Autumn and Winter discussion...

[summer blizzard]

SPOT THE DIFFERENCE...

[Derbyshire_snow]

Sorry i am novice when it comes reading charts like that what does all that mean?

Edited October 5, 2006 by Derbyshire_snow

[kold weather]

Intresting models at the moment, esp at the sort of mid-range with the charts seemingly showing a southerly as the Scandi high just is a too far east and the Icelandic high a touch too strong. I do still have alittle nagging feeling that this type of set-up could be the one that sets in, though its very early days and a general weakening of the jet would leave us looking pretty as it queitens down as winter goes along.

(Those charts above certainly do suggest a cold month though it could be more of the dry easterly type given the main lower area of pressure is to the south.)

Edited October 5, 2006 by kold weather

[Big Bear]

Sorry i am novice when it comes reading charts like that what does all that mean?

Based on Summer Blizzards comparison to Feb 63 - it means a below average and potentially snowy (widespread) month ...I expect a sharp NE feed from Scandinavia with pressure values like those.

January even more interesting with real easterly components.

Does anyone have an idea of how accurate Roeder's forecasts are when it comes to winter LRFs?

[johnholmes]

less than some others, better than some!

[acbrixton]

Sorry i am novice when it comes reading charts like that what does all that mean?

The first chart is a forecast of anomalies in sea level pressure (calculated from a lomg term norm) for February 2007. It indicates extensive high pressure over Greenland/Iceland ridging to Scandinavia and low pressure to the south of the UK. As winds in the northern hemisphere blow clockwise around high pressure and anticlockwise around low pressure the chart indicates cold north easterlies and the possibility that precipitation connected with the low preesure to the south might fall quite extensively as snow.

The second chart is an archive chart showing upper air pressure anomalies during the noriously cold month of February 1963. Although it does not show sea level pressure anomalies the upper air featues indicated would have been more or less replicated at sea level. In the case of February 1963 there is extensive high pressure around Greenland and Iceland and again low pressure to the south of the UK.

I woould be very surprised if the forecast chart for February 2007 proves accurate...

Regards

ACB

[SMU]

I would concur. This old chestnut seems to get as many outings as the 1947, 1963, 1987 (and now seemingly 1969) charts!

Evening All-

The wolfgang Roeder C harts are nothing Short of Specatular-

They point to persisitent Scandi Blocking through Dec Jan & Feb-

The blue ones do indeed point to positive height anomalies which is great news for the Winter Rampers-

This forecaster was considered VERY accurate last year with predictions......

Lets hope his track record lasts till April 07.............

IF those pressure anomalies do indeed transpire then you could almost transpose they Berlin temperature anomaly departures to the SE of england

Probable Temperature Deviations from Average 1961-90

from October 2006 to Februar 2007 at Berlin in Kelvin:

Oct Nov Dec Jan Feb

1.5 1.8 -0.3 -2.9 -1.6

OH Yes........... Come to Papa

S

PS SB- nice re-analysis chart- thats just pure ramping.........

Edited October 5, 2006 by Steve Murr

[Snowyowl9]

Assuming these charts and patterns were actually to come about - I don't think GP was necessarily saying a massive mild breakdown. That Feb 69 chart is a classic battleground chart and in these sitautions there are sometimes milder incursions from the south-west before the cold fights back again. That is certainly what used to happen frequently in those days.

Tamara

We had a battleground this last March the first since 1996 as I remember.

If that Feb 69 chart came off again all our christmases will of come at once

Saw that 1969 chart for the 1st time yesterday nice

This thread has certainly shifted rapidly since last night and there`s some fascinating posts on here too especially with what those sea pressure models are showing.

Edited October 5, 2006 by Snowyowl9

[SMU]

We had a battleground last year the first since 1996 as I remember.

If that Feb 69 chart came off again all our christmases will of come at once

Saw that 1969 chart for the 1st time yesterday nice

This thread has certainly shifted rapidly since last night and there`s some fascinating posts on here too especially with what those sea pressure models are showing.

Charts like this would arise IF those anomaly charts arose in Feb.........

S

[Anti-Mild]

I wonder if we could persuade Philip Eden to attempt something similar. He has a good record at forecasting pressure anomalies for the following month and it would be interesting to see a longer range stab.

[Snowyowl9]

Charts like this would arise IF those anomaly charts arose in Feb.........

S

Hi Steve.

That`s a stunning chart looked very windy on there...

1979 was an amazing winter as it continued on and off until may.

Hopefully we`ll get an easterly battleground this year instead of a south/SE but it was great to see that last March even so..

[The Eagle]

I see the ramping has begun

Im definatley holding off for a good while longer before commenting on long range predictions but im cautiously optimistic after reading through some of the excellent detail on this thread.

That 1979 chart is quite amazing. Didnt last long though.

[Thundery wintry showers]

I remember Wolfgang Roeder's forecast of a bias towards northerly and north-westerly winds in November 2005 and thinking "what the hell is he thinking?", then after frequent northerlies in the second half the actual mean sea-level pressure anomaly chart came out close to the prediction.

