WSET.com - ABC13Winter Outlook: Expanded by Sean Sublette

When we prepare the winter outlook, we use a method of long-range forecasting that has become wildly popular over the past decade. Instead of just using observations and computer simulations of the atmosphere, we look at very large-scale patterns which often repeat themselves.

For example, we had an unusually hot summer in Virginia and the Interior Southeastern United States (Figure 1). At the same time, we watched some important changes take place regarding water temperatures in the Pacific Ocean. These changes are important because the ocean and atmosphere are deeply intertwined, and the things that happen in the atmosphere upstream from us will affect us later in time.

Specifically, there was a noticeable drop in the equatorial water temperatures in the central and eastern Pacific Ocean (more correctly, the temperature anomalies) during the 2010 calendar year. In January, those temperatures were abnormally high (El Niño). But, during the spring and summer, those temperatures dropped substantially, and they are now abnormally low (La Niña).

Likewise, we looked into the northern Pacific Ocean. We noticed the same pattern (warm to cold). It was not as dramatic, but definitely perceptible. That pattern is known as the Pacific Decadal Oscillation (PDO).

With these things in mind, we went back into the atmospheric and oceanographic records to look for times when these events occurred simultaneously. We noticed that during 1998, there was an abnormally hot summer in Virginia, while at the same time, the Pacific Ocean was transitioning from abnormally warm to abnormally cool.

For the more scientifically and statistically inclined, you should know we looked at the phase of the QBO (quasi-biennial oscillation) and the GLAAM (global atmospheric angular momentum). These wind patterns were also similar to what was observed in 1998.

So, we looked at what happened in the winter that followed the summer of 1998. The short version: Warm (Figure 2).

All three months of meteorological winter (December, January, and February) were above normal, with February's temperatures much above normal. There was some suggestion in the 1998-99 pattern that January may be cooler and wetter than December and February.

With that in mind, we are going with the idea that if there is a significant winter storm this season, it is most likely to come in January. Otherwise, all three months this winter will have temperatures above normal. And snowfall will be below normal, which is dramatically less than last year.

And with the temperatures higher than last year, it also suggests ice will be more of a problem this year than last year. However, we did not see any obvious signs of a crippling ice storm.

And just for fun, after we were done, we peeked at The Old Farmer's Almanac. Their summary was for a slightly colder than normal winter with below normal snowfall. So we agree with half of that (snow).

And our biggest difference is in the January 2010 temperature forecast. We are going slightly above normal, and they are going below normal.

So, we'll see.