Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 239 PM EST Wed Dec 07 2016 Valid 00Z Thu Dec 08 2016 - 00Z Sat Dec 10 2016 ...Heavy snow possible over the Sierras... ...Heavy snow possible in favored areas downwind from the Great Lakes... ...A mix of rain, freezing rain and snow possible over interior portions of the Pacific Northwest and Northern California... ...Temperatures will range 15 to 35 degrees below average over the Northern/Central Rockies and High Plains... Much of the Upper Midwest, Great Lakes and Northeast will likely have snow over the next few days. A deep low pressure center, associated with a cold front tracking east over the Atlantic Ocean, will slowly lift north of the Great Lakes reaching Newfoundland and Labrador by Friday. Stronger winds on the backside of the low will be oriented where the lakes will enhance the snow amounts. Favored areas downwind of the Great Lakes will have lake effect snow Higher elevation snow and rain will develop over parts of the Central Appalachians/Lower Great Lakes eastward to the Northeast/Northern Mid-Atlantic during the overnight hours and will slowly wind down from west to east by Friday morning. Cold air pooled against the Rockies will surge southward into the southern Rockies and southern Plains this afternoon and evening. Building high pressure over the northern and central High Plains will keep a much colder airmass in place, resulting in numerous locations with temperatures 15 to 35 degrees colder than average for the rest of this week. A plume of moisture streaming in from the Pacific will pass through the Pacific Northwest, portions of the Great Basin and the Intermountain region will interact with a system pushing inland from the Pacific Ocean. Coastal areas will have rain; however it will quickly transition to a wintry mix over the interior and snow in the mountains. A boundary moving over Southern Florida will aid in producing showers and thunderstorms over the region over the next couple of days. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php