Longest Summer Monthly -NAO Streak In Recorded History Finally Ends

[bluewave]

The longest  summer month -NAO streak in the recorded history has finally come to an end

at an incredible 19 months in a row.

 

2006 1.27 -0.51 -1.28 1.24 -1.14 ........0.84 0.90 -1.73 ...-1.62 -2.24 0.44 1.34
2007 0.22 -0.47 1.44 0.17 0.66 .......-1.31 -0.58 -0.14... 0.72 0.45 0.58 0.34
2008 0.89 0.73 0.08 -1.07 -1.73.... .-1.39 -1.27 -1.16... 1.02 -0.04 -0.32 -0.28
2009 -0.01 0.06 0.57 -0.20 1.68 ....-.1.21 -2.15 -0.19... 1.51 -1.03 -0.02 -1.93
2010 -1.11 -1.98 -0.88 -0.72 -1.49.. -0.82 -0.42 -1.22.. -0.79 -0.93 -1.62 -1.85
2011 -0.88 0.70 0.61 2.48 -0.06..... -1.28 -1.51 -1.35... 0.54 0.39 1.36 2.52
2012 1.17 0.42 1.27 0.47 -0.91...... -2.53 -1.32 -0.98.. -0.59 -2.06 -0.58 0.17
2013 0.35 -0.45 -1.61 0.69 0.57...... 0.52

 

 

We can trace the change in this pattern back to the spring when the polar vortex made

a rare appearance in May which was different than the 2007-2012 period. 

 

 

 

 

 

 

The other major difference in the Arctic pattern this spring from 2007-2012 was the 

record breaking March -AO blocking episode.

 

2007 2.034 -1.307... 1.182.. 0.544 0.894 -0.555 -0.397 -0.034 0.179 0.383 -0.519 0.821
2008 0.819 0.938..... 0.586.. -0.455 -1.205 -0.090 -0.480 -0.080 -0.327 1.676 0.092 0.648
2009 0.800 -0.672 ....0.121.. 0.973 1.194 -1.351 -1.356 -0.054 0.875 -1.540 0.459 -3.413
2010 -2.587 -4.266. -0.432 ..-0.275 -0.919 -0.013 0.435 -0.117 -0.865 -0.467 -0.376 -2.631
2011 -1.683 1.575... 1.424 ..2.275 -0.035 -0.858 -0.472 -1.063 0.665 0.800 1.459 2.221
2012 -0.220 -0.036 ..1.037. -0.035 0.168 -0.672 0.168 0.014 0.772 -1.514 -0.111 -1.749
2013 -0.610 -1.007 .-3.185. 0.322 0.494 0.549