Autumn and Winter

[Snowly does it]

I'd rather it didn't. I feel rather disillusioned with Northerlies these days! Down here in Sussex/Oxford, Northerlies aren't much use. Too many mountains in the way. And those annoying lows which don't want to come closer than denmark...grrr.

Let's hope the GH slips on all the ice and ends up over scandi, bringing both of us metres of snow and ice and burst pipes...

An Omega block would suit.

I get snow from northerlies and easterlies so I am easy on that!

[Dawlish]

Well Paul, if you flipped that coin a thousand times, you would have to expect a run like we're currently in at some point wouldn't you. Just because its the here and now doesn't necessarily mean its a never ending upward trend.

No, you are right BB, it doesn't mean it is a never ending upward trend, but I work in odds and probabilities with the weather and I know that the odds of continuing an established trend are shorter than those for that trend changing.

If there was no upward trend, then the probability of getting a cold, or a warm winter, would be 50:50, evens. However, this warming is well established. Unfortunately we are in a chaotic system and it is not the same as flipping a weighted coin, to determine a biased outcome. Too many factors are involved to calculate the exact probability. That's why I'm relying on the monthly data from that established trend. That shows me that, over that length of time, there hindcast probablity of getting a month above average, has been at least 70%, colder, only 20% = 2/7 a warm month. It is actually higher for a warmer year. Add in the continuing trend and I estimate the probability doubles, that the trend itself will continue, after 20 years of it being established. I wish I was maths trined to degree standard and I had the training to calculate that probability more precisely! My stats are undergraduate level and that really doesn't equip me to be much more precise.

So, 7/1 against the trend reversing, 1/7 it will continue. Not certainty; I don't deal in certainties, but they are easily good enough odds for me to back the trend.

Now that is terribly simple probabilities and better minds than my small excuse for one, have developed computer models that can calculate how far the trend can take us. They can factor in, or out, CO2, but the models show that we will not change this trend, whatever happens this century, even by reducing CO2 levels; we are locked into it. I don't actually believe that, but add the computer predictions to my own calculated probability and the argument for continued warming is very persuasive. I've been persuaded and it now has to take a very good argument to show me faults with that reasoning.

That's why the one year/18 month trend stuff counts for nothing with me (honestly, sorry to say that, believers in that tiny sample), statistically, it counts ziltch, there is no statistical relevance to it. If that's harsh, for the ones that wish for colder conditions again, maybe it's worth reassessing why they believe that it will get colder? I won't be persuaded by the "well it happened, so it can happen again" argument. Statistically, that is unlikely - not impossible, just unlikely.

There more good, scientific reasons why I feel the warming trend will continue than there are good scientific reasons why it will stop. I'm just backing the clear scientific favourite. if you feel otherwise BB, I've got a different thread waiting for your virtual tipple-stake!

Paul

Edited September 29, 2006 by Dawlish

[kold weather]

The problem with last year is that as TWS said, everything was a touch too far east for us to et the strongest of the cold shots, equally the milder air was to ofar west so we were stuck inbetween the two main airmasses, hardly suprising that we had a close to normal winte rin terms of temps. Indeed the winter was dominated by HP cells either just to our east or over us, which meant we had pretty static average weather overall, though we did see what a true inversion can do as well, having several proper ice days in Feb across large parts of S.England and the Midlands.

[SMU]

I shouldn't have to spend time continually amending your incorrect assumptions and misrepresentations of what I post.

Suffice to say, it might not have occured to you Dawlish, but I am trying to post (like everyone else) to a forum beyond just yourself and, frankly, don't want the same GW rhetoric being stuffed down my throat everytime I try and participate on here. Not because I can't face it, or wish to refute its obvious existence, nor because I have to go upstairs to get a pillow to cover my head away from the 'truth' but because you say the same thing at every possible opportunity and I feel I cannot post without you popping up everywhere with the same thing.

I do not profess to have great in depth knowledge and certainly don't expect everyone to agree with me, but, strangely enough to you, I can wake up every morning aware of your alleged grave consequences for the British winter - and as much as I love snow and it will be indeed very disappointing to me if your predictions come true I won't need counselling if it doesn't, because it won't pay my bills or keep a roof over my head.

Hope the irony in all of that is not lost.

Furthermore, I do not expect you to accept my opinion, (nor care a jot whether you do actually), but would ask as nicely as possible that you desist from discrediting my posts, and others, with very tiresome pie in the sky hopecasting jibes. That is where the 'prevailing atittiude' lies.

Thank you

Tamara

Evening SP/All-

I was sitting here mulling over my thoughts for the forthcoming Winter & its probably a good time to indulge in at least one half decent post before the latter stages of Autumn presents me with another opportunity to issue a Winter Forecast-

Most of the 'talk' this year has ben around global Warming & How subsequent temperature records have been broken as a result, indeed this has held true for large parts of the US where records have tumbled, & also manifested itself here in the form of the July Pattern & September pattern-

If however people 'assume' that this years records are an automatic precursor for a warm winter they should think again- The common denominator for record breaking in terms of temperatures is a highly blocked scenario with stable & consistent Cold or Warm air advection-

And this has been the case nearly ALL summer long for the Western part of Europe-

Heres a chart from one of the hottest days of the Summer- The 500 Anomalies clearly sitting over Central Europe-

http://www.wetterzentrale.de/archive/2006/...cka20060719.gif

Lovely........

