Autumn and Winter discussion...

[Big Bear]

I see the GFS is maintaining the trend for low pressure skirting over/under the UK throughout October.

With high pressure taking hold over northern Europe & Scandy.

http://www.wetterzentrale.de/pics/avnpanel1.html

Interesting pattern developing here

[Derbyshire_snow]

I see the GFS is maintaining the trend for low pressure skirting over/under the UK throughout October.

With high pressure taking hold over northern Europe & Scandy.

http://www.wetterzentrale.de/pics/avnpanel1.html

Interesting pattern developing here

Is that a good or bad sign for us cold lovers

[Derbyshire_snow]

Good, I would say.

Tamara

shh don't go getting me all excited

[Paul]

Ok a quick look at the CFS today, shows a similar pattern to the last week - November looks fairly mild with the odd cool/cold interlude with the most likely source of these brief cold spells being the north.

If the CFS is correct with the pattern, then this sort of chart could well be common:

Into December and signs of the jet wanting to pull south during the month - the timing of this varies from run to run, but the fact it is keeping the trend there is an interesting thing to keep watching. Today's run has a northerly kicking in during the first part of the month:

Looking a bit further ahead - Jan looks a real mixed month - when it's cold it could be very cold, when it's mild it could fool people into thinking it's spring! Into Feb - signs of an east/west battle - definitely something to watch and perhaps in tune with roeders latest update.

Now the obligatory plug - all the charts from the CFS are available within Netweather extra

[Thunder Snow]

Ok a quick look at the CFS today, shows a similar pattern to the last week - November looks fairly mild with the odd cool/cold interlude with the most likely source of these brief cold spells being the north.

If the CFS is correct with the pattern, then this sort of chart could well be common:

Into December and signs of the jet wanting to pull south during the month - the timing of this varies from run to run, but the fact it is keeping the trend there is an interesting thing to keep watching. Today's run has a northerly kicking in during the first part of the month:

Looking a bit further ahead - Jan looks a real mixed month - when it's cold it could be very cold, when it's mild it could fool people into thinking it's spring! Into Feb - signs of an east/west battle - definitely something to watch and perhaps in tune with roeders latest update.

Now the obligatory plug - all the charts from the CFS are available within Netweather extra

Hows the xmas chart looking

[Stratos Ferric]

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.

The one reliable aspect of the British winter is that irrespective of the real prospects for cold, the possibility burns very strongly in one or two minds. I gather that SATSIGs HQ is firing up the systems as we speak.

[SMU]

Updated Thoughts:

Here was my post 2 weeks ago-

Winter LRFS's are as old as the Hills, All with varying degrees of success, Lets be clear the measurements of accuracy CANNOt be applied in the same way as measuring a model accuracy at say 5 days which we tend to see through RMS errors etc from the model statistics Site-

At BEST the Parameters to Measure & Forecast against Are Temperature & Rainfall- as departures from the norm-

The third & one in which I think the MET office should entertain is the Pressure anomalies laid out for the Season-

This then links in the thinking around the forecast correlating back to expected temperature & rainfall anomalies-

I think people get TO hung up with detail- No Snow event, No Storm can be Forecast Weeks, Months in advance- what CAN be estimated is the Relashonship that the teleconnections have with the regions forecast for-

This will obviously include SSTA's, Snow Cover, Stratospheric temps, Maunder Mins etc....

We are only just starting out on this journey towards a 'Decent' LRF especially when we look at the Americans who use these all the time around the Energy businesses, trust me there are people out there that make significant amounts of money based around their LRF's-

What we have here though ( & I have said this before) is one or two organisations -Like The Met office/ Net weather / Metcheck who are taking the first steps into attributing time & Investment into these products- because After all they are 'Products' & marketable ones at that-

For those that still have reservations around how good we can ever get should remind themselves of how often the statement ' It cannot be done' has actually been proved wrong-

This is particularly relevent when we start discussing this winters forecasts, - The Met office one will be much speculated & forgive me for trying to second guess their outlook- Im strongly looking towards a milder than the norm outlook due to the relashonship between the SSTA around Iceland during the Early Summer for the following Winter-

