Here's a 10-day mean SST in Reanalysis that spans the month of December in 3 blocks. It is scaled to be ~ 80°F-90°F. Of course you've heard about Australia's warmth. The +SSTa have intensified near WA/NT/QLD. Some SST approaching 90°F there.
EPS TC forecast in the next 10 days. This is why the RMMs are forecast to spike into phase 4-6.
Information from BOM on their tropical season: bom.gov.au/cyclone/climat…
1 thought I had this morning is that the warming of the "warm pool" over time + seasonal SST shift south from autumn to winter could be contributing to wave train behavior that favors similar outcome year after year over N. America from Nov to early Jan. (1/2)
The seemingly cold first half, then turning warm late Dec thing has been a reoccurring theme. For example, here's the mean daily departure for Philadelphia for recent Dec/Jan. And we're doing this again this year. (2/2). 
well, anyway, it's just a thought. I haven't looked into it yet: anomalous warmth at its most poleward influence in autumn sets off wave train that favors -EPO. By late Dec, the annual cycle redistributes probability throughout the Tropics, which then...
heightens the strongest -OLR trends that are in IO-Maritime.
the annoying part of this whole thing is that once some evidence or early ideas become established around a possible identifiable mechanism, the system will probably shift again into a new paradigm. :P
