© NCEP/NCAR
The slideshow at the bottom shows the temperature anomalies for the past 4 years between June 1 and August 7. A common feature is the warm spot over Greenland which is a signature of a Negative NAO. Opposite of winter when such a condition would be very cold there is a strong correlation to southern summer heat between the months of June and August.
While it is expected to be cool from in the regions in yellow note that the correlation is significant in fairly small areas (brightest yellow) compared to the south US where the heat is quite strongly favored.
The strong cooling evident in recent years is most likely a product of the current deep solar minimum and decline in irradiance which we are experiencing. While proclamation of a coming Ice Age is premature it is clear that the unexpected quieting of the sun is the most likely explanation for what appears to be a cooling trend.
Slide Show
© NCEP/NCAR
