Winter 2010/2011

[cooling climate]

The NAO and AO may be loosely defined as teleconnections but they do not dominate or lead. They are calculated as a result of the pattern, cc. The underlying pattern may lead to a season or period of time when a particular positive or negative AO/NAO predominates but, I stress again that this is a result of the underlying other teleconnections. I see the common misconception still persists with you. I could, if I wanted work out the average pressure difference between Lands End and John o'Groats and call this indice the BI indice, and grade this positive or negative depending on the difference from average. These readings would no way influence the pattern of weather we receive. The NAO and AO are the same but over a greater and different area.

c

What do you think Enso is, differences in pressure between Darwin and Tahiti. The PNA index again pressure differentials

I could go on. The AO and NAO are no different. When the AO is strongly +or - like for instance last winter it played a very big role in the weather that affected the northern hemisphere.The same can be said for the NAO. it really is that simple.

Take for example winters like 1947 and 63, the dominant players that affected the UK and Europes weather was the AO and NAO. I am quite sure many times prior to these winters and after them we had similar enso conditions and other

teleconnections that were similar but we did not see winters like these, why not ?. The reason was the AO and NAO.

Edited September 17, 2010 by cooling climate

[Gavin P]

Brace yourself, La Nina threatens wetter, colder NW winter ...........http://2012realorfiction.blogspot.com/

Isn't that in relation to the Unites States Pacific North-West?

[phil nw.]

This is wrong.The AO and NAO are also teleconnections and at times can lead or dominate the pattern.

I think Chiono`s. post explains things quite clearly CC.

NAO and AO indexes are just measurements of the Upper Air Sypnotics as i understand it.

They are not dynamic such as an Ocean Current,they are just a reflection of the Sypnotic Pattern.

Edited September 17, 2010 by phil n.warks.

[chionomaniac]

What do you think Enso is, differences in pressure between Darwin and Tahiti. The PNA index again pressure differentials

I could go on. The AO and NAO are no different. When the AO is strongly +or - like for instance last winter it played a very big role in the weather that affected the northern hemisphere.The same can be said for the NAO. it really is that simple.

Take for example winters like 1947 and 63, the dominant players that affected the UK and Europes weather was the AO and NAO. I am quite sure many times prior to these winters and after them we had similar enso conditions and other

teleconnections that were similar but we did not see winters like these, why not ?. The reason was the AO and NAO.

Whereas a certain state AO and NAO can teleconnect to give us a certain type of weather, they are in fact still only an index themselves and can only be positive or negative, as a result of other factors.

And that is where I will leave it .

Edited September 17, 2010 by chionomaniac

[AderynCoch]

I think Chiono`s. post explains things quite clearly CC.

NAO and AO indexes are just measurements of the Upper Air Sypnotics as i understand it.

They are not dynamic such as an Ocean Current,they are just a reflection of the Sypnotic Pattern.

That sums it up pretty nicely. NAO is simply a comparison between two nodes of pressure (Iceland and the Azores) rather than a driving force in itself.

[weathe20]

Bar-stewardi's blog has been updated now and hes says a "normal" winter for the uk but drier, and with central/eastern europe having a very hard winter......mmmmmmmmmmmm

http://www.accuweath...m/ukie/laminate floori-europe-blog.asp?partner=accuweather

What did his blog say this time last year? Might be interesting to see if we can find out.

[k19]

Hi all, been a while since I've been on, maybe this is the start of the thousands of users coming out of hibernation (reversed I suppose). Anyway I like to think we will have an amazing winter, but can't help but notice that La Nina is present. I'm still new to meteorology, but I would say that this leads to an atlantic dominant winter. Not only this but SST's are higher in the northern atlantic, when in fact we need them lower. Can anyone shed some light on this? Thanks

[cooling climate]

Whereas a certain state AO and NAO can teleconnect to give us a certain type of weather, they are in fact still only an index themselves and can only be positive or negative, as a result of other factors.

And that is where I will leave it .

Fair enough. Some people are willing to learn others are not.

As they say you can lead a horse to water but.......

[Typhoon John]

54/55 looks about the closest analogue for the Winter to me:

Pressure anomalies:

December

January

February

Combined

That year had frequent snow events from December throughout the Winter and across the country but generally snowier further North. I'd think compared to recent times (last year excluded) it would be considered a very snowy Winte. The Feb CET was 1.2 and the AO and NAO for the DJF was negative. PDO, ENSO, QBO and Solar conditions were similar to this year (so far) and the only difference was a cooler Atlantic than we have now. The other shout would be 55/56 but while similar there are more differences to 2010 than 54/55.

