Probabilistic Heavy Snow and Icing Discussion NWS Weather Prediction Center College Park MD 352 PM EST Sat Mar 07 2020 Valid 00Z Sun Mar 08 2020 - 00Z Wed Mar 11 2020 Days 1-3... ...Western U.S.... A front associated with a weakening upper level trough will bringing moisture that gets lifted into the terrain of WY Tetons, Wind River, and UT Uintas tonight into early Sunday, with lift declining as the 700 mb wave deamplifies and moves out of these ranges. Light to moderate mountain snows are expected in these ranges, with moderate probabilities of 4 inches and low probabilities for 8 inches of snow. Confluent low-mid level flow and sporadic modest 700 mb vertical velocities allow light snow to continue through Sun and Sunday night in these mountains. On Tuesday, a closed low off the southern CA coast starts drifting east northeast and gets closed enough that precip develops. Snow starts in the highest elevations of the mountains of southern CA, including the higher elevations of the southern Sierra Nevada mountains. Several inches of snow are possible. The highest is shown in the colder NAM solution, with better agreement of lighter amounts among the other models/ensemble means. With the low still off the coast at the end of day 3, the snow is expected to extend beyond this period. ...Northern New England... Confluent low-mid level flow advects deep layer moisture, with lift over a low level frontal boundary causing snow to develop in northern Maine on Day 2. As the low pressure moves just north of Maine, the warm front is expected to progress north across interior Maine. This allows snow to initially continue into Monday night, with a question mark about the warm advection allowing a change over to mixed sleet and light freezing rain Monday night into Tue. Locally heavy snow is possible before any change over. the day 3 forecast shows a moderate to high risk of four inches but low risk of 8 inches. For Days 1-3, the probability of significant icing (0.25-inch or greater) is less than 10 percent. Petersen