Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 356 AM EDT Sat Jul 08 2017 Valid 12Z Sat Jul 08 2017 - 12Z Mon Jul 10 2017 ...Severe thunderstorms and flash flooding possible for the Ohio Valley Friday night... ...Above average temperatures expected for much of the western U.S. with afternoon thunderstorms.. A cold front will continue to travel south into the Gulf Gulf states and east through the Mid-Atlantic and Northeast over the next few days. Showers and thunderstorms will generate along and ahead of this front, possibly producing periods of heavier rainfall. Flash flooding may be possible across portions of the lower Mississippi Valley and New England today. A secondary cold front will pass through the Upper Midwest and Great Lakes region this weekend which will bring another round of showers and thunderstorms. This system will have better potential for heavy rain - flash flooding may occur over portions of the Upper/Middle Mississippi Valley on Sunday. For the West, an upper-level ridge will remain anchored near the Four Corners regions and will cause extremely hot conditions to persist through weekend. Excessive Heat Warnings are in effect for much of the Desert Southwest through tonight, with temperatures around 10 degrees above average. Farther north into the Great Basin and Northern Rockies, temperatures in the 90s and 100s are expected this afternoon, which is 10 to 20 degrees above average. Numerous daily temperature records may be tied or broken. The heat will expand eastward into the Northern Plains by Sunday. Isolated thunderstorms are expected in the interior western U.S. as well, mainly during the afternoon. Campbell/Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php