The thing to take away from this ISNT the heat though- its the Flow patterns & the fact of the reduced capacity of 'Westerlyness'

Heres a quote from Philip Edens site regarding July-

Mean monthly sea-level pressure was above normal over practically the whole of continental Europe, but near to or below normal over much of the North Atlantic. The main anomaly centres were +7mbar near Stockholm and –7mbar in mid-Atlantic. For its combination of high pressure and frequent southerly winds over the UK July 2006 hasno parallel during the instrumental record. It is hardly surprising that such a month should break so many records.

& heres the one for June..

Mean monthly sea-level pressure was above normal over most of Europe including the British Isles. The first half of the month was very anticyclonic, and although the second half was rather more changeable there was no extended spell of cyclonic or westerly weather. In the last 30 years only the Junes of 1995 and 1988 were more anticyclonic.

Again the key here is Reduced Westerly flow-

Moving on though through the Autumn & Onto the outlook for Winter we have to make distinctions between GW & Synoptics and GW & Air masses-

I often think here that people mix the 2 & jump along to an unlikely conclusion-

In terms of GW & Synoptics there is NO tried & tested correllation to intimate that because of GW a certain situation doesnt occur or vice versa- the data span is to short & doesnt cover enough of the Earths Natural Oscillations & cycles to present any hard facts-

There is no doubt it is a factor & will become ever more so, but for the time being we cannot quatify/speculate on the ACTUAL Linear Correlation of the Two-

If however we refer to GW & Air Masses then you would certainly find a more receptive audience on my behalf because this is where it is doing the damage-

The Equatorial Air Masses MUST by default be warming, Not as quick as the Pole- but none the less the depth & intensity of heat drawn up through Continental interiors is certainly on the increase this is of course with the assistance of drier Soil moisture- it is noticable that top temperatures at the height of any southerly plume are 2/3 degrees warmer than before-

To echo this here is a map of where the most warming has occured in the last 30 years-

The continental Interiors.....

Also Note there are NO areas of Cooling in the Northern Hemisphere..........

Obviously this warmth is not reserved for Summer- The Winter Air Masses MUST be less potent than they were say 20 years ago due to the GW factors effecting the pole:-

Reduced Ice pack coverage reducing latent heat transfer-

Increased ocean span absorbing more incoming solar radiation-

Large +VE SST anomalies across the Northern Hemisphere-

To that end there will come a point whereby the Marginal Snowfall situations that used to occur across the UK will be lost perhaps forever-I think the first to go will be those occasions where we have Cold Polar North westerlies, I know TWS will be able to dig out some charts where the -5C line followed a big loop out of the Artic & Still managed to make it to our shores-

These were Marginal & I think the air mass will be SO modified unless your at considerable elevation rain & sleet will replace Snow-

I do want to be clear here though, the Marginal events like that may be on the verge of distinction but back around the compass East Past 0 degrees & the Air masses are still plenty good for snowfall-

I suppose as it stands my current 'tipping' point of Air mass feed to become Unfavourable would be anything past approx 30 degrees west ( if the 0 Line was Due North)- Hope that makes sense-& assuming everything is constant with previous Cold spells-

Now that that point is established I would like to add one further point & thats the baseline for our Minima CET - With the Exception of Feb 1986 we have NEVER had a 100% Northerly/Easterly Month - So with that in mind we will ALWAYS have a period of warmer Air mass-

Going on the basis that ALL air masses have been modified upwards I would have to say that the baseline probably hovers somewhere around the 0.5 to 1C mark- & I guess if we were to experience another Jan 79 which saw a -0.4 CET I think the return would be Somewhere within the 'NEW Goalposts'.....

Remember though I do NOT endorse a total fundamental Change in our Synoptics due to GW- just a distinct re-allignment of the Margins -

Anyway, onto the Prelims for this Winter-

With a full 9 weeks still to run to Winter Starts there can be NO doubt that even with the best Analogues in the world, the best forecasters/Forecasts the most up to date data things can still move & change at pace and to that end a Winter forecast issued today or for that matter in ANY part of September is inherantly a waste of time-

What we can do is Speculate on the Current data & Trends & project those onto Winter-

The current Watch word is ENSO/El nino whatever you wish to call it-

The key here is Weak to Moderate-

Having looked at the NINO Ensemble data ( Havent got it to hand right now) the Ensemble mean & Clustering ALL come in within the bounds of Weak to Moderate- there are very few memebers that point to a Strong event-

