Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 224 PM EDT Wed Apr 20 2016 Valid 00Z Thu Apr 21 2016 - 00Z Sat Apr 23 2016 ...Flash flooding possible for portions of the Gulf Coast and Mississippi valley... ...Severe thunderstorms possible for portions of north central Texas... ...Warm temperatures expected to continue Thursday for the northwestern U.S... The upper-level low and frontal boundary that have plagued the central U.S. with showers and thunderstorms for the past few days will finally begin to move eastward tonight through Friday. Showers and thunderstorms may still result in locally heavy rainfall through tonight across portions of the western Gulf Coast, and lower/middle Mississippi valley -- and flash flooding is a continued possibility. Additionally, the Storm Prediction Center is forecasting a slight risk of severe thunderstorms across portions of north central Texas through tonight. On Thursday, the system will move east, spreading showers and thunderstorms across the Ohio and Tennessee valleys and into portions of the Northeast, Mid-Atlantic states, and the Southeast by evening. The trailing end of the frontal boundary will keep showers and thunderstorms in place one more day on Thursday for the lower Mississippi valley, before drier air filters in behind the front on Friday. Rain and thunderstorms will continue across the eastern states on Friday as the front approaches the coast by Friday evening. The West will remain generally dry through Thursday -- although showers will begin to move into the coastal Northwest Thursday afternoon as a front approaches. Very warm temperatures will continue across the northwestern U.S. on Thursday, with high temperatures forecast to be 10 to 25 degrees above average. The front will spread showers and even a few thunderstorms into the interior West on Friday, with snow confined to the highest elevations. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php