Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 356 AM EDT Fri Apr 13 2018 Valid 12Z Fri Apr 13 2018 - 12Z 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 robust storm system will move across the central U.S. bringing multiple hazards throughout the weekend. Snow is forecast for much of the Northern/Central High Plains and Upper Mississippi Valley/Upper Great Lakes as cold, moist air wraps around the central low. As the low deepens, wind speeds will increase causing snow to blow and drift-- Blizzard Warnings are in effect from northeast Colorado to South Dakota and southwest Minnesota, with Winter Storm Warnings, Winter Weather Advisories and Winter Storm Watches in the surrounding areas. Snowfall amounts up to 20 inches can be expected in parts of South Dakota and northern Nebraska. As the surface low moves eastward, the area of heavy snow will also shift into the Upper Midwest and Great Lakes by Saturday--where winter storm watches have been issued. Across the Southern Plains, a very pronounced dryline and cold front will sweep across the southern states. Widespread to numerous thunderstorms will develop along and ahead of the boundary as deep southerly flow transports northward in the Southern Plains and lower Mississippi Valley. The Storm Prediction Center has highlighted much of the Mississippi Valley and areas east as having an enhanced risk for severe thunderstorms today and Saturday. In addition to the threat of damaging winds and winds, heavy rain will be possible for the Lower Mississippi Valley...where slight to moderate risks for excessive rainfall are in effect for most of Louisiana, Arkansas and western Mississippi. Flash flooding will be possible. 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. Temperatures across much of the Eastern Seaboard will be average average for mid-April, with high temperatures approaching 15 degrees warmer from the Mid-Atlantic states to New England. Once the front passes, much cooler air will surge into the north-central states. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php