Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 453 PM EDT Thu Aug 15 2013 Valid 00Z Fri Aug 16 2013 - 00Z Sun Aug 18 2013 ...Heavy rain expected across the eastern Gulf Coast and the Southeast on Friday and into the weekend... ...Below normal temperatures prevail from the central Plains eastward into the Mid-Atlantic and the Southeast... A refreshingly cool air mass from Canada has already settled across much of the eastern part of the nation, bringing temperatures down to more than 10 degrees below normal to some areas. The high pressure system associated with the cool air is expected to remain in place through the weekend, which will continue to bring pristine sky conditions reminiscence of fall rather than August. Rain will be suppressed well to the south where a front is expected to be quasi stationary across the Southeast and near the Gulf Coast. There appears to be a continuous supply of moisture from the Gulf of Mexico which will overrun the stationary front, resulting in moderate to heavy rain along with thunderstorms across the Southeast through the weekend. By Sunday, moisture from a tropical system in the southern Gulf may inject addition moisture into the frontal system. On Friday, upper-level energy over the northern High Plains near a stationary front is expected to trigger showers and thunderstorms over parts of the Northern/Central Plains. Elsewhere, an upper-level trough and a weakening front approaching the Pacific Northwest will produce scattered areas of light rain and isolated thunderstorms mainly from the coastal areas into the Cascades through the weekend. Kong Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php