So based on that I'd expect something fairly similar this year but perhaps a bit warmer and a bit less snowy due to the warmer Atlantic. Temps and rainfall below average and slightly above average snowfall throughout the DJF period .

[Thundery wintry showers]

1954/55, although not outstandingly cold, ended up as one of the snowiest of the century in northern districts:

http://www.weatheronline.co.uk/reports/philip-eden/The-cold-winter-of-1955.htm

[Weather-history]

54/55 looks about the closest analogue for the Winter to me:

.

So based on that I'd expect something fairly similar this year but perhaps a bit warmer and a bit less snowy due to the warmer Atlantic. Temps and rainfall below average and slightly above average snowfall throughout the DJF period .

If that is the case then expect a very mild December. That winter didn't really get going until the change of the year.

[cooling climate]

54/55 looks about the closest analogue for the Winter to me:

Pressure anomalies:

December

January

February

Combined

That year had frequent snow events from December throughout the Winter and across the country but generally snowier further North. I'd think compared to recent times (last year excluded) it would be considered a very snowy Winte. The Feb CET was 1.2 and the AO and NAO for the DJF was negative. PDO, ENSO, QBO and Solar conditions were similar to this year (so far) and the only difference was a cooler Atlantic than we have now. The other shout would be 55/56 but while similar there are more differences to 2010 than 54/55.

So based on that I'd expect something fairly similar this year but perhaps a bit warmer and a bit less snowy due to the warmer Atlantic. Temps and rainfall below average and slightly above average snowfall throughout the DJF period .

Solar activity was much higher then, in fact I think we were in the peak period of the strongest solar cycle (19) of the twentieth century.Lower solar activity such as what we have seen the last few years can lead to more blocking episodes and persistant weather patterns especially over the Atlantic and Europe (although not all climatologists agree with this).

Another theory is that in +QBO years with maximum solar activity such as 54/55 MMW's (major midwinter warmings also known as sudden stratospheric warmings ) and blocking episodes are more likely than in low solar +QBO years such as this one.

Myself I think that the low solar activity will again aid in further blocking episodes and a - AO and NAO index at times at least.

Edited September 17, 2010 by cooling climate

[Typhoon John]

Monthly averaged sunspot numbers for 1954, 1955 and then 2010 so far. You can make your own comparisons but it looks quite similar to me, i.e., minimum conditions.

YEAR MON  SSN   DEV
1954  1   0.2   1.3
1954  2   0.5   1.8
1954  3  10.9  13.7
1954  4   1.8   3.8
1954  5   0.8   2.4
1954  6   0.2   1.3
1954  7   4.8   4.8
1954  8   8.4   6.9
1954  9   1.5   3.0
1954 10   7.0   7.0
1954 11   9.2  13.9
1954 12   7.6   8.8
1955  1  23.1  11.7
1955  2  20.8  12.9
1955  3   4.9   6.8
1955  4  11.3  11.9
1955  5  28.9  17.6
1955  6  31.7  22.1
1955  7  26.7  16.1
1955  8  40.7  26.1
1955  9  42.7  27.3
1955 10  58.5  37.2
1955 11  89.2  34.9
1955 12  76.9  13.8

2010  1  13.2   7.3
2010  2  18.8   9.3
2010  3  15.4   7.0
2010  4   7.9   8.3
2010  5   8.8   9.0
2010  6  13.5   7.8
2010  7  16.1   6.8
2010  8  19.6  11.9

Source

Adjusted 10.7 cm Flux is similar too. Source

[cooling climate]

Monthly averaged sunspot numbers for 1954, 1955 and then 2010 so far. You can make your own comparisons but it looks quite similar to me, i.e., minimum conditions.

