Think Snow, Tweet Snow !!!

Tuesday, January 6, 2009

The package is arriving on schedule

And with the help of some of the more higher resolution model guidance one can start to get a better feel for the exactitudes. In this particular case I like to look at model cross sections which gives you the 3 dimensional perspective on our upcoming storm and specifically the prospects for an all snow event. It still is likely that we see a few hours of sleet tomorrow afternoon but the total sleet will be minimal and there is a chance that we see none at all. With the upper mountain closed, sleet is not the worst thing in the world anyway and can add some density to the snow, a characteristic that we most certainly lacked during the December powder-fest.

Snow and minimal sleet Wednesday then terrain enhancement Thursday
The snow is on schedule beginning sometime before dawn on Wednesday, changing to sleet for a bit during the afternoon and then going back to snow Wednesday night. Most encouraging is that the dynamics are aligning for an extended period of terrain enhanced snow Thursday. I get some questions about this from time to time and I get lazy and don't answer them from time to time (my apologies its nothing personal). When we get impacted by storms such as the one Wednesday, the lower troposphere remains relatively stable due to inversions while the atmospheric lift is often provided in the middle troposphere and is considered mechanical. The lower troposphere de-stabilizes when the inversion is removed and the warmest part of the troposphere is the surface (or close to it). Its very counter-intuitive because the heaviest precipitation can often occur with such inversions while a valley location such as Burlington can have a partly sunny day when its unstable. On these unstable days, when enough moisture is present, the mountains are able to take advantage of the instability and the high terrain becomes the focus of snowfall. Thursday's snow will be terrain enhanced even if it isn't a perfect case study for the above description. The important part is that it should provide for some nice fluffy powder on top of the snow and sleet on Wednesday. I still think this is a 8-16 inch event but I am conservative on Thursday's snow totals so the final tally has a good chance of landing on the high side of this range.

Cold and the chance for two garden variety snows
There is the "Alberta Clipper" and the "Manitoba Mauler" but I do not have a good name for anything from the Pacific or from the Canadian province of British Columbia specifically. I will think on that over the next few days but our next system over the weekend will originate from that most beautiful Canadian province. There remains debate on its impact on interior New England and there are indications that the storm and its snow will fall too far south. The cold will have begun and will have done so on Friday. There is a real chance that temperatures for the 10 day period beginning on January 10th and ending the 20th will not break 20 degrees (-7C for you Canadians). The most intense part of this cold may be delayed until around the time of January 14th when a clipper system has a chance of bringing some additional snow to Mad River. As far as the weekend goes however, there is a chance of snow on Saturday and temps will be in the low teens during the day and a shade below zero at night.

3 comments:

steve@jpr said...

May I suggest...

Britsh Columbian Back-cracker...

steve@jpr said...

May I submit...

British Columbian Back-cracker.

KingM said...

BC Bruiser?