Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 401 PM EDT Thu Apr 12 2018 Valid 00Z Fri Apr 13 2018 - 00Z Sun Apr 15 2018 ...Major storm system to bring heavy snow, flash flooding and severe weather hazards across the central and eastern U.S... A late season winter storm is currently moving across the Rockies and will bring multiple hazards over the U.S. through the next few days. On Friday, cold air and moisture will wrap around a strengthening surface low and produce heavy snow in parts of the northern and central Plains. Snowfall amounts up to 20 inches can be expected in parts of South Dakota and northern Nebraska. In addition, high winds will also accompany this storm. Consequently, blizzard conditions are expected along parts of the High Plains of Colorado and northwest Kansas northward into South Dakota. As the surface low moves eastward, the heavy snow will also shift eastward into the Upper Midwest and Great Lakes by Saturday--where winter storm watches have been issued. Farther south, the strong cold front associated with this system will sweep across the Mississippi Valley and southern Plains on Friday into Saturday. Deep southerly flow will feed an abundance of moisture throughout the southern Plains and lower Mississippi Valley. With plenty of instability in place, thunderstorms will fire off ahead of the cold front by Friday afternoon and continue into the lower Mississippi Valley by Friday night. These thunderstorms have the potential to produce heavy rainfall that could lead to flash flooding. The Storm Prediction Center has also issued an enhanced risk of severe weather from the southern Plains to the middle Mississippi Valley for Friday. By Saturday, the line of thunderstorms will continue to move in the Southeast and Tennessee Valley--continuing the threat for flash flooding and severe weather. Please see www.spc.noaa.gov for more information on severe weather and WPC's excessive rainfall outlook for further information on the flash flooding potential. Ahead of the cold front, high temperatures will be upwards of 15 degrees warmer than average for this time of year especially across the Mid-Atlantic and Northeast on Friday and Saturday. However, much colder air will filter behind the front and spill across the Plains, Upper Midwest, and Great Lakes. Reinhart Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php