Probabilistic Heavy Snow and Icing Discussion NWS Weather Prediction Center College Park MD 252 PM EDT Thu Mar 31 2022 Valid 00Z Fri Apr 01 2022 - 00Z Mon Apr 04 2022 ...Central Rockies... Day 1... Shortwave trough moving onshore the Pacific Northwest today dives southeast and deepens as it swings through the Central Rockies through tonight. Height falls and forcing for ascent provided by the left exit region of the 100 kt jet streak will lead to modest snow amounts for the Absarokas and Bighorns in WY and western Colorado. WPC probabilities for 4 inches are slight to moderate through 12Z Friday before tapering off quickly during the day Friday. ...Great Lakes and Northeast... Day 1... Digging mid-level vort max currently over MN/WI this afternoon swings through the Great Lakes this evening and across the Mid-Atlantic and Northeast Friday. This feature will provide the necessary lift for isolated/scattered snow showers. Some of these showers could be vigorous and lead to snow squalls thanks to steepened lapse rates, modest MUCAPEs of a few hundred J/kg, and sufficient moisture in place. Downwind of Lake Erie and Ontario are likely to pick up a few inches (slight/moderate signal for 2"+) while the favored upslope region in WV has 40-60 percent probabilities for 1-2". ...Northwest... Days 2-3... Another round of unsettled weather comes to the Pacific Northwest during the Day 2/3 period as a shortwave trough moves through. Increased moisture and broad forcing for ascent will lead to snowfall accumulation above 4-5kft and the latest WPC probabilities show moderate to high probabilities for 4" over the WA Cascades then slight/moderate probabilities across northern Idaho and northwest Montana. For Days 1-3, the probability of significant icing of at least 0.25" is less than 10 percent. Taylor ~~~ Key Messages for March 31 - April 1 Snow Squalls ~~~ -A strong cold front will push through Northeast tonight while colder temperatures filter into the Great Lakes and Ohio Valley this evening. -Scattered snow squalls may develop and move over the Ohio Valley/Great Lakes region tonight. Snow squalls are likely during the day on Friday from the central Appalachians and Lower Great Lakes toward the interior Northeast and Mid-Atlantic. -Intense but brief snowfall within these snow squalls can rapidly reduce visibility and lead to dangerous driving conditions, particularly on high-speed roadways. -Little to no accumulation is expected outside of the higher terrain, but slick spots may develop on bridges and overpasses.