Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 357 PM EDT Mon May 15 2017 Valid 00Z Tue May 16 2017 - 00Z Thu May 18 2017 ...Conditions will be wet and cool with a storm system entering the Pacific Northwest Monday night...with late season snow expected over the higher elevations... ...Heavy rain and severe thunderstorms will be possible from the Southern/Central Plains to the Upper Midwest the next few days... ...Temperatures will be well above normal beneath an upper ridge shifting eastward from the Upper Mississippi Valley to the Great Lakes and Ohio Valley... Conditions will be wet and cool with a vigorous upper low expected to drop from the Pacific Northwest to the Central Great Basin and Rockies over the next few days. A strong surge of Pacific moisture ahead of the system should allow for periods of heavy precipitation over the favored terrain of the Pacific Northwest and northern Rockies Monday night into Tuesday...and lowering temperatures behind the associated cold front should lead to late season snowfall accumulations over the higher elevations. Heavy rain and strong to severe thunderstorms will be possible from the Southern/Central Plains to the Upper Midwest early this week as anomalous Gulf moisture continues to pull northward ahead of a mean Western U.S. upper trough. Gerhardt Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php