Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 301 PM EST Tue Dec 19 2017 Valid 00Z Wed Dec 20 2017 - 00Z Fri Dec 22 2017 ...Heavy snow possible over the Southern Cascades... ...Snow over the Northern/Central Rockies, Northern Plains, and Great Lakes... ...Heavy rain possible over parts of the Lower Mississippi Valley into the Tennessee Valley/Southern Appalachians... Upper-level energy over Texas will move eastward off the Southern Mid-Atlantic Coast by early Thursday morning. Moisture from the Western Gulf of Mexico will move inland over the Western Gulf Coast/Lower Mississippi Valley and into parts of the Southeast through Wednesday evening. Rain and thunderstorms will develop over parts of the Southern Plains into the Lower Mississippi Valley/Tennessee Valley that will expand eastward into the Southern Mid-Atlantic by Wednesday morning. The rain and thunderstorms will come to an end west to east starting Wednesday morning into Thursday. Meanwhile, a strong upper-level trough over the Northwest will move southeast to the Great Basin/Southwest by Thursday. The energy will aid in producing rain and higher elevation snow over the Pacific Northwest and snow over the Northern Intermountain Region/Northern Rockies. Overnight Tuesday, rain and higher elevation snow will expand into parts of Northern California and Central California by Wednesday afternoon. Snow will also expand into the Great Basin and the Northern High Plains also overnight Tuesday. More to Follow Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php