Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 249 PM EST Wed Feb 10 2016 Valid 00Z Thu Feb 11 2016 - 00Z Sat Feb 13 2016 ...Heavy rain over the Olympic Peninsula and heavy snow possible for the Cascades... ...Lake effect snow downwind from the Great Lakes... ...Temperatures will be 10 to 20 degrees below average from east of the Plains to the Northern/Central Appalachians and the Southeast... Much of the eastern third of the US will be in a colder, active pattern over the next few days. A deep upper-level trough will be present through the weekend and arctic air will spill south and east with each wave. Cold air flowing over the open waters of the Great Lakes will generate bands of heavier snow, which will affect areas downwind of the lakes. Numerous Lake Effect Snow Warnings are in effect from Michigan to New York. Winter Storm warnings are also in effect for western counties of Michigan. Snow will also develop over the higher elevations of the Northern/Central Appalachians and portions of the Northeast through Thursday evening. Temperatures for areas east of the Plains to the Northern/Central Appalachians and the Southeast are forecast to range 10 to 20 degrees below average. Snow will be possible for portions of the Northern Plains as an upper-level disturbance moves through. Accumulations are forecast to be generally less than 4 inches for South Dakota and Iowa. Western North Dakota and northeast Montana will likely have 3-day accumulations ranging from 4 to 8 inches. The Pacific Northwest will be in an active wet pattern through the end of the week as multiple fronts approach from the Gulf of Alaska. A plume of moisture streaming into the region will increase precipitation over much of coastal Washington and Oregon. Coastal areas and the Olympic peninsula could have rainfall amounts up to 7 inches. Mountain snow is also expected - the Cascades could have accumulations of 6 to 18 inches with isolated higher amounts possible. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php