I suspect their NAO outlook will say +VE phase, Milder & Possibly wetter than the average- UNLESS THEY USE MORE UP TO DATE SST CHANGES-

However I hinted at the prospect of an Extreme Winter ( Against the recent Norm) Rather than a Normalised Winter due to the Forcing thats going on in the atmosphere-If we look at the Teleconnections & SST'AS there NEVER seem to be any anolgues to measure against these days ( Measuring data goes back to the 50's) Everything appears to be an Extreme, or have extreme anoamlies involved- ( polar anomaly included)

This where I think thinking outside the nine dots comes in-

To forecast this Winter- using the NAO relashonship is not enough of the pie from My Perspective, The data that will need to be as UP TO DATE as possible will need to span the tropics, The Poles, The oceans ,The Stratosphere & So on-

My Winter Outlook will be released late- again the preliminaries ( thats the data from a CURRENT standpoint) suggest a similar Winter ( AT LEAST START) to Last, Pos NAO with BIG neg heights towards Greenland & LOW frequencies of Northerlies- Not to much peoples pleasure- this is of course unless SSts change dramatically in the atlantic-

The core of the cold- which has to be said has developed early & to a better depth will Strongly Manifest itself to the East with the Polar vortex Probably displaced in 2 locations-

The key here this year COULD well be the strength of the Pacific Jet- Its was anomalously fast last year with assistence from the Negative PDO & Easterly QBO -

As we head into early Sept the QBO isnt where it was last year (Its Westerly) & we correlate a weaker jet back to the OVERALL pattern observed last winter you will all know this could be VERY significant....

Afternoon All-

The lastest round of Data Continues to encourage me in terms of 500 Mb flow patterns & teleconections-

If we observe the NAO data for September-

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

This is nothing short of ASTOUNDING & people should take note of what correlates to what in terms of Extreme weather-

For Novices that have little or no experience of Teleconnections & how they behave should remember this-

The AO, PNA, NAO, POL, & Others are all measured against Pressure differentials-

The closer they are to Neutral the LOWER the amplitude will be of the jet stream-

Taking this one step further SUSTAINED Extremes of Temperature for specific regions only occur when teleconnection data comes make further away from Neutral- because the assumption is that Positive or negative extremes are indicitive of very blocked situations-

( Note here I havent mentioned El nino,SStA (PDO), QBO or Stratospheric temps - this is because these are NOT teleconnections measured in pressure differentials they are cause & effect ON teleconnections)

For the record IMHO the best set up for the UK for Cold & Snow is-

Highly Neg AO, Highly neg NAO, Highly Pos PNA, Highly NEG POL- Once this is locked in - The PNA being the least contributor-

to prove this here is the data for early- 1963

NAO 1963 -2.12 -0.96

AO1963 -3.311 -1.721

PNA1963 0.600 0.800

POL not available-

Anyway as an example of a HIGH AMPLITUDE phase of a teleconnection I have picked the top 15 negative NAO Charts of the last 50 years and added the corresponding chart- incidentally number 15 is a chart from 2005-

Again if your a novice to this these are good examples to demonstrate a HIGH AMPLITUDE phase of the jet- & NAO

I will only image the top one & link the others-

Here they are-:

