of the Southern Plains/Lower Mississippi Valley into parts of the Upper Mississippi Valley/Upper Great Lakes... ...Heavy rain for parts of the Pacific Northwest/Northern California... ...Heavy snow for the Cascades and parts of the Sierras as well as the Salmon River and Sawtooth mountains... A strong storm over the Southern Rockies will slowly move eastward to the Central Plains/Middle Missouri Valley by Sunday evening. The system will produce snow over parts of the Southern/Central Rockies that will move into parts of the Central/Northern Plains from Saturday afternoon into Sunday. Also on Sunday evening, snow will develop over parts of the Upper Mississippi Valley. In addition, rain will develop over parts of the Southwest/Southern Rockies on Saturday morning, ending by Saturday evening. As the storm moves out of the Rockies, moisture rich air will move northward over the Southern/Central Plains into parts of the Lower/Middle Mississippi Valley by Saturday evening and into the Mississippi Valley/Upper Great Lakes by Sunday evening. The moisture will aid in producing showers and thunderstorms over parts of the Southern Plains on Saturday morning and expand northward into Central Plains/Middle Mississippi Valley by Saturday evening. By Sunday morning the showers and thunderstorms will be limited to the Lower Mississippi Valley and edging into parts of the Tennessee Valley by Sunday evening. Rain will also develop over parts of the Central Plains into Middle Mississippi Valley on Saturday afternoon into Saturday evening. Rain will extend from the Middle Mississippi Valley into parts of the Upper Mississippi Valley/Upper Great Lakes on Sunday. East of the storm, an east-west front extending from the Middle Mississippi Valley to Southern New England will lift northward as the storm moves on to the Plains. Moisture overrunning the boundary will produce rain over parts of Ohio Valley/Great Lakes into parts of the Northeast through Sunday. Moisture from the Atlantic will move over parts of Florida on Sunday. The moisture will aid in producing rain over parts of Southeastern Florida, likewise, on Sunday. Meanwhile, onshore flow ahead of the next front will produce rain and higher elevation snow over parts of the Pacific Northwest/Northern California into parts of the Northern Intermountain Region on Saturday morning. The next front will move onshore over the Pacific Northwest overnight Saturday moving inland to Northern Rockies/Great Basin and Southern California by Sunday evening. The system will produce additional rain and higher elevation snow over the Pacific Northwest into the Northern Rockies through Sunday evening. The rain and higher elevation snow will move into Northern California by Saturday evening and expand into Central and parts of Southern California on Sunday morning into Sunday evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php