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Wednesday, March 11, 2009

Cold weather returns but snowfall through the weekend will be a struggle

The remnants of a what was once a viciously cold arctic air mass in western Canada will make its long expected arrival Thursday but stability parameters are too high right now to support much measurable snow. Tomorrow marks the beginning of what negative NAO has produced in terms of a weather pattern. The trough in the jet stream will re-position itself in the east through the weekend, weaken slightly, and then strengthen significantly into next week as all three major teleconnection indices briefly fall into the favorable category before turning mixed again by the 18th of the month. The cold however will be of the dry variety and will be accompanied by healthy amounts of sun on Thursday, Friday and at least part of Saturday. Afternoon temperatures on Saturday should finally respond nicely to the sunshine and will creep above the freezing mark during the afternoon and will thus soften the base a bit.

The re-amplification of the trough in the east will begin to occur Sunday as an impulse in the jet drops due south out of eastern Canada. This will be the first of two powerful March jet impulses in a span of a few days. These types of disturbances are very common in March and can often stir things up rather efficiently and produce some big snows. This system unfortunately will drop southeast in a trajectory that will make it nearly impossible for a big storm to develop. We can expect a flurries and snow showers Saturday night and Sunday evening but a light accumulation is about the most that can be expected. The above freezing temps from Saturday will turn to temps of the below freezing variety Sunday.

Chilly but not uncomfortable temps will continue to grip much of New England through Monday as the second of the aforementioned jet disturbances dives south out of the western Great Lakes. This upper air system brings with it more potential as far as big snow is concerned as it will carve a very deep trough along the east coast by the middle to later part of next week. There is all sorts of disagreement on specifics but the potential for an east coast storm is there for now. Good chance it also goes out to sea but this folks is what March madness is about. I am sure we will see a few interesting twists and turns regarding next week. We do now it will stay relatively chilly through most of the week and we shouldn't lose much of the base that remains.

Much of the key features in the long wave pattern will be pushed eastward, again the result of a slight re-arranging of our teleconnection indices. A good chunk of the country will warm by March 20th but whether or not this warmth reaches New England and eliminates our chances for new snow remains a question. There remains a chance with the continued downstream blocking in the jet stream, that conditions remain cold across the northeast.


alison said...

Are you the Josh Fox from Ward Melville HS?

Jim Jenkins said...

What are the chances of March going out like a lion? Roar or mew?

dave said...

Just one more?

The Package said...