Another Cool Arctic Summer
For the second summer in a row temperatures north of 80N latitude have trended at or below average. As you can see in the graph below, the mean average temperatures this summer have trended below normal. The green line represents normal temperatures will the redline showing observed temperatures. If you pay close attention to the red line on the left side of the graph, you can see that Arctic temperatures were above normal. Those above normal temperatures happened during the first three months of the year (January to March). The reason? Remember the intrusions of the Arctic air into the U.S. last winter, especially the Polar Vortex? When the Arctic air moves south off the areas north of 80 degrees latitude and into the lower 48 states you will have Arctic temperatures that will go above normal (as the coldest air has moved south).
The cooler than normal summer in the Arctic may help set the stage for more cold intrusions into the lower 48 states again this winter and perhaps in similar fashion to what we experienced during the winter of 2013/2014.
The graph below shows the temperature trends in the Arctic during the summer of 2013.
Notice the similarities between the two graphs during the summer season (between days 125 to 250).