In-depth weather discussion issued Wednesday, Dec. 27
One of the most significant snow events for our region in a long time, possibly heavier than last February’s system is encroaching on our doorstep to the west and to the north. I will say that this system has the potential to produce widespread power outages and road closures due to the amount of snow still on trees and the additional heavy snowfall forthcoming. Winter storm warnings have already been issued through Saturday for the entire region so will include the details below with more specific snowfall amounts in the forecast. Cold air remains in place but a significant piece of very cold air associated with the Hudson Bay low currently resides over northern Manitoba in Canada and will rotate south and west towards Saskatchewan and eastern Alberta over the next 24 to 30 hours. At the same time, another upper level low and associated surface low will move in off the Pacific. The interaction of these two systems will cause light to moderate snow to break out beginning Thursday morning with increasing intensity throughout the day. These first two systems will produce mainly fluffy, dry snow for most areas and could bring initial snowfall amounts of 4 to 8 inches in the valleys with 6 to 12 inches for the mountains through Thursday night. A brief break is possibly early Friday morning for most areas yet the upslope regions on the West side of the Cabinet Mountains such as Bull Lake, Noxon and Heron may not see much, if any break. A much stronger surface low will move onshore into Washington on Friday while the cold Hudson Bay low backs in a little more from the Northeast placing Northwest Montana in the classic set-up for heavy snowfall. In fact, higher elevations along with those areas along the Continental Divide may well experience blizzard or even whiteout conditions. For our region, the higher elevations in the mountains above say 6000 feet may see blizzard conditions while valleys will see moderate to at times heavy snowfall, possibly as heavy as 2 inches an hour at times. This second system looks to last perhaps 24 hours before beginning to wind down late Saturday afternoon. By the time all is set and done it is looking like most valley areas across Lincoln and Sanders Counties will see anywhere from 18 to 36 inches of snowfall in a 40 hour period which is very impressive for this region. Mountains above 4000 feet are likely to see 3 to 4 feet with locally up to 5 feet in the Cabinet Mountains. Again the snow will start off rather dry and fluffy but warmer air will be moving in and at least for valleys the snow will likely become denser and heavier which, when combined with the heavy snow currently on the trees across the region, may cause many broken trees and possibly power outages along with road closures. This is looking like at least a 3 plow storm if not more. Keep the shovels, snow blowers and plows ready. Once these two systems move out, northwest flow will establish and occasional weak disturbances will bring clouds and a few snow showers at times. Overall a very active few days coming up but finally some moderating temperatures, yet remaining below average. On a side note, the long range models are indicating a flip in the pattern across North America and the North Pacific next week from the strong positive PNA pattern we have been in to a fairly strong negative PNA pattern. The pattern is also beginning to show some remarkable similarities to the pattern of the heaviest winter on record across our region which was the winter of 1951-1952. Are we in for a repeat of that year? Libby’s record snow depth was recorded in January of 1952 of 44 inches. The snow depth is the amount of settled snow on the ground, not under trees or where piled up but simply settled. To put that in perspective to last winter, the greatest snow depth measured in Libby last winter was “only 38 inches” but that was near the Libby airport whereas the 1952 measurement was near where Rosauers is located. Time will tell but it is looking more and more likely that we may end up with a decent winter yet..