Number One Most negative NAO chart since 1950 is the Third of March 1962-

Then in Order-

13/02/78

http://www.wetterzentrale.de/archive/ra/19...00119780213.gif

10/03/51

http://www.wetterzentrale.de/archive/ra/19...00119510310.gif

02/03/62

http://www.wetterzentrale.de/archive/ra/19...00119620302.gif

14/02/78

http://www.wetterzentrale.de/archive/ra/19...00119780214.gif

11/02/78

http://www.wetterzentrale.de/archive/ra/19...00119780211.gif

11/03/51

http://www.wetterzentrale.de/archive/ra/19...00119510311.gif

10/02/78

http://www.wetterzentrale.de/archive/ra/19...00119780210.gif

22/02/65

http://www.wetterzentrale.de/archive/ra/19...00119650222.gif

04/03/62

http://www.wetterzentrale.de/archive/ra/19...00119620304.gif

12/02/78

http://www.wetterzentrale.de/archive/ra/19...00119780212.gif

01/03/62

http://www.wetterzentrale.de/archive/ra/19...00119620301.gif

27/02/62

http://www.wetterzentrale.de/archive/ra/19...00119620227.gif

09/03/58

http://www.wetterzentrale.de/archive/ra/19...00119580309.gif

11/02/60

http://www.wetterzentrale.de/archive/ra/19...00119600211.gif

& Of course 25/02/2005.....

http://www.wetterzentrale.de/archive/ra/20...00120050225.gif

Remember the -NAO extreme doesnt always promise Cold & Snow for us but must have a very high linear correlation of around 0.8/0.9-

We now turn our attention back to the NAO- Data for September is In-

AUG -1.73 SEPT -1.62 ....

WOW-

Firstly there has never been in the 50 years of recording NAO data an August & September below -1 on the NAO Scale- that means the last 2 months in terms of NAO have been Extremely blocked relative to the Norm-

The NEAREST match with a NAO of around -1.6 in Sept, A negative August & Negative October ( Assuming this Oct is NEG)

is..................

1968

Here is the recorded CET for D,J,F for 1969....... 3.0, 5.5 & 1.0- March 3.3

I must emphasize at this point I am NOT fond of analogue years in any way shape or form so whilst 1969 is a lovely match its a little crude at this point to base a winter forecast around this insular measure-

With this in mind & the fact that its the first week in October we are still in the preliminary stage of Winter projections & why October we await October NAO with baited breath- another Neg month would only have 2 anlogue matches- 1994 & 1968

This then finally brings me onto my Winter forecast- I have decided to move away from Analogue forecasting as i firmly believe there are NO true analogues- sure there are trend data which can & WILL be considered but the FINAL decision for 500 anomaly pattern will be less bias to historical analogues & an equal bias to current 500 Mb global flow anomalies-

The word extreme & blocked continue to feature heavily in my thoughts- NOT because Im a hopecaster but because the closest teleconnection the NAO has performed in the last 8 weeks at RECORD culmlative amplitude levels- Should October deliver a similar result- say sub -1.2 it will really heighten expectations...............

Steve

PS worthy of note is todays Day 10 500 Mb anomaly comparison....

http://www.meteo.psu.edu/~gadomski/ECMWF_0z/hgtcomp.html

Huge Northern blocking...

Edited October 6, 2006 by Steve Murr

[johnholmes]

interesting post Steve and one for the newbies, or those like me who have great difficulty in getting their heads around all these terms should copy and save somewhere to refer to.

Thanks

John

[Big Bear]

Excellent post Steve

I really enjoy your analysis every time. It's so good to have your knowledge & experience shared here once again as we approach another winter season with hopefully lots of snow and that easterly we all long for. :excl:

Like Roeder's early prediction, I find all these examplenentory European LRF charts so interesting. The signs are good but before we start wetting ourselves let just remember we've all been here before and the chance for a mild winter realistically stands stronger than a cold one.

[Dawlish]

Ok a quick look at the CFS today, shows a similar pattern to the last week - November looks fairly mild with the odd cool/cold interlude with the most likely source of these brief cold spells being the north.

If the CFS is correct with the pattern, then this sort of chart could well be common:

Into December and signs of the jet wanting to pull south during the month - the timing of this varies from run to run, but the fact it is keeping the trend there is an interesting thing to keep watching. Today's run has a northerly kicking in during the first part of the month:

Looking a bit further ahead - Jan looks a real mixed month - when it's cold it could be very cold, when it's mild it could fool people into thinking it's spring! Into Feb - signs of an east/west battle - definitely something to watch and perhaps in tune with roeders latest update.

