Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 341 PM EST Thu Nov 19 2015 Valid 00Z Fri Nov 20 2015 - 00Z Sun Nov 22 2015 ...Accumulating snow is forecast for parts of the Middle Missouri Valley into the Great Lakes... ...Temperatures will be 10 to 15 degrees below average over parts of Northern/Central Rockies and High Plains... A front along the East Coast arching into the Gulf of Mexico will move out over the Western Atlantic by Friday evening. The boundary will linger over Southern Florida through Saturday morning. Showers and thunderstorms will develop along the front over Florida on Thursday evening into Friday morning before moving off the coast. Rain will develop over the East Coast from the Southeast to the Northeast ending over the Mid-Atlantic/Southeast by Friday morning. The rain will continue over the Northeast through Friday evening. Light snow will develop over parts of the Upper Great Lakes through Friday afternoon. A second front over parts of the Pacific Northwest to the Central High Plains will move southeastward to the Middle/Lower Mississippi Valley to parts of the Southern Plains/Lower Rio Grande Valley by Saturday morning. Rain will develop over parts of the Pacific Northwest/Northern California into parts of the Great Basin ending by Friday morning. Snow will develop over parts of the Northern Intermountain Region and the Northern/Central Rockies ending by Friday evening. As the system moves onto the Plains, moisture from the Western Gulf of Mexico will move northward over the Southern/Central Plains late Thursday night moving eastward to the Middle Mississippi Valley and the Western Ohio Valley by Saturday morning. Snow will begin to develop over parts of the Northern/Central Plains by early Friday morning ending by Friday evening. The snow will move into parts of the Middle Mississippi Valley by Friday afternoon and expand into the Upper Great Lakes Friday evening into Saturday. Rain will develop over parts of the Middle Mississippi Valley into parts of the Western Ohio Valley by Friday afternoon into Friday evening. Overnight Friday rain will develop over parts of the Lower Mississippi Valley into the Western Gulf Coast with a few embedded thunderstorms by Saturday morning. Behind the storm high pressure will develop over the Rockies. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php