THATS ALL WE NEED TO KNOW- Theres no need to get hung up on x,y & Z- as long as we stick within those bounds the 'probability' of El NINO Assisting our Winter rather than hindering it Goes up-

Remember again- I do NOT subscribe to the theory that EL nino is the ultimate factor in deciding our Winter- but one of the factors' in the mixing pot-

NAO & AO-

Things are moving at pace within this particualr Sector of the Teleconnections- The NAO has been considerably Negative lately & this is assisting in driving the SSTA Pattern for the Winter-

The NAO:http://www.cdc.noaa.gov/people/gary.bates/tele/nao.gif

Also a review of the recent changes in the atlantic basin are encouraging to say the least-

CLICK TO ANIMATE-

The recurving of Tropical Storms Partially induced by the NAO & Current pressure patterns have continually assisted in the upwelling of the surface water to the East of Newfoundland- to that extent that that the anomalies are 'BEGINNING' to take on a better look in terms of predisposing the atmosphere towards a Negative NAO-

We are by No means there yet- however enough has changed away from the May / june anomlies to see the even the Met office backtrack somewhat on the second preliminary Winter outlook-

As for the AO- Similar & still a wild card- Last year Stratospheric Warming events allowed for a Strongly negative Phase of the AO to continually repeat the high lattitude blocking scenarios- This didnt come into play for NW europe until the Latter part of the winter- Almost Spring...

As for the jet stream itself heading on towards this Winter, we are again encouraged by the weakened state, Also worthy of Note is the Change in Direction of the QBO-

For those who arent to familiar with its existence its a zonal Wind anomaly that either enhances or weakens the pacific jet- Fortunatly in its current position its Nothing like last year & we WONT see a howling pacific jet smashing our blocking to bits-

The other factor in the pacific is to monitor the PDO- This is again Negative however the trends SHOULD be back towards neutral & positive as we head into Winter ( This is because El NINO Winters dont tend to conincide with Negative PDO Winters)-

So where do I currently stand in terms of this Winter-

Well from the perspective of someone who studied statistics you would have to say the overwhelming trend is for an Above average Winter- Anyone with a reasonable grasp of Trends & data plotting can see the graph is climbing... HOWEVER Statistical forecasting in weather ISNT a good tool to have in the bag as it doesnt take into consideration rapid change or short term outlier events away from the overwhelming trend & this is where the human input comes in-

All things considered to write off this Winter by just basing thoughts on historical statistics is VERY foolish, espcially when we consider one of the PRIMARY drivers of the intense westerly dominated regime of the 90's is now reaching its weaked phase ( Of course im talking to the Sunspot Minima)-

The combination of a Sunspot Minima, Potential Forced negative NAO Pattern, Weak to Moderate EL nino ( Weakening the Polar jet with the energy going into the subtropical jet), Continuation of Negative AO phase & Weak Pacific Jet ALL point to a Winter that SHOULD deliver Cold rather than Warmth-

Irrespective of Statistics in the last 20/30 years gone by the probability of getting a below average WINTER as a whole I would say is higher that getting a warmer one-

Remember this quote from model performance - the same can be said for short term climalogical changes-

When the model consensus or majority cluster begins to breakdown… WATCH THE SHIFT TOWARDS the Model A or M.O. solution. Incremental changes towards the M.O. solution will often lead a forecaster to make incremental changes in the forecast usually because of concerns over model uncertainty and consistentency issues. This is often a mistake. Once there is a discernible shift towards the Model A / M.O. solution… it is often wise to make large changes in the forecast that is reflective of the Model A OUTLIER solution.

Best regards

Steve

Edited September 29, 2006 by Steve Murr

[Dawlish]

Evening SP/All-

I was sitting here mulling over my thoughts for the forthcoming Winter & its probably a good time to indulge in at least one half decent post before the latter stages of Autumn presents me with another opportunity to issue a Winter Forecast-

Best regards

Steve

errrr....you know what I said about a "great post" sometimes not having great logical content.......that's one of the best posts I've read on here for weeks. I might not agree with all of it, especially the bit about statistical weather forecasting not being a good tool to have in the bag and writing off this winter (which I certainly have never done, my odds show that clearly), but that argument, Steve, at least holds together. It'll be interesting to see whether your thoughts come to reality. It actually caused me to miss the first 5 minutes of Rebus, because I enjoyed re-reading it and replying to it so much.

In many ways, I hope you are right(!) - but I would give you only a 20% chance of being right and as a bookie, I wouldn't offer you 5/1

Super post, Steve, I meant what I said!

Regards, Paul

Edited September 29, 2006 by Dawlish

[SMU]

errrr....you know what I said about a "great post" not having great content.......that's one of the best posts I've read on here for weeks. I might not agree with all of it, especially the bit about statistical weather forecasting not being a good tool to have in the bag and writing off this winter (which I certainly have nevre done, my odds show that clearly), but that argument, Steve, at least holds together. It'll be interesting to see whether your thoughts come to reality. It actually caused me to miss the first 5 minutes of Rebus, because I enjoyed re-reading it and replying to it so much.

