Bob Ryan's UPDATED outlook for winter 2011
Here we are in December, already. Today is the first day of winter, as defined by the climate records kept by us meteorologists and NOAA’s National Climatic Data Center. (Spring begins on March 1.) Are you ready for some real cold, snowy winter weather this year?
Well, looking at a few of the latest trends, which do give us hints about the season ahead, I’m now more afraid that this will not be a great winter for snow lovers. You may have read about the research correlating the snowpack and snow cover in Siberia with cold patterns in North America. Long story short: A quickly developing Siberian snowpack seems to tie in with a harsher winter in the eastern U.S. But here’s what the latest snow-cover anomalies look like in Asia and North America. You can see they're below average across the Northern Plains and also nothing unusual in Siberia:
What about temperature trends in October and November? They don't bode well for folks who love to build snowmen. This was one of the warmest Novembers ever in New England, and here in D.C. the month was more than 2 degrees milder than average. October also was mild across much of the country and New England, as you can see from the NCDC's map:
In past winters, when October and November have both been mild to our north, the following months are more likely to be relatively easy or mild rather than very cold. And of course there is the ongoing La Niña pattern, which is not a sign of truly frigid winters. Take a look at this graphic from NASA showing the expected influences of La Niña this winter:
And finally, if you’re not tired yet, here is the “official” winter outlook from NOAA’s Climate Prediction Center:
All of which looks like an average or milder-than-average winter to me.
That's not all bad: Such winters are easier on the heating bills than the winter of 2009-2010, which was almost 3 degrees colder than average and full of a record 56 inches of snow.
I still think we should expect one to three big storms, but with a mild pattern they're more likely to be rain producers than snow producers around the D.C. area. The wild card? That would be the Arctic Oscillation, which can’t be predicted more than a few days out. When it is strongly negative as in the great 2009-2010 winter it means a very cold pattern in the east. But right now, there's no sign of anything like that.
The pattern does look like some of that Alaska cold, where it has been -41 degrees already this month with November being about 10 degrees colder than average, will slide to our north and give us cold shots from time to time. But nothing prolonged. In summary, this winter looks average to milder than average with near-average snow.