Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 244 AM EDT Sat Aug 20 2016 Valid 12Z Sat Aug 20 2016 - 12Z Mon Aug 22 2016 ...Severe thunderstorms possible for portions of the Great Lakes... ...Heavy rain and flash flooding possible for portions of Texas... ...Dangerously hot temperatures expected for portions of the Pacific Northwest... A cold front will bring showers and thunderstorms to areas from the Upper Midwest and Great Lakes to the southern plains today. Some storms could be severe across portions of the Great Lakes. Please refer to products issued by the Storm Prediction Center for further details on the severe weather threat. On Sunday the cold front will move east, bringing showers and thunderstorms to the Northeast and Mid-Atlantic regions. Behind the cold front, a much cooler air mass will move into the central U.S. High temperatures today will be 10 to 20 degrees below average for much of the central and northern plains. Cooler temperatures behind the front will spread into the Great Lakes and Ohio valley on Sunday, and into the Northeast by Monday. Farther south, the cold front will become stationary across the southern plains by Sunday. Storm may produce heavy rainfall today and Sunday across portions of Texas, and flash flooding is possible. High pressure aloft will keep the West Coast hot and dry through the weekend. Dangerously hot temperatures are expected once again today across the Pacific Northwest, where afternoon highs are forecast to be 10 to 20 degrees above average. Some areas could surpass 100 degrees. The ridge of high pressure will begin to break down on Sunday, allowing a cold front to approach the Pacific Northwest late on Sunday. Temperatures will be slightly cooler on Sunday relative to today, but significantly cooler temperatures, much closer to normal levels, are expected by Monday in the wake of the cold front. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php