Monday, September 2, 2013

Positive QBO Strengthens; Negative QBO Chances Diminish

The Quasi-Biennial Oscillation, a wind-related phenomenon that can strengthen or weaken the polar vortex in the wintertime, is strengthening in its positive phase- a sign that the polar vortex may also strengthen when winter comes around.

The image above shows the last few years' QBO values up until the present day. You can see the recent strengthening trend in the positive QBO. This most likely means we will not end up in a negative QBO. This new development doesn't really hamper my winter forecast, but it does mean we have to hope for a good blocking high pressure pattern in the upper latitudes to help induce stratospheric warming events that could then weaken the polar vortex. This whole development is good news for those of you wishing for a warm winter, but as I said, it wasn't the biggest of surprises, and does not affect my winter forecast much.

I do maintain my belief that the positive QBO should weaken as we head into winter, and the current idea is that either a weak positive QBO or neutral QBO will be the end result for this winter. Until then, however, this is all educated speculation.