In many ways, I hope you are right(!) - but I would give you only a 20% chance of being right and as a bookie, I wouldn't offer you 4/1

Super post, Steve, I meant what I said!

Regards, Paul

Cheers Dawlish I will take a Virtual Smirnoff ice at 5:1 for a below average Winter- hopefully giving me 5 virtual smirnoffs.......

S

Edited September 29, 2006 by Steve Murr

[smich]

Great debate on this thread.

This GLOBAL warming issue continues to be discussed here purely in relation to our local "corner" of the earth. But as a worldwide issue, it's implications are immense - and complicated. Far beyond the logical "equator becomes unbearable/Spain becomes Sahara/as does France/ Britain resembles Spain/ Scandinavia resembles UK/ Arctic melts etc. outcome.

The mechanisms don't just include the atmosphere of course, but not just SST's either - salination issues must be included along with ground temps, the solar cycles, etc etc I could on...

...actually I am! But Steve is right, it's all too easy to say that certain synoptics and weather are less likely to happen because of GW. But there are too many other factors (with hitherto unforeseen consequences) to consider before Cold Lovers here need to write off winter!

Smich

Edited September 29, 2006 by smich

[wellington boot]

Thanks Steve. That was the most informative and lucidly argued post I've read on here for a while. I was going to write something about the El Nino/PDO/NAO predictions/effects myself, but it's just as well you did it for me, as you clearly have a far more comprehensive understanding of these matters than I do with my rather sketchy knowledge (though I feel slightly less sketchy now).

I find it interesting that the forecast for the NAO this winter has changed so quickly from predicting a slightly positive oscillation,

North Atlantic Oscillation

Forecast for Winter 2006/7

Issued: 25th August 2006

by Prof Mark Saunders and Dr Adam Lea

Benfield Hazard Research Centre, UCL (University College London), UK

Forecast Summary

The North Atlantic Oscillation is forecast to be slightly above-norm during the

coming winter (1st December 2006 - 28th February 2007).

to predicting a negative one. Is this the sort of thing which can work as a trend, so that changing factors which have obviously led to modifications in NAO forecasts, keep changing in the same way, so that forecasts go even more negative?

[SMU]

Thanks Steve. That was the most informative and lucidly argued post I've read on here for a while. I was going to write something about the El Nino/PDO/NAO predictions/effects myself, but it's just as well you did it for me, as you clearly have a far more comprehensive understanding of these matters than I do with my rather sketchy knowledge (though I feel slightly less sketchy now).

I find it interesting that the forecast for the NAO this winter has changed so quickly from predicting a slightly positive oscillation,

to predicting a negative one. Is this the sort of thing which can work as a trend, so that changing factors which have obviously led to modifications in NAO forecasts, keep changing in the same way, so that forecasts go even more negative?

Yes-

The main swing MUST be around the SST changes- although a Sharp Stratospheric warming event which generally takes 3 weeks to propergate downwards will also assist-

This next 8 weeks is going to generate SO much speculation- If we get a below ave Oct or even Nov- the expectation will go through the roof... lets just hope we dont get another Oct 74 onwards.....

S

Edited September 29, 2006 by Steve Murr

[Polar Continental]

Evening SP/All-

To that end there will come a point whereby the Marginal Snowfall situations that used to occur across the UK will be lost perhaps forever-I think the first to go will be those occasions where we have Cold Polar North westerlies, I know TWS will be able to dig out some charts where the -5C line followed a big loop out of the Artic & Still managed to make it to our shores-

These were Marginal & I think the air mass will be SO modified unless your at considerable elevation rain & sleet will replace Snow-

Best regards

Steve

Hi Steve, thanks very much for a superb and very informative post, and at times the reading proves a bitter pill to swallow for us cold/ snow lovers.

As you say though all is not lost, with the right set-up there is absolutely no reason why we shouldn’t enjoy a good old cold snowy winter, nearly winter 2006.

But there is no denying that snowfall in the UK is becoming a rarer phenomenon, getting the right synoptics was much easier to come by 20 or 30 years ago, I can remember widespread snowfall occurring on Polar maritime air and even returning PM quite frequently during the 60’s and 70’s, indeed in recent years it has at times been difficult to get a decent snowfall from a direct northerly onJanuary 27th 2004 a widespread rain event, thankfully though this was eventually compensated by the famous thunder snow event.

Finally the charts below say it all, PM air over a long Atlantic fetch brings the –5c line all the way down to southern Enland, I wonder

Paul

[BLAST FROM THE PAST]

Some excellent posts and particularly big Steve Murr yet again informative with backed up reasoning.

