Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 438 AM EDT Mon Aug 10 2015 Valid 12Z Mon Aug 10 2015 - 12Z Wed Aug 12 2015 ...Heavy rain expected for portions of the Central and Southern Plains and New England... Showers and thunderstorms will be possible today through Wednesday morning for portions of the Pacific Northwest as pulses of energy move through the flow aloft. Monsoonal moisture and daytime heating will aid in the development of thunderstorms for Mexico, as well as, the Central and Southern Plains. The nature of the expected storm environment for this afternoon over northeast New Mexico will support higher rainfall rates. Amounts on the order 1 to 2 inches will be possible. Rapid runoff may lead to flash flooding along the Front Range through Tuesday morning, and through Wednesday morning for the Four Corners region. The quasi-stationary frontal system of the Upper Midwest and High Plains has a wave of low pressure over the Middle Mississippi Valley that will move northeastward to far Eastern Ontario by Tuesday. The boundary will merge with the Upper Great Lakes front on today. The combined front will move eastward to the Northern/Central Appalachians and southward to the Southern Plains/Lower Mississippi Valley by Tuesday morning. This system will be the main player for the eastern half of the U.S. Showers and thunderstorms will develop along and ahead of the boundary. New York state and northern Pennsylvania will have favorable conditions for periods of heavy rainfall as storm motion is expected to be rather slow. Flash flooding will be possible for these locations. Showers and thunderstorms will pop up ahead of the front near the Gulf Coast, however moisture amounts are expected to be around or less than 0.5 inch. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php