Yellow Evan wrote:TropicalAnalystwx13 wrote:The walker circulation, which describes tropospheric air flow across the Pacific, looks nothing like an El Nino--in fact, it more resembles a La Nina at this point. Despite an impressive westerly wind burst associated with a record-strong phase 5 MJO pulse, continued forcing is unlikely as we progress towards spring. Latest maps show the formation of a new upwelling kelvin wave across the Central/East Pacific. Things are not looking good for an El Nino.dexterlabio wrote:maybe this almost El Nino blip last year is all because of the PDO turning positive.....maybe the +2.51 reading is a sign that we are getting past the negative PDO era?
The negative PDO era just began a few years ago. Short-term rises in an otherwise negative PDO era are completely normal.
It began around 1998. There's a good chance IMO the -PDO could be over.
Possibly, but we won't know for at least a few years if there was a true regime shift of the PDO back to warm. Also keep in mind that the PDO has variations over a range of frequencies- so it may just be a "mini-positive era" beginning- possibly similar to the one that occurred in the early 2000s. Similar positive values have occurred since 1998- the PDO value of December 2002 was 2.10. However, it is hard to determine if the negative era began in 1998 (as opposed to the late 2000s).
I have a question: I understand how ENSO drives the PDO- but what I do not understand is how the PDO has an effect on ENSO? Does it really? I have read that negative PDO is more favorable for strong la ninas - but I don't quite understand how PDO could dynamically effect ENSO.