I must admit I am getting fed up with the term goal posts being moved etc cold sources lessening. The chart Steve illustrated re warming...IF that went back another 20-30 years the picture would be wholly different...it would clearly show arctic cooling...without a doubt, no arguments. The arctic was warmer by some distance in the 30s and 40s. The effect of the Arctic sea absorbing warmth from solar radiation is negligible, most of it is in darkness for 6 months the rest is 17% max compared to tropical latitudes...spread that out over 12 months and hey presto. The winters of the 40s were bonechillingly cold with a 1C anomalously warmer arctic...hmmm goalposts moved...give me a break. USA has experienced severe early snowfall with record cold temps during Sept..as Steve has alluded to synoptics are the player...oh and they still bring the goods if they are right.

Anticipation builds..and so it should. Another spell of blocking beckons, lively weather approaches early Oct as predicted pre chart range and a flip equivalent of Nov 05 is approaching, not as cold but Autumn will be very obvious.

Ignore the info if you wish...the cold sources still exist..ask why the baseline does not include the 30s and 40s...Because if it were the arctic would show cooling....ooooh we can't have that we are in irreversible global warming!

Enjoy the approaching winter...it will be......

BFTP

Edited September 29, 2006 by BLAST FROM THE PAST

[Hiya]

Some excellent posts and particularly big Steve Murr yet again informative with backed up reasoning.

I must admit I am getting fed up with the term goal posts being moved etc cold sources lessening. The chart Steve illustrated re warming...IF that went back another 20-30 years the picture would be wholly different...it would clearly show arctic cooling...without a doubt, no arguments. The arctic was warmer by some distance in the 30s and 40s. The effect of the Arctic sea absorbing warmth from solar radiation is negligible, most of it is in darkness for 6 months the rest is 17% max compared to tropical latitudes...spread that out over 12 months and hey presto. The winters of the 40s were bonechillingly cold with a 1C anomalously warmer arctic...hmmm goalposts moved...give me a break. USA has experienced severe early snowfall with record cold temps during Sept..as Steve has alluded to synoptics are the player...oh and they still bring the goods if they are right.

Anticipation builds..and so it should. Another spell of blocking beckons, lively weather approaches early Oct as predicted pre chart range and a flip equivalent of Nov 05 is approaching, not as cold but Autumn will be very obvious.

Ignore the info if you wish...the cold sources still exist..ask why the baseline does not include the 30s and 40s...Because if it were the arctic would show cooling....ooooh we can't have that we are in irreversible global warming!

Enjoy the approaching winter...it will be...... <_<

BFTP

I agree.

Do you happen to have a graph that shows these Artic temprature changes?

[SMU]

Some excellent posts and particularly big Steve Murr yet again informative with backed up reasoning.

I must admit I am getting fed up with the term goal posts being moved etc cold sources lessening. The chart Steve illustrated re warming...IF that went back another 20-30 years the picture would be wholly different...it would clearly show arctic cooling...without a doubt, no arguments. The arctic was warmer by some distance in the 30s and 40s. The effect of the Arctic sea absorbing warmth from solar radiation is negligible, most of it is in darkness for 6 months the rest is 17% max compared to tropical latitudes...spread that out over 12 months and hey presto. The winters of the 40s were bonechillingly cold with a 1C anomalously warmer arctic...hmmm goalposts moved...give me a break. USA has experienced severe early snowfall with record cold temps during Sept..as Steve has alluded to synoptics are the player...oh and they still bring the goods if they are right.

Anticipation builds..and so it should. Another spell of blocking beckons, lively weather approaches early Oct as predicted pre chart range and a flip equivalent of Nov 05 is approaching, not as cold but Autumn will be very obvious.

Ignore the info if you wish...the cold sources still exist..ask why the baseline does not include the 30s and 40s...Because if it were the arctic would show cooling....ooooh we can't have that we are in irreversible global warming!

Enjoy the approaching winter...it will be...... <_<

BFTP

Hi BFTP-

Interesting thoughts there matey, and yes to back up what you say ive including a temp profile of the artic from the 1880's to date-

There is a clearer warmer spell in the 30's & 40's-

The overall trend is warmer- however over a longer timespan-

I suppose the thing that can be gleened most here is the fact that if the Artic was WARMER in the 30's / 40's than the recent absence of snow/ marginal events must have seen the air mass modified more from other influences like SSTA's-

Again if you look at this SUMMER- this is just an example- the pole has a cold anomaly- but look at the mid lattitudes....

Remember this data though is from 70N-90N- to which there is still room for different data between 70N & where we lie at around 45 N-

regards

Steve

Graph in post Hiya.......

Edited September 30, 2006 by Steve Murr

[Dawlish]

Thank goodness for some decent argument away from the......"it was colder last winter, so we've got a really good chance of it being colder this winter", stuff. And no-one getting upset! Marvellous!

Hi BFTP-

The overall trend is warmer- however over a longer timespan-

I suppose the thing that can be gleened most here is the fact that if the Artic was colder (Ed, I know you meant warmer, Paul) in the 30's / 40's than the recent absence of snow/ marginal events must have seen the air mass modified more from other influences like SSTA's-

regards

Steve

Graph in post Hiya.......

