Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 357 PM EDT Wed Mar 29 2017 Valid 00Z Thu Mar 30 2017 - 00Z Sat Apr 01 2017 ...Severe thunderstorm potential through Thursday over the Middle/Lower Mississippi and Tennessee Valleys... ...Heavy snow likely for the Northern/Central Rockies, Great Basin and Wasatchs... ...Heavy rain for portions of the Pacific Northwest and the Lower/Middle Mississippi Valley... Widespread showers and thunderstorms are forecast for much of the central U.S as a robust low pressure system tracks across the Midwest and through the Tennessee/Ohio valley. The Storm Prediction Center has identified conditions favorable for continued support for severe thunderstorms development across the Middle/Lower Mississippi valley and western portions of the Tennessee valley today and Thursday. Additionally, some of these storms may produce heavy rainfall; which may increase the threat for flash flooding. Refer to SPC's Convective Outlooks and WPC's Excessive Rainfall Outlooks for specific details. This system is expected to reach the Appalachians/Mid-Atlantic region by Friday afternoon and will usher in showers and thunderstorms to much of the Eastern Seaboard. Snow may develop over parts of the Upper Great Lakes overnight Wednesday and into Thursday evening. Upper-level energy over the Eastern Pacific will push onshore the West Coast by early Thursday morning; which will allow an upper-level low to develop over the Great Basin by Thursday evening. A stream of moist onshore flow will slowly weaken as it migrates southward to southern California. Rain and highest elevation snow is forecast for the Pacific Northwest into parts of the Northern Rockies this afternoon and evening -- spreading into the northern Great Basin and Central Rockies as snow levels lower by Thursday evening. Heavy snow will likely occur along the Northern/Central Rockies and the northern portion of the Great Basin. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php