beng

http://icecap.us/images/uploads/PDO_CYCLE.gif The PDO flips look pretty obvious to me. This cycle is well recognised and has been discussed for years by climate scientists - so not something that should have come as a big surprise to climate modellers. It's also correct that not all PDO cycles last 30 years - this can vary. The current cold cycle could be a blip or something sustained, we'll have to wait and see - but either way it appears to be impacting global temperatures - at least as far as Hadley and the satellite measuresments go - GISS looks a bit on its own at the moment. I was browsing through one of my wife's books this morning called 'We are the weather makers' which is by Tim Flannery and published in 2006. It makes frequent references to a step change in global warming in 1976, funnily enough the exact same time the PDO flipped into its warm phase. I will add to anyone wanting to read the book that it has some controversy - especially the inclusion of the legendary hockey stick graph - not to mention a couple of apparently stranded polar bears on the front-cover!

Just speculation on my part, but I can't help wondering whether this circulation was in response to the climax of the positive PDO phase (NASA now believe we have just entered the negative phase) and that this in turn results in a large amount of ice/snow melting in the far North Atlantic - which then leads to a subsequent slowing of the North Atlantic Drift - resulting in the cool phase of the AMO cycle - http://news.bbc.co.uk/1/hi/sci/tech/7376301.stm The next couple of years will be interesting and we may see further accelerating loss of artic ice, or a reversal if this is the natural trigger for the cold AMO.

Wow - if it keeps growing at that rate we're going to have a seriously cold summer Seriously thanks for posting the update and it just goes to show how we should monitor the data over weeks not days when it's prone to a few errors like this I'm wondering whether there's a similar error with the drop in the ice at the Antarctic, but it's not so easy to spot.

http://arctic.atmos.uiuc.edu/cryosphere/IM...m.region.2.html http://arctic.atmos.uiuc.edu/cryosphere/IM...m.region.4.html I suspect there's a problem with the data at Cryosphere at the moment - there's no way that amount of ice melted overnight.

Seeing as the topic of ozone layer depletion has come up - apparently there maybe new data suggesting the cause is natural http://www.nature.com/news/2007/070924/full/449382a.html I don't have access to the article so I'd be interested in knowing whether anyone's read it?

The thing is though that according to the climatic data that's out there, most of the warming has occured in the Northern Hemisphere - so even if we did see a reduction in the polar westerlies down there - why shoud this then expose Antartica to the effects of the warming trend - given it's been primarily focused in the Northern half of our globe. Based on the current trend, yes it would likely warm somewhat, but not to any alarming level - not unless the IPCC is correct with its most extreme possibility of a 5c+ rise in the next century - in which case I suspect the polar westerlies probably wouldn't save it anyway

Hi Gray-Wolf, Sounds like we agree then that the warming in Antartica is focused on the peninsula then (although you believe it will ultimately spread). Do you have anything you could post regarding the circumpolar winds and how they have changed in the region, I'd be quite interested in reading up about that? Ben

http://www.osdpd.noaa.gov/PSB/EPS/SST/data...ht.4.1.2003.gif http://www.osdpd.noaa.gov/PSB/EPS/SST/data...t.3.30.2004.gif http://www.osdpd.noaa.gov/PSB/EPS/SST/data...t.3.29.2005.gif http://www.osdpd.noaa.gov/PSB/EPS/SST/data...ht.4.1.2006.gif http://www.osdpd.noaa.gov/PSB/EPS/SST/data...t.3.30.2007.gif http://www.osdpd.noaa.gov/PSB/EPS/SST/data...t.3.31.2008.gif I don't think anyone will argue that's there's been a reduction in Antarctic sea ice on the Western side of the peninsula, but it does seem to be a fairly localised warming to me - indeed it would appear that overall global sea temperatures have cooled somewhat in the last 5 years. I would guess it's a natural event personally, but I doubt at this point we can prove it either way. They key thing to watch this year is the arctic sea ice and how much melt happens - but that's for another thread.

Talking of sea temperatures - http://weather.unisys.com/surface/sst_anom.html Current sea surface temp anomalies show much of the Antarctic coastline slightly below average, apart from to the west of peninsula which is above average (and has been for a few years now).

7.9c for me - just below average. Presumably the wamring of April as a month in recent years is indicative of earlier spring/summer in the UK - likewise the warming of Sept is indicative of a delayed onset to Autumn. I'm going for a more traditional CET year hence the punt at just below average.

6.2c

Apologies if someone's already mentioned this, but aside from human induced climate change, could the shift in the pacific jet have been a result of the warm phase of the PDO? Weren't easterlies quite rare in the last warm PDO episode at the start of the last century too - maybe a small straw to clutch at anyway given the PDO should be due to switch soon (and is in the cold phase this winter - not that it's helped us this year of course!). To the north of Scandinavia we have seen a big reduction in the average sea ice extent in recent winters - which again could be influencing the jet in that region, but I couldn't give a good reason for this to reverse unless we see a sustained spell of negative enso conditions allowing some global cooling.

