Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 401 PM EDT Wed May 20 2015 Valid 00Z Thu May 21 2015 - 00Z Sat May 23 2015 ...Showers and thunderstorms will move across the Ohio/Tennessee Valleys today into the Mid-Atlantic tomorrow... ...Showers and storms remain in the forecast across the mountain West and southern/central Plains... Low pressure in the Tennessee Valley will move northeastward towards and off the Mid-Atlantic coast by Thursday evening. This will help to spread showers and thunderstorms across the Ohio/Tennessee Valleys this evening and into the Mid-Atlantic region tomorrow. In the vicinity of the low itself, some more organized rainfall may develop with embedded strong to severe thunderstorms possible near the southern Mid-Atlantic coast along the frontal boundary. By Thursday afternoon, the southern portion of the front is expected to settle along the Gulf coast and across the southern Plains with return moisture off the Gulf of Mexico keeping showers and thunderstorms in the forecast through Friday. Meanwhile, yet another system off the Southwest coast will continue to produce showers and thunderstorms across portions of the Intermountain west through the forecast period. As this same system moves inland on Thursday, southeasterly flow ahead of the system will pull significant moisture into the central/southern Plains and High Plains leading to a well organized area of showers and thunderstorms developing Thursday afternoon and evening. Given the recent heavy rains across this same region, some flash flooding could certainly be possible. Santorelli Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php