Winter's closing in, the rollercoaster has began early with the introduction of some mental far out there charts. To continue the hype, why not do an analogue eh? Well, I have you dude 'cause this is going to be the thirteenth analogue for Winter 2018-19 and it's going to be on Winters following Octobers with similar Eurasian snow cover extent to October 2018.
Coming up with years similar to snow cover extent of one particular year can be a difficult task especially considering no year is the same at all. Every year is unique. Thankfully, Judah Cohen of Atmospheric and Environmental Research (AER) produced this lovely graph below showing Eurasian snow cover anomalies of every October from 1967 to 2018 using Rutgers' Global Snow Lab data. Without this wonderful piece of work, this analogue would have been far more tedious or even be non-existent so thank you very much to Cohen and Rutgers.
The years that looked most similar from the above graph to me were Winters 2010/11, 2004/05, 2000/01, 1999/2000, 1996/97, 1982/83, 1978/79 and 1973/74. This is what the 500mb height anomaly reanalysis looks like when you combine these Winters together and it's quite amazing ain't it. There is above average heights over and just to the south of Greenland with below average heights in the central North Atlantic into southern and central Europe - even into the east of Europe. This leaves us pulling in north to northeasterly winds. This would be a cold Winter if it were to verify with decent snow potential. In terms of the individual Winters, not the worst package at all but 1999/2000 was a stinker and 2004/05, 1982/83 and 1973/74 were very forgettable for the most part. 2010/11 started off epic with the coldest December since 1890, 1996/97 started off similar but far far less extreme and 1978/79 was a severely cold, snowy Winter.
The Decembers look very snowy and cold with deep below average heights over much of Europe and Greenland blocking sending the NAO into very negative territory and northeasterly winds being keen. Similar to the above Winters overall reanalysis but even more extreme with the below average heights over Europe which would mean even more snow potential. Could be an epic month for snow (by December standards) if it were to verify. Not too shabby, not shabby at all!
The Januaries just look anticyclonic with northern blocking continuing but sending a ridge down to the UK and Ireland. Would be seasonable with numerous frosty conditions. Not a lot of snow though!
The northern blocking lessens in February with an Atlantic ridge setting up and below average heights over Scandinavia if a bit far to the east. This would be a fairly cool month I think but nothing exceptional and certainly not a very snowy month either as the trough is to the east of Scandinavia. A few northerly shots possible but again nothing remarkable. Nevertheless, like January, would still feel reasonably seasonable.
That's the thirteenth analogue done and dusted. Some really intriguing signals for December in this analogue as it highlights the possibility of a very cold to snowy month with the Winter slowly calming down in terms of blocking as the season goes but remaining on the cool side.
Winter 2018/19 forecast releases on Tuesday, November 27th, it's coming home as some people say! Coming home for Christmas that is..... oh wait.