Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 331 PM EDT Thu Jul 09 2015 Valid 00Z Fri Jul 10 2015 - 00Z Sun Jul 12 2015 ...Severe thunderstorms possible for portions of the Mid-Atlantic as well as portions of the southern High Plains... ...Flash flooding possible for portions of the Mid-Atlantic and Northeast, southern and central plains, and mountain ranges of the West Coast... The weather pattern across the contiguous U.S. will be an active one through the short range forecast period. An area of low pressure and associated cold front will move across portions of the eastern U.S. this evening, bringing showers and thunderstorms. The most widespread showers and thunderstorms are expected across portions of the Mid-Atlantic and Northeast this evening into tonight. The cold front and the precipitation will move offshore Friday morning. The Storm Prediction Center is forecasting a slight to enhanced risk of severe thunderstorms across portions of the Mid-Atlantic region this evening/tonight. Please refer to products issued by SPC for further details on the severe weather threat. Additionally, locally heavy rainfall will result in the possibility of flash flooding for some areas of the Mid-Atlantic/Northeast tonight. A warm front will drift slowly northward across the central U.S. over the next couple days. This frontal boundary will serve as a focus for development of rounds of showers and thunderstorms. One such area of showers and thunderstorms is forecast to develop across the southern/central plains this evening and move eastward across the middle Mississippi valley tonight, and then into the Ohio valley on Friday. Another round of thunderstorms may develop along the warm front across the central plains Friday afternoon/evening. Additional showers and thunderstorms may develop in association with a trough and surface low in the southern High Plains. The Storm Prediction Center is forecasting a slight risk of severe thunderstorms through tonight across portions of this area. Heavy rainfall from thunderstorms may result in isolated flash flooding as well over much of the southern/central plains. An upper-level low moving into the western U.S. combined with monsoonal moisture will result in scattered showers and thunderstorms over much of the West. Flash flooding may result from locally heavy rainfall through tonight. across the higher terrain in central/northern California, western Nevada, and southern Oregon. The upper-level ridge of high pressure that has been across the Northwest for quite a while will begin to weaken somewhat, allowing temperatures to decrease over the next couple days. Temperatures will remain 5 to 10 degrees above average on Friday, but will fall to near or just a few degrees above average by Saturday. The weakening ridge will also allow for the development of some showers and thunderstorms by Friday afternoon over the Northwest. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php