Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 301 AM EST Fri Nov 13 2015 Valid 12Z Fri Nov 13 2015 - 12Z Sun Nov 15 2015 ...Heavy rain expected for the Pacific Northwest... ...Below average temperatures expected for the central and eastern U.S... Strong onshore flow in the Pacific Northwest will transport moisture from the north central Pacific into the region through the next couple days. A cold front will move onshore in coastal Washington today, but will become stationary by Saturday as a more intense area of low pressure develops along the front offshore. This will keep rain in the picture, heavy at times, through the weekend for coastal areas of the Northwest. The stronger area of low pressure offshore on Saturday will be associated with an amplifying upper-level trough, which will help the cold front move quickly south Saturday night, spreading rain into much of California by early Sunday morning. Rainfall amounts across the Northwest will vary widely with terrain -- but 2 to 6 inches should be relatively common through Sunday morning, with higher rainfall totals in the Olympics and the Cascades. Additionally, as this deepening upper-level trough moves onshore early Sunday, snow levels will lower in the Cascades. Heavy snowfall amounts of 1 to 2 feet are forecast in northern portions of the Cascades in Washington. Snow will also spread across much of the Sierra Range and the northern Intermountain West by early Sunday. An upper-level trough will be in place across the eastern U.S. through the next couple days, with a relatively strong upper-level disturbance forecast to move across the Great Lakes today and across the Northeast by tonight. This disturbance, along with a secondary cold front at the surface, will bring a scattered mix of rain and snow showers to portions of the Great Lakes and Northeast through tonight. A few rain or snow showers may persist across the Northeast into Saturday. High temperatures today are forecast to be 5 to 10 degrees below average across the Great Lakes -- and these temperatures will spread into the eastern U.S. for Saturday. Southerly return flow west of a surface high pressure area will begin to spread moisture across the southern plains and portions of the Four Corners region by Saturday. This moisture will result in scattered showers and thunderstorms across these areas on Saturday, persisting into Sunday. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php