Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 257 PM EST Sat Feb 17 2018 Valid 00Z Sun Feb 18 2018 - 00Z Tue Feb 20 2018 ...Heavy snow possible over the Cascades/Northern Rockies and parts of the Upper Great Lakes... ...Heavy to moderate snow possible over parts of the Northeast... ...Rain/freezing rain possible over parts of the Middle/Upper Mississippi Valley... Developing low pressure over the Southeast will move northeastward out over the Western Atlantic by Sunday morning. The storm will produce rain from parts of the Southern Ohio Valley/Southern Mid-Atlantic southwestward to the Lower Mississippi Valley/Western Gulf Coast that will move off the Southern Mid-Atlantic Coast by Sunday morning while dissipating from the Southern Appalachians to the Tennessee Valley late Saturday night. Snow will develop over parts of the Northern Ohio Valley/Great Lakes into the Northern Mid-Atlantic that will expand into the Northeast overnight Saturday while ending over the Ohio Valley/Upper Great Lakes. The snow will move off the Northeast Coast by late Sunday afternoon into evening. Additionally, overnight Saturday, moisture from the Western Gulf of Mexico will flow northward over the Southern Plains aiding in the development of scattered showers and thunderstorms over parts of the Southern Plains on Sunday morning into Sunday evening. Meanwhile, a second storm over the Northwest/Northern Rockies will move southeastward into the Great Basin/Central Rockies into the Middle Mississippi Valley by Monday. The system will produce rain and higher elevation snow over parts of the Pacific Northwest with snow over the Northern Rockies on Saturday evening. Overnight Saturday the associated front will sink southward to Central California continuing to the Southwest by Monday. The snow levels will lower over the Northwest into the Northern Intermountain Region/Northern Rockies. Snow will develop over parts of the Pacific Northwest Coast by Sunday morning. Coastal rain and snow will move into parts of Northern California on Sunday and into parts of Central California overnight Sunday into Monday. In addition overnight Saturday, snow will expand into parts of the Northern Plains that will continue to expand into the Upper Great Lakes Sunday afternoon into Sunday evening while moving into parts of the Middle Mississippi Valley overnight Sunday. The aforementioned moisture moving northward over the Southern Plains will push into the Central Plains/Middle Mississippi Valley by Sunday evening continuing to move northeastward into the Western Ohio Valley/Upper Great Lakes overnight Sunday into Monday. Showers and thunderstorms will move northeastward with the moisture over parts of the Central Plains/Middle Mississippi Valley by Monday. Rain will also develop over parts of the Tennessee Valley/Southeast overnight Sunday expanding into part of the Mid-Atlantic by Monday. On Monday into Monday evening, an area of rain/freezing rain will develop over parts of the Middle Mississippi Valley moving into parts of the Upper Mississippi Valley by Monday evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php