Winter 2012 / 2013 Part 2

[cheeky_monkey]

Thats about average for Altnahara.! A repeat of the -15 to -20 locally would be awesome.!

On a side note, does everyone else agree that the range of temps that the human body can endure is quite remarkable? From the blinding desert heat of 50+ C to the quite chilly -50+ C in the Antarctic.....

not really without clothing you would not last long at either of those temperatures.

[Cheshire Freeze]

I have now!

..........

Or uncle Bart could pay a visit....

To see these sort of charts in January would have quite a few of us ripping our hair out.

These charts are from two consecutive runs of the CFS, both equally as grim.

Edited October 3, 2012 by CreweCold

[Gavin Hannah]

Of course, clothing is what makes all the difference. But still, wearing the most hi-tech stuff there is, you will still feel the effects of the Antarctic extremes.

[Cloud 10]

Is that the polar vortex setting up home over the UK?

Not quite over the UK,but i would take it!

Looks even better from a Northern Hemisphere perspective.

[UV-RAY]

Or uncle Bart could pay a visit....

To see these sort of charts in January would have quite a few of us ripping our hair out.

It depends whether November and December are something like December 2010, if so then I could live with charts like that. Though the greedy part of me would like to see something exceptional akin to the Maunder Minimum, but I always was greedy!

[Cloud 10]

Or uncle Bart could pay a visit....

That's the 00z run,probably some data missing.

[Cheshire Freeze]

That's the 00z run,probably some data missing.

It serves as a reminder that for all the eye candy on offer from the runs of the CFS, something similar to a Bartlett could transpire in reality. Seeing charts like that is a sobering thought, pure ugly output.

[Cloud 10]

It serves as a reminder that for all the eye candy on offer from the runs of the CFS, something similar to a Bartlett could transpire in reality. Seeing charts like that is a sobering thought, pure ugly output.

Very true CC,tis nothing but pure eye-candy although there is a definite lean

towards northern blocking for December from the CFS at the moment.....

[UV-RAY]

I place no faith in the CFS regardless of what it shows, it's all about trends and the CFS is as it always is, all over the place. The MetO probability charts are still showing a consistent signal and have been doing for the last three months.

[Don]

Or uncle Bart could pay a visit....

To see these sort of charts in January would have quite a few of us ripping our hair out.

These charts are from two consecutive runs of the CFS, both equally as grim.

Those charts are about as ghastly as it could get for cold weather lovers! A repeat of February 1998? Wouldn't need a winter coat!

[SMU]

Nice post Steve, an pretty much agree.

A couple of thoughts on the issues you've raised.

Long range weather forecasting

I would liken long range forecasting to being rotated on a carousel with a bow and arrow trying to hit an archery target. Even if you don't hit the target, getting close on a reliable basis places you in a better position than just relying on models alone. The bottom line here is some attempt to understand and predict the dynamical processes in the weather - climate system must go hand in hand with use of climate models. Where the two methodologies agree, confidence is increased.

Fad / fashion

This one makes me smile, but ultimately I think it reflects more of a lack of understanding rather than a continual raising and discarding of variables. A few years ago the idea that sea surface height and temperature over the Equatorial Pacific would have an impact on global weather patterns was faddy. Now it is a case of routine monitoring. The idea that the temperature of the polar stratosphere (both colder and warmer than normal) has a significant influence on the circulation in the northern hemisphere in winter was until a few years ago, faddy. Now it is routinely monitored. You get my point?

Just because these variables are not shouted about does not mean they have gone away. All of our teleconnective analyses are like a complex spiders web. Whichever way you come at it, ultimately it leads to the same destination focusing on zonal wind anomaly and placement of ridges and troughs. I would also suggest that the state of the Arctic Oscillation is of most interest to us in Europe as the associated anomalies show a significant influence on winter / summer patterns.

Sample size

I'm not a statistician and I don't know the sample size for statistical robustness with climatic modelling. However, I would suggest that with all the white noise that exists in the atmosphere, any anomaly pattern that comes out of say 10 samples (and we have two winters / summers per year) is starting to show the way. If we can test the theory with the mirror image analysis (i.e does it work in the opposite direction), that adds to the confidence that we're onto something.