YEAR MON  SSN   DEV
1954  1   0.2   1.3
1954  2   0.5   1.8
1954  3  10.9  13.7
1954  4   1.8   3.8
1954  5   0.8   2.4
1954  6   0.2   1.3
1954  7   4.8   4.8
1954  8   8.4   6.9
1954  9   1.5   3.0
1954 10   7.0   7.0
1954 11   9.2  13.9
1954 12   7.6   8.8
1955  1  23.1  11.7
1955  2  20.8  12.9
1955  3   4.9   6.8
1955  4  11.3  11.9
1955  5  28.9  17.6
1955  6  31.7  22.1
1955  7  26.7  16.1
1955  8  40.7  26.1
1955  9  42.7  27.3
1955 10  58.5  37.2
1955 11  89.2  34.9
1955 12  76.9  13.8

2010  1  13.2   7.3
2010  2  18.8   9.3
2010  3  15.4   7.0
2010  4   7.9   8.3
2010  5   8.8   9.0
2010  6  13.5   7.8
2010  7  16.1   6.8
2010  8  19.6  11.9

Source

Adjusted 10.7 cm Flux is similar too. Source

You are correct, cycle 19 maxed out around 56/57 although the solar output was

starting its ramp up during 1955.

[Kentish Kiwi]

Fair enough. Some people are willing to learn others are not.

As they say you can lead a horse to water but.......

Apologies for the confusion, I do not think it is a driver as such driver as such but if given the

opportunity to become strong in either index it can dominate the weather pattern imo anyway.

But surely that's only because it's giving a 'reading' of what the pressure patterns are at the time, and therefore if a certain pressure pattern is strong enough (with the AO/NAO giving a strong reading of negative/positive as a result), then obviously the pressure systems are able to 'override' other teleconnections/drivers, but this is not to say it is the AO which is effecting the weather.

This may be a rather extreme comparison, but isn't it like saying the CET is a driver of the weather, in the sense that it gives a figure as a result of the weather and is indicative of the situation in terms of temperature, however it is obviously nothing close to a 'driver' and is simply a measurement, usually compared and contrasted to average. Chiono has gone out of his way to explain it as clearly and concisely as you could hope for, yet you still choose to argue against what seems to be a pretty straight forward and clear cut concept.

[Turnedoutniceagain]

**sigh**

Page 10 and it's turned into a punch-up !!

[Weather-history]

I think Chiono`s. post explains things quite clearly CC.

NAO and AO indexes are just measurements of the Upper Air Sypnotics as i understand it.

They are not dynamic such as an Ocean Current,they are just a reflection of the Sypnotic Pattern.

Yes, I always thought AO and NAO are just measurements that tell us the degree of particular pressure patterns. ie its a measurement of an effect and not a cause.

Edited September 18, 2010 by Mr_Data

[cyclonic happiness]

**sigh**

Page 10 and it's turned into a punch-up !!

You sigh alot T,O,N,A! lol!

I do think this winter is going to be a continuation of the last 3 what with all the odd things that are going on (volcanic eruptions higher than normal, a maybe shutting down gulf stream, although no-one seems to be able to giva clear answer as to what it's doing, la nina although no-one seems to be able to give a clear answer....you know the rest etc)

We can all see that things have changed from the endless atlantic drudgery in winters of the past 3 years, it seems to me that the atlantic only ever comes alive during the summer nowadays and what with the jet stream refusing to go much further north than even scotland alot of the time, we can almost expect colder winter than we've had during the 'atlantic phase' which was i'd say '89-2007.

Of course I don't know how this winter will turn out , but I do believe that there may be a few changed opinions if we have another one along the same theme as the last few?

**sigh**

Edited September 18, 2010 by cyclonic happiness

[Thundery wintry showers]

Winter 2007/08 was quite a westerly winter actually, December 2007 was a cooler version of 2006 with westerlies early and late and cold anticyclonic weather in the middle, while January 2008 started off with a 36 hour easterly then turned westerly. February was westerly early and late with a long anticyclonic spell on the 8th-20th.

2008/09 had less westerlies than usual in December and February but January was more westerly than usual, though the westerlies on that occasion were not particularly mild.

[BornFromTheVoid]

Prey tell what the hell is that to do with you. He offered his opinion and I was putting across mine.

A bit of advice, when you don't know what you are talking about it is better to stay silent and be thought

a fool rather than speak up and remove all doubt.

Chill out CC, you seem to have a temper like you're avater! No need to go on insulting people, heed your own advice.

I'm hoping this winter will provide a little more snow than the last, which despite the cold, was below average snowfall-wise for most of Ireland. Deepest snow was just 15cm for a few hours last January.

Has the southerly tracking jet stream been maintianed the last few months? I presume it would help with getting any prolonged cold...

[Gavin P]

Winter 2007/08 was quite a westerly winter actually, December 2007 was a cooler version of 2006 with westerlies early and late and cold anticyclonic weather in the middle, while January 2008 started off with a 36 hour easterly then turned westerly. February was westerly early and late with a long anticyclonic spell on the 8th-20th.

