Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 239 PM EST Tue Feb 17 2015 Valid 00Z Wed Feb 18 2015 - 00Z Fri Feb 20 2015 ...Temperatures will be 20 to 35 degrees below average over portions of the Upper/Middle Mississippi Valley to the Great Lakes/Ohio Valley... ...Light snow over parts of the Northeast... A front extending from the Great Lakes to the Southern Plains/Lower Mississippi Valley will move southeastward to off the Mid-Atlantic and Gulf Coasts by Thursday. The system will produce light snow over parts of the Great Lakes into parts of the Ohio Valley/Middle Mississippi Valley and Oklahoma that will move eastward to the Mid-Atlantic Coast/Northeast by Wednesday evening and linger over parts of the area through Thursday morning. Behind the storm, lake effect snow will develop downwind from the ice free lakes and over parts of the Central Appalachians on Wednesday into Thursday. In addition, cold high pressure over West-Central Canada will move southeastward to the Middle Mississippi Valley by Thursday. Upslope flow associated with circulation around the area of high pressure will produce light snow over parts of the Northern High Plains on Thursday morning. Meanwhile, a front over Florida will move southeastward out over the Atlantic by Wednesday afternoon. The boundary will produce rain and showers/thunderstorms over parts of Florida on Tuesday evening that will likewise move southeastward out of Florida by later Wednesday morning. Additionally, weak upper-level energy and weak onshore flow will aid in producing light rain along parts of the Pacific Northwest Coast on Thursday morning. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php