Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 308 AM EST Sun Dec 03 2017 Valid 12Z Sun Dec 03 2017 - 12Z Tue Dec 05 2017 ...Heavy snow possible for the Upper Mississippi Valley... ...Heavy snow possible for parts of the Northern/Central Rockies... ...Heavy rain possible over parts of the Upper Great Lakes... A developing strong storm over the West Coast will move eastward to the Upper Great Lakes by Monday evening. The system will produce coastal/lower elevation rain and higher elevation snow over the Pacific Northwest and parts of Northern California into the Northern Rockies that will expand eastward into parts of the Northern High Plains/Central Rockies by Sunday evening. Overnight Sunday, the rain and snow will end over the Pacific Northwest and Northern California as snow develops over parts of the Northern Plains. On Sunday, moisture from the Western Gulf of Mexico will stream northward over the Southern Plains into the Upper/Middle Mississippi Valley. As the storm moves into the Mississippi Valley, showers and thunderstorms will develop over parts of the Upper/Middle Mississippi Valley and the Upper Great Lakes early Monday morning that will expand southward along the boundary into the Middle Mississippi Valley/Southern Plains on Monday afternoon into Monday evening. In addition, heavy snow will develop over parts of Northern Plains/Upper Mississippi Valley on Monday into Monday evening. Also on Monday, the showers and thunderstorms will move into parts of the Great Lakes. The snow will end over the Northern/Central Rockies by Monday evening. Meanwhile, upper-level energy over the Mid-Atlantic will aid in producing light rain over parts of the Southern Mid-Atlantic and Southeast Coast on Sunday morning ending by Sunday afternoon. Additionally, as the moisture moves over the Southern Plains, upper-level energy over Northern Mexico will move eastward to the Southeast Coast by Monday evening. The energy will aid in producing showers and thunderstorms over Western Gulf Coast that will expand northward into the Southern Plains on Sunday that will expand into the Lower Mississippi Valley by Monday evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php