Now the obligatory plug - all the charts from the CFS are available within Netweather extra

I wonder if it is worth netweather keeping a check on the accuracy of these CFS forecasts. Indeed, are there figures from CFS on their accuracy? I am concerned that these charts will be taken as accurate forecasts by some, when in fact, any forecast for November/December/January should come with an enormous health warning.

Although these look like "real" charts for those times, we can only guess at the actual likelihood of them coming true. I would think, at best, they are forecasts charts with a lower probability than the Met Office NAO forecast has. They are fun to look at and specultae about, but I have real reservations about their actual usefulness. To me they are opinion, rather than forecast.

Paul

[Big Bear]

I wonder if it is worth netweather keeping a check on the accuracy of these CFS forecasts. Indeed, are there figures from CFS on their accuracy? I am concerned that these charts will be taken as accurate forecasts by some, when in fact, any forecast for November/December/January should come with an enormous health warning.

Although these look like "real" charts for those times, we can only guess at the actual likelihood of them coming true. I would think, at best, they are forecasts charts with a lower probability than the Met Office NAO forecast has. They are fun to look at and specultae about, but I have real reservations about their actual usefulness. To me they are opinion, rather than forecast.

Paul

Ever the pecimist, Paul

of course they are experimental. I don't think a hefty reminder is necessary every time these come out. Newcomers will gather this by reading the thread anyway. Without LRFs, then how would we learn and compare results for future lessons and forecasting methods.

[kold weather]

Some intresting points on here. I noted how similar some of the patterns during July looked at the mid 1980's period in the Pacific. Now I've just seen the NAO comprasions that GP posted up and the closest period I could find was also the mid 80's. On the El nino front I'm not sure exactly what state we were in the mid 1980's but appears we were shifting from a La Nina to El nino during that period much like we have just seen this year so far. Also the 1968 comprasion is also extremely encouraging as well that Steve points out.

Four out of the five years that have been mentioned all had at least5 one pretty severe outbreak, indeed one had the most severe recorded easterly of all time...need i say what that was!

Also worth noting all those years that have been noted including the 1994/5 had a below average March.

As for the exampe that Paul gave from the CFS, it ties in very well with i thought December would be quite like, and it was also quite often how the weather was in the mid-80's Decembers that were nothing at all of real note. Still a long way off but I can sense that people are slowly starting to get more excited as more and more LRF forecast at least one period of decent cold.

Edited October 6, 2006 by kold weather

[Paul]

As I've said on many occasions - you can't expect those daily charts to come off. The point of a climatic forecast system is to pick trends etc though which is what they are useful for. Not sure how you're getting to discussing it being opinion or fact - in fact they're neither of those, they're forecasts!

At the current time we have just the charts available, over time we'll be creating other features around the data, including trending items and some form of verification.

Even within netweather extra itself there is a warning on there not to follow specific forecasts with this model as they change from day to day, trendwise though it's fairly solid and that imo is the correct use of this data.

[The Eagle]

Updated Thoughts:

WOW! What an excellent analysis, I agree with BB though. A mild winter probrably favourite atm. This is an excellent thread. Im more optimistic now

[Dawlish]

Excellent post Steve

I really enjoy your analysis every time. It's so good to have your knowledge & experience shared here once again as we approach another winter season with hopefully lots of snow and that easterly we all long for. :excl:

Like Roeder's early prediction, I find all these examplenentory European LRF charts so interesting. The signs are good but before we start wetting ourselves let just remember we've all been here before and the chance for a mild winter realistically stands stronger than a cold one.

I know people enjoy Steve's analysis, BB, and there is a terrific amount of knowledge and potential for learning in there, but the reason many people enjoy the analysis is because the analysis contains pointers to cold. The cold rampers, generally, aren't open to listening to a point of view which indictates a probability of warmth, even to the point of getting upset about it being expressed.

".....as we approach another winter season with hopefully lots of snow and that easterly we all long for." is a comment that shows exactly what I mean. Some of us are looking forward to the winter charts with just the same anticipation as we look at any charts. Snow would be really interesting, but record January temperatures would be just as interesting to me. We don't all "long for" anything. Many of us are just constantly fascinated by what comes along and are really intersted in the changing gfs charts, whatever they show.