Wolfgang may have been okay last winter, but his forecasts for 2003/04 and 2004/05 weren't so good; December 2003 and January 2005 anomalies were predicted quite accurately if I remember rightly, but the other four months were well out.

I think in general it's very difficult to make that kind of forecast more than a month in advance, so no matter who does it, accuracy is unlikely to be higher than around 30%. It's worth a try, certainly, but it's only experimental. The most one can do and have a decent chance of being accurate seems to be the sort of general seasonal summary that Ian Brown does on this forum, and that the Met Office successfully did for last winter.

[Optimus Prime]

A similar even to that 1979 chart could have occured last December if it wasn't for low pressure breaking up the block coming in from Greenland;

The intensity of the cold would not had been as dramatic as that of February 1979 because of a warmer continent

In comparison;

However the fact still remains, last win ter had close to record breaking cold over Russia and Eastern germany had their coldest winter ever and Europe as a whole was colder then average. Not to mention that incredible snow in Japan.

And of course Scotland having record snow depths in early March

[Glacier Point]

Evening All-

Probable Temperature Deviations from Average 1961-90

from October 2006 to Februar 2007 at Berlin in Kelvin:

Oct Nov Dec Jan Feb

1.5 1.8 -0.3 -2.9 -1.6

OH Yes........... Come to Papa

S

October if anything could be more than the 1.5 anomaly. This could actually be good news for coldies as it would be a portent for increased strength of anomalies switching between strongly positive and negative. This has some logic in terms of sustained ridge - trough development through the Autumn - more cold air gets pumped southwards sustaining blocking west-east setting up bigger cold pools into the winter and so on.....

I think we commented early on this summer of a possible winter of extremes. Perhaps ?

time for a lie down, that's far too much ramping for one day.

[The Enforcer]

I can imagine the pandemonium on here if a chart like that pops up this winter, especially within say T+96. Unfortunately, all that glistens is not gold, especially for those not in the SE corner of England.

[BLAST FROM THE PAST]

Some interesting posts and quietly exciting inputs too!

What do I mean...well our very own Ian Brown, GP, Steve Murr, SB all inputting positively although cautiously...but I see into that. The teles are looking good, the MET O have changed their forecast yo potential cold developing later in the winter [pretty significant] as Wolfgang is only showing this ...and of course there's our friend Roger J Smith...wait til what he has to say as we enter Jan . And this all nestling in with my quiet little thoughts and method....watch out! watch out! the 1st 10 days of January are about

BFTP

Edited October 5, 2006 by BLAST FROM THE PAST

[The Enforcer]

accuracy is unlikely to be higher than around 30%.

Perspective at last - this is just one forecast - when they all tally there will have been a breakthrough.

it is not in the bag yet.

Quite. I'd argue it hasn't made it into the supermarket delivery lorry yet.

[Thundersquall]

Perspective at last - this is just one forecast - when they all tally there will have been a breakthrough.

Quite. I'd argue it hasn't made it into the supermarket delivery lorry yet.

And probably not even into the depot!

[BLAST FROM THE PAST]

Trends and signals...they are not showing the opposite yet

BFTP

[The Enforcer]

Something tells me this is going to be the best wonter ever and that SATSIGS is going to be very busy. In fact, I'm surprised some alerts haven't already been issued.

[thunderstrike]

hahaha

We do this every year

[Glacier Point]

September NAO data out - second big negative in a row following August.

http://www.cdc.noaa.gov/Correlation/nao.data

fairly unsual in its occurence - the last time was during the mid eighties - but how significant it is impossible to say. I suspect that phasing between La Nina and El Nino episodes may have some contribution but this would only be a hunch.

Of more significance perhaps is the high degree of disconnect between AO and NAO. During September, the AO - NAO correlation is 0.7. So a big -ve NAO (-1.73) should have seen a big -ve AO ? No way Jose -

http://www.cpc.ncep.noaa.gov/products/prec...ex/ao.sprd2.gif

more a positive AO from the look of it although we still await the final data from CPC.

What does this mean ? Basically the two oscillations are behaving independently of each other which is very, very unsual. What does this mean for the Winter ? Very hard to draw any firm conclusions yet and all we can safely say that this a statistical quirk.

It's worth watching the NAO over the next month or two to see if a trend develops, particulalry given the SSTAs in the northern Atlantic which IMO are highly conducive to a -ve state. Of note so far has been the modality of the NAO trending very +ve or very -ve with no neutral values this year. Also, 5/9 months were with the NAO in -ve state this year.

GP

[shuggee]

The forecast weak El Nino and its link to winter is discussed in today's Weather Eye:

http://www.netweather.tv/forum/index.php?s...st&p=796005

[BLAST FROM THE PAST]

As far as I can make out, the blue lines, with +ve values attach indicate a positive anomaly from the long term average in terms of SLP; i.e. if over Denmark the long term SLP for January is 1007mb (just a random figure), then W.Roeder indicates that the average SLP for Jan '07 will be somewhere in the region of 1019mb.

Obviously the opposite applies for the red lines with -ve values attached.

Hope that helps.

Yes that is correct. Below is from Wolfgangs site

red: negative deviations [lower pressure] blue: positive deviations [higher pressure]

BFTP