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Snow And Ice In The Northern Hemisphere Autumn/Winter 2014


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Posted
  • Location: Ripon , North Yorkshire 41m/135ft ASL
  • Weather Preferences: heat and cold, storms and blizzards...zonal a no no
  • Location: Ripon , North Yorkshire 41m/135ft ASL

Only the very start of Glaciers are forming, Non appearing yet only Neve.. It's amazing how many have sensationalised this. Instead of what the scientists were really there for!

Perhaps they are only existing on northern facing slopes because of the huge dumping of snow the mountains had last winter.

 

or has nathan rao... been there for his jollies  :rofl:

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Posted
  • Location: Exile from Argyll
  • Location: Exile from Argyll

If anyone fancies reading up on the theory here are two relativity accessible papers on the concept and a case study of 09/10. As stated by snowking it has been found greater snow advance equates to increased chances of -AO (by promoting a stronger more expansive Siberian high pressure system, which can later increase the probability of strat warming- see paper one). As highlighted by snowking -AO is never a guarantee of colder winters in our part of the world for reasons outlined, so that is something to keep in mind. Other factors such as the QBO are also important. The easterly phase of the QBO (e.g. last winter) is stronger than the westward, and thus can inhibit stratospheric warming events regardless of snow advance conditions.  When in westward phase (e.g. this coming winter) upward-propagating Rossby waves (e.g. from a strong Siberian high pressure system) , are directed at the polar vortex, increasing their interaction with the average zonal flow. Sorry a bit off topic but wanted to show why some of us are quite interested in the snow advance this coming winter, given a few other background factors (QBO, ENSO) are favourable.

 

http://www.nws.noaa.gov/ost/climate/STIP/FY11CTBSeminars/jcohen_062211.pdf

http://web.mit.edu/jlcohen/www/papers/Cohenetal_GRL10.pdf

 

The warm arctic old continents theory is also interesting to look at (search James Overland). That centres around decreasing sea ice and a warmer arctic, and its interaction with the overlying atmosphere and mid-latitude climate

 

Am I misunderstanding your terminology here? - last winter was west QBO and this winter will be east QBO

Edited by Gael_Force
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Posted
  • Location: Leeds (Roundhay) 135m
  • Location: Leeds (Roundhay) 135m

Am I misunderstanding your terminology here? - last winter was west QBO and this winter will be east QBO

 

Sorry yes should have checked it. Last winter was W-QBO, this coming winter E-QBO. The post has been edited, thanks DRL :)

Posted Image

Edited by Mark Bayley
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Posted
  • Location: Surrey and SW France.
  • Location: Surrey and SW France.

Some recent research articles on the things that may influence our winter weather patterns. I don't see a solar/weather/climate thread so will pop it in here.

 

http://www.issibern.ch/teams/interplanetarydisturb/wp-content/uploads/2014/04/Mursula_03_2014.pdf

 

http://www.atmos-chem-phys.net/13/6275/2013/acp-13-6275-2013.pdf

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Posted
  • Location: Skirlaugh, East Yorkshire
  • Location: Skirlaugh, East Yorkshire

Please keep this thread to snow and ice discussion and not climate discussion, there's a whole section for that.

 

Thanks

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Posted
  • Location: Nr Chelmsford, Essex
  • Weather Preferences: Hurricanes, Thunderstorms and blizzards please!
  • Location: Nr Chelmsford, Essex

Is it a little melodramatic to say...'and so it begins'!!!!  

 

Let's see if the snow 'chunk' is still there tomorrow.

 

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Posted
  • Location: Purley, Surrey - 246 Ft ASL
  • Weather Preferences: January 1987 / July 2006
  • Location: Purley, Surrey - 246 Ft ASL

Is it a little melodramatic to say...'and so it begins'!!!!  

 

Let's see if the snow 'chunk' is still there tomorrow.

 

Posted Image

 

Sorry.............are we not aloud a bit of a joke.

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Posted
  • Location: Nr Chelmsford, Essex
  • Weather Preferences: Hurricanes, Thunderstorms and blizzards please!
  • Location: Nr Chelmsford, Essex

Sorry.............are we not aloud a bit of a joke.

 

Er, yes?

 

Anyway, yesterday's 'chunk' has grown considerably.  Maybe now a 'super-chunk'?!

 

cursnow_asiaeurope.gif

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Posted
  • Location: Orleton, 6 miles south of Ludlow
  • Location: Orleton, 6 miles south of Ludlow

Er, yes?

 

Anyway, yesterday's 'chunk' has grown considerably.  Maybe now a 'super-chunk'?!

 

cursnow_asiaeurope.gif

Must be a superchunk. If that was in the UK most of the country would be covered in snow!

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.

I think the most important thing to remember about Cohen's theory is that the correlation is between Snow Advance across Eurasia in October, and the overall winter AO index (the faster the rate of advance, the more likelihood of a negative AO index) - and that alone is fraught with difficulty in terms of pinning down the detail for our tiny little island. 

