Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 342 AM EDT Wed Sep 4 2013 Valid 12Z Wed Sep 4 2013 - 12Z Fri Sep 6 2013 ***Another cold front to move through the Eastern U.S.*** ***Upper low and widespread rainfall for the Pacific Northwest*** ***Scattered showers and storms for the Western U.S.*** The first cold front this week that moved through the Eastern U.S. has taken most of the showers and thunderstorms out to sea, and weather more typical of September has arrived east of the Mississippi River. Looking ahead to the end of the work week, another cold front will move through the northeastern quadrant of the country as an upper level trough amplifies over eastern North America. A pristine airmass from Canada can be expected behind this front for the Great Lakes, Ohio Valley, Mid-Atlantic, and Northeast with crisp mornings and mild afternoons, along with very low humidity and very clear sky conditions. Over the Pacific Northwest, an upper level low near the coast will slowly move eastward and result in a developing cold front over this region. The upper level energy, in combination with a weak surface low, will likely result in widespread light to moderate rain developing over interior parts of Washington, Oregon, and western Idaho to close out the week. Some of the highest peaks in the Cascades mountain range may even see some snow showers! Elsewhere across the continental U.S., isolated to scattered showers and storms can be expected for the Desert Southwest and into the Inter-Mountain West with lingering monsoonal moisture in place. Localized heavy rainfall will be possible. Warmer than average conditions are expected for the western High Plains with upper level ridging in place. D. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php