Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 235 AM EDT Sun Aug 21 2016 Valid 12Z Sun Aug 21 2016 - 12Z Tue Aug 23 2016 ...Heavy rain and flash flooding possible across portions of Texas... ...Showers and thunderstorms expected today across much of the eastern U.S... ...Cold front to bring cooler temperatures to the Pacific Northwest by Monday... A cold front will move east from the Ohio valley into the Northeast and Mid-Atlantic region today, bringing showers and thunderstorms to much of the Eastern Seaboard into tonight. The trailing end of the frontal boundary will become stationary from Texas to the lower Mississippi valley, keeping showers and thunderstorms commonplace through today and tonight. Storm may produce heavy rainfall across portions of Texas, and flash flooding will continue to be a threat. The stationary front will remain across the same areas on Monday and Tuesday, but will begin to slowly weaken. As a result, showers and thunderstorms should become more scattered in nature. Behind the cold front, a cooler air mass will move into areas from the Upper Midwest and Ohio valley today to the Northeast and Mid-Atlantic on Monday. Afternoon high temperatures are forecast to be 5 to 10 degrees below average in these areas. A ridge of high pressure that has kept hot weather in place across the Pacific Northwest the past couple days has begun to weaken. As a result, a cold front will move into the Pacific Northwest from British Columbia late today. The cold front will be accompanied by very little in terms of precipitation, but it will usher a cooler air mass into the region in its wake. Portions of interior Washington, and much of Oregon will still see one more day of above average temperatures today, but temperatures should decrease to near or slightly below average for most of these areas on Monday. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php