Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 259 PM EST Thu Feb 08 2018 Valid 00Z Fri Feb 09 2018 - 00Z Sun Feb 11 2018 ...Heavy snow possible from Chicago Illinois to Detroit Michigan... ...Heavy rain possible over parts of the Tennessee Valley... ...Temperatures will be 15 to 30 degrees below average from the Northern High Plains into the Northern/Central Plains... A front extending from the Middle Mississippi Valley northwestward to the Northern Rockies will expand eastward into the Lower Great Lakes/Northern Appalachians and move southward to the Ohio/Tennessee/Lower Mississippi Valleys to the Southern Plains and across parts of the Southern Rockies into the Great Basin by Saturday. Cold high pressure over Southwestern Canada will slowly sink southward into the Northern High Plains and the Northern/Central Plains by Saturday, too. circulation around the surface high and the front will aid in producing snow over parts of the Northern Rockies/Northern High Plains that will slowly wane over the region overnight Friday into Saturday. Snow will also develop over parts of the Northern Plains into the Middle Mississippi Valley/Upper Great Lakes that will slowly expand eastward into the Lower Great Lakes/Northeast on Friday. Some rain will develop over parts of the Ohio Valley and Southern New England overnight Friday into Saturday. The snow will also move southward into the Central Plains on Friday and into parts of the Central Rockies overnight Friday into Saturday. Meanwhile, moisture from the Gulf of Mexico will move northward over the Gulf Coast overnight Thursday advancing as far north as the Ohio Valley and Mid-Atlantic by Saturday. Light rain with embedded thunderstorms will develop over parts of the Central/Eastern Gulf Coast by Friday afternoon. The rain will expand northward into parts of the Ohio Valley and the Mid-Atlantic by Saturday morning. Showers and thunderstorms will extend as far north as parts of the Middle Mississippi/Tennessee Valleys and the Southern Mid-Atlantic by Saturday. Elsewhere, onshore flow will aid in producing coastal rain over parts of the Pacific Northwest ending by Friday morning when the onshore flow becomes parallel to the coast overnight Thursday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php