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Friday, March 15, 2013

Nice looking snow producer looking more likely Tuesday

Terrain enhanced snow finally found its way to the mountain Thursday and the result was some surprising snow totals Thursday. There are many years where the combination of a little instability and low level moisture will result big powder days for the high elevations of VT. We have had so little of it this year that I have been somewhat afraid to predict it, but the Thursday fluff proves that the Green Mountains can still bring it under the right circumstances. The nearly 10 inches Thursday combined with the bit of snow Friday evening has MRG back in the winter spirit. And best of all more is on the way.

No new snow for the weekend as very cold, very dry  high pressure builds over New England. The airmass is capable of sending temperatures back toward zero, perhaps even below zero Sunday and Monday mornings. Most importantly though, the airmass will be an important building block in establishing a healthy overrunning surface for our upcoming winter storm Monday night into Tuesday. The weather system will be a conglomerate of low pressure centers with one moist storm moving out over the southern plains Sunday while another brings now and wind to the Dakotas and Minnesota at the same time. The storms are not likely to phase and the southern stream system is expected to strengthen and eventually prove to be the prevailing precipitation producer along the east coast. There is some dissension amongst the models regarding the amount of mid level warm air that gets thrusted into the state as the aforementioned storm approaches. The European model has had a more consistent handling of this evolution and is thus the favored solution as of now which is good news for us. Snow should develop Monday night, continue into Tuesday and within this period of snow should be a burst of very heavy snow since this is one of the more moist systems to impact the region this year. Snow totals could be around a foot by later Tuesday and some additional snowfall is possible from instability associated with the lagging decaying low pressure center Wednesday and Thursday. In short, it will be a very wintry week in Vermont and should be one of the best of the season at MRG.

The blocking is still the main driver of the pattern. Interestingly it is not the NAO or PNA but larger scale AO (Arctic Oscillation) which will be off the charts in the negative direction during the last 10 days of the month. This is what we saw in 2010 and this will certainly act to thwart any major thaws through the end of the month. In 2010 however we did see a very suppressed jet stream as a result of the strong blocking and we should see this again. March is a quirky month so you never now whats going to pop up on the forecast radar but my guess is that see a relatively dry 10 days following the snow in the middle of next week. The storm I had mentioned that could threaten the east coast around March 24th will have some difficulty moving up the coast.


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