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Thursday, February 15, 2007

President's Holiday greatness and then a pattern shift

The public information statement from the National Weather Service in Burlington will have storm totals from around the region if anybody is interested. Many reports will come from valley locations, the higher terrain including ski country did even better.
We have now officially erased what was the equivalent of a 20 point deficit in a basketball game and hold a lead as we proceed to crunch time. It has taken 32 consecutive days of below freezing temperatures at MRG, several small storms and then one very big one to complete the deal but we now have established an above normal base leading into President's day holiday. Give mother nature a pat on the back but we don't want her to get complacent. After a glorious weekend with additional chances for fresh powder there are forecast challenges and shades of grey by the time we reach the last weekend in February.

Memorable Presidents Day holiday - very cold however for Monday
It will be cold and blustery through Friday with temperatures on the mountain struggling to make it past 10. Saturday should see some moderation as temps climb into the teen with less winds. Skiing in powder is a great way to stay warm over the next few days and terrain induced snow beginning late Thursday will add to the almost 70 inches of snow which has fallen at MRG in the last week. If i try to get too specific about what is going to fall and when I will surely confuse everyone and bust all at the same time. Lets just say that in the time frame beginning Thursday evening and ending Saturday morning we could see an additional 4-10 inches with the wide ride range accounting not only for uncertainty but also elevation on the mountain. At some point on Saturday a break in the snow is likely as clipper passes well to our south and acts to stablilize the lowest 8,000 feet of the atmosphere. Once the clipper clears the east coast Sunday it will allow another impulse to take aim on the region late Sunday which could bring a burst of terrain enhanced snow and another 5-10 inches by Monday morning. Although a powder day appears very likely on Monday, it will be windy and very cold with temperatures at least 10 below in the morning and struggling to make it above zero during the afternoon. So in summary, we have new snow predicted for lift opening on 3 out of the 4 days between Friday and Monday. Friday and Monday are cold and blustery, Saturday and Sunday are not as cold.

A new pattern to emerge
As next week progresses, the pattern across the entire U.S. will to begin to respond to the pronounced changes across western North America. The ridge over B.C. which triggered the intense cold across the Midwest and East Coast will be replaced by a large trough. Western ski resorts from California to Colorado will surely have a lot to brag about by the last weekend in February. We, on the other hand have to start playing defense because troughing in the west means there will be a real driving force to push warm air northward over the East and Midwest. Is there some good news here ? Yes. This pattern change is not being driven by the AO index which is expected to stay on the negative side of zero over the next two weeks. Ridging across Greenland will also help to counteract any warm-up. This is distinctly different to the situation in early December when every possible indicator was saying warm and snow-less for weeks on end. Additional help comes from the cold Great Lakes. All 5 have some ice on them and Lake Erie is now completely frozen. A broad area of snow cover also helps although the snow cover now is not all that unusual for this time of the year.

The forecast for next week - A significant temperature moderation
So here it is. Tuesday's temps will moderate significantly and there could be some warm advection light snow leading to a light accumulation. A much stronger southern branch storm will then progress eastward on Wednesday and Thursday and the concern here is that there is not much cold air left for it to work with. It may in the end turn out to be so cut off from the receding polar jet, that its impact on Vermont is minimal. If it does proceed northward and affects New England, more snow could be in the forecast but temperatures will be a lot closer to freezing. Overall I still think its a very good week to ski but we will start to notice the changes in the pattern by the middle of the week.

Rest of February
The very unsettled western U.S. is likely to send more very moist and potent systems eastward through the end of February. We are going to lean heavily on the NAO and specifically the ridging in Greenland to help prevent these systems from taking that abominable track up the St. Lawrence Valley. The positive angle here is that the region is likely to see another significant snowfall from a strong storm. The negative angle is that we are unlikely to win every battle and may have to deal with precipitation other than snow at some point before the month ends. With all that said, I am fairly optimistic and think we could make out okay over the next two week in spite of the gradual loss of our cold.

The Quick Summary
Snow, snow and more snow through Monday (President's day) . After a brutally cold Monday, a new pattern will assume control, one of less cold and frequent storms which will hopefully bring only snow.

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