Think Snow, Tweet Snow !!!

Tuesday, December 25, 2007

Good news is hard to find on Christmas Day but I am looking

Merry Christmas !!! Sunday's rain knocked the snow depth near the Mt. Mansfield Summit to 48 inches, down 8 from its peak of near 56 inches and still well above average for this time of the year. It is the quality of the snow which took the biggest hit however since crust now plagues the Vermont Woods from Stratton to Jay Peak. The most dominant feature going forward has been, is now and will be the consolidated and very powerful jet in the northeast Pacific Ocean. The valve controlling the flow of arctic air into the U.S. has been temporarily shut as a result and now the longwave pattern is sending storms on a perilous course. La Nina has brought its chickens home to roost and going forward into January looms an uphill pattern as the now marginally unfavoarable pattern has a chance to turn downright awful after January 4th. Until that time we have a chance at scoring some individual victories and we will get a chance to detail those in this post.

Through Saturday
Calm winds and slightly above average temperatures will make for some comfortable weather as far as skiing is concerned both Wednesday and Thursday. Thursday will be the day which features more in the way of clouds and eventually some light snow late in the day. There is a good chance this light snow continues into the night dusting MRG with a very light accumulation (1-3 inches). The disturbance responsible for the light snow is a very weak one but will be followed quickly by more organized weather system which approaches late Friday. This, stronger weather system will take dead aim at Lake Huron which to be blunt is a deplorable track in terms of bringing new snow to Vermont. Consequently, there will be a push of warm air ahead of the passage of this storm and it will be tough to keep precpitation in the frozen variety. Some of this "warming" will get cut off at the pass as this storm will try desperately to re-center itself off the New England coast. This is a very close call with a few very different options still on the table. If the coastal "cyclogenesis" can occur efficiently then precipation would ramain mostly snow even if more of it gets confined to Maine. The other option would involve a period of sleet or freezing rain before a return to snow or flurries occurs Saturday.

What about those individual victories ??
Our best hope for big time new snow comes around the time of New Years as the pattern takes a temporary turn for the more amplfied thanks largely to the Davis Straits blocking which is trying to ease the pain of this regime. It becomes rather complicated because there are two weather systems in this time frame, a very tight temperature gradient and considerable disagreement amongst the computer guidance. The outcome is therefore very up for grabs and extremely sensitive to slight changes in the track of either weather system. Precipitation from the first storm would arrive late on Sunday although the American model suggests there is little if any impact from this system. Assuming we do get an impact (which is about 60%) then precipitation could be snow, mixed, precpitation, rain or all three depending on the track and evolution of this system. The second system will hypothetically impact the region on January 2nd or 3rd and is of the "snow or no" variety which means that the chance for rain is limited. This second system is a product of the clash between La Nina's southeast ridge and the push of colder temeperatures resulting from the temporary pattern amplification. The storm will pass to MRG's south which is a good for keeping precipitation in the form of snow but if the storm were to travel too far south then little or no impact would be the result.

The taste is sour not sweet after January 4th
After January 4th, the pattern has a very ugly and bitter appearance. The taste is not horse radish either which I can eat in large quantities on almost anything but rather some dairy product still sitting in your fridge that has seen better days. Both the european and american ensemble guidance now indicate a very large signal of warmth after January 4th across the eastern U.S. and southeast Canada. The driving force of such a pattern is a combination of of the persistent and very agitating jet in the northeast Pacific and some of the teleconnection indices, specifically the AO, which has turned quite unfavorable in recent days (much more than what was expected just a week ago). Regarding the AO, there is actually a time gap between what the value of the index and the impact of that index on the weather at MRG. For instance the AO was negative for the last half of November and into early December but then turned postive by December 6th. The weather at MRG was was golden from late November to the Winter Solstice. I will therefore offer that the AO index which is currently a positive 2 will ultimately have a much more negative impact on the weather going forward into early January. We can certainly hope for better results verses the one I am suggesting but I am not optimistic as of now.

Merry Christmas again to everybody out there. Be safe this holiday season !!

1 comment:

cheap custom paper writing said...

Well it sounds like it’s chilly and snowy out there. Anyway I must say you have some great writing skills because this post is very well written.