[OCTOBER PATTERN INDEX (OPI) MONITORING WINTER SEASON 2014-2015]

 

I have made a simple calculation about the correlation between October's OPI and the average temperature of following winter in the 850 hPa level for a big portion of UK. (I provide the values i used in the end of this post)

 

So i took the October's OPI value and the following winter's average temperatures in degrees Celcius in the 850 hPa level for december+january+february, for the area that is defined by 5° W to 0° E and 50° N to 55° N (that contains most of England and Wales) and have calculated Pearson's r correlation coefficient and Kendall's tau.

The values of temperatures have been acquired from NOAA and the values for OPI from a post here.

 

So the calculated values between October's OPI compared to following December+January+February average temperature in 850 hPa were:

 

Pearson's r = 0.76

 

Kendall's tau = 0.55

2-sided p-value = 0.0000014

 

Pearson's r value is relatively high and shows that something might going on with this OPI thing.

Even more, in the Kendall's calculation, we see a smaller correlation but a very interesting p-value, since the almost zero 2-sided p-value shows that assuming(the null hypothesis) October OPI and average temperature of DJF are independent, we have an extremely small chance of obtaining this 0.55 correlation if October OPI and average temperature of DJF are independent.

So we must assume they are dependent with a +0.55 (positive) correlation.

Positiv emeans that when the value of October OPI is large(get's larger) the average temperature of DJF is large(get's larger) also and when the values of October OPI decrease, the value of average temperature of DJF decrease also.

 

So all in all there is something interesting with this OPI.

And it seems to suggest that a correlation with your winter's temperature lies between them. A positive OPI brings warmer winter and a negative colder. With the aforementioned correlations of course. This is NOT a strict 1 to 1 rule of course.

 

 

The data:

(For example for year 1980:

OPI value is for October 1980

Average temperature(in 850 hPa) is for December 1980 + January 1981 + February 1981)

YEAR	OPI	AVG1976	-1,75	-3,311977	-0,95	-1,901978	-1,80	-3,081979	-0,50	-1,711980	-0,05	-2,051981	-0,40	-1,771982	-1,10	-1,841983	-0,30	-1,511984	-1,80	-2,191985	-1,90	-3,311986	-1,30	-2,381987	-0,45	-0,981988	+1,45	+0,491989	+0,25	+0,061990	+0,55	-2,611991	+1,10	+1,651992	+1,75	-0,011993	-0,15	-2,141994	+0,70	-0,841995	-0,65	-2,051996	-0,75	-1,021997	-0,75	+0,311998	+0,10	-1,061999	-0,20	-1,462000	-0,75	-1,262001	+0,45	-0,482002	-0,90	-1,232003	-0,70	-0,622004	+0,30	-1,572005	-0,70	-1,102006	+0,85	+0,472007	+0,75	+0,902008	+0,25	-1,032009	-3,15	-3,882010	-0,85	-1,902011	+0,65	-0,852012	-1,65	-1,902013	+1,60	-0,53

 

I checked the data you kindly provided and came up with the same results as yourself (along with an R² value of 0.5723704) However,  this is just taking these values on blind faith rather than substance so it leaves many questions to be answered.