Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 218 PM EDT Sun Jul 16 2017 Valid 00Z Mon Jul 17 2017 - 00Z Wed Jul 19 2017 ...Heavy rain and flash flooding possible over parts of the Southeast... ...Severe weather possible across parts of Northeast and Northern Plains on Monday... ...Heavy rain and flash flooding possible over parts of Arizona... A stalled frontal boundary will linger over the Southeastern U.S. and become a focus for showers and thunderstorms from the Gulf Coast to coastal Carolinas. These storms will tap into deep moisture leading to heavy downpours and potentially some flash flooding issues, especially from southern Alabama to eastern North Carolina. The frontal boundary will eventually dissipate, with precipitation becoming more widely scattered by Monday afternoon. Further north, a cold front crossing the Great Lakes will become stalled across western New York and the Ohio Valley. Moisture will be rather limited at first but once the stalled frontal boundary over the Southeast dissipates on Monday, that will allow moisture to surge northward up the eastern seaboard with an uptick in shower activity across the Northeast. Some thunderstorms could be severe across parts of the Northeast and heavy downpours could lead to some flash flooding issues. A cold front will push across the Northern Plains with thunderstorms expected along and ahead of the front. Those storm could become severe as well. Monsoonal moisture will continue to drive thunderstorm activity across the Southwest through the short range period. The most consistent thunderstorm activity should be over Arizona Sunday where a good surge of low level moisture is expected. Flash flooding will be a concern with the heavy downpours over the desert terrain. Krekeler Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php