Wednesday, May 21, 2014

Positive QBO Beginning to Weaken; May Signal Cold Upcoming Winter

It does look like the positive phase of the Quasi-Biennial Oscillation is ending as we progress into summer, a move that may herald a cooler than normal upcoming winter. The Quasi-Biennial Oscillation (QBO) is an oscillation measured by the direction and intensity of winds in the middle of the stratosphere, usually around the 30 millibar level. When the QBO is in its positive phase, winds are called 'westerly', as they flow from west to east at an anomalously high speed. The positive QBO typically strengthens the polar vortex, thus resulting in a warmer than normal winter for lower latitudes. The negative QBO is when winds at the 30mb level are 'easterly', or going from east to west. Since this is the opposite direction as typical low pressure circulation in the Northern Hemisphere, the polar vortex is weakened, and cold weather tends to permeate the lower latitudes more frequently in the winter. Going by this, it would be plausible to associate this weakening +QBO with what could be a destabilized polar vortex next winter. This may mean additional opportunities for the polar vortex and associated cold weather air masses to penetrate deep into the United States, as they did last winter.

I discussed how my analogs for the upcoming winter showed upper latitude blocking, a feature that would be enhanced with the presence of a neutral, or more likely weak negative QBO phase. At this point, it is too early to tell whether we will be in a definitively negative QBO or a neutral QBO next winter, but the general concept of the weakening +QBO is clear, and this could be another element to a chilly winter ahead.



Anonymous said...

Ugh!!!! Really?? I have followed you religiously since the beginning of this past winter. You have been spot on, every single time, I was planning to do some outdoor landscaping improvements this summer, I guess I will spend my summer winterizing instead!!!

Anonymous said...

Andrew, that's good to know about chance of colder winter but am wondering about summer? Am hearing chatter about a cooler summer or will it have a similar temperature distribution as as last year in the conus? A summer outlook will be greatly appreciated :) Thanks.

Anonymous said...

What? I'm lost!
I think I'm confused...I don't get it at all. What happened to the warm one I think I read?
This is not good at all.
I don't think I could go thru the evil twin of last winter this winter coming up.
Andrew, Thank you for the updates, but I hope this doesn't happen.

BearCub said...

I've been reading that El Nino will not be "Super”, it will weaken by fall, winter will be cold and snowy. Get ready for cold winters for the next 30 or so years. The following statement has nothing to do with you Andrew. Your long range forecast are pretty $#3$&8 good. The following is for predictors of a warming climate. They are not taking into account that the Sun has normal cycles of more/less energy output. The Sun is believed to be heading into a Maunder Minimum, which is the cycle of less energy output. Now, if you take the Earths normal tilt during the winter and add in less energy from the Sun, you get colder winters. Think about it. During winter, Earth is closer to the Sun than during The Summer. Just the slanted angle of the Sun's rays hitting the Earth causes it. So disregarding less energy from the Sun affecting Earth's temperature is ludicrous...and yet, that is exactly what is happening.

Anonymous said...

I to am confused about this summer, cool or hot? I remember I think 4 years ago we were at a cabin for the 4th of July & it was the coldest, rainiest on record everywhere! We were totally miserable! Now...we are going to a cabin again this 4th of July I prey its warm & dry!
What say you Andrew?