Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 343 PM EDT Wed Sep 02 2015 Valid 00Z Thu Sep 03 2015 - 00Z Sat Sep 05 2015 ...Flash flooding possible across portions of Arizona and New Mexico... ...Above average temperatures expected for the eastern two-thirds of the country... Monsoonal moisture across the southwestern U.S. will result in scattered afternoon and evening showers and thunderstorms through the next couple days. Moisture and rainfall rates may be sufficient this evening to produce isolated areas of flash flooding across eastern portions of Arizona and western portions of New Mexico. A cold front of Pacific origin is moving across the northern Intermountain West today. This front will begin to move into the northern plains by early Thursday morning, while the trailing end of the front becomes stationary across the Intermountain West. This front will bring showers and thunderstorms to northern portions of the Intermountain West on Thursday, with showers and thunderstorms possible across the northern plains Thursday night and the Upper Midwest by Friday afternoon. Behind the cold front, temperatures will 10 to 20 degrees below average across much of the Pacific Northwest and portions of the northern Intermountain states on Thursday and Friday. A cold front will move southward from Canada into the Lower Great Lakes and the Northeast on Thursday, with scattered showers and thunderstorms possible along the front. This cold front will move into the Mid-Atlantic states on Friday, with a scattered showers and thunderstorms still possible. Farther south, a moist and unstable atmosphere will remain in place through Friday across the Gulf Coast and portions of the Southeast, keeping scattered afternoon and evening showers and thunderstorms in place. High pressure at the mid and upper-levels of the atmosphere will promote above average temperatures across much of the eastern two-thirds of the nation. The most significant above average temperatures will occur from the northern plains to portions of the Northeast and Mid-Atlantic where temperatures of 5 to 15 degrees above average are expected. Temperatures may approach 20 degrees above average across the Dakotas on Thursday. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php