New to this game, but I thought I would add a little if I can.
Most recent down welling (warming phase) of a kelvin wave started ~at the dateline at the end of October on a similar trajectory as K1 and K2 with roughly a 3-4 week lag time lag time between warming the Nino 4 region and affecting the 1+2 region. This has been witnessed 4 times in 2015, notably two successive times in jun and July not allowing any upwelling cooling phase to intervene producing a net warming effect upon Nino 3.4 region.
Currently the Nino 4 and 3.4 regions are at 1.8 and 3.1 degrees above average respectively and will probably not be able to rise any further. Expect the Nino 4 region to decrease relatively quickly towards the months end. However the 1+2 region has not yet experienced the warming from the KW, expected probably this week or the the next. The last KW pushed the 1+2 temps 0.6 degrees in a week, so expect a similar kick if not more...possibly up to 2.6 or 2.7 this time as the waters cool climatologically.
Although the Nino 3 region is nowhere near how warm it was in Nov/Dec 1997, this truly basin wide event will be historic and has already broken atmospheric indices relating to upper level wind anomalies documented by some research over the pond. Closer to home the amplified wave pattern which should continue as the heat anomaly strengthens in the east Pacific. This should continue to provide some opportunities for some north or NE air outbreaks, but will only be transient. It has been said that these amplified or excited rossby waves can increase the likelyhood of strat vortex interference but there are many other drivers which may inhibit this, this winter.
If surface advection feedbacks start to emerge in the new year across the West Pacific, a Modoki signature may emerge which may have some implications for the winter back to which some here may re-ignite some interest after what will be a predominantly wet and windy start to winter.
I will try and post some graphics to add to this once I work out how to do it on my phone...?!
Cheers.