2008/09 had less westerlies than usual in December and February but January was more westerly than usual, though the westerlies on that occasion were not particularly mild.

February 2008 was a very extreme month here during that anticyclonic period. Temps by day reached 10-12c frequently, whilst by night minima of -5c was not uncommon. I believe February 2008 has the biggest deviation between the average maximum and minimum temperatures since I started keeping my own weather records in 1993.

January 2009 was a pretty good example of ***Whispers*** COLD ZONALITY.

Edited September 18, 2010 by Gavin P

[Ladyofthestorm]

A while back I said that I would wait to see what the hurricane season would bring to our shores. Right now we have two major tropical systems in the atlantic, and if the GFS is to believed none will make it over as extra tropical features. Instead they will slowly degrade while moving towards Greenland. We did see something like this earlier on this year, with weather systems in the atlantic almost being turned on there heals and going off in the opposite direction. This year it has started even earlier.

The NAO is also negative and continues to be stubbornly so.last year at this time it was positive and brought along with it a spell of wet and windy weather that broke my hubbys wind turbine.

Its been what I would call a benign summer and continues to be so as we move into autumn. I cant see no let up in the current situation. I think we could very well be in for a repeat of last winters slack, very cold airflow, but this time starting much earlier. We just need that air to cool over the continent and we will get what europe gets most years.

There has been another thread about the gulfstream, it has switched off, but it hasnt got the power it should have at this time of the year either. If the southern ocsillation can swtich moods Im sure the gulfstream is more than capable of slowing down as well.

[johncoolj]

A while back I said that I would wait to see what the hurricane season would bring to our shores. Right now we have two major tropical systems in the atlantic, and if the GFS is to believed none will make it over as extra tropical features. Instead they will slowly degrade while moving towards Greenland. We did see something like this earlier on this year, with weather systems in the atlantic almost being turned on there heals and going off in the opposite direction. This year it has started even earlier.

The NAO is also negative and continues to be stubbornly so.last year at this time it was positive and brought along with it a spell of wet and windy weather that broke my hubbys wind turbine.

Its been what I would call a benign summer and continues to be so as we move into autumn. I cant see no let up in the current situation. I think we could very well be in for a repeat of last winters slack, very cold airflow, but this time starting much earlier. We just need that air to cool over the continent and we will get what europe gets most years.

There has been another thread about the gulfstream, it has switched off, but it hasnt got the power it should have at this time of the year either. If the southern ocsillation can swtich moods Im sure the gulfstream is more than capable of slowing down as well.

good post you seem to know a lot

your say the gulf stream hasent got the power it should have what percent do you think its weakend by like 20 percent or what

also will this effect uk ireland tem,ps this winter

[phil nw.]

Yes the Atlantic has been relatively quiet for prolonged periods for some time now.

The NAO index chart below shows the negative state since May and going forward-

The jetstream still weak and fragmented here---

Blocking medium term forecasts shows the continuing lack of Low pressure in it`s usual place-to our West/North West.

An interesting Winter to come--If the Status Quo in this Pattern remains, that`s for sure.

[kippure]

A while back I said that I would wait to see what the hurricane season would bring to our shores. Right now we have two major tropical systems in the atlantic, and if the GFS is to believed none will make it over as extra tropical features. Instead they will slowly degrade while moving towards Greenland. We did see something like this earlier on this year, with weather systems in the atlantic almost being turned on there heals and going off in the opposite direction. This year it has started even earlier.

The NAO is also negative and continues to be stubbornly so.last year at this time it was positive and brought along with it a spell of wet and windy weather that broke my hubbys wind turbine.

Its been what I would call a benign summer and continues to be so as we move into autumn. I cant see no let up in the current situation. I think we could very well be in for a repeat of last winters slack, very cold airflow, but this time starting much earlier. We just need that air to cool over the continent and we will get what europe gets most years.

There has been another thread about the gulfstream, it has switched off, but it hasnt got the power it should have at this time of the year either. If the southern ocsillation can swtich moods Im sure the gulfstream is more than capable of slowing down as well.

Perfect Summary of whats going on right now. I do see what you are saying about atlantic systems not been able to break through, Low pressure systems are just dieing out in the north atlantic and heading to greenland. When the blocking starts to develop out over the west atlantic like last year, its going to be another cold winter.To me its not "if" any more just "when".