Strangely Enough, The Pacific Decadal Oscillation (PDO) Seems To Correlate Better With Precipitation In Albuquerque Than San Francisco

Friend Jerry notes:

I see that some people are blaming the harsh winter in the eastern US on the PDO.

But he's skeptical:

Preliminary analysis: correlation between subzero days in South Bend, Indiana vs December-January-February PDO index = 0.08. Correlation with average PDO index for previous year = 0.07.

ABQ Annual Precipitation vs. Annual avg. PDO * 10, 1949-2013. R-squared = 0.20. (To my surprise, according to National Weather Service (NWS), ABQ precepitation was nearly normal last year - 9.32 inches. According to NWS:

"This was the 6th year in a row with below normal precipitation, although 2013 was only 0.13 inches below the official 30 year normal of 9.45 inches (1981-2010). The long term annual normal precipitation (1892 to current) is 8.56 inches. 2013 was the 76th driest (46th wettest) on record since 1892."

Similarly, San Francisco Precipitation vs. Annual Avg. PDO*10, 1960-2009. R-squared = 0.04 (corrected for July 1 - June 30 water year - labeled in end year).

Jerry describes his efforts:

I also tried correlating the average FALL PDO index with the occurrence of subzero temps in South Bend, to see if there was any PREDICTIVE value in the index. Result: Rsq = .00001. I'm concluding that the PDO index is about as useful for forecasting as the Farmer's Almanac.

I'm not quite so ready to throw the PDO away:

I'm intrigued about its usefulness for Southwestern drought. Some connections work - Eastern Australia's precipitation swing from 2006 - 2011 vs. ENSO, for example.

Jerry warns about the seductions of ENSO:

I think that the usefulness of the ENSO index is what has misled some people into thinking that the forecasting problem can be reduced to the calculation of indices.

When I saw "some people", I include a local TV weathercaster. He attributes the harshness of this winter to the fact that the PDO is in its negative phase, conveniently forgetting that the previous two winters, during which the PDO index as also negative, were mild, with NO subzero temperatures at all.

Yes, consistency is a silly thing!