I do not need much more of an increased sampe size to be confident that certain variables are good or bad for European cold in winter. For example, strong La Nina evolving in the summer which will interfere with the Brewer Dobson Circulation and generate feedback loops which reinforce a strong polar flow and associated low heights across the Arctic.

Time scale for release of forecasts

October is the month for winter data. No doubt about that. However, I think it's worth while forming a private idea in say September and testing this in October, particularly in terms of stratospheric winds and temperatures.

Definately agree about measures for seasonal forecasts.

HI Stewart-

In term of the 'fad' I agree around the fact that these are all now routine review, however this in itself is a problem - until unknown variables cease to keep revealing themselves then we wont ever start to build a picture, as it is theres a hell of a lot of noise in the forecast, we dont need any more-

That said I dont think there can be many more in terms of variables identified, however what we dont always consider is that one of the variables could start to move out of the current boundary on which we have an upper & a lower limit of expectation-

Arctic ice being one of them-

Assuming thats a big correlator to the AO then remember last year the scale on the review chart had to be scaled down to -6!-

So its possbly a case of not so much new fads coming, but could the variability of some exceed our limits that we base our forecasts on.

In terms of sample size & variables- what I guess im referring to is forecast refinement & forecasting winters that are VERY cold or VERY mild..

I agree we can build up a FAIRLY robust picture on the current sample size, however with time comes refinement & that refinement would give us the ability to forecast the bracket of cold ( or mild) that we could fall into-

At the moment I believe the info we have- Especially the artic sample size on feedbacks from 2001 is to small because within that only 11 years of data exists based around relashonship with all the other measures, the problem is the 10 years data for the arctic is always changing- in terms of bigger melt = larger feedback = larger anomaly

so its not like a historic variable where- generally X state = Y outcome ( IE La nina / El nino)

Until the artic bottoms out on melt or becomes ice free then we cant base a huge correlation of historic years because each year +1 has a greater atmospheric feedback than the other- till eventually MAYBE it turns the rest into noise-

What I would say is that I disagree with your October month as being the month you can finalise a forecast-

If you look at the 2001 - 2012 height anomaly for December-

then the background trend probably generated by the arctic will see us forecast cold for december-

However look at last year the arctic signal was overpowered by the strat.

That signal WASNT forecast & if you were forecasting in october & ignoring the strat then it would have been wrong-

http://www.cpc.ncep....mb9065_2011.gif

The cold anomaly developed at 30 HPA in the first week of November-

So forecasting on Oct is to early IMHO- especially if your using your A + B + C = D where A = Stratospheric tempAssumption.

I went back & reviewed the Winter forecast for 2011/2012 ( released on 25th Nov)

http://www.netweathe...mmary-2011;sess=

& Im surprised you didnt focus more on the stratosphere & how cold it was at the time- almost record cold & how the AO would have responded......

http://www.cpc.ncep....mb9065_2011.gif

remember the Key month for Stratospheric temperature varience to the Norm is November ( In terms of first 'available' time for big varience to the norm)

In summary again, looking at all the variables & for the fact that the feedback to the atmosphere seems primed to greenland blocking it 'feels' as though we could almost release a forecast now- however time would be better spent forecasting the stratosphere temp through the solar outputs & BDC as opposed to getting into to much detail just yet.

The stratosphere is CURRENTLY running exactly on the curve of average- so we await where it goes, however 6 weeks of monitoring before we do.

cheers

S

Edited October 3, 2012 by Steve Murr

[phil nw.]

A good point re,The Stratosphere and how much it will cool as we get closer to Winter Steve.

Another reason why i can`t have any confidence in the CFS 500 charts for Winter.How can any model know what the state of the Vortex will be in say 2 month`s time-assuming the Strato.is a key driver of it.?

Edited October 3, 2012 by phil n.warks.

[stewfox]

Simply statistically speaking, the Arctic ice extent's record lows are more significant than the Antarctic ice's record: the Arctic broke its own all-time record at least 20 times at the end of this summer / early September, not to mention that every day since the start of August has been a date record (http://www.ijis.iarc...aice_extent.htm). The Antarctic broke its date record on just a few days.

