Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 259 PM EDT Tue Mar 28 2017 Valid 00Z Wed Mar 29 2017 - 00Z Fri Mar 31 2017 ...Severe thunderstorms over the Southern Plains today - slight risk Wednesday and Thursday for Middle/Lower Mississippi and Tennessee valleys... ...Heavy snow likely for the northern Cascades and the Central Rockies... ...Heavy rain possible over parts of the Pacific Northwest and the Central/Southern Plains/Lower Mississippi Valley... Showers and thunderstorms developed early this morning as a backdoor cold front pushed into the Northeast and Mid-Atlantic regions and as separate cold front moved into the Appalachian region from the west. Precipitation will persist into Wednesday as the frontal boundary pushes offshore. Much of the Northeast and Great Lakes region will remain cooler as cold Canadian air seeps in with the surface high. Additionally, snow with a few pockets of rain/freezing rain, will be possible through Wednesday for portions of New England. An upper-level low will slowly exit the Rockies and move eastward into the adjacent High Plains allowing frontogenesis over much of Texas and Oklahoma. Rain and higher elevation snow is forecast for portions of the Central/Southern Rockies and the adjacent High Plains through Wednesday evening. The showers and thunderstorms will expand eastward into the Middle and Lower Mississippi Valley -- tapering off over the Southern Plains. The Storm Prediction Center has identified much of Oklahoma and north/central Texas as having a slight risk for severe thunderstorms this afternoon and evening -- with moderate risk over southwest Oklahoma and western North Texas. The threat area for severe weather will shift to the Middle and lower Mississippi valley and the western extent of the Tennessee Valley on Wednesday and Thursday. Additionally, periods of heavy rainfall will be possible today over portions of Oklahoma and Texas and across the Midwest on Wednesday. Much of the Pacific Northwest will have widespread precipitation thanks to onshore flow along with multiple upper-level disturbances. Rain and higher elevation snow is forecast from Washington to northern California and east through the Great Basin and the Intermountain West Coastal areas will likely have periods of heavier rainfall intensity. The northern Cascades and sections of the Central Rockies will likely have heavy snow over the next few days. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php