Winter is about to roar back to life in northern Vermont with heavy snowfall close to a virtual certainty on Thursday and I am hopeful that we can expand the good tidings past this week and into early March. We certainly have some of the right ingredients with blocking expected to emerge over Greenland allowing the NAO index to move decisively into negative territory. A similar pattern emerged in March of 2018 following a rough month of February and Mad River Glen received over 80 inches of snow.
The President's Day holiday Monday is still mild one, especially across valley locations where readings are expected to climb into the lower 40's. It won't be quite as warm across the high country however and a brief period of above-freezing temperatures late in the morning into the early afternoon will be replaced by elevation sensitive snow showers late in the ski day. A mostly wet inch of snow is possible by 4 pm and another inch or two is possible during the evening as winds turn and blow more favorably off an unfrozen Lake Champlain. Though temperatures may climb above freezing again in valley locations Tuesday, I don't see this occurring across the high country tomorrow or the rest of February.
A stronger clipper system is expected to bring more snowfall late on Tuesday. This will occur after several hours of sunshine in the morning and a few more hours of cloudiness early in the afternoon. The snow Tuesday is expected again late in the ski day into the early evening and is likely to accumulate 2-4 inches. The better moisture with this system is actually south of us and portions of the southern Green Mountains and Berkshires could receive up to 6 inches. The storm will also return arctic air into northern New England for Wednesday and help establish a critical jet max over the maritimes of Canada capable of ensuring that the cold airmass that is expected to build over eastern Canada remains entrenched over northern New England late in the week.
The strong late week winter storm has some similarities to the early February event last year in that both produced an intense temperature gradient over the eastern United States. This storm, like the one last year, will feature an elongated west to east area of low pressure, that will torch locations with 80 degree temperatures over portions of Virginia, the Carolinas and points southward. Vermont might as well be living on a different planet with arctic air actually strengthening its grip on the region as snow arrives very early on Thursday. Northern Vermont is positioned beautifully for an extended period of overrunning snowfall beginning in the pre-dawn hours Thursday and extending into early Friday. It's a storm featuring La Nina's best personality trait after a month where we saw La Nina at its absolute worst. In terms of snowfall amounts, some caution should be advised as changes could occur in the next few days, but we've seen a good consensus emerge over the last 24-48 hours for a widespread 1-2 foot event for northern Vermont. Some sleet is possible for the MRV but this is more likely and more problematic in central and southern Vermont. Temperatures after early Thursday will generally be in the teens and drop into the single numbers as snowfall ends Friday ensuring a rather dry snowfall event. Arctic air then dominates the weather picture Friday night into early Saturday dropping temperatures well below zero on Saturday morning before sunshine warms readings back into the teens in the afternoon (It will not be a repeat of the arctic event Feb 3-4).
There's plenty more potential action after the Thursday/Friday event this week with clouds returning to the region late on Saturday February 25th and some new snowfall possible for the ski day on Sunday, the 26th. The European Ensemble is, as of late Sunday producing an exceptional signal for something very significant on Tuesday February 28th. This is not receiving much support from the American Ensembles though there is some hints of an event on the Canadian Ensembles. More generally, it is the European that has for the last several days, indicated a more beneficial snowfall and temperature outcome for northern New England from this upcoming -NAO driven pattern. I will suggest however that there is some similarities to the December -NAO which favored arctic air more in western North America and kept northern New England cool but not cold relative to climatology. We are likely to see another cold intrusion following the potential storm February 28 but are likely to see some milder March days scatter themselves into the weather picture as well, especially as we get toward the first full weekend of the month (4th and 5th). Overall though, its hard to complain about the outlook for the next 10 days and the benefits of this setup could certainly extend out further into March.
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