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Beyond the Taste of Spring, a Fascinating Pattern

Jan 31, 2012; 11:07 AM ET

Tuesday, 11:30 a.m.

Almost all of the 'arctic' air has retreated from the playing field overnight as a warm front has moved into far upstate New York and into New England. Temperatures have zoomed up toward 50 already in Providence, thought it's stuck in the 30s still at Boston's Logan Airport that sits on the water. In my backyard, it's already at the projected high for the day, and it's only 11 a.m.! We'll end up with temperatures more typical of the second week of April rather than the end of January when all is said and done, and that's after a slew of records bit the dust on Monday up and down the Plains and into parts of the Midwest. A bunch more will be wiped out this afternoon, and more may go down for the count on Wednesday.

There's no debate about how things will change from this week to the next. Here's a comparison of projected temperature anomalies from week one to week two, starting with the 12z Monday GFS ensemble seven-day means for today through next Monday:

That is a massive area with temperatures forecast to average a dozen or more degrees above normal, stretching from the Great Lakes to the central Plains on north. What winter? Phil who? Six more weeks of this? Bring it on!

That's all nice and good, though it does raise some issues, such as a premature start to the growing season and the risks that might entail; the lack of a strong enough cold to kill bugs this winter that would ordinarily happen; lack of snow to melt going into the spring snowmelt season and a lack of overall moisture in some areas heading into the growing season. Those are interesting questions that deserve their own separate columns, but I'm not going there today. Maybe some quiet day ahead.

Still, as pleasant as this will be for people like me and many others, it will turn cooler next week. Here are the latest 6z GFS projections of seven-day temperature means from Tuesday, Feb. 7, through Monday, Feb. 13:

That's a considerable change, though the daily means don't necessarily show any real arctic cold in the pattern. And that's fascinating when you look at the big picture setup. Look at the Arctic Oscillation forecast going forward:

That's very negative and a forecast that implies plenty of cold amassing in the high latitudes of the Northern Hemisphere (just ask Alaska!) and good reason to deliver that cold to lower latitudes.

Now look at the PNA forecast:

That strongly correlates to western ridging, and if there's a ridge in the West, chances are good there will be some degree of a downstream trough, with a northwest flow in between. Indeed, if you look at the ensemble forecasts, this is clearly being born out:

That's next Wednesday evening. Sure looks like a classic setup for a massive arctic outbreak - strong ridge nosing up into Alaska (hey, even across the pole into northern Asia!), a deep downstream trough and an upper-level low just north of Hudson Bay. Yet the GFS ensemble forecasts have nominal cold. The European weeklies have a pocket of cold over northern New England into Quebec, but massive warmth most everywhere else next (save for Texas and Florida). Even the NAEFS just has a neutral look to it:

The main problem is the source region of the air mass dumping into that trough. Go back and look at the week one temperature anomalies. That's not only a big area with temperatures of a dozen or more above normal for the next seven days, but how about 20 degrees or more above normal in a massive area of Canada! I don't care what you do to that air mass, but as a leopard can't change its spots, nor can an air mass that warm suddenly transform itself into an arctic one!

So, yes, it will turn cooler, but the core of the cold air actually backs westward into Asia and may well stretch all the way to Europe. The upper pattern is so convoluted that the 'normal' rules just don't work, and a simple pattern diagnostic will give you the wrong answer. It's a fascinating pattern, in that the very things you want to see, including a definable southern branch of the jet stream, to bring cold into the country, and potentially produce storminess (and, of course, snow), are all in place. However, the end result may well be completely different.

And yet I feel somewhat compelled to say that the active southern branch combined with at least a chillier air mass may still find a way to manufacture snow for some. The question is who, and right now that's just a hard thing to see, let alone pinpoint.

Once beyond next week, there are signs the trough relaxes, the flow flattens and more mild air spreads back out across the country.

The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or AccuWeather.com