Personally, I'm far more interested in trying to forecast correctly from the long-range gfs, than I am trying to forecast a particular type of weather. Snow is a real event, as we get so little in GWUK and it will be great to try and hone my gfs LRF method on winter charts and see if I can continue the success I've had over the summer, but there is no way I'm going to be constantly looking for one type of weather at the expense of all others. That's just so selective as to be silly to me. I'll bet I get called a cold ramper, amongst other things, at some stage this winter when I make a "spot" of colder weather. mind you there will be so many spotting cold weather as soon as it appears at the edge of reality on the T+360gfs, that I'm sure my own spots will be drowned. I just hope those people are prepared to keep a public record of what they do and have their record of LR prediction open to scrutiny, instead of claiming "I saw that 2 weeks ago", when cold comes, when they've been crying that particular "wolf" week after week, then got lucky.

It will snow this winter. It will also get cold. Overall, I think the chances are that it will be milder than average and I am more than happy to explain those reasons in depth on any thread in which someone asks me to.

Paul

[Stratos Ferric]

I wonder if it is worth netweather keeping a check on the accuracy of these CFS forecasts. Indeed, are there figures from CFS on their accuracy? I am concerned that these charts will be taken as accurate forecasts by some, when in fact, any forecast for November/December/January should come with an enormous health warning.

Although these look like "real" charts for those times, we can only guess at the actual likelihood of them coming true. I would think, at best, they are forecasts charts with a lower probability than the Met Office NAO forecast has. They are fun to look at and specultae about, but I have real reservations about their actual usefulness. To me they are opinion, rather than forecast.

Paul

Paul,

You and I know that there is a direct cube relationship between the extent to which any LRF projects cold and the extent to which it is supported, particularly in one or two favoured locations. our cautions are completely sensible, but I guess in a world of warmer winters dreaming is the one fort that can never be assailed.

[Dawlish]

As I've said on many occasions - you can't expect those daily charts to come off. The point of a climatic forecast system is to pick trends etc though which is what they are useful for. Not sure how you're getting to discussing it being opinion or fact - in fact they're neither of those, they're forecasts!

At the current time we have just the charts available, over time we'll be creating other features around the data, including trending items and some form of verification.

Even within netweather extra itself there is a warning on there not to follow specific forecasts with this model as they change from day to day, trendwise though it's fairly solid and that imo is the correct use of this data.

Nice one Paul, thank you about the verification bit. Very interesting. I'll look forward to it.

When you say "trendwise though it's fairly solid" are you referring to the CFS charts? If so, how have you come to the acceptance that the trends are "fairly solid" and what data are you basing that on?

Paul

Edited October 6, 2006 by Dawlish

[Paul]

When I say fairly solid, I should emphaise fairly at this point as I've not been watching it long enough to draw any reasonable conclusions - I've just been watching it for the past week ish and it maintains similar trends for each month through each forecast run.

It's a pretty well respected model, so I think it's fair to place some faith in it.

[Dawlish]

When I say fairly solid, I should emphaise fairly at this point as I've not been watching it long enough to draw any reasonable conclusions - I've just been watching it for the past week ish and it maintains similar trends for each month through each forecast run.

Ah! It's maintained similar trends for the past weekiDoh a dumb swear filter got the better of me Like I said, it's a forecast with, very likely, a low accuracy. Great to look at and speculate about. Must be taken with a lorryload of salt. It will be good to see the analysis at the end of a season, or a year. Nice charts though. Good addition to the site for discussion.

Paul

[Paul]

Not sure why it is likely to have low accuracy to be honest - yep any individual chart is likely to be extremely low accuracy at a range of x months but you can't expect any more from a long range climatic model. It's not designed to be used for individual specific forecasts, it's designed to give a more trend based forecast for a period. Which many would say it does very well.

[Dawlish]

Paul,

You and I know that there is a direct cube relationship between the extent to which any LRF projects cold and the extent to which it is supported, particularly in one or two favoured locations. our cautions are completely sensible, but I guess in a world of warmer winters dreaming is the one fort that can never be assailed.

