The QBO is an oscillation of winds in the upper levels of the atmosphere around the tropics, generally a westerly QBO strengthens the north Atlantic jet stream and hence affects the NAO in a positive manor, the opposite is thought to do the opposite.
Data compiled by Kasim Awan
Using winters 1948-49 to 2016-17.
Average Winter CET England Temperature during an easterly QBO: 4.129
Average Winter CET England Temperature during a westerly QBO: 4.636
Average Winter CET England Temperature during a weak QBO signal: 4.633
Since 1949, the average winter CET temperature was: 4.466
The average winter CET for an easterly QBO deviates from average by: -0.337
And for a westerly QBO: 0.17
A neutral QBO: 0.167
Projected QBO for winter 2017-2018: Easterly: -10.1
This is the second time since 2012/13 we have seen an easterly QBO develop and be pronounced in the winter months.
The last time this happened was 2014-15 and was the coldest winter since 2013.
During 2015- early 2017 the QBO was westerly for an unusually extended period of time.
Therefore this adds huge amounts of low confidence on what will happen this winter.
Although the QBO’s stats may be aligning nicely this year, this is just 1 set of stats for one factor, others factors will come into play soon, and could swing the pendulum either way.
It’s about how the other factors align with these to produce a unique set of variables for the winter of 2017-2018.
Tune back in on the 15th of September when we will discover if the Siberian field is supportive of a bad winter in the UK for 2017/18.