Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 357 PM EDT Thu May 21 2020 Valid 00Z Fri May 22 2020 - 00Z Sun May 24 2020 ...Continued heavy rain and flooding for portions of the Mid-Atlantic region through early Friday morning... ...Unsettled weather across portions of the central to southern Plains with scattered strong to severe thunderstorms into the weekend... ...Showers, mountain snow, and below average temperatures from the Northwest into the northern Great Basin... A slow moving upper level low over the Ohio Valley, which has been partly responsible for 5-10 inches of rain and flooding from southwestern Virginia into the western Carolinas over the past 3 days, will slowly track northeastward through Saturday. This movement will continue a good threat for heavy rain over the eastern Carolinas tonight with heavy rain and flooding remaining a concern farther inland across the Piedmont into the Blue Ridge Mountains where copious amounts of rain have already fallen over the past few days. The widespread heavy rain threat will diminish on Friday into Saturday but scattered thunderstorms will still be present which may exacerbate ongoing flooding across the region. Over the Great Plains, a slow moving warm front and dryline will serve as foci for strong to severe thunderstorms over the next two days. High low level moisture with origins from the Gulf of Mexico and a favorable jet orientation aloft will help contribute to daily chances of convection from portions of Kansas into Oklahoma and Texas through Saturday. The Storm Prediction Center has a Slight Risks for severe thunderstorms over northwestern Oklahoma into western Kansas as well as western Texas this evening and tonight, with another Slight Risk on Friday farther east for portions of the Ozarks into northern Texas. In addition to threats of tornadoes, straight line winds and hail, flash flooding may accompany these thunderstorms producing a few inches of rain over a relatively short time frame. Below average temperatures will be in store for the northwestern U.S. as well as the northern Great Basin over the next few days owing to a large upper level trough over the western U.S. with a series of impulses moving through the region. High temperatures are expected to run 10 to 20 degrees below average on Friday and Saturday across much of the northwestern quadrant of the country, helping to support the potential for accumulating snow for the higher terrain, especially western Wyoming into southwestern Montana Friday night into Saturday where 6-12 inches of snow is forecast. Otto Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php