Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Sun Jun 11 2017 Valid 00Z Mon Jun 12 2017 - 00Z Wed Jun 14 2017 ...There is a slight risk of severe thunderstorms over parts of the Upper Great Lakes and parts of the Central High Plains... ...Heavy rain possible over parts of the Upper Mississippi Valley/Northern High Plains/Northern Rockies and Great Basin... ...Temperatures will be 10 to 25 degrees below average over parts of the Great Basin/Pacific Northwest/California and the Southwest... ...Snow possible at highest elevations of the Sierras/Great Basin/Northern Rockies... A front extending from Southeastern Canada to the Great Lakes southwestward to the Central High Plains will unit with a reinforcing front moving southward out of Central Canada by Monday afternoon. The boundary will extend from the Northeast across the Great Lakes into the Northern Plains by Tuesday. Showers and thunderstorms will develop along and ahead of the front over the Upper Great Lakes into the Upper Mississippi Valley/Middle Missouri Valley. Overnight Sunday, the showers and thunderstorms will extend southwestward along the boundary into the Central Plains. Across the Southeast and the Gulf Coast showers and a few thunderstorms will focus along a dying boundary. Moisture from the Gulf of Mexico will move northward over parts of the Lower Mississippi Valley and the Central/Eastern Gulf Coast through Monday. In addition, upper-level impulses will move over the area, too. The moisture,upper-level energy, and diurnal heating will produce showers and thunderstorms over parts of the Lower Mississippi Valley to the Southeast through Monday. An upper-level trough will dig southeast through the West as a steady stream of Pacific moisture moves inland. This system will usher in rain over parts of the Pacific Northwest/Northern California and east into parts of the Northern Rockies... with snow possible over the Cascades and likely at the higher elevations of the northern Great basin and Northern Rockies. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php