Winter 2012 / 2013

[BLAST FROM THE PAST]

-ve QBO for winter anyone? The descending white is the -ve QBO phase, looking spot on for winter. No guarantees of cold, but one favourable factor. -ve QBO phase about every 2 years, note Dec 2010? Also note though that some major cold spells occurred without this so its just part of the puzzle.

BFTP

[SnowObsessor90]

No gulf stream is warm current part of the global oceanic circulation, and always comes up from the Caribbean/Gulf of Mexico. If it slows or stops....we're in trouble and FORGET Dec 2010.....that will be an average winter month.

BFTP

Round about which time would you expect the cold to first make inroads then?, the end of December, beginning of Jan etc? I'm not asking you for a diirect forecast btw as that would be silly at this early stage, just a rough estimate based the info we currently have on hand.

Edited September 17, 2012 by Anonymous21

[SMU]

Evening All Im going to paste this on here & on TWO-

My time these days is limited, reserved for the one liners & jesting around the far reaches of FI from the GFS & at this early juncture the CFS 9 month runs...

This winter has generated a lot of hype - already the seasonal rampers are beginning to come out of hibernation- but whether logged on or not most are lurking in some guise across the year.

Ive seen a fair amount of commentary across this last 10/15 days around Winter & even some long range forecasts dropping in from some- its important to disinguish between winter thoughts/ideas V a forecast- Anyway more of that in a moment-

Autumn is getting a lot of coverage now- not least because of the record ice melt in the arctic- but also because people are searching for that connection between Autumn patterns & Winter weather-

The bottom line IMHO is that you cannot take surface obs over the UK Sept- Nov & correlate them to some form of signal for winter-

Reason: The mean location of the polar front is still generally north of the UK & because of this- a background signal of a +VE 500 height anomaly over the pole with a weak -AO signature doesnt always land a specific weather pattern for the UK because we are not close enough to the margin of the polar front- This sort of anomaly will have a greater effect along 60-70N where the jet flow is more amplified.

As Autumn wears on especially mid to late November then there would be some applicable data to correlate polar anomalies V the UK obs because we are then in the realms of where the mean location of the polar front is moving towards the UK ( or shall I say closer to 50N)

If the jet is higher in amplitude in Autumn then what I would say the UK will see northerly incursions of colder air at earlier dates, however in the 'mean' its probably not enough to distort the overall temperaure CET, maybe shave some off the NET plus anomalies we have seen in the last decade.

Its also worth mentioning at this stage the ice anomaly & how this teleconnects to Autumn- more specifically NOVEMBER.

This is a month where the stratosphere doesnt have a massive effect on the mean Westerlies - this is because the range of temps in the stratosphere doesnt get cold enough to propergate down before we reach December - so essentially the Stratospheric profile in november is MUTE.

The dataset since 2001 ( remember this date ) suggests that because of the reduction in ice cover the feedback into the atmosphere produces a weaker thermal gradient & a weaker jet-

You will note the 10 year MEAN average for the NH for November.

Note the Anomalous +VE profiles over the central atlantic- now for the UK at the weaker end of the scale this is a cool & unsettled flow, & if you get a stronger anomaly the UK will be cold with winds prevailing from the North.

As we know, excluding 2012 the lowest arctic ice cover anomaly for the summer melt in September is 2007- so if there is really a strong correlation between Arctic ice coverage & atmospheric 500 MB signatures then really instead of looking at WINTER D,J,F the key month is November- ( not just for the Uk but more the NH picture)

Below we have November anomalies for 2001 > 2006-

As you can see not much in the way of Anomaly-

Now look from 2007- 2011-

WOW look at that height anomaly in the west atlantic- For the UK because that anomaly is so far west it doesnt correlate to a cold UK- because again we are still not close enough to the mean location of the polar front & it appears to be more of a west based -NAO

However what it does illustrate the mean westerly flow is WEAKER-

illustrated another way-

note the massive negative anomaly in the mean westerly flow across the atlantic.

My commentary for this autumn- Bearing in Mind we are ENSO Neutral & have the BIGGEST arctic ice anomaly on record will mean that we should see a NET reduction in the 50-60 N zonal Wind.