 

You won't need me to explain this one to you but for the benefit of any newbies reading, here's a nice image demonstrating the differences between a Positive and Negative AO index:

 

image001.jpg

 

As you can see the biggest effect is a change from net westerlies (positive phase) to net easterlies (negative phase) around the Arctic regions. This infers that high pressure is likely to be in place around these regions given the clockwise motion the flow follows under high pressure in the Northern Hemisphere. You may also notice this ties in closely with a sudden stratospheric warming event, where the winds change from net westerly to net easterly much higher up in the atmosphere and often such an event downwells in to the lower reaches of the atmosphere and leads to a negative AO index.

 

The problem of using this to forecast for the UK alone is that there are plenty of examples in history of a negative AO index being in place but the UK simply being in "the wrong place" (doubtless for any newer members you will see examples once again this winter of one of Nick Sussex's Shortwave horror shows) with regards to the overall longwave pressure pattern setup. Usually this would result from a negative AO but either a positive or west-based negative NAO, leaving the UK out in the warm whilst other parts of the Northern Hemisphere bask in the glory of winter cold.

 

But of course the crucial take-home from Cohen's theory is that a high Snow Advance Index significantly increases the chances of colder than average conditions during winte. That is about as far as we can take it for now.

 

Of course there is also the October Pattern Index (OPI) from Italian researchers to take in to account, but as far as I can see there has been little progress on this over the last few months which is a shame as I believe we were awaiting a true English translation of the research so as to better understand the specific patterns suggested. 

 

Anyway, a little off topic but a fascinating subject and one that deserved further attention I feel :)

 

SK

 

Thanks for the reply but is it purely about the rate of increase during Oct or does starting from a high base at the beginning of Oct have any impact at all?,  Is there any way you can composite the SAI on the NOAA website and then roll forward to winter?

 

 

As for teaching Newbies about the AO and NAO, I find its easier to just teach them the pressure pattern as they seem to get confused and think its too technical, its a very simple thing to understand but it did confuse me at first.

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Posted
  • Location: St Albans, 95m asl
  • Location: St Albans, 95m asl

The theory suggests that it is rate of increase during October that has the greatest impact (owing to a whole range of chain reaction factors which culminates in the formation of a stronger than usual Siberian HP - assuming a fast rate of advance - which in turn drives Wave 1 activity within the Stratosphere)

So in fact a high base state in early October could be detrimental.

As far as composites go I do not know of any specific parameters available on the NOAA website to map the rate of increase.

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Posted
  • Location: Nr Chelmsford, Essex
  • Weather Preferences: Hurricanes, Thunderstorms and blizzards please!
  • Location: Nr Chelmsford, Essex

Well the white pixels are hanging on and starting to spread a bit wider......will they be there tomorrow though?  

 

cursnow_asiaeurope.gif

 

 

Also, it looks as though the Arctic Sea ice is holding up better this year.  Few more weeks of losses still to come but at least it's looking more positive:

 

sea_ice_only.jpg

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Posted
  • Location: Netherlands
  • Location: Netherlands

The theory suggests that it is rate of increase during October that has the greatest impact (owing to a whole range of chain reaction factors which culminates in the formation of a stronger than usual Siberian HP - assuming a fast rate of advance - which in turn drives Wave 1 activity within the Stratosphere)

So in fact a high base state in early October could be detrimental.

As far as composites go I do not know of any specific parameters available on the NOAA website to map the rate of increase.

 

Yes, we don't need snow in the end of september or early october days and it has to fall south of 60N.

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Posted
  • Location: Surrey and SW France.
  • Location: Surrey and SW France.

I was reprimanded for posting scientific articles up-thread but I think it is important to look at the drivers of the patterns that will bring the snow. Some of us have a deeper interest than just a green map with a splodge of white on it - would be better if the images were saved - the majority of posts just update to the most recent image.

 

http://nldr.library.ucar.edu/repository/assets/osgc/OSGC-000-000-019-877.pdf

 

 

Using NCEP–NCAR reanalysis and Japanese 25-yr Reanalysis (JRA-25) winter daily (1 December–

28 February) data for the period 1979–2012, this paper reveals the leading pattern of winter daily 850-hPa

wind variability over northern Eurasia from a dynamic perspective. The results show that the leading pattern

accounts for 18% of the total anomalous kinetic energy and consists of two subpatterns: the dipole and the

tripole wind patterns. The dipole wind pattern does not exhibit any apparent trend. The tripole wind pattern,

however, has displayed significant trends since the late 1980s. The negative phase of the tripole wind pattern

corresponds to an anomalous anticyclone over northern Eurasia during winter, as well as two anomalous

cyclones occurring over southern Europe and in the mid- to high latitudes of East Asia. These anomalous

cyclones in turn lead to enhanced winter precipitation in these two regions, as well as negative surface

temperature anomalies over the mid- to high latitudes of Asia. The intensity of the tripole wind pattern and

the frequency of its extreme negative phase are significantly correlated with autumn Arctic sea ice anomalies.

Simulation experiments further demonstrate that the winter atmospheric response to Arctic sea ice decrease

is dynamically consistent with the observed trend in the tripole wind pattern over the past 24 winters, which is

one of the causes of the observed declining winter surface air temperature trend over Central and East Asia.

The results of this study also imply that East Asia may experience more frequent and/or intense winter

extreme weather events in association with the loss of Arctic sea ice.

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