Just giving my latest thoughts for the coming season as we start November.

Firstly, it really does seem that the warmer the September, the greater the chance of a mild Winter following.  Out of the top 5 warmest Septembers (2016 aside), only one has been followed by a cold Winter, and 3 have been followed by a mild Winter.  Not only that, but there has never been a cold Winter following a September with a CET greater than 15.2C.   Seeing as September 2016 had a CET of 16C, this does cast some doubt over whether Winter 2017 can be cold at all.

Next, I've been looking at the ENSO index and noticed something during the long periods when the ENSO index hardly changes, normally around the neutral mark.  I think that when you get a long period (at least 12 months) where ENSO stays at neutral, it seems to greatly increase the risk of a cold Winter.  Just having ENSO at neutral for a short period doesn't seem to have the same effect.  It's when the ENSO region is more volatile, swinging wildly from one state to the other, that seems to bring mild and stormy Winters to the UK.    So again, my thinking is that because ENSO neutral was only reached in the Summer,  it's simply not a long enough "bedding-in" period to increase the risk of a cold Winter in the UK.  If it had been hovering around neutral for the last 12 months, I would've gone for a colder Winter risk.    The Winter of 2014 is an odd one out in that respect, but that can be explained by high solar activity in that year.

Then on to the October synoptic anomaly chart for October 2016.  There was a very strong High anomaly over Scandinavia, and Low Pressure over Greenland.  Very few other years have such a striking pressure anomaly over Scandinavia, but there are some years which had a fairly similar overall pattern.  These years are 1951, 1952, 1959 and 2005. These Octobers led to a mix of outcomes for November, but 3 of them led on to a rather cold Winter, just one leading to a milder Winter.  So, the October 2016 pressure anomaly does perhaps give some hope of a colder Winter to come.

Finally, I ran a composite on what I think are currently the best matched years to this year, taking ENSO, Solar activity and the October pressure anomalies into account.  The 3 years I came up with were 1951, 1995 and 2005.   Very interestingly, this results in all months between November and February being cold, with an overall dry theme for much of the time, especially in January.

So obviously there are mixed signals at the moment, will be interesting to see how November pans out.  Will make a final call for Winter 2017 nearer the end of November.

For those interested in the technical detail this is a good place to start

http://www.metoffice.gov.uk/research/climate/seasonal-to-decadal/gpc-outlooks/user-guide/technical-glosea5

This is JFF, but nevertheless interesting to see the first mention of snow in my local 7-day forecast :

http://www.xcweather.co.uk/forecast/egerton_kent

EDIT: the snow symbol has gone on the latest run... quelle surprise!

Its interesting to see how METO deals with key indicators for its month outlook.

ENSO  Predicting a neutral or weak La Nina event.They say a weak La Nina state which they say is expected to diminish the strength of the normal westerly flow across the UK in early winter.

SST'S The pattern of current anonmalies is not thought to have an important influence on the atmosphere.

QBO Current westerly phase is expected to persist through outlook period which is associated increased tendency for a strong wintertime  stratospheric polar vortex

So we have ENSO with cool signal,QBO with a warmer one.

METO then introduces the following  comment

"Nevertheless while the polar vortex has now become established,numerical prediction systems indicate a high chance that it will be disrupted rather than strengthen as it usually does at this time of year.Such a disruption increases  the chance of surface weather patterns that block the passage of the usual Atlantic weather systems tat affect the UK in winter."

Unfortunately METO leave us hanging because there is no mention of the likely mechanism that leads to disruption!

Any answers?

Things appear to be shaping up very differently this year. An interesting lunchtime read. 

https://www.aer.com/science-research/climate-weather/arctic-oscillation

"So, what are the latest indications for the coming winter? Professor Adam Scaife, head of long-range prediction at the Met Office Hadley Centre, explains: “The risk of a cold start to winter has increased to 30% this year. Statistically, however, it is still more likely that the UK will experience a normal start to winter, but there is an increased risk of cold snaps between now and Christmas.”

Adam added: “Several factors, including tropical rainfall, are known to drive UK and European winter conditions: following a strong El Niño last year, the tropics are now influenced by a weak La Niña and unusual rainfall conditions in the Indian Ocean.”

https://blog.metoffice.gov.uk/2016/11/03/what-does-this-winter-have-in-store/ 

Perhaps the answer lies in the use of the word "nevertheless". Regardless of any of the big-picture factors, such as ENSO etc. (and let's face it, trying to tease a winter forecast out of those never really gets us anywhere), the actual physics of the atmosphere and oceans right now have led them to their conclusions by way of the models. You have to drill down to hard numbers and calculations rather than nominating some big, over-arching index to estimate what might happen.

That's just my interpretation, mind.

From this article published by the Met Office

http://www.metoffice.gov.uk/research/news/2016/early-winter-outlook        ..........what a wonderful use of the English language:

"It is only for contingency planning, where the impacts of cold weather could be high, that a heightened risk of a relatively low likelihood event may warrant some mitigating actions".

Why?

Why would a specific 30 day period in the Earth's orbit have an effect on a specific 90 day period in the Earth's orbit of which there is a 61 day  period in between those two periods?

Well, it has been suggested that warm Septembers in the modern era mean a mild winter, though as I said a few weeks back, it just looks that September has warmed just as much as the DJF period over the last 29 years.

It is a hell of a call given the way the QBO has gone and solar activity being someway off the minima cycle. And we have seen with the latest round of publicly available long range NWP, these models are trending back towards business as usual. 

I can only assume that they see Stratospheric factors leading to disruption of the PV, I'm looking forward to seeing how the first half of this month unfolds, but if in 10 days or the PV and +ve NAO are in situ, that call will be under a lot of pressure given the persistence of this set-up in the modern era.

[quote=Gusty;835026]

Things appear to be shaping up very differently this year. An interesting lunchtime read. 

https://www.aer.com/science-research/climate-weather/arctic-oscillation

Read it, read it again, thought about it, re read it, and came to three different conclusions. So I read it again in a quiet dark room and eventually came to the conclusion that this winter could..... Be interesting from a cold lovers point of view, but will remain unconvinced at this early stage.

Not only do these two bolded statements contradict one another, but there is a whiff of statistical convenience about the latter statement. To qualify, if that had read 15.2 or greater, the point would have flumped:

The following Septembers had a 15.2C CET (following winter temps in brackets).

1750 (3.2); 1779 (1.4..brrrr!) 1898 (5.2 - okay one fits the theory); 1961 (3.6) 2006 (4.1). Add to that that only 13 Septembers have had a >15.2C CET and one feels one must question one's statistical significance.

Well I'd sooner put my trust in what the MetO have to say rather than listen to endless inane ramblings about the mythical "modern era" tbh.

The NOAA QBO figure for October has been published. Shows a continued strengthening of the westerly QBO which is consistent with the Met Office contingency planners forecast comments.

The QBO figure for October is 12.83 which is almost as high as the previous peak of 13.38 last October. Not helpful for encouraging blocking patterns during this winter but only one of many factors to take into account. A couple of years ago we had a record easterly QBO and we still had a mild winter.

http://www.esrl.noaa.gov/psd/data/correlation/qbo.data

I don't think they are 'inane ramblings' when you look at the figures, or the the clear persistence of +ve NAO pattern once established.