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Wednesday, February 7, 2007

Cold through next week now with more active pattern ready to take over in time for President's Day

I have decided that complaining about a relatively snowless cold pattern is bad karma. December of 1989 was the coldest on record for many locations in eastern North America but the cold was not accompanied by a lot of snow in the northeast. A 13-year old weather nerd named Josh Fox had the nerve to complain about the lack of snow and the winter collapsed and that December was followed by a January and February of near unprecedented warmth and lack of snow. The Mount Mansfield snow depth from that year tells of that tragedy in graphic (no pun intended) detail.

This years graph still shows us behind as I pointed out a week ago but gradually making up ground. What is more important is that any slight consternation I may have exhibited in the last post about the middle and end of February is now replaced by exuberance and anticipation of what lies ahead. Fears of any precipitation other than snow (I honestly wasn't that fearful) are now gone and the question over the next two weeks will be whether or not northern and central Vermont can score big points in the more stormy pattern which expected to prevail beginning next week.

Through the Upcoming Weekend
There is not much change in the thinking through the weekend. There are two very weak impulses which will spin rapidly around the polar vortex through Friday morning. There is enough low level instability and left-over Lake Ontario moisture to squeeze a few very wind driven inches out over the mountains. The wind, however will make the near zero degree cold feel much worse, particularly on the summits Thursday. Friday should be mostly dry and not quite as cold or as windy and the weather from a temperatures and wind standpoint will improve even more on Saturday (Saturday mountain temps will make it into the teens). A stronger impulse embedded in the polar jet is expected to begin impacting the region during day Saturday. There is very little moisture with this system but a few inches over the high terrain is certainly a reasonable guess at this point. What is more of a challenge is trying to figure out which of the two weekend days will have new snow at lift opening. At this point the snowfall (if any) has the best chance of occurring late in the day or in the evening which would make Sunday the day with new snow at first tracks time (again if any does fall). Saturday will be the better of the two days from a wind and cold standpoint since Sunday's temps are expected to drop accompanied by stronger winds.

Cold Sustains Through Next Week With Talk of East Coast Snow
The first detail that needs to be put in order concerns the temperature moderation idea I put forth for next week in the last post. This suggestion needs to be put to bed at once since the 5 day period beginning Monday the 12th could very well be colder than the same 5 day period beginning this past Monday at MRG. Cold in New England is triggered by different mechanisms then cold across the upper Midwest and the jet confluence zone which is shown to set up over the Canadian Maritimes early next week is one of the biggest drivers of below normal cold across the north country. Even if the wind early next week proves to be less of a factor relative to the upcoming few days, morning temperatures of -10 or -20 will certainly exceed this weeks numbers. The stage is then set for a big east coast snow event as the confluence zone combines with an approaching storm system to produce cold air damming and lots of precipitation. The question for us relates back to whether or not we stay dry in such a set-up as we did in Presidents day 2003 and the Blizzard of 1996 or whether the storm proceeds up the coast and shares the love. A consensus of model guidance suggests the snow falls to our south with the Canadian model being the lone hold-out and showing us getting a big storm. The jury is still deliberating this one and I would not be surprised if we are talking storm by the end of this weekend.

The Presidents Day Holiday has a Very Promising Look
And now a quick word on the overall pattern leading in to the all important President's day holiday. Ideally, the snowiest times at MRG occur when it is cold but without the disruptive force of a massive Polar Jet such as the one which currently exists. Preliminary indications are that we may very well achieve such a goal. The storm next week (middle of next week to be specific) will mark the beginning of a much more active weather pattern. The break-down of the elongated western ridge is the culprit and will lead to a succession of moist weather systems which will cross the country beginning with the system in the middle of next week. The break down of the western ridge means the Polar Jet will relinquish its grip on the country, but very cold arctic air at the surface will remain over much of eastern Canada and continue to be a factor in New England thanks to the AO which is expected to remain negative and a positive jet anomaly signature over Greenland (one driver of the NAO). When you boil this all into a forecast for the Presidents day holiday and subsequent week, it means at least few chances for significant amounts of new snow.

The Quick Summary
Only light amounts of new snow with the wind and cold through Sunday. The temperature for moderation is out for next week and is instead replaced by talk of east coast storms and a more active, snowier pattern ahead.

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