Wednesday, February 22, 2012

Is Winter Over For Real?

Did it ever really start? Yes, it has been a pathetic winter all in all, with all sorts of warm winter top 10 lists making room for a newcomer. And yes, the calendar does say that meteorological spring begins about a week from now. Of course, as we all know, meteorological spring doesn't mean winter ends. We’ve had plenty of snow threats in March and April in the past. It's popular "folk meteorology" to suggest that these sorts of winters breed awful, miserable springs. And the groundhog said 6 more weeks of winter, right? So let’s take a peak at what March at least may bring.

To be up front: Based on all available latest looks warm. Let’s start with the latest CFS forecast from earlier. Weeks 1-2 are shown at right, taking us through March 7th. The CFS is a climate model run by NCEP. It’s in its second version and apparently has been improved substantially. This winter, it has had an exceptional track record, especially given the low bar it had previously been set at. It has maintained ideas of warmer than normal weather, which have verified. Of course, the European weekly and monthly outlooks have also done quite well. It could just be that the global weather regime is better suited to more accurate climate models (which are run on much different parameters than the usual GFS and European models we look at day to day) and we could see major failure of these models when something in the pattern really changes (it becomes "unglued"). We simply don’t know...just know it’s had a hot hand (quite literally) of late, so we'll ride that wave until it shows signs of breaking.

The week 3-4 composite from the CFS is shown at left, taking us into mid-March. And with nothing in the near term, the general consensus is that winter will remain at bay (impacting Canada and occasionally the Northern Plains, Rockies, and Northwest) for the time being.

"Modelology" is one thing. But even looking more in depth at what is dominating globally right now, the picture doesn't honestly change much. With a weather pattern supporting cold air retreat to the Arctic and Alaska, little to no cold air shown in Siberia (the AO, EPO, WPO indices all remain positive), and a building Southeast ridge...there’s little support for any cold in the Eastern US (except maybe at times in New England) over the next 3-4 weeks.

Worth noting that the best comparison nationally to this winter is 2001-02. Many of you may remember that spring where we saw 90s in April. I recall studying for finals at Rutgers University in New Brunswick, NJ outside most of the week. It was certainly odd (though admittedly, I enjoyed it).

So is winter really over? Maybe. All it takes is a couple days of the right factors to produce a snowstorm and a brief chill (Coincidentally, today's 12z European model run shows just that at the end of next week. That's not a guarantee by any means, but it just furthers the point). No, winter's not over for certain, but the proverbial “fat lady” is warming up backstage.