Monday, November 25, 2024

Thanksgiving snow and plenty of early season cold weather to follow through early December

 A beautiful early winter pattern stands directly in front of us as the thanksgiving holiday approaches. It's been a struggle in New England to sustain any type of below normal temperatures over the past year, but an excellent stretch of cold begins Tuesday evening thanks mostly to a very favorable EPO set up in the Pacific and some high lattitude blocking over the northeastern Eurasian continent. The best part of this story is the snowfall which comes in the form of a significant dose on Thanksgiving and this storm will give the whole region a very wintry feel that will extend well into December thanks to the pattern. 

A moisture-starved storm will bring some rain and mixed precipitation to much of Vermont as passes over the Ottawa River in Canada early on Tuesday. Some snow can be expected close to the Canadian border but not much south of that. Drier and colder air will then settle in Tuesday evening which will begin what we hope is a multi-week stretch of sub-freezing temperatures on the mountain. Such an occurrence isn't easily achievable in the middle of winter and is a special sort of challenge in early December. 

Our Thanksgiving storm gathers its moisture Wednesday over the Midwest and will continue to strengthen as it moves over the Ohio Valley during the evening. Models continue to jostle over the track which is a bit surprising at this stage in the game, but I feel very comfortable betting on the Euro output which places Vermont in one of the better areas for snowfall on Thursday. Northward shifts are always a good bet, but are especially likely to happen early in the season thanks to what is usually a weaker polar jet and thermodynamic feedbacks from the Great Lakes. This track, would place the storm just west of the New Hampshire seacoast for Thanksgiving dinner and then up through eastern Maine after that. A classic holiday snowfall would be the result, beginning early on Thursday and continuing well into the evening. The snowfall would be widespread, falling both over valley areas along with the high country with elevation impacting snow consistency more than anything else. Some mixing with sleet and or freezing rain is a very real possibility early Thursday evening. Those details need to be ironed out in a day or two. In the meantime we can establish some early snowfall expectations of 7-15 inches. Without the mixed precipitation threat, I would go higher, but I expect a powdery finish to this storm regardless with a chilly, wintry and snow showery Friday (even though the accumulating snow should remain closer to the Great Lakes). 

A weak mid latitude Pacific jet set up (synonymous with -EPO) will combine forces with the aforementioned high latitude blocking scheme with the trifecta support coming from ridging which is expected to develop in western North America over the next week. This means cold weather through December 10th that will undoubtedly be accompanied by additional chances for snow. Almost all early season cold setups produce snowfall in northern New England and I would fully expect multiple chances at some snowfall next week. Champlain enhancement will contribute as might a storm that models have yet to resolve. A very encouraging start to the season which will produce plenty of snow clover, snow showers and sub-freezing temperatures as Mikaela Shiffrin skis for her 100th win this weekend at Killington this weekend.

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