The "fort" will be lain low by outcome over the years, SF. I can't help that, neither can you, neither can anyone. The wishers for cold can fight the "battle" for as long as they wish, but in a warming world, there will be fewer cold spells, cold winters and "victories". Reality is a domain the cold-wishers find hard to inhabit!

I don't actually take that military analogy at all. I'd lust much rather operate within a schema that gives probabilities which have a reasonable accuracy and not one in which my hopes are likely not to come true.

Paul

Edited October 6, 2006 by Dawlish

[SMU]

I know people enjoy Steve's analysis, BB, and there is a terrific amount of knowledge and potential for learning in there, but the reason many people enjoy the analysis is because the analysis contains pointers to cold. The cold rampers, generally, aren't open to listening to a point of view which indictates a probability of warmth, even to the point of getting upset about it being expressed.

It will snow this winter. It will also get cold. Overall, I think the chances are that it will be milder than average and I am more than happy to explain those reasons in depth on any thread in which someone asks me to.

Paul

Paul- I would be interested in the counter arguement for a milder Winter this year- Apart from the current 'historic statistical one'-

I started a thread on another forum that relates to a NO analogue forecast- which would include the use of NO historical data-

This then leaves with current trends & current data to be taken at face value- Perhaps your answer would be different ...

I suppose it all boils down to how much bias you put on historic data / trends influencing one year- as opposed to 'current' climate change & data trends influencing one year....

I think thats probably where we both differ....- none the less I hope that this high level of debate is sustained throughout the winter & doesnt decend into the issues we all had before....

best regards

Steve

Edited October 6, 2006 by Steve Murr

[Dawlish]

Paul- I would be interested in the counter arguement for a milder Winter this year- Apart from the current 'historic statistical one'-

I think thats probably where we both differ....- none the less I hope that this high level of debate is sustained throughoutthe winter & doesnt decend into the issues we had before....

best regards

Steve

My argument centres completely on the odds of a colder, or a warmer winter occurring, Steve. I have no synoptic device for forecasting this winter. The synoptic forecasts issued by individuals are not accurate enough to be useful, whereas my probabilty forecast, based upon a GW trend, has been highly accurate, compared to any other method presently being used.

"the issues we had before" were mainly due to the fact that you find it hard to believe that the forecasts for a cold winter can suffer such a statistically devastating argument. My own arguments stayed at the same level all the way through, as they will continue to do - but they will focus on the UK's reactionj to the GW trend being the best indicator of what kind of a winter we are going to have. Synoptic forecasts of cold/mildness in a coming winter, at this distance are so flawed in terms of their accuracy as to be next to useless. Thus, others, following those forecasts and "ramping" a cold winter as a result, make someone who doesn't believe in the accuracy of those forecasts in the first place, just shake their head.........and nobody can claim their forecasts are accurate.

And I mean - nobody. No matter how much somebody might really, really, want to believe them.

Paul

Edited October 6, 2006 by Dawlish

[Paul]

Interesting article here on the CFS if anyone is interested:

http://www.nws.noaa.gov/ost/climate/STIP/cfs_vresolution.htm

[TEITS]

The "fort" will be lain low by outcome over the years, SF. I can't help that, neither can you, neither can anyone. The wishers for cold can fight the "battle" for as long as they wish, but in a warming world, there will be fewer cold spells, cold winters and "victories". Reality is a domain the cold-wishers find hard to inhabit!

I don't actually take that military analogy at all. I'd lust much rather operate within a schema that gives probabilities which have a reasonable accuracy and not one in which my hopes are likely not to come true.

Paul

Until GW completely removes the possiblity of a cold winter the cold lover's on this forum shall continue to be in full force. Beside's this who know's what the future brings and without the aid of either a crystal ball or a time machine there is no way we can be sure what our weather is going to be. To assume our future climate is going to be warmer just because of recent warming is rather foolish IMO and lacks an understanding of our climate.