Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 251 PM EDT Wed May 03 2017 Valid 00Z Thu May 04 2017 - 00Z Sat May 06 2017 ...Severe thunderstorms and flash flooding possible across portions of the lower and mid Mississippi valley... ...Warming temperatures expected for much of the western U.S... A low pressure system is expected to rapidly take shape across the southern plains and lower Mississippi valley today bringing heavy rainfall and severe weather to the region. Deep moisture from the Gulf of Mexico will be drawn northward across the lower Mississippi valley fueling heavy rain and thunderstorms into this evening. Severe weather potential will be confined to eastern Texas to the central Gulf coast, mainly near or south of a warm front lifting north into the lower Mississippi valley. Thunderstorms could continue overnight but will remain close to the Gulf coast as they move eastward. The severe weather threat will shift to parts of the Southeast for Thursday. Further north, moderate to heavy rainfall is expected to the north of a stationary boundary draped from the southern plains through the Tennessee valley. Heavy rainfall will be tied to this boundary as it eventually lifts northeast with the surface low, spreading heavy rain to the Ohio valley. Flash flooding will be possible across the lower and mid Mississippi valley today with heavy rain expected over already saturated soils. The flash flood threat will shift to the Ohio valley for Thursday. High pressure will dominate the weather pattern across the western U.S. through the short range forecast period, with generally dry conditions expected to prevail into early Thursday. Above average temperatures are also expected, with high temperatures reaching 10 to 20 degrees above average for many areas. By Thursday afternoon, a Pacific frontal boundary will approach the West Coast, spreading showers and a few thunderstorms into the Northwest through Friday morning. Krekeler/Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php