Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Sat Aug 18 2018 Valid 00Z Sun Aug 19 2018 - 00Z Tue Aug 21 2018 ...Active weather continues for the East Coast... ...Heavy rainfall expected to impact parts of the Plains and Mississippi Valley through the remainder of the weekend... ...Air quality will remain a concern across portions of the Western U.S., as well as across the Upper Midwest... A cold front stretching from New England to the southern Plains will be the focus for showers and thunderstorms throughout the south and east through the remainder of the weekend. The best thunderstorm activity will be along the frontal boundary as warm moist air pulling in from the Gulf of Mexico clashes with a colder airmass moving in from the north. The northeastern portion of the front is expected to continue shifting southeast and off the Atlantic Coast through tomorrow, tapering off rain chances across the Northeast. But for today, portions of the coastal northern Mid-Atlantic region are within a Flash Flood Watch. Meanwhile, a deepening low pressure system over the Southern Plains will ramp up the frontal system here as it begins shifting northeastward for Sunday and the first part of the work week. The Storm Prediction Center has outlined an area across the Panhandles of Texas and Oklahoma, as well as far northeast New Mexico and southeast Colorado as being in a slight risk for severe weather through tonight. A Severe Thunderstorm Watch is in effect for eastern Colorado and northeast New Mexico through this evening. There is also a slight risk for excessive rainfall and flash flooding for much of this same region issued by the Weather Prediction Center. The slight risk for excessive rainfall will shift with the deepening low pressure center towards the eastern Plains for Sunday, and into the Middle Mississippi Valley, Ohio Valley, and Upper Great Lakes for Monday as it begins to interact with another cold front dropping in from Canada. Marginal risks for severe weather will also accompany portions of this system during this time. Fire weather concerns continue across the western U.S., with impacts spreading across the northern U.S. as well. Red flag warnings remain in effect through late this evening for southwest Wyoming and central Utah due to a combination of high winds, low humidities, and the threat of low precipitating thunderstorms sparking new wildfires. A Dense Smoke Advisory is in effect for north-central Montana due to nearby wildfires. Furthermore, Air Quality Alerts remain in place across portions of the West and Northwest, including much of the Northern Great Basin, due to smoke pollution. Large wildfires in south-central Canada are also advecting smoke southward, resulting in Air Quality Alerts for much of Minnesota. Wix Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php