Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 AM EDT Sat Apr 13 2019 Valid 12Z Sat Apr 13 2019 - 12Z Mon Apr 15 2019 ...Severe thunderstorms and flash flooding expected today for eastern portions of the Southern Plains into the Lower Mississippi Valley... ...The severe thunderstorm and flash flood threat will shift east to the Appalachians for Sunday... ...Warmer temperatures expected for the Great Plains on Monday after very cold Saturday... A potent spring storm system will move through the Southern Plains and Lower Mississippi Valley today and is expected to bring widespread hazardous weather to the region. Thunderstorms are expected to expand in coverage through the remainder of the morning across Texas and the southeastern half of Oklahoma as an area of low pressure begins to organize. The threat for hazardous weather will pickup during the afternoon and evening hours as favorable conditions aloft and near the surface materialize. The Storm Prediction Center is forecasting a Moderate Risk for severe storms, including tornadoes, large hail and damaging straight line winds, from portions of far eastern Texas into northern Louisiana and western Mississippi through tonight. While these storms will also be capable of heavy rain and flash flooding, the greatest threat for flash flooding will exist a bit farther north from the Oklahoma/Texas border into much of Arkansas and the Memphis metropolitan area. It is here that a widespread 2-4 inches of rain is expected through Sunday morning. The storm system will lose some of its intensity for Sunday but will continue to pose a threat for severe storms and flash flooding into the Tennessee, Upper Ohio Valley and Appalachians. One to two inches of rain is expected ahead of the low pressure center (forecast to track from the Lower Mississippi Valley into New England) and attendant cold front and severe storms will remain possible. On the north side of the system, temperatures will be cold enough to support light ot moderate snowfall accumulations from northern Illinois into Lower Michigan. High temperature departures will be well below average for most of the Great Plains today as high pressure takes hold, but the largest departures, in excess of 30 degrees below average, will be in the Texas Panhandle today with forecast highs in the 30s and low 40s. These temperatures combined with gusty northerly winds will result in wind chills in the 20s at times. A change in wind direction back toward southerly will allow a warm-up however with highs expected in the 70s and 80s from West Texas into the Central Plains for Monday, roughly 10-15 degrees above average. Unsettled conditions will be in store for the northwestern U.S. through the weekend starting with a cold front which will cross Washington and Oregon later today. Rain and higher elevation snow will follow the frontal passage inland bringing light to moderate accumulations. Rain and snow showers will extend through the day on Sunday but should remain light and scattered in nature. Yet another storm system will approach the West Coast late Sunday night likely bringing a renewed round of rain and mountain snow for the beginning of the work week to Oregon and northern California. Otto Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php