Hurricaneman wrote:looks to me like the PDO is dropping like a rock, could be the thing thats needed to get La Nina going
If you're interested you can learn something new while also unlearning a common misconception about the PDO and how it relates to ENSO. The following quote is from an article by Bob Tinsdale that I linked to earlier in this thread:
“THE PDO IS DEPENDENT UPON ENSO ON ALL TIMESCALES”
. . . ENSO drives the Pacific Decadal Oscillation, not the other way around. . . .Thus, my repeated statement in blog comments whenever the relationship between the PDO and ENSO is discussed: the PDO is an aftereffect of ENSO…that’s also impacted by the sea level pressure and related wind patterns of the North Pacific.
The drop we are seeing now in the PDO is primarily because it is only now reflecting the SST drops we saw months ago in ENSO (PDO lags ENSO by months). ENSO is the main driver of changes in the PDO - most obviously in the major PDO fluctuations that occur in less than decadal time frames. The other notable driver, for the purpose of our current dialog, is the wind patterns in the North Pacific. Although these wind patterns have decadal trends or tendencies to support a negative or positive PDO, they also have a lot of near-term variability.
In short, the current dropping PDO, in addition to reflecting an ENSO cooling lag, could also be related to relatively temporary north atlantic winds - which unlike the trades have no known direct effect on ENSO.
Perhaps a better way to look at the PDO is as another indicator of the state of ENSO, in a hindsight kind of way. Because there is greater discrepancy between the PDO, which is still positive after many months, and ENSO, which is mildly negative, this suggests that ENSO didn't have much built up momentum or propensity for going into a nina state in the first place (i.e., in hindsight). Bob does a better job than I of explaining this for sure!
https://bobtisdale.wordpress.com/2014/04/20/the-201415-el-nino-part-5-the-relationship-between-the-pdo-and-enso/PS: In a way, all this hubbub about the PDO takes our eyes off of the real prize, which is the decadal variations in the character of ENSO itself. The PDO gives us a measurable window into those variations because it is clearly driven by those variations. We have so much to learn about ENSO, we've barely even scratched the surface.