Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 356 PM EDT Tue May 16 2017 Valid 00Z Wed May 17 2017 - 00Z Fri May 19 2017 ...Heavy rainfall and severe thunderstorms possible from the Southern Plains to the Upper Midwest through Thursday... ...Wet and cool conditions are expected across the Western U.S. with late season snow in the higher terrain... ...Above normal temperatures expected across much of the Eastern U.S. this week... Moisture streaming northward ahead a vigorous upper-level low and cold front pushing through the Central U.S. this evening will allow for numerous showers and thunderstorms to develop from the Southern Plains to the Upper Midwest. Some of these storms may be severe and contain heavy rainfall capable of producing flash flooding. The Storm Prediction Center is highlighting a slight to moderate risk of severe weather across much of the central states, while WPC has highlighted a marginal to slight risk for flash flooding across the same areas. As the upper low lifts through the central Plains and the Upper Midwest, the possibility for severe weather and heavy rainfall will continue across portions of the Upper Midwest on Wednesday and Thursday. A second upper level low will drop from the Pacific Northwest tonight to the Central Great Basin and Rockies Wednesday and Thursday. This will spread rain and high elevation snows across much of the Northwest, Great Basin, and northern and central Rockies. Several inches of snow, possibly up to a foot, will be possible across the mountains with winter storm warnings, watches, and winter weather advisories in effect. Once the upper low reaches the central Rockies on Thursday, the threat for severe thunderstorms and heavy rainfall will return for portions of the Southern Plains. Temperatures across the West will also be well below normal with afternoon highs as much as 10 to 25 degrees below normal. Across the Eastern U.S., above normal temperatures are expected underneath of an upper level ridge pushing slowly eastward from the Ohio Valley to the Northeast U.S.. Afternoon high temperatures may be 10 to 20 degrees above normal in some places across the Ohio Valley, the Mid-Atlantic, and the Northeast this week. Santorelli Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php