Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 409 PM EDT Wed Sep 21 2016 Valid 00Z Thu Sep 22 2016 - 00Z Sat Sep 24 2016 ...There is a slight risk of severe thunderstorms over parts of the Upper Mississippi Valley... ...Heavy rain possible over parts of the Upper Mississippi Valley into parts of the Upper Great Lakes... ...Heavy rain possible over parts of the Great Basin into parts of the Northern Rockies and Northern High Plains... An upper-level low over the Southeast will slowly weaken by Friday morning. The upper-level low will produce showers and thunderstorms over parts of the Southern Mid-Atlantic/Southeast through Friday. Meanwhile, a front extending from the Great Lakes to the Central Rockies will move into the Northeast by Thursday morning. Moisture will pool along the boundary aiding in the development of showers and thunderstorms from the Upper Great Lakes to parts of the Northern Plains by Wednesday evening that will continue through Friday. In addition, rain will develop over parts of the Northeast Thursday afternoon into Friday. Additionally, an upper-level low over the Pacific Northwest will deepen while moving into the Great Basin by Friday. The system will produce showers and thunderstorms over parts of the Pacific Northwest to the Northern High Plains and southward to the Southern Rockies to the Southwest that will expand into the Central High Plains by Friday. The showers and thunderstorms will end over California and the Western Great Basin Friday morning as well. The precipitation will also end over parts of the Pacific Northwest overnight Thursday before starting again on Friday as a front moves onshore. Furthermore, snow will develop over some of the highest peaks of the Great Basin Thursday night into Friday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php