After a bunch of research, we've come to a pretty solid conclusion here in the Weather Center.

We believe that the winter of 2006-07 will be:

-Slightly Snowier than Normal-

-Slightly Cooler than Normal-

There is a lot of time and thought that went into this. We all did our own individual research and we're going to touch a little on why.

1.) El Nino

Research exists in our Weather Blog, tying weak to moderate El Nino years to wet and cool autumns. So far this autumn (Sept, Oct, Nov), we appear to be on track for above normal precipitation and below normal temperatures. This would fall in line with a sample 6 El Nino autumns we took, that had El Nino conditions similar to what we are seeing now. Additionally, we have already seen signs of this, but El Ninos also average above normal snowfall in the autumn.

In the winter, El Ninos that are weak or borderline weak-moderate (like what we are expecting now) are generally considered to be slightly cooler, but also drier than normal. So why above normal snowfall for this winter? If you check out that blog entry, most El Nino winters have slightly above normal snowfall. Couple that with a typically above normal snowy autumn, and we think you have some good base statistics for your winter.

One interesting note about El Nino years. They are notorious for quieting down (snow-wise) in late February. So while we won't rule out March as a snowy month, we feel that much of winter will be contained between now and mid February.

2.) Autumn Trends

This is a very subjective thought, but it pays to watch what happens in the autumn to foretell what will happen in winter. We have seen a very active autumn. We look at the jet stream, the winds in the upper atmosphere. In most winters, and El Nino years especially, there are two pronounced jets, a subtropical jet (usually across the southern US) and a Polar Jet (what is referred to as the northern stream; the one that delivers us our shots of cold air in winter). The Polar Jet has been especially active this autumn. While in some winters it is difficult to sustain long periods of cold for so long, things continue to be very active, and wave after wave of cooler air continues to dive into the Eastern US. We feel that this is a good sign we could end up cooler than usual. Additionally, with two fairly active jet streams, this usually lends to at least a few decent sized storms impacting folks. This could help turn on the lakes a bit more than normal this winter.

Also, there was a pretty cool link found between early season heavy lake effect snows in Buffalo and snowier than normal winters here in CNY, which can be found here.

Additionally, and back to the El Nino...when the southern, subtropical branch of the jet stream gets active like this (and we've also seen signs of this in this autumn), you can occasionally set up scenarios in which warm air tries to sneak in, but can't overcome the cold at the ground. This is called overrunning, and this is a classic setup for ice events. There will be a higher risk for some type of ice event this winter than in a normal winter.

3.) Hurricane Season

The hurricane season of 2006 in the Atlantic will go down as a major flop in the forecast department. El Nino tends to provide stronger subtropical jets (discussed above) that rip storms (shear) apart. Fewer storms mean fewer chances of storms recurving to the north and east. New research has been done out of Florida State University that suggests in years when fewer storms recurve, winters in the US tend to be more active. The paper can be found here. That being said, this year saw a low number of recurving storms which *could* make a difference this winter (cooler/busier than normal).

4.) Record wet summer?

Surprisingly, this has very little to no correlation toward winter weather here in CNY. In fact, there was a split between the years that saw more snow than normal or less snow than normal.

There are a couple of other factors going in to this forecast. We'll update that later on this month.