NOAA draws the line at -0.5C and the BOM at -0.8C. And thanks for the reply and the well written blog post. I think the CPC's winter forecast is going to fail because the lack of Arctic sea ice on the Atlantic side brought on record early snow in Siberia, intensifying the jet stream over Asia and the Pacific ocean. The temperate N Pacific has now cooled substantially, amplifying the temperature gradient with the subtropics. Thus, the strong Pacific jet is locking in for the winter. https://www.aer.com/science-research/climate-weather/arctic-oscillation "SSTs/El Niño/Southern Oscillation Equatorial Pacific sea surface temperatures (SSTs) continue to be weakly cooler than average (Figure 14) and most winter ENSO forecasts are for weak La Niña conditions. La Niña conditions favor a negative Pacific/North American (PNA) pattern that produces cold anomalies in the northwestern US and warm anomalies in the Southeastern US. But the big story of late has been the rapidly cooling SSTs across the mid-latitudes of the North Pacific. These cool waters seem to be a result of the very cold temperatures that developed across Siberia this October. The cold air across Siberia both being advected out across the North Pacific and strengthening the westerlies across the North Pacific have dramatically cooled SSTs in the North Pacific. This seems analogous to the winters of 2013/14 and 2014/15 when cold temperatures in Canada cooled North Atlantic SSTS and strengthened the Jet Stream to record speeds as it headed towards Europe. This dramtaic cooling of SSTs demonstrates we are more confident that the atmosphere forces SSTs than SSTs force the atmospehre in the mid-latiudes. Warmer than normal SSTs to the north near Alaska and colder than normal SSTs across the mid-latitudes, could favor a southward shift the in the Jet Stream across the North Pacific this winter. The cool waters across the mid-latitudes could help strengthen the Aleutians low further south opposite to what might be expected during La Niña."