As this period gets underway, an Alberta Clipper is moving through the Northeast, where many coastal locations will see their first snowflakes of the season before the new week gets underway. Accumulations will be on the light side, because even though the Clipper will explode into a strong once it gets offshore, that transformation will take place too far out to sea to produce more than a few inches of fluffy snow. In the wake of the passage of the Clipper, arctic air will arrive. Another outbreak of significant lake effect snow can be expected, and snowmaking operations will be going just about round the clock in the low elevation...mountain locations are now involved in what will be one of the best runs of snowmaking conditions of this season.

Lake effect snow has really piled up this week in the Midwest...Michigan in particular has gotten a good shot in the arm...both the northern sections of the Lower Peninsula and entire U.P. have been very snowy of late, and that will continue for the next few days. Western New York resorts have also benefitted from the contrast between the arctic air aloft and the relatively warmer water of the lakes. As I mentioned earlier, the snowfall thus far in the West has been a bit sparse, but earlier this week, a short wave trough grazed the mountains of Colorado and produced a good sized dump that allowed trail counts to take a sizable jump.
 
This week promises to be a busy one, from a forecaster's point of view, especially east of the Mississippi. Early in the week, a short wave trough will move through the central Rockies, with another trough that is currently off the coast of southern California moving through southern Rockies. It doesn't look as though the two systems will phase, which would result in a major snowmaker, but each impulse will be capable of producing light to moderate snow, which the resorts in the region will take with a smile at this point.

By the time we get to the week of the 15th, it looks as though a deep trough will dig into the Rockies, which will help generate meaningful snows in many resorts that need it desperately as holidays approach. The East will have a warmer than normal week from the 15th to the 20th, with a battle zone set up in the Great Lakes...a variety of precip types can be expected in the middle of the country during the struggle between air masses. As I said, the question is whether or not the eastern warmup/western cool down during the week of the 15th represents a transient deal or a change to a more persistent pattern.

Right now, I think that cold air will once again return to the eastern half of the country just a few days before Christmas. The arctic oscillation, which helps to tip off changes in air masses, is signaling the period of moderation, but it is also indicating that the cold will return rather quickly. So, overall, I think that the bulk of this month will be colder than normal in the eastern half of the country, with the biggest deviations from normal, and thus the more consistent snow threats, will be found in the Great Lakes and upper Midwest. The East and Southeast will have a great snowmaking opportunity for much of the next week, along with some natural snow, and the West will see their most dramatic wintry weather arrive during the week of the 15th. All in all, I continue to be optimistic about the run-up to the holidays...seems like every skiing and riding region of the country will have some weather that will help them get the slopes ready for the onslaught.