Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 336 AM EDT Fri Aug 17 2018 Valid 12Z Fri Aug 17 2018 - 12Z Sun Aug 19 2018 ...Slight risk of severe thunderstorms and flash flooding for the Northeast with heavy rainfall impacting areas from the Mid-Atlantic to the Southeast... ...Monsoonal rains may lead to flash flooding across the Southwest... ...Fire weather continue for the western U.S. through tonight... Active weather is expected across regions from the Northeast to the Tennessee Valley southward into the southern Plains today. A front slowly pushing eastward combined with with deep southerly flow pulling abundant moisture northward will create an environment conducive to showers and thunderstorms. By this afternoon and evening, scattered to widespread thunderstorms are expected especially across the Northeast, Mid-Atlantic and Ohio Valley. Heavy rainfall is expected particularly along the surface front lifting northward into the Northeast and New England where there is a chance of excessive rainfall. In addition, a slight risk of severe thunderstorms is also expected for parts of the Northeast and New England this afternoon. Another batch of heavy rainfall will concentrate across parts of the Southeast and Tennessee Valley. By Saturday, the front will be draped across the Mid-Atlantic and into the southern Plains--creating more rounds of convection across these regions along with much of the Southeast. Some lingering showers can be expected for the Northeast; however most of the heavier precipitation will be farther south. By Sunday, as the front sinks south and east, precipitation will begin to taper off across the Mid-Atlantic while continuing across the Southeast and southern Plains. Monsoonal moisture will continue to move into the Southwest which will fire off convection throughout this region through the weekend. Most of the activity will occur in the late afternoon and evening. Flash flooding will be a concern for areas in favorable terrain and urban regions. Check the latest WPC excessive rainfall outlook to see which areas are of the most concern. Fire weather will be a concern for areas across the Pacific Northwest and Intermountain West today as isolated thunderstorms could trigger additional fires via lightning. Gusts from these thunderstorms could also quickly spread fires. Most of this area is under a red flag warning which expires tonight. By Saturday, a cold front will move south across this region bringing showers and thunderstorms from the northern Plains to western Montana. By the end of the weekend, thunderstorms across the Plains can be expected--where there is a marginal risk for severe thunderstorms for the High Plains and a slight risk of excessive rainfall for parts of the southern Plains. Reinhart Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php