The strongest indicator this winter ha sbben the QBO
The QBO (Quasi-Bennial Oscillation) is a quasi periodical oscillation of the equatorial zonal wind between easterlies( -) and westerlies(+) in the tropical stratosphere.It is measured at 30mb height.
The average length of the the oscillation is around 26-29months.It is however asymmetric,with the amplification of the easterly being nearly twice as great as the westerly.In addition on average the easterly cycle lasts o about 30% longer than the westerly.
It is possible , looking at the data set to work out for each year (1953/4 to Dec 2013) to work out the type affecting each year and the strength and length of each cycle.
The summary of my analysis is
1.There is no correlation beween postive and negative cycle years and the winter CET.The average across the series for easterly( -years) is 4.3 c and the + years are 4.3 too.!
2.If a subset of years with particularly high +or - values is used the relevant CETs are 4.27 v 4.26.
3.Using a measure which combines number of months in a cycle with values of each month all mothst then selecting the higher value years gives an avearge CET of 3.8c for strong -ve years and 4.1 for strong +v years unlikely to be statistically significant.
4.The overall conclusion is clear.I seems that on its own it can't explain winter circulation patterns.It may be that this year in the absence of any other indicators then it has played a part but could b other little known facts as well.!
originally posted in Model ouyput thread b uy really belongs here