Temp: 1.5c Precip: 50% Very hard call to make - wish I could make the prediction in a couple of days since it's not totally clear whether the block to the East will hold out there or not. Anyway here goes: I suspect that given the size of the block and the tendency for lower heights in Eastern Siberia, this block is not going to go too far - basically I think we are looking at a North Westwards displacement of the normal Siberian High during early January - this block should transfer towards Greenland later in the month as the jet begins to die with atlantic temperatures continuing to cool. If this pattern holds true, then we're looking at a very cold January - with the potential for snow at times, but also milder periods early in the month before the jet dies a little and the cold really takes over. Now the East winds are likely to be as cold as they've always been, but we also have to take into account the warm atlantic cycle - so any westerly spells early in the month will be milder than would otherwise be expected. My CET prediction is therefore 1.5c - but if we get an extreme easterly outbreak (eg Feb 91/Jan 87) which is possible, then we could go lower. It's just possible of course that the block collapses completely after this weekend - in which case my forecast could be well out - but I think this is probably a decreasing possibility given the recent trend in the ECM model.

Not had time to look at this in too much detail, but I'll go for: 4.0c Generally wet and average temps to start, possible cooler and more blocked from the East around of just after Christmas.

You may be right. Using the 6 minima I've listed (which I had the data for) - and assuming a 2 in 3 chance that la nina occurs in the year of the minima (based on 3 signals - la nina, el nino, neutral - and allowing for the possibility that enso can switch during the year) then the approximate probability of it happening randomly would be 64/729 (~2 in 25). It's interesting, but obviously the limited dataset I've used means it could simply be random chance.

This might be coincidence - I'm honestly not sure, but every run up to solar minimum in the last 50 years or so has had la nina conditions - the minimum we're now approaching is no different in that respect. I don't have any data further back than that though. http://www.cpc.ncep.noaa.gov/products/anal...ensoyears.shtml (1955, 1964,1976, 1986, 1996, 2007) If there is a real link then perhaps the implication might be that a significantly reduced solar cycle as some are predicting, could trigger a more negative enso phase. The other natural cycle that switched into its warm phase in the mid 90s was the AMO - http://www.aoml.noaa.gov/phod/amo_faq.php - on top of that we had the warm PDO cycle switch on in 1978 - so oceans will naturally have been absorbing less CO2 (it's proven that warmer oceans absorb less). That doesn't preclude AGW having some part too, but I would anticipate much of the reduction to date would have been natural.

I suspect that with la nina now kicking in and some possible global cooling occurring as a result, next year might come in below 10c - although it will of course depend on the local conditions around the UK.

CET: 10.8c Rainfall: 80% Mainly warm and fairly wet in the first week. Then becoming a bit colder as winds swing more easterly, but dry. Later in the period I think we'll see high pressure over the top of the UK allowing some fog and frost in places. Turning a bit more unsettled in the last week.

Radio Five live just forecast highs of only 10 or 11c across most of England and Wales tomorrow - sounds like there's some inconsistent forecasts going out at the moment

Thanks Carinthian.

Hi Carinthian - I notice the surface pressure is listed at around 1032mb on the webcam - yet the GFS charts for the N Pole are indicating a value closer to 1015mb http://www.wetterzentrale.de/pics/Rhavn061.html is it possible the global model is under-estimating the pressure there - or do you think maybe the weather station pressure reading is too high? Good to see on the latest 12z run that the PV is shown focused just N of Scandinavia for at least the next 5 days. Hopefully it can stick around there for a while. B)

Wow beginning to look properly wintry there now - also looks the sea might be freezing over too (although that could be low cloud as it's quite hard to tell given the conditions there now).

http://www.arctic.noaa.gov/latest/noaa4.jpg The ice at the pole isn't looking too great at the moment - at least on the above webcam. At least the temperature is now below freezing there, so won't be too long before the melt pools freeze over.

The MO is referring to the UK temperature not the CET. I think (and feel free to correct me I'm wrong) parts of W Scotland may have had quite a warm summer (relative to the average). Certainly across most of England, Wales and Eastern Scotland I would say the summer has been poor and below average. I'm not sure what stations go into the UK mean temp but perhaps they are stations more prone to the Urban Heat Island effect. Certainly the CET figure is a longer standing record and would seem more in tune with my perception of this summer.

13.2c, 120% of rainfall. I think it will start settled with a weak NW flow and chilly nights. Rapidly becoming unsettled, and zonal. I suspect there will be a fair number of Polar Maritime days allowing chilly nights (in between the bands of rain) producing a fairly cool month (again). Look for blocking in the W Atlantic and a strong jet over the top down through the UK with potentially stormy weather towards the end of the month as the temperature gradient increases and cold air hits the relatively warm waters South of Greenland. :o