It's the 50th anniverary of the great winter of 62/63.Unfortunately no nailed on 50 year cycle to usher in a repeat performance in winter 12/13! Last winter brought to an end a run of three consecutive colder tha average winters,with a CET of 5C ,0.5c above average.The highlight was the two week cold spell in February which partly offset the dominant mildness.So what are the main winter indicators currently suggesting for winter 12/13?
The latest (27th August) ENSO diagnostic discussion from NCEP NOAA.The summary has most models predicting the move from ENSO neutral to El Nino this autumn,and with El Nino continuing into northern hemisphere winter.However it does not look like a strong El Nino dipping from a peak of around 0.9 to below 0.5 by the end of winter.Nevetheless this suggests above average winter temps.
2.North Atlantic sea surface temperatures.
As Gavin P observes in his thread on SSTs and the NAO forecast,the May alignment of SST's suggests a postive NAO and therfore a wetter warmer winter
Last winter had the postive NAO for four years (and indeed the met office I believe forecast an NAO of around 1.4 not far from DJF figure of around 2.2(Osborne).There may be other factors like ENSO which support a postive NAO.
Solar sunspot activity in the last 8 months averaged around 60 with August being 63.The solar cycle last forecast from NOAA has a maximum in May 2013 of 90. On current form that looks a bit high with cycle 24 being very weak compared to 23.Work at reading University suggests that the coldest winters in the cycle are around solar minimum not solar maximum.Values of around 60 preceded last winter so if anything solar activity aslo suggests a warmer than average winter.
Currently strong east to west flow -27.84.This looks to be near maximum with the upper air flow falling off sharply and maybe reversing during winter.To be honest I'm not sure whatt such an outcome means.Any offers?
6.Jet sream/Northern blocking.
The summer has been notable for northern blocking and a south diplaced jet.But as we saw last autumn summer blocking does not neccessarily persist through to winter.
The only indicator currently showing colder than average is the CFS forecast for DJF.The precipitaion pattern suggests HP to the east of the UK and below average temps across the bulk of Europe.However this time last year the CFS maps suggested a similar thing and were wrong (the streghening La Nina was a possible reason for change.)
There has been a huge amount written on the relationship between autumn weather type and the following winter.There is only one that is statisticallylly significant and that is warm dry autumns tend to be followed by above average winter temps.And we wont know that until the end of November!
So at this stage I would go for another above average winter.What do you all make of the indicators so far?
Edited by user 17 October 2012 15:00:25(UTC)
| Reason: Not specified
I have no idea what the upcoming winter will bring...however I have to take issue with a couple of your points.
1) An El Nino in the region of 0.5-0.9 is not a strong one and thus, so I believe, could actually promote HLB (high latitude blocking) rather than preclude it. This is, of course, if you believe in a solid link between ENSO and the UK winter.....from what I have read the correlation is patchy at best.
2) Sea temperatures, I'll admit, I have little expertise on; however I've read conflicting thoughts on whether a positive temperature anomaly around the North Atlantic/ Greenland area actually promotes high latitude blocking in the area or increased cyclogenesis. So I don't think any firm thoughts can be extrapolated from the set up at the minute.
3) NAO isn't a forecast tool....it's a measure of the here and now....the difference in pressure between Greenland/Iceland and southern Europe/ the Azores.
4) I've been monitoring the CFS long range charts on Meteociel for the past month or two now and there has been a significant signal for blocking to take up residence towards the N,NE and NW over the winter months.....especially during Jan and Feb. Obviously this means little at this range but it's something to keep one eye on.
I'll also add that last year the winter was almost certainly shaped by the cold statosphere, the late Jan/early Feb cold spell coincided with a warming of the strat that had been mostly below normal all winter (hence the westerly regime). This year, ozone levels are looking to be slightly elevated on last year which could mean a warmer strat and more opportunity for blocking to take hold.
As with most years at 3 months out, winter could go either way....either mild or cold! (maybe even average :P )
Edited by user 04 September 2012 18:31:08(UTC)
| Reason: Not specified
Have to agree with you Crewe cold. I have been perusing the daily cfs nine month runs ever since the whole of the winter season came into the frame and they show distinct tendency towards some very potent and possibly long lasting cold spells for the coming winter from blocking spells to the northwest , north east and east. Infact the one thing that seems almost completely absent in these runs is the prospect of a completely mild winter.
What factors lead to this statement? It would be helpful if some brief reasons could be given. The prediction is of no value to the reader unless we have some clue about the basis on which it is made.
How do you think this winter in the UK will be affected by the summer sea ice in the Arctic Ocean melting to a record minimum amount and is still melting?
Could the gulf stream / north Atlantic drift even shut down?
Welcome Sunnylee. Regarding your Gulf Stream query, a shutdown is currently thought to be unlikely
The ability of cold to pool in the Arctic may not be held back too much this winter, as the thin ice typically recovers very fast after such extensive melting, so restoring the region across which cold pooling can occur (but I should add that it's only thin ice, so it can melt very readily the following season).
However, the extra moisture from the Arctic Ocean in autumn may lead to increased snowfall in regions such as Scandinavia, which could encourage blocking highs to develop there. I'm still waiting for some well informed opinions on that one in the climate forum...
I'm not sure what impact the extra fresh water from Arctic ice melt could have, if any...?
My personal suspicion is that, with quite low solar activity continuing and the large loss of Arctic sea ice this year, the winter weather will be driven by blocking features far more than would be considered normal. This might mean long periods of very cold weather, but if, say, a block forms over eastern Scandinavia and is supported by ridging from the Azores, then we can end up in a run of mild or very mild weather.
Therefore, it's the signals for where the blocking is most likely to take hold that are of most interest to me this autumn.
Solar sunspot activity in the last 8 months averaged around 60 with August being 63.The solar cycle last forecast from NOAA has a maximum in May 2013 of 90.On current form that looks a bit high with cycle24 being very weak compared to 23.Work at reading University suggests tha thecodest winters in the cycle are around solar minimum not solar maximum.Vlaues of around 60 preceded last winter so oif anything solar activity aslo sugeests a warmer than average winter.
Solar activity is still rather low.. SFI @138 at the time of writing.
I'm not sure how much the depressed activity actually has on the UK winter climate, however the 3 cold winters did coincide with a remarkably sleepy sun. It (the Sun) was quiet last winter and that was above average temp wise... but as you point out there are many more factors than solar activity.
I'd suggest that solar activity alone points to a colder than average winter, however all your other yardsticks are valid. I agree with your prognosis.... I wish it would snow and snow though.
Edited by user 04 September 2012 22:36:15(UTC)
| Reason: Not specified
Its still too early for me to say as many of the things I look at are still to play out (as I explained in the video at the weekend)
However, on Justin's thoughts, perhaps this Tweet might help clear up where he's coming from;
As if summer hasn't been cool enough, a professional weatherman whispers: "Stand by for a bone-chilling winter."
How 'bout some meat on dem bones Gav?
Playing devils advocate didn't it come out after the fact that the Met Office had warned the government about December 2010 a couple of months before the fact.
Maybe it was just a good guess.
Very interesting. Thanks for posting.
So I take it you won't be paying for the winter musings of James Madden and Mark Vogan then?
Edited by user 04 September 2012 23:14:14(UTC)
| Reason: Not specified
There will be a lot of cold weather this winter - we have just had our 6th bad summer in a row and this summer was by far the worst.
This summer like the others has the 1950s and 1960s written all over it - The winters in that period were often cold ones.
Not all of them - but a lot of them.