Just a paste from an email I forwarded to some people re the recent talk of possible upcoming La Nina conditions. Thought some here may be interested:
Interesting to see EC's latest seasonal forecast run that came out today still seems to be suggesting a moderate probability/signal of above average winter rainfall (overall) for QLD/NSW and parts of SA with some stronger signals near the QLD east coast... although the actual forecast amounts aren't a huge margin above average at this stage. It's also still showing a strong signal of above average near-surface temps for much of Oz except northeast NT and around the central Qld coast, although again, not by that much according to the ensemble mean. The MSLP and 500hpa height fields show a belt of pretty big positive anomalies across the far south of the continent. CFS (US) and the multi-model EUROSIP forecasts look pretty similar with their precip and temp forecasts as well. Haven't had a chance to look at the others such as NASA/GMAO and this month's UK run hasn't been finished yet but noticed POAMA's winter rainfall suggestion was similar to the others. The important disclaimer here is that the forecast skill of dynamic models isn't too crash hot during autumn and spring.
So in a nutshell, they still seem optimistic for reasonable winter rainfall around inland and eastern Oz as well as parts of SA. Not sure if the overall warm temp anomalies for the rest of Oz would be due to warmer mins or warmer max's though. I'm guessing it might be partly due to the residual heat left in the system after the recent El Nino. If the eastern Oz rainfall eventuates, it seems consistent with the upcoming return to neutral or possibly even La Nina conditions - see below links:
P.S. JMA's ensemble run on the 13th suggests the areas for the peaking of frontal activity/cyclogenesis for Week 2 (20th to the 27th May) to be southwest of WA and near eastern/southeastern Oz before becoming a bit more zonal for Weeks 2 to 4.
Attachment 1 - SST anomaly forecasts for the NINO 3.4 region (central/eastern Pacific) from all the major dynamic and statistical models until early next year. Sustained strong negative values imply La Nina conditions. Many dynamic models have been going for a return to neutral or La Nina values by this winter since the end of last year:
Attachment 2 - This forecast is created by combining different models and weighting the result towards the higher performing ones. It gives a handy picture of the probabilities of La Nina, El Nino and neutral conditions occurring this year:
Ken.