Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 258 PM EST Wed Jan 05 2022 Valid 00Z Thu Jan 06 2022 - 00Z Sat Jan 08 2022 ...Coastal heavy rain and mountain snow threat from the Pacific Northwest into the northern/central Rockies and central High Plains... ...Heavy Lake effect snow threat to continue through Friday... ...Much below normal temperatures will spread from the Great Plains into the Midwest... ...Another winter storm possible from the Tennessee Valley to the Northeast Thursday into Friday... An active weather pattern will continue to direct a plume of Pacific moisture towards the Northwestern U.S. the next couple of days. This will result in a threat for heavy to excessive rainfall, mainly for favorable upslope regions along the Washington and northern Oregon coasts where WPC is currently highlighting a slight risk in this location for Friday. Meanwhile, sufficient cold air will spill into the Pacific Northwest and northern/central Rockies setting the stage for potentially significant snowfall in the higher terrain, measured in feet. Accumulating snow and ice is also possible in the lower elevations of eastern Washington into Friday. A low pressure system lifting across the Great Lakes region and into eastern Canada will allow for heavy lake effect snow as chilly westerly winds blow over the still relatively warm lakes. Favorable locations downwind of the lakes could see 6 to 12 inches of snow, with locally higher amounts. Behind this system, arctic air will surge farther south and east into the Great Plains and eventually the Midwest by Friday. Sub-zero daytime highs will engulf the northern Plains the next couple of days while temperatures as much as 20-25 degrees below normal will overspread the central Plains, parts of the southern Plains, and eastward into the Midwest and Ohio Valley on Friday. By Thursday, a wave of low pressure is forecast to develop along an arctic front draped across the Deep South. Moderate snowfall is possible to the north of the front from Kansas into Missouri where at least a couple of inches of snow is forecast. As the low tracks through the Southeast on Thursday, heavy snowfall is expected to develop across parts of the Tennessee Valley into the central Appalachians, with some ice farther to the south across southern/eastern Tennessee and northern Mississippi and Alabama. The combination of snow and ice may cause hazardous road conditions through Thursday night in this region. As the low moves off the Mid-Atlantic coast and rapidly deepens offshore, accumulating snow will also spread into the Mid-Atlantic and the Northeast, where a few inches are possible. Higher amounts may be realized across especially eastern portions of New England, but exact amounts remain uncertain and highly dependent on the exact track of the low off the coast. Santorelli Graphics are available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php