Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 355 PM EDT Fri Aug 19 2016 Valid 00Z Sat Aug 20 2016 - 00Z Mon Aug 22 2016 ...Severe thunderstorms and locally heavy rain possible across portions of the southern and central plains... ...Dangerously hot temperatures expected for portions of the Pacific Northwest... A slow moving cold front, extending from the Hudson Bay through the Great Lakes to the central/southern Plains, will be the focus for scattered to widespread showers and thunderstorms for the next couple of days. Severe thunderstorms as well as locally heavy rainfall will be possible across portions of the southern and central plains. Additional information on the severe thunderstorm risk can be found on The Storm Prediction Center's webpage. As the front progresses, the showers and thunderstorms will spread from the southern Plains up to Upper Midwest and areas east. Ample moisture near the trailing end of the boundary in Texas will likely result in lingering convection - periods of heavy rainfall will likely increase the threat for flash flooding. Cold air surging into the northern Rockies and surrounding Plains in the wake of the frontal passage will bring more fall-like temperatures to the region. A vast area will have high temperatures registering 15 to 25 degrees below average. Below average temperatures will overspread much of the central and northern plains on Saturday, with temperatures 10 to 20 degrees below average. Much of the Pacific Northwest will be hot and dry this weekend and into early next week under high pressure aloft. Temperatures are forecast to be significantly warmer than usual for mid-August - many locations will have maximum daily temperatures of 15 to 25 degrees above average through Saturday. Some areas across western Oregon and Washington could surpass 100 degrees. An approaching cold front will slowly breakdown the ridge; which in turn temperatures will begin to cool down. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php