Probabilistic Heavy Snow and Icing Discussion NWS Weather Prediction Center College Park MD 300 PM EST Sun Jan 16 2022 Valid 00Z Mon Jan 17 2022 - 00Z Thu Jan 20 2022 ...Mid Atlantic through the Interior Northeast... Days 1-2... As a northern stream shortwave continues to amplify to its northwest, the deep low over the Southeast will begin to accelerate to the north -- tracking through the interior Mid Atlantic, before lifting across Upstate New York and northern New England on Monday. Overall, not many changes to the previous forecast, with the track still favoring snow changing to rain, with only minor snow accumulations along the I-95 corridor from Baltimore to Boston this evening. Well to the north and west, heavy snow is still expected. Coupled upper jet forcing, overlapping low-to-mid level frontogenesis will help support impressive snowfall rates, with the latest HREF guidance indicating rates in excess of 2 inch/hr within the comma-head as it lifts across eastern Ohio, western Pennsylvania, western and central New York overnight into Monday. Farther east, highly anomalous southeasterly low level inflow ahead of the low will support heavy amounts from the Berkshires and southern Greens to the White Mountains, where thermal profiles are expected to support mostly snow. As the system lifts into Canada, strong northwesterly flow in the wake of the system will support lake effect snow showers in the lee of the eastern Great Lakes late Monday into Tuesday -- bolstering snow accumulations across portions of central and western New York, and western Pennsylvania into the central Appalachians. Across eastern Ohio, western Pennsylvania, and western New York, WPC probabilities indicate that accumulations of 8-12 inches or likely through late Tuesday. This includes the Pittsburgh, Cleveland, Buffalo and Rochester metros. Locally heavier amounts possible, especially in the lee of Lake Erie. Similar totals are expected for the higher elevations of the Catskills, Adirondacks, Berkshires, southern Greens, and the Whites. ...Upper Midwest to the Northern Rockies... Days 2-3... A clipper system is forecast to dive southeast from western Canada Monday night and then move east along the Canada-U.S. border from North Dakota to Minnesota on Tuesday, before continuing east across the northern Great Lakes Tuesday night into Wednesday. This is expected to produce a stripe of light to moderate snows across northern Minnesota and the U.P. of Michigan. A period of southeasterly flow ahead of the system is expected to bolster amounts along Minnesota's North Shore on Tuesday. Similarly, locally heavier amounts are expected across the Keweenaw Peninsula. Well to the west, the system's trailing cold front is forecast to drop south across the northern Rockies -- supporting locally heavy accumulations across the northerstern Montana and northern Idaho ranges. Pereira ~~~ Key Messages for Winter Storm Affecting the Eastern U.S. January 16-17 ~~~ -- Heavy snow rates greater than 1â€/hr are possible along and just west of the Appalachians today and Monday. Significant impacts to travel are likely. -- Ice accumulation will expand northward through the interior Mid-Atlantic states this evening, creating hazardous travel conditions. -- Heavy snow is expected along the Appalachians into the interior Northeast. Significant snow totals are likely across much of West Virginia northward through western Pennsylvania/New York, and the higher elevations of New England. This could result in dangerous travel and scattered power outages. -- Along the Atlantic coastline, strong winds and coastal flooding are likely. Some locations may reach moderate flood levels, with inundation affecting some coastal roads and structures.