Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 347 AM EDT Fri Oct 16 2015 Valid 12Z Fri Oct 16 2015 - 12Z Sun Oct 18 2015 ...Flash flooding possible for portions of the southwestern U.S... ...Below average temperatures will spread from the Midwest into the eastern U.S... Ample moisture and an upper-level disturbance moving into southern California will keep scattered to numerous showers and thunderstorms in place across much of the southwestern U.S. today into Saturday. The disturbance will drift northward on Saturday, with showers and thunderstorms becoming more widespread across portions of the Great Basin and Wasatch. Rainfall may be heavy in some areas, and flash flooding is possible today and Saturday. Additional showers are expected on Saturday across the Pacific Northwest as a frontal system move onshore. This frontal system will move into the interior West on Sunday, bringing additional showers and thunderstorms this area. A strong cold front will move across the eastern U.S. today. The front will bring rain showers to portions of the northeastern U.S. Behind the front, a much cooler air mass is in place. This air mass will result in high temperatures 5 to 15 degrees below average across the Great Lakes and Midwest today, before spreading across most of the eastern U.S. on Saturday. High temperatures on Saturday will range from 5 to 20 degrees below average across the eastern half of the country, with the coldest temperatures across parts of the Northeast. A series of upper-level disturbances will keep scattered showers in place from the Great Lakes to the Northeast even behind the front. Sufficient cold air may be in place for snow to mix in with the rain showers across portions of the Great Lakes and Northeast through much of the weekend. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php