Probabilistic Heavy Snow and Icing Discussion NWS Weather Prediction Center College Park MD 338 AM EST Sun Jan 12 2020 Valid 12Z Sun Jan 12 2020 - 12Z Wed Jan 15 2020 ...Maine... Day 1... Low pressure lifts northeast along a frontal boundary across northern New England this morning. Shallow cold air north of the boundary will support a stripe of freezing rain with 10 to 30 percent probabilities for an additional quarter inch over eastern Maine through today. Meanwhile, deeper cold air to the north will support sleet and snow, with the southern end of a stripe of heavy snow across northern Aroostook County where moderately-high probabilities exist today for 8 or more inches. ...Pacific Northwest to the Northern Rockies... Days 1-3... The next system in an active pattern for the northeast Pacific shifts southeast from Vancouver Island to northern WA today. Pacific moisture below a deep trough axis and left exit region of a 150kt jet streak and snow levels decreasing from around 2000ft this morning to around 500ft by this evening will promote heavy snows for most any elevation with lowland snows as the precip tapers off tonight behind the system. Day 1 probabilities are moderate to high for 18 or more inches in the WA/OR Cascades and moderate for the Blue Mtns and northern Rockies of ID/MT. A cold core low sets up over the mid BC/Alberta border tonight which directs the next shortwave trough farther south...into the OR coast Monday with persistent onshore flow across the Pac NW then through Tuesday night. Day 2/3 48 hr probs for 18 or more inches are high for the OR Cascades - an area that started this past week much below normal for seasonal snowfall. ...Western Great Lakes... Days 2/3... The system approaching the Olympic Peninsula this morning will track across the northern tier of the CONUS through Monday night with surface low pressure connecting with Gulf-sourced moisture as it tracks east across SD Monday. This low tracks to Lake Superior Tuesday with Day 2.5 probabilities for 4 inches around 30 percent over northern MN, particularly along the north shore in the Arrowhead of MN. Jackson