Yes and if there is a real link between Arctic temperatures and UK temperatures (which, though the link sounds as if it should be an obvious one, the graph shows a clear link only in the present warming trend) just think how much warmer our latitudes are likely to be, when (much more likely than "if", in my opinion - trend-changing odds again), the Arctic warms further and we lose the present-day cooler-than-the-30's/40's influence? Only speculation, as I'm not sure we can link Arctic temps to warmer/colder BI conditions at all, but both the Arctic and the BI will be affected by GW, as it continues to progress.

Paul, in a very wet Dawlish, with a very depressed dog.

PS I hope the breakfast GW debate from a warmer point of view hasn't spoiled your cornflakes, folks.

Edited September 30, 2006 by Dawlish

[BLAST FROM THE PAST]

Steve, Dawlish et al

Indeed it is of interest on how much the arctic temps affect the UK. Steve maybe SSTA are to be looked at but its a very 'odd' anomaly considering the winters that bit from 1940 onwards...that is why I remain on the side that correct synoptics and long enough stability will bring biting cold to the UK. I am awaiting the interest from many as we see a switch take place soon with the GHP building and very autumnal weather setting in, but most importantly the continued theme of northeryl blocking is not going to go away...hope you're drying out down in lovely Devon Paul <_<

BFTP

Edited September 30, 2006 by BLAST FROM THE PAST

[TEITS]

Thank goodness for some decent argument away from the......"it was colder last winter, so we've got a really good chance of it being colder this winter", stuff. And no-one getting upset! Marvellous!

After reading the post's on this thread im not sure that is a fair reflection of what some have said on here. By what I have read member's like SP commenting on the fact that last year not only did we have the synoptics but the record breaking cold pool in Russia proves a cold spell like 81/87 is very possible. Like SP what we need is the two of these to come together.

Let's face it nobody know's what is going to happen this winter but you cannot assume this winter will be cold just because of last winter but equally you cannot expect this winter to be mild just because of previous mild winter's. If using past weather to predict the future weather was so easy then many LRF would be far more successful. You need to judge each winter on it's own merit's so the best way of getting an idea for this winter is to keep a close eye on the latest data SST's for example over these next 6 weeks.

[SNOW-MAN2006]

September 2006 Forecast review:

This years september forecast was in accurate. My expectations of warmer weather not persiting was wrong to start which then madeway for a pattern change to allow the forecast to become only 20% accurate. Overall C.E.T was 16.6(+2.9) and my forecast C.E.T was to be 14,which it wasnt.

October 2006 Forecast:

1st-6th:

Mild- warm tmperatures as we see bands of showery rain move west to east at times. On the 6th it is looking like a wet day with temperatures cooling off slightly. This period will see an average temperature of 13.

7th-12th:

Cooling down further to below average with frosts common in this period on higher ground. Temperatures just making it into double figure with fewer bands of rain than of late with high pressure situated to the north east allowing northeasterly winds to prevail.

13th-20th:

Wet and possibly windy as the Scandi. high lets northerly winds plummit down across th UK. With low pressure to the west it will be wettest in the west but rain everwhere at times. Still cool with temperatures continuing to struggle to reach double figures away from the far south and south west.

21st-31st:

The jet is taking a more southerly track around the Scandi high allowing the weather to remain cool and possibly get colder. Winds may continue from the north but rain is likely to persist as the jet breaks off to drag bands of rain towards the uk. Low pressure will track south allowing the south to get most chance of rain.

SNOW-MAN2006

[Snowyowl9]

Evening SP/All-

To that end there will come a point whereby the Marginal Snowfall situations that used to occur across the UK will be lost perhaps forever-I think the first to go will be those occasions where we have Cold Polar North westerlies, I know TWS will be able to dig out some charts where the -5C line followed a big loop out of the Artic & Still managed to make it to our shores-

These were Marginal & I think the air mass will be SO modified unless your at considerable elevation rain & sleet will replace Snow-

As for the jet stream itself heading on towards this Winter, we are again encouraged by the weakened state, Also worthy of Note is the Change in Direction of the QBO-

For those who arent to familiar with its existence its a zonal Wind anomaly that either enhances or weakens the pacific jet.

The intense westerly dominated regime of the 90's is now reaching its weaked phase( Of course im talking to the Sunspot Minima)-

The combination of a Sunspot Minima, Potential Forced negative NAO Pattern, Weak to Moderate EL nino ( Weakening the Polar jet with the energy going into the subtropical jet), Continuation of Negative AO phase & Weak Pacific Jet ALL point to a Winter that SHOULD deliver Cold rather than Warmth-

Irrespective of Statistics in the last 20/30 years gone by the probability of getting a below average WINTER as a whole I would say is higher that getting a warmer one-

Remember this quote from model performance - the same can be said for short term climalogical changes-

Best regards

Steve

Fantastic post Steve and I`ve picked out 3 very interesting points to me which makes for a balanced and very interesting reading.

