The storm this past weekend turned into a big tease, tracking too far off shore and failing to deliver for most of Vermont, depositing snow in New Hampshire and Maine instead. It all is part of a rather inauspicious start to the winter season which has been dominated by mild air in November and a big miss to start December. Though the weather pattern for the next 10 days has some limited potential, models are only limited amounts of snowfall right now and we have not eliminated the rain/ice risk.
Though arctic air is in very limited supply across North America right now, the jet stream is carving out a deep enough trough to sustain several days of sub-freezing temperatures (through Wednesday). Aside from flurries and an occasional snow shower, snowfall will be limited thanks largely to a strengthening storm off the eastern seaboard which has the effect of robbing us of our moisture. That said, a weak but fast moving jet stream impulse marking the approach of milder air should bring some limited snowfall to the northern Green Mountains late Wednesday. Temperatures Thursday are expected to eclipse the freezing mark across low lying areas but the risk for snow showers remains Thursday over the high country. I can't promise too much from all of this but a few inches is possible with the best chance for 6 inches from Stowe northward to Jay Peak.
Following a dry day Friday, we can expect another more significant storm to impact us this weekend. I can't say I am too delighted with the picture the models are painting as of Sunday. We still lack a supply of arctic cold and the approaching storm in the Plains appears intent on maturing rapidly over the Mississippi Valley and ultimately occluding well before reaching the eastern seaboard. Unless much of this storm's energy transitions to the coast, we are looking at an ice/rain type situation on Saturday with little hope for any snowfall.
As promised, arctic air will become more prominent over Canada beginning this weekend as a broad area of ridging in the jet stream stretching from Scandinavia to Greenland will allow colder air to bleed southward in North America. As this is happening however, the ridging in western North America will break down while the jet stream in the Pacific strengthens. Much of eastern North America will thus be dealing with conflicting teleconnections indices with the -AO/NAO favorable but the +EPO/-PNA more unfavorable. We can still expect some cold weather accompanied by snow showers Sunday into Monday and that cold weather should be the strongest of the season so far (not saying much) and remain entrenched into the middle of the week. At that point, another storm system will be approaching and it will mark another opportunity to take a step forward on the season.
Beyond the middle of next week, we will continue to have some limited support from the Arctic Oscillation which is a big improvement relative to last year when we had basically none after the middle of December. Still, the jet stream in the Pacific and in western North America appears a little problematic. We can often survive the former so long as the EPO doesn't get too positive but a lot of jet energy and cold will become focused on western North America by late next week and will become one of the more glaring jet stream features on the globe. Though it doesn't automatically point toward a sustained torch (especially with the competition from the AO) it will make the storm track potentially difficult. It also looks very much like a weather pattern one might see during a La Nina.
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