Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Sat Jul 08 2017 Valid 00Z Sun Jul 09 2017 - 00Z Tue Jul 11 2017 ...There is a slight risk of severe thunderstorms over parts of the Northeast, Southern Mid-Atlantic, and parts of the Central Gulf Coast... ...There is a slight risk of severe thunderstorms over parts of the Southwest... ...Heavy rain possible over parts of the Middle Mississippi Valley and Southern Mid-Atlantic... ...Temperatures will be slightly above average over parts of the Southwest... A front extending from the Northeast to the Mid-Atlantic and westward to parts of the Lower Mississippi Valley will move eastward off the East Coast and dissipate by Monday. Showers and thunderstorms will develop along and ahead of the boundary from the Northeast to Mid-Atlantic and from the Southeast to Western Gulf Coast that will end over the Northeast and Northern Mid-Atlantic by Sunday morning. The moisture rich air over the Southeast to the Western Gulf Coast will aid in producing showers and thunderstorm over the region through Monday. Over the western United States an upper-level ridge will remain anchored near the Four Corners regions and will cause extremely hot conditions to persist through weekend. On Friday many record high temperatures were set, including 116 degrees at Las Vegas and 122 degrees at Palm Springs, California. Excessive Heat Warnings are in effect for much of the Desert Southwest through Saturday night, with temperatures remaining even hotter than these arid or desert regions are used to experiencing. 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 once again. 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. Farther east, a cold front will continue to move into the Gulf states, extending northeastward through the Mid-Atlantic and Northeast. Showers and thunderstorms will form along and ahead of this front, producing periods of locally heavy rainfall. Flash flooding is 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 greater potential to produce heavy rain, and flash flooding may occur over portions of the Upper/Middle Mississippi Valley on Sunday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php