Thursday, December 24, 2009

2009 may end with a bang !!

Dry air stemming from high pressure center over Quebec will help improve visibility through Christmas. We won't see much in the way of snow through Christmas day but light winds and seasonable temperatures should provide the opportunity to loosen up the legs on the groomers. We have been watching our post-Christmas storm for more than a week and in the end it will be a disappointment. Precipitation will arrive in the form of snow late on Saturday and is likely to turn to a mix of sleet and freezing rain for a time on Sunday. The problematic layer of warmth is only indicated to be about 1-2 degrees C so the possibility of turning this to a snowier forecast remains but chances are starting to dwindle. Temperatures at the surface will struggle to get above freezing and if they do, it will hardly dent the base. This storm in the end will be a much greater concern for the Upper Midwest and its impact on the east will be forgotten about in short order.

I am much more excited looking at the possibilities for Monday. The storm as discussed will occlude across the Midwest and will ultimately bring a deep pocket of instability across New England Monday. The unstable layer could for a time be greater than 10,000 feet which would be more impressive than at any point last year. With the winds at varying levels of the lower troposphere aligning, the prospects for terrain enhanced powder look very good Monday. So good in fact that I can confidently say much of the Green Mountain chain could get a 6 inch or more shot of powder during the day Monday. Arctic cold arrives Tuesday and although snow showers should continue the chances for an accumulation drop off. The drop in temperatures will also not go unnoticed. Temperatures should hover in the low 20's with snow falling at oscillating intensities Monday. Readings will fall to the single numbers however for Tuesday and Wednesday and wind chills will be well below zero for Tuesday.

Our southern branch might be cooking up more of the good stuff around New Years day. In the coming days, I think some of the medium range models will come up with some sort of consensus that includes an east coast storm and perhaps a big one around New Years Day. There is so much jet energy along the Gulf Coast that it is proving very difficult for the models to make sense of what to do with it all. We have already seen a few occasions where model data is simply underdone on the potency of this jet energy along the Gulf Coast. You can't call the American GFS model underdone this morning as it "bombed" a storm off the New England coast New Years Day. The European shows a much weaker version. One might normally bet on the more benign of the two advertised scenarios but I would not want to fight the southern branch this year so lets be cautiously optimistic and see if this can sort itself out into a snowy forecast for us as 2009 ends and 2010 begins. Ensembles have also given us the gift of an extension on our blocking pattern which will include favorable NAO and AO teleconnection indices through the first week of January.

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