Thursday, December 13, 2012

Sunday Stormy Sunday

It seems like stormy patterns always like to coincide with mid-terms and finals. Its not as if I don't already have enough distractions (thanks a lot Redditt). As such, I am taking this time meant for studying to discuss the upcoming changes in our weather.

First, I must point out how dry November and early December have been. In November alone we finished the month almost 3 inches below normal for precipitation. After the onslaught of Sandy and the early November snow, things have been pretty tranquil around these parts. Not for long.

Beginning Sunday, its as if mother nature flipped a switch and said "game on". Several short waves (fancy term for storms) are going to spin up from a suddenly very active and tilted jet stream.After Sunday, there are going to be about 3-4 more storms taking aim at the region over the period of about 1 week. Now, it is worth noting at this point that the operational models that we use to make forecasts have traditionally sucked at handling big pattern swings. Like my father, they dislike change. With that said, there are a large amount of discrepancies and disagreements among the models and as such no forecaster is confident about the conditions from Sunday-Thursday of next week.

Two problems exist in my mind.

1.) What happens on Sunday? A small and weak system will start the parade of storms off by Sunday morning. It is very likely that everyone gets a little snow in the morning but at some point, there is going to be a change to a mixed precip and rain. But there is no agreement on when this happens and until there is a consensus, many questions remain. Here is a little insiders knowledge from the weather world. When there is no agreement among the major models for a period just 70-80 hours away AND there is a major pattern swing in the mix, you might be sh#@ out of luck trying to predict anything with greater than 50% confidence beyond 3-5 days.I can't even say what the conditions will be like at the Patriots game! Which brings us to...

2.) The all important cold air! It's pretty simple. No cold air means no snow. I bet you didn't know that. In order to get cold air to stick around in these early season storms (yes it is still early), we must have a strong enough source (High Pressure) that is located close enough by and is also aided by some large atmospheric blocking to keep it from escaping. Without firmly entrenched cold air and an offshore track, any ocean storm that develops close enough is likely to result in too much low level warmth in most areas. And it appears that we are going to be on the cusp of some retreating cold air.

That seemed like a mouth full. Essentially what this means is that we are in wait and see mode. I can tell you that tomorrow and Saturday will be sunny and chilly, especially Saturday. By Sunday morning, I think light snow breaks out for us all. At some point, that snow will change to rain. Snow and mixed precipitation will hold on longer for interior areas, say west of 495. Some ice can't be ruled out in spots. It should dry out by Monday morning but then the guessing game begins. A potential big storm remains a possibility next Wednesday.

That is all. Go out and see the Geminid meteor shower tonight! Clear skies for peak viewing time after 10pm!