The 1st one is very realistic and I agree that will happen as I`ve noticed these polar N/NW don`t deliver nowhere near as much as years ago,makes for bleak reading

as GW is concerned,and that chart you showed with the northern half warming by 2c and over some parts of the south hadn`t changed.

I`ve learned something from the 2nd point QBO,last years pacific jet was strong there was no doubt.

I have learnt so much from reading this site and your posts.

:lol:

And with these near record breaking months this summer it`s got to balance out some where.

And finally for this winter atleast we have a good chance of something delivering with more blocking and less westerly influence,we live in hope for this winter atleast.

S9.

Edited September 30, 2006 by Snowyowl9

[SMU]

Having read views from both sides of the fence (and some excellent ones ) I still haven't changed my mind that the goalposts have not moved as much as many think.

I'm not sure that airmasses from each quarter have all modified upwards on an across the board seasonal basis. If record cold is still able to appear in parts of the world then this suggests to me that with the correct synoptics in tandem with those cold pools then exceptional cold can still occur in this country. I'm only looking at the numbers on the recent wezzerzentrale records. Frankly, as far as I am concerned, it does not matter how often it occurs, the fact is it can still happen and that should be good enough. So, for starters I would still not question the potency of a real polar continental airstream nowadays - to give a good illustratration of my doubt. No, we haven't seen one for a while, but that does not mean it is a reflection that the goalposts have moved so much that it cannot still happen or that it is a given that the airmass if it did happen would be modified upwards!

At most, these assumptions are at present premature, as I have repeated and a result, perhaps, of too much arm-chair GW fatigue.

Tamara

Polar Continental always the best for true cold...........

Especially for me & you.... :lol:

S

[SNOW-MAN2006]

September 2006 Forecast review:

This years september forecast was in accurate. My expectations of warmer weather not persiting was wrong to start which then madeway for a pattern change to allow the forecast to become only 20% accurate. Overall C.E.T was 16.6(+2.9) and my forecast C.E.T was to be 14,which it wasnt.

Update to previous forecast (including charts)

October 2006 Forecast:

1st-6th:

Mild- warm tmperatures as we see bands of showery rain move west to east at times. On the 6th it is looking like a wet day with temperatures cooling off slightly. This period will see an average temperature of 13.

Click on the link below to look at this sector in more detail:

7th-12th:

Wet and cool at first before we see a change to more settled wather for a time as winds turn westerly. But rain always in the north and at times in the west.

Click below to see a slightly detailed outlook:

13th-20th:

A dominant high over Europe will make low pressures continue to track there way north over the country. This will mean that the south remains dry and the north will remain wet with windier periods at times (the chart below reflects this- it is in word due to unable to upload):

21st-31st:

The jet is taking a more Northerly track around the Euro high allowing the weather to remain cool and possibly remain milder. Winds may continue from the west but rain is likely to persist as the jet breaks off to drag bands of rain towards the uk. Low pressure will track north allowing the north to get the most chance of rain.(jet chart shown in word Doc again):

You may notcie some changes to the forecast from the previous one. This is due to a change in the models. This run has been a much milder one in the last forecast and just goes to show that forecasting 2 weeks out bring changes. Charts have been added to show what i wrtie and to help people understand the forecast. I am expecting colder runs but i have altered the forecast in conjunction with the charts. I hope you enjoy the forecast and can see the GFS' view of the month ahead.

My estimated C.E.T for October is 9.5 but according to current charts it is likely to be much higher. The change in each run of charts shows that winter is approaching and scenarios change in each run. But whatever the weather i can be sure that october will see rain,sun and winter approaching

Thank-you

SNOW-MAN2006

p.s could a moderator delte a post posted 3 minutes before this one as a the internet dissconnected posting my unfinished forecast without me knwoing. thank-you.

Done it for you :lol: Tuggy

Edited September 30, 2006 by tugmistress

[moses]

Thanks Steve. That was the most informative and lucidly argued post I've read on here for a while. I was going to write something about the El Nino/PDO/NAO predictions/effects myself, but it's just as well you did it for me, as you clearly have a far more comprehensive understanding of these matters than I do with my rather sketchy knowledge (though I feel slightly less sketchy now).

I find it interesting that the forecast for the NAO this winter has changed so quickly from predicting a slightly positive oscillation,

to predicting a negative one. Is this the sort of thing which can work as a trend, so that changing factors which have obviously led to modifications in NAO forecasts, keep changing in the same way, so that forecasts go even more negative?

Who has predicted a negative NAO?

Thank goodness for some decent argument away from the......"it was colder last winter, so we've got a really good chance of it being colder this winter", stuff. And no-one getting upset! Marvellous!

Yes and if there is a real link between Arctic temperatures and UK temperatures (which, though the link sounds as if it should be an obvious one, the graph shows a clear link only in the present warming trend) just think how much warmer our latitudes are likely to be, when (much more likely than "if", in my opinion - trend-changing odds again), the Arctic warms further and we lose the present-day cooler-than-the-30's/40's influence? Only speculation, as I'm not sure we can link Arctic temps to warmer/colder BI conditions at all, but both the Arctic and the BI will be affected by GW, as it continues to progress.

