Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 356 AM EDT Mon Oct 19 2015 Valid 12Z Mon Oct 19 2015 - 12Z Wed Oct 21 2015 ...Heavy rain possible across portions of the western U.S... ...Temperatures expected to moderate across the eastern U.S. through the next couple days... An upper-level trough across the western U.S. will remain in place through the next couple days. A relatively slow-moving surface frontal boundary will also move slowly eastward across the Intermountain West today into tonight. A moist and unstable air mass in place in combination with the frontal boundary and upper-level disturbances moving through the trough will result in scattered to numerous showers and thunderstorms once again today across much of the Intermountain West. On Tuesday, surface front will begin to move more quickly eastward into the plains, while lingering across the higher terrain of Colorado and Utah. By this time moisture will increase across New Mexico and western Texas, with numerous showers and thunderstorms expected in those areas late Tuesday into Wednesday morning. Heavy rainfall will be possible both today and Tuesday, and flash flooding is possible for some areas. Showers will also be possible for the Pacific Northwest today as a weakening frontal system moves onshore. The Northwest will dry out for Tuesday, however. A cold front will move southward across the Great Lakes and Northeast Monday night into Tuesday. A wave of low pressure will develop along the front across the Upper Midwest Tuesday night into Wednesday. Scattered showers will be possible along the front, with a few thunderstorms possible across the Midwest by Wednesday. Temperatures will gradually moderate across the eastern U.S. through mid-week. High temperatures today are expected to be 5 to 15 degrees below average across much of the East, but these temperatures should warm by Tuesday, with temperatures near average expected. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php