Today's storm was easily the definition of over performing. Scroll past ads for much more, if they get in the way.
In southern Vermont, this will go down in history as one of Vermont's biggest and most intense snowstorms on record.
As of 4 p.m., I don't think all the totals are in, but they are impressive. At a 1,800 foot elevation in Ludlow, a whopping 44 inches of snow fell. That's awfully close to the single storm record in Vermont - 50 inches in Readsboro in March, 1947.
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| Via Twitter. A parking lot at Okemo Ski Area in Ludlow today. There are two trucks buried in the foreground. |
Even more remarkable was how much snow managed to fall in such a short period of time. Almost all the snow fell in just an 18 hour period.
Snowfall rates in some of the hardest hit towns was probably three or four inches per hour, which is almost unheard of. Especially since those rates sustained themselves for three or four hours or more.
An example: West Rutland reported 27 inches of new snow. My sister in West Rutland reported the snow depth went from six inches to 20 inches in just over three hours. That's a snowfall rate of roughly 4.5 inches per hour!
An intense band of snow, caused in large part by converging wind and air masses on the northwest flank of the storm, caused this intense snow. The storm also had a lot of moisture to work with from sources in the Pacific, Gulf of Mexico and the Atlantic Ocean.
The cold air in place ensured the snow was light and fluffy, so it would accumulate faster.
It's pretty common to have a band of heavier snow pretty far to the northwest of a coastal storm. The unusual thing here was how intense this snow was. Especially considering that in the grand scheme of things, the parent storm was not especially intense.
I'm hoping somebody much smarter than me in meteorology can explain in more detail why this storm was so special and wild and extreme. Any takers? Please reply.
If you were outside the band, amounts tapered off quickly. Pittsford, Vermont got 14 inches of snow, about half of that down in West Rutland, which is just ten miles away.
Central Vermont got pretty much the expected two to six inches of snow. While southern Vermont is guaranteed a white Christmas, not so in the northwest corner. My place in St. Albans, Vermont mustered just 0.2 inches of snow.
The snow band that produced the incredible snows in Vermont extended west and southwestward through the Capital District of New York and on into southwestern New York and central Pennsylvania. There were numerous reports of 30 to 40 inches of snow in this band.
All that snow in Vermont and in most of this band of huge dumpage was powdery, so power failures weren't much of a problem. As of mid-afternoon, no real power failures were reported anywhere in Vermont.
The powdery nature of the snow also means it will settle quite a bit Places that had three feet of snow today will only have perhaps two feet on the ground by the weekend, without any melting.
Some thawing will occur Sunday through Wednesday, but it won't be that warm. Which means snow blasted southern Vermont is in for a white Christmas, as noted above.
One more thing to watch: Late this afternoon, skies were clearing. When there's an unusually deep, fresh snow pack, temperatures can really plunge if skies are clear and winds are light. Cold spots in southern Vermont could get way, way below zero tonight.
Contrast that with areas of northwestern Vermont where little snow fell. Up in places like Burlington and St. Albans, expect temperatures in run of the mill December lows of 5 to 10 degrees above zero.
After today, there won't be any really exciting weather to talk about for at least a week. Some fast moving, moisture-starved systems will come through from time to time, bringing gusty winds and just light rain and snow showers.
It's possible things could get "interesting" in one way or another around Christmas Day, but it's too soon to know for sure.
Videos. Click on the YouTube logo on each video to make them bigger and easier to seel.
First one: This morning in Belmont, Vermont.
Letting the dogs out this morning in Chester, Vermont:
Some possible reasons for the exceptional snowfall despite the lack of a very strong storm:
ReplyDelete1. Storm attacking a fresh cold air mass (first of the season) while waters off the East Coast are exceptionally warm, both increasing the temperature contrast and the moisture brought into the storm. The temperature contrast leads to very strong forcing for upward motion (frontogenesis) despite the relatively weak surface low pressure.
2. Much of the forcing for upward motion and therefore precipitation happens to be concentrated into one heavy band, instead of spread over two or three like many other winter storms.
3. The maximum upward motion and therefore precipitation generation occurred over the dentritic growth zone, an atmospheric layer with a near-perfect temperature for the big, dendrite snowflakes that accumulate quickly (i.e. high snow to liquid ratio).
4. The heavy band moved mostly parallel to its orientation, maximizing its duration over any one spot, creating a narrow area of extreme snowfall. This also means that while areas not affected by the band still got a big snowstorm, it wasn't particularly extraordinary.
A neat thread: https://twitter.com/JackSillin/status/1339723912205230081