Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 334 AM EDT Thu Sep 19 2013 Valid 12Z Thu Sep 19 2013 - 12Z Sat Sep 21 2013 ...Strong to severe thunderstorms along with above average temperatures are expected ahead of a frontal system as it pushes southeastward across the central U.S.... ...Showers and thunderstorms returning to the Northwest on Friday... A strong cold front associated with a well-defined upper level trough moving out of the northern Rockies is forecast to sweep across the central U.S. over the next couple of days. Warmer temperatures and tropical moisture transported by strong southerly winds ahead of the front are forecast to contribute to the development of showers and thunderstorms. Some of these storms may turn severe later today as denoted by the slight risk for severe weather extending from the upper Great Lakes back into the central Plains in the Storm Prediction Center's Day 1 Outlook. On Friday this risk is expected to shift further east along with the front into the lower Great Lakes and OH valley regions. As the southern extent of the front drops south through the southern Plains on Fri, some of the moisture and upper level energy associated with tropical cyclone Manuel may get drawn northeastward into TX, fueling widespread moderate to locally heavy rains from the Big Bend region toward the eastern parts of the state. In the West, another cold front is expected to approach the Northwest on Fri, bringing with it showers and thunderstorms into western WA, OR and far northern CA. Pereira Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php