This is without even mentioning that the Arctic's ice is far more significant for the British Isles, or that the Arctic's ice is traditionally far more stable (the Antarctic generally comes close to completely melting out in the Southern Hemisphere's summer), or that the summer minimum extent is far more important in terms of ice albedo...

While the Arctic smashing its records may be parallelled with the Antarctic breaking record highs, there is no 'global equilibrium' between Arctic and Antarctic ice. Ice extent is below average globally.

There is small global downward trend of sea ice but as per the attached but its hardly marked. Whats going on in the Arctic may effect UK weather (however its not a done deal yet as some have said)

http://www.climatech...and-Trends.html

Also open question give most of Northern Eurasia and Northern America is generally colder in winter then the arctic what effect does that have on the assumed global changes in the thermal gradient from Arctic to Equator ?

Edited October 3, 2012 by stewfox

[Met4Cast]

Come on Fred, it's simple addition: What's the resulting balance, if you add the respective losses and gains of the Arctic and Antarctic sea-ice extents? In other words, is there any evidence supporting the contention, that the Solar Min (who can deny that some kind of minimum is occurring?) has caused a net increase in global, oceanic ice-cover?

Clearly, there must be something-else in play here...CO₂?

What about the AMO? We're in a warm period at the moment, surely that has the ability to increase Arctic Ice melt due to the warmer seas? This then of course leads to greater feedback and cooler SSTs to the North of the UK leading to an increased chance of Northern Blocking.

Obviously way more complicated as others have already gone into within this thread, but I haven't seen the warm AMO mentioned anywhere yet.

My personal view is that lower ice MUST have an effect, how and what is the questions, the ice melt is clearly being caused by something, but that doesn't mean it's going to have no effect whatsoever. All that extra energy has to go somewhere

Edited October 3, 2012 by Daniel AKA WMD

[Methuselah]

I don't think that it's really a question of if, but more of how and how much. And I, for one, do not profess to know the answer to either...Let alone to both!

[Methuselah]

What about the AMO? We're in a warm period at the moment, surely that has the ability to increase Arctic Ice melt due to the warmer seas? This then of course leads to greater feedback and cooler SSTs to the North of the UK leading to an increased chance of Northern Blocking.

Obviously way more complicated as others have already gone into within this thread, but I haven't seen the warm AMO mentioned anywhere yet.

My personal view is that lower ice MUST have an effect, how and what is the questions, the ice melt is clearly being caused by something, but that doesn't mean it's going to have no effect whatsoever. All that extra energy has to go somewhere

So yet another piece of the puzzle, D? That's my point: all these factors make a contribution, but making any sense out of them is harder than may at first appear...

[BornFromTheVoid]

What about the AMO? We're in a warm period at the moment, surely that has the ability to increase Arctic Ice melt due to the warmer seas? This then of course leads to greater feedback and cooler SSTs to the North of the UK leading to an increased chance of Northern Blocking.

Obviously way more complicated as others have already gone into within this thread, but I haven't seen the warm AMO mentioned anywhere yet.

My personal view is that lower ice MUST have an effect, how and what is the questions, the ice melt is clearly being caused by something, but that doesn't mean it's going to have no effect whatsoever. All that extra energy has to go somewhere

This may interest you...

Using sensitivity statistics derived from the models, assuming a linear relationship, we attribute 0.5–3.1%/decade of the 10.1%/decade decline in September SIE (1979–2010) to AMO driven variability.

The study itself is here http://iopscience.io...9326/7/3/034011

The September trend is now over 13% loss per decade, as of the 2012 minimum.

Anyone that thinks that the minor Antarctic gains balance the Arctic losses need to look a little more at the polar regions and the processes operating there. There is no balance.

[bobbydog]

This may interest you...

The study itself is here http://iopscience.io...9326/7/3/034011

The September trend is now over 13% loss per decade, as of the 2012 minimum.

