NASA has just drawn our attention to their interesting map of the PDO (Pacific Decadal Oscillation) anomaly for April 14–21. As NASA says, “…while the La Niña was weakening, the Pacific Decadal Oscillation—a larger-scale, slower-cycling ocean pattern—had shifted to its cool phase.”
This issue is important to the “greenhouse” debate and arguments over the causes of “global warming” because the ~1976 PDO shift to more positive anomalies can be seen clearly as a warming jump in many long term temperature data. A warming jump that looks unlikely to be caused by small steady increases in the trace gas, atmospheric carbon dioxide.
Much is written on the PDO and just 2 other pages include “The Pacific Decadal Oscillation (PDO)” with a long term graphic of monthly anomalies and, “A Pacific interdecadal climate oscillation with impacts on salmon production”
There is no evidence linking the rain trend to some over-arching force of climate change. It is obvious that natural cycles dominate the graphic. Link to more detailed comments on 
