Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 248 PM EST Wed Dec 16 2020 Valid 00Z Thu Dec 17 2020 - 00Z Sat Dec 19 2020 ...Major winter storm to bring a plethora of impacts across the Mid-Atlantic and Northeast this afternoon and Thursday... ...More unsettled weather expected across the Northwest over the next couple of days... A major winter storm is developing off the Mid-Atlantic coast and producing heavy snow and icy conditions from the southern and central Appalachians to the the metro areas of Washington D.C., Baltimore, and Philadelphia this afternoon. Frigid temperatures supplied by a strong dome of high pressure over eastern Canada are in place throughout the Northeast as deep moisture from the storm system streams north towards the region. As temperatures warm at low levels along the I-95 major metro areas from D.C. to Philadelphia, look for snow to transition to an icy wintry mix, thus causing treacherous travel conditions there this evening. The combination of snow, ice, and gusty winds could lead to tree damage and some power outages. Farther inland, snow will fall heavily from the central Appalachians and interior Northeast to southern New England this evening and into Thursday morning. Snowfall totals in these areas are expected to range between 1 and 2 feet with over 2 feet of snow possible from central and northeastern Pennsylvania to the Catskills. As the storm strengthens off the New Jersey coastline tonight, strong onshore winds will generate coastal flooding from Delaware to the Jersey Shore. Flooding from heavy rain is also possible this evening across portions of the coastal Mid-Atlantic where temperatures are too warm for wintry precipitation. In addition, severe thunderstorms may produce damaging winds and isolated tornadoes across the Outer Banks in eastern North Carolina this afternoon. Areas expecting heavy snow accumulations can expect to witness dangerous, if not impossible, travel conditions and isolated power outages. Many locations from eastern West Virginia to far southern Maine are forecast to see a foot of snowfall accumulation. In some areas, this would be more snow in one event than was seen all of last winter. Snowfall amounts are expected to drop off dramatically to the south and east as sleet and rain are expected to mix in. Continue to monitor your local NWS office's forecast for the latest information regarding current watches/warnings/advisories. Also, each morning through Saturday are likely to feature temperatures dipping well below freezing throughout the northern Mid-Atlantic and Northeast, resulting in re-freezes and areas of black ice. Elsewhere, the Pacific Northwest will become stuck in an unsettled weather the next couple of days as a pair of potent frontal system crosses the region today and again on Friday. Latest forecasts indicate 1 to 3 inches of rainfall are likely during this time frame along the immediate coastline from northern California to Washington. From the Cascades and Sierras, as well as other higher elevations of the Intermountain West, 1 to 2 feet of snow could fall through Friday night. In the Heartland, mostly dry conditions and moderating temperatures will be the theme through the remainder of the work-week. Mullinax Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php