Paul, in a very wet Dawlish, with a very depressed dog.

PS I hope the breakfast GW debate from a warmer point of view hasn't spoiled your cornflakes, folks.

I'm surprised no one has mentioned the north atlantic drift or whatever it's called - and the fact that it is slowing down would give us greater chances of bad winters - or is this just the daily express getting too excited???

[Snowyowl9]

Who has predicted a negative NAO?

I'm surprised no one has mentioned the north atlantic drift or whatever it's called - and the fact that it is slowing down would give us greater chances of bad winters - or is this just the daily express getting too excited???

The NAD does seem to of gone into a very quiet phase topic wise now don`t know why.

I remember seeing the programmes on TV a couple of years ago about the possible next ice age.

I enjoyed watching them programmes

Global dimming was another whoops I`m going of topic.

[chilly milly]

Temperature seems to be dropping really slowly tonight. Its still 15C out there which is warmer than last night. Which is good for the September record, but not for those impatient for Autumn

[Thundery wintry showers]

I see Tamara's point, but in itself it doesn't suggest that the goalposts haven't moved upwards.

No matter where the current baseline stands, there will always be variation- be it mild or cold variation- either side of the mean. If the continental interiors occasionally fell about 10C below the 1961-90 average, say, and then a background warming of 1C was added to the baseline, all other things being equal it would still be possible for those areas to fall 9C below the 1961-90 average.

Global temperature anomalies also vary either side of the mean- e.g. the Northern Hemisphere was exceptionally warm in January 2005, but in January 2006 the positive anomaly relative to 1880-2004 was only 0.18C, which is close to the average for 1961-90 and probably below that for 1971-2000. Thus with the baseline briefly being back to that of the 1961-90 period, it stands to reason that the potential for significant cold pooling was as great as back then. However, that was a one-off- e.g. by Summer 2006 the Northern Hemisphere was at near-record warm levels again.

Unfortunately Steve is probably right with regards those polar NW'lys, which in themselves have become rare in recent years- the most recent example of a long-fetch W/NW'ly that brought widespread snow was way back in March 1995. 18 January 2005 was a recent example of a long-fetch W'ly from a cold source, and it delivered only sleety stuff for most. However, recent years (e.g. 3 February 2003, 25 December 2004) suggests that NW'ly blasts with a relatively direct track from the Arctic can still bring widespread snow events for the time being.

Here's the set of charts for 2 March 1995- note the airmass source!

http://www.wetterzentrale.de/archive/ra/19...00119950302.gif

http://www.wetterzentrale.de/archive/ra/19...00219950302.gif

and the 18 Jan'05 failure:

http://www.wetterzentrale.de/archive/ra/20...00120050118.gif

http://www.wetterzentrale.de/archive/ra/20...00220050118.gif

[Dawlish]

Frankly, as far as I am concerned, it does not matter how often it occurs, the fact is it can still happen and that should be good enough. So, for starters I would still not question the potency of a real polar continental airstream nowadays - to give a good illustratration of my doubt. No, we haven't seen one for a while, but that does not mean it is a reflection that the goalposts have moved so much that it cannot still happen or that it is a given that the airmass if it did happen would be modified upwards!

At most, these assumptions are at present premature, as I have repeated and a result, perhaps, of too much arm-chair GW fatigue.

Tamara

7/2 a colder winter, Snowp. Not never; 7/2 against, based on the evidence of the last 15-20 years. You are so quick to castigate anyone who misrepresents your posts, yet you quote something that no-one on here, to my knowledge, has never said; i.e. that there there will never be a severly cold winter again. There will be a cold, or even a severe winter, really, there will, but the odds are against it in any one named year. If you have "armchair GW fatigue", then gird your loins again, because UKGW is not going to go away. The odds are that it will be with you for the rest of your natural.

Paul

I see Tamara's point, but in itself it doesn't suggest that the goalposts haven't moved upwards.

No matter where the current baseline stands, there will always be variation- be it mild or cold variation- either side of the mean. If the continental interiors occasionally fell about 10C below the 1961-90 average, say, and then a background warming of 1C was added to the baseline, all other things being equal it would still be possible for those areas to fall 9C below the 1961-90 average.

Global temperature anomalies also vary either side of the mean- e.g. the Northern Hemisphere was exceptionally warm in January 2005, but in January 2006 the positive anomaly relative to 1880-2004 was only 0.18C, which is close to the average for 1961-90 and probably below that for 1971-2000. Thus with the baseline briefly being back to that of the 1961-90 period, it stands to reason that the potential for significant cold pooling was as great as back then. However, that was a one-off- e.g. by Summer 2006 the Northern Hemisphere was at near-record warm levels again.

Yes. I agree. Good stats, well shown.

Paul

Edited September 30, 2006 by Dawlish