Anyone that thinks that the minor Antarctic gains balance the Arctic losses need to look a little more at the polar regions and the processes operating there. There is no balance.

so, if i understand this correctly, the study is saying that loss of arctic sea ice is in part, due to a natural slowing (as part of a multi-decadal cycle) of the atlantic conveyor (gulf stream to some...). (and probably the basis for some of the alarmist 'gulf stream shutting down' stories) i assume this would lead to SST anomalies and explain why there is no (direct) link (as all the ocean currents are linked) to antarctic sea ice growth.

[Met4Cast]

This may interest you...

The study itself is here http://iopscience.io...9326/7/3/034011

The September trend is now over 13% loss per decade, as of the 2012 minimum.

Anyone that thinks that the minor Antarctic gains balance the Arctic losses need to look a little more at the polar regions and the processes operating there. There is no balance.

Thanks, interesting read!

[Glacier Point]

HI Stewart-

In summary again, looking at all the variables & for the fact that the feedback to the atmosphere seems primed to greenland blocking it 'feels' as though we could almost release a forecast now- however time would be better spent forecasting the stratosphere temp through the solar outputs & BDC as opposed to getting into to much detail just yet.

The stratosphere is CURRENTLY running exactly on the curve of average- so we await where it goes, however 6 weeks of monitoring before we do.

cheers

S

Would agree that November provides a more definitve pointer with the teleconnectic variables as they seem to run the same way as the following three months, so a trend is formed then.

However, during October, the following will be apparent:

- SSTA pattern across the hemisphere (I take lagged anomalies from October pattern as the winter fix);

- ENSO state;

- QBO / solar interface;

- snowcover trends; and,

- some of the variables which hint at how much upward zonal wave deflection we are likely to see in subsequent months over the Siberian sector, setting in train a weakening of the stratospheric vortex (this is tropospheric precursor to wave breaking and warming episodes in the stratosphere).

In case of the latter, if we take the 10 strongest -ve AO and +AO winters and look at them in terms of surface meridional and zonal momentum flux, we get trace patterns for October which are mirror opposites, and coincidentally, opposites to the following November for these variables.

So, for surface meridional heat flux, we look at the North Atlantic for the trace pattern in October:

+AO winter >

-AO winter >

The following November (and winter) for interest..

+AO winter >

-AO winter > (note just what an opposite to October this is)

For surface zonal momentum flux in October the areas to focus on would appear to be over Siberia

+AO winter >

-AO winter >

and the following winter

+AO winter >

-AO winter >

I suspect this all ties into the weather patterns which persist open water over the Arctic early on, weakening the U-field gradient and generate the meridional pattern which allows for more severe Arctic outbreaks over the continental interiors.

By the 3rd week October, we should have enough data in to decipher which of the two patterns we are heading towards.

Edited October 3, 2012 by Glacier Point

[Andy_]

Wintry precipitation over Bingley, interesting indeed!

Edited October 3, 2012 by Andy163

[SMU]

surely the above applies more towards jan and Feb as theres a distinct lack of warming events in December-

The october meridional flux over siberia may correlate to a winter -ao but have you broken down the relashonship inbetween months as im sure of the 10 years listed i bet there isnt a consistent 500 mb pattern that best fits D J F

S

[chionomaniac]

GP, Am I right in thinking that the Atlantic heat flux values last winter suggested that a January strat warming was on the cards. I just can't remember the link to the paper that this theory is based on.

[feb1991blizzard]

Wintry precipitation over Bingley, interesting indeed!

Look at the observed for 2100hrs here, havent seen any but i only just looked out the window at 22.52

EDIT: its just changed, it had sleet for 2100hrs!!!!!! cant believe even Saddleworth moor would have wintry PPN, its only about 1.5km off sea level.

Edited October 3, 2012 by feb1991blizzard

[Andy_]

Look at the observed for 2100hrs here, havent seen any but i only just looked out the window at 22.52

EDIT: its just changed, it had sleet for 2100hrs!!!!!! cant believe even Saddleworth moor would have wintry PPN, its only about 1.5km off sea level.

Haha it's nice to see on a chart anyways, what joy the little snow symbol can bring even if it has a raindrop next to it