Think Snow, Tweet Snow !!!

Saturday, December 15, 2012

Lots of storminess, lots of precipitation types

As they like to say, let the games begin !!! In what should be one of the more active weeks of weather this calendar year, the region will see a bit of everything. The news is not all good but there is certainly plenty of news and after what should be a true roller coaster ride of weather conditions through Christmas Eve, the mountain should be much closer to an opening.

As of Saturday afternoon, there were not too many places in the U.S. that were seeing below-freezing temperatures but interior New England was one of those places. The culprit was a decaying but at one time quite intense piece of Arctic air centered over Quebec. The cold, dry airmass slipped into the region just ahead of the first round of precipitation expected to arrive in the form of snow during the middle of the day Sunday. I know the weather forecasts for Sunday have been all over the map and even as of now, models have yet to agree completely on a precipitation type through Sunday night. Various forecast sources seemed to have formed a consensus (that I agree with)  calling for a period of snow through Sunday night. The snowfall intensity will be mainly in the light to occasionally moderate range allowing for snowfall totals to to be in the modest 2-5 inch range. With temperatures only a few degrees away from the freezing mark, snowfall will generally be wet.

4 days ago, we discussed a second and more vigorous piece of upper air energy which will act as a potent steroid (for lack of a better word) in this whole weather situation. The upper air support, described in the meteorology community as a "shortwave", will commence its impact early Tuesday. Prior to this, the loosely entrenched area of cold weather over New England will continue battling it out with a push of milder weather from the south. The result will be the periodic continuation of either mixed precipitation or snow depending on what package of model guidance you believe. For the most part however, temperatures should stay at or below freezing in spite of whatever precipation falls Monday. This vigorous injection of upper air support will unfortunately begin to tilt the scale of this cold vs warm battle in the wrong direction. This is a situation I discussed somewhat in the previous update. As exciting as some of these amplifications look in a medium range model, and as much upside potential in terms of snowfall they can bring, the lack of a reliable supply of cold air can lead to some lousy results, especially early in the season. In this case, we will see an exploding area of precipitation Tuesday probably get wasted as cold air slowly gets scoured out of northern Vermont allowing for a period of rain Tuesday. This remains a tenuous situation and a few slight changes in the evolution of Tuesday's system could yield a different result. The storms amplification will ultimately allow colder temperatures and some snow to return for Wednesday although temperatures will remain near to just below the freezing mark through Wednesday and into Thursday.

When it comes to weather, it seems everything comes in streaks. It is largely analogous to a baseball player who has hitting slumps and periods when he hits lots home runs in a short period of time. The upcoming period can certainly be described this way. After the the snow, mixed precipitation and rain in the Sunday-Tuesday time frame, another even feistier weather system will move out of the Rockies and into the Plains and Midwest Wednesday into Thursday. This is yet another system capable of amplifying the jet stream in a profound way but do so with only limited cold air and probably do so too early. By Thursday evening, cities like Chicago north through much of Wisconsin could see near blizzard conditions if some of the medium range models are correct, but an amplification so far to the west allows warmer temperatures and rain to again threaten New England for a period beginning Thursday night or during the day Friday. Fortunately this situation is fluid and the ridging in eastern Canada will prevent this storm from tracking too far into the Canadian provinces before transferring some of its energy to the New England coast. This means that rain will turn to snow and snow showers and could persist through the weekend into Christmas Eve with some significant snowfall accumulations and colder temperatures. By the end of all the storminess, there should be a good amount of snow on the mountain and hopefully we have an opening day in our sights.

The end of 2012 should continue to feature temperatures that are in the above normal category but not excessively so. A few runs of the European ensembles have indicated a storm around the time of the 27th and 28th. That weather system is a long way off still but has promise at least as of now. The pattern as a whole should continue to be a ruled by a ridge in the west-central Pacific (near the dateline) and a ridge in eastern or central Canada. This is not the most ideal situation in the world but it is not totally adverse either. We have yet to see anything resembling an upper ridge in the western part of Canada which is necessary for a sustained outbreak of arctic cold and below normal temperatures.

1 comment:

Zach said...

Why do the snow gods hate us?