This will manifest itself with increased blocking over high lattitudes- with a high chance of a big +VE anomaly situated close to Southern Greenland-

The central location of this high pressure will generally dictate our temps - however I would say in terms of Precipitation theres a greater chance of being drier than Normal, however temperatures look to be average to slightly above for Sept & above average again for October -

If you reanalyze the anomalies for Oct 2007-2011 & even 2001-2011 there is NO signal to colder temps for us-

I would say November will be below average this year because of the clear - NAO signal- its just how far east the 500MB anomaly stretches into iceland etc-

So then Winter-

Its Sept 17th & I can already see Winter forecasts arriving in the threads from different sources- For liable sake im not naming these people, however at this stage we need to differentiate between Winter thoughts & a winter forecast.

YOU CANNOT ISSUE A WINTER FORECAST IN SEPTEMBER..... WHY:- because the temperature & strength of the Stratospheric vortex for the winter is undefined at this date-

( We can guess what it might be- but real time data for November & right on the doorstep of Decemeber will always be the pinion for a forecast.)

What we can do at the moment is take the background signal & see whats been happening to the heights over the Northern Hemisphere-

Calling back on my date of 2001 I have chosen this date because it alligns with a study completed on the arctic ice coverage from 2001 - 2010-

This was published by the IMIS & heres an abstract part- ( thanks Nouska for the link)

http://www.tellusa.n...view/11595/html

there is a LOT of detail in this artical, feel free to browse & read at your leisure- however I will paste the summary below - & the Pressure anomalies highlighted from 2001-2010 ( low ice) V the pressure defined across 1990-2000 ( high Ice)

We showed that Arctic heating anomalies due to low sea ice concentrations in late summer (August/September) trigger changes in baroclinic systems in autumn because of an earlier onset of baroclinic instability that influences the structure of large-scale planetary waves in the following winter. The baroclinic structure of the direct response in autumn is linked to different patterns of pressure anomalies at the surface and in the mid-troposphere, which are related to the decrease in sea ice concentration. Decreased static stability and changed meridional temperature gradients induce an earlier onset of baroclinicity north of 75° N with greater amplitude.

Winter heat fluxes on baroclinic scales are increased in the whole Arctic troposphere, whereas a non-linear adjustment leads to decreased heat fluxes associated with planetary waves. Arctic EP fluxes due to planetary waves during winter are enhanced between 700 and 200 hPa in the latitudinal belt north of 65° N during the low sea ice phase.

The barotropic structure of the atmospheric response in winter is connected to similar patterns of pressure anomalies at the surface and the mid-troposphere. The pattern over the North Atlantic relates the sea ice decline in late summer to a negative NAO phase in winter. The barotropic pattern over the Pacific due to changes in Arctic sea ice concentration is connected to a distinguished planetary wave train over the region.

These results deliver a dynamical background for understanding the role of Arctic sea ice decline on the Arctic temperature amplification and its impact on mid-latitudes contributing to the recent shift to the negative NAO phase. The reduced sea ice concentration at the end of the Arctic summer has the potential to change the large-scale circulation in the following winter that could feed back on the sea ice concentration. This sea ice–atmosphere relationship suggests a potential for use in operational Northern Hemisphere seasonal forecasts. Sea ice cover loss has the potential to preferentially shift the probability density function of the AO/NAO to the negative phase, in agreement with the investigations by Overland and Wang

As you can see rather like November there is a consistent anomaly across Greenland & further East.- this is consistent with a shift of the observed phases of the AO & NOA to a more negative state-

Its also worth noting that 2010 ( the last year of the study) was the LOWEST year in recorded ice volume- ) with 2011 lower & 2012 looking to be lower still- the lowest ever infact.

Another way of illustrating the net effect is reanalysing the 2001-2010 500 ANOMALY data for D J F across the NH-

this is what it brings-

As we can see there is a considerable anomaly in the NH- its consistent with the IMIS report- that Southern Greenland has the biggest + VE Anomaly & there are some minor negative anomalies in central Europe.

It is very clear that the arctic ice study data is correct & that the last 11 years have earmarked a turning point in the pressure patterns over the pole- I guess you can call this 'man made' if you have a AGW agenda around what the human race does.

Its easy now just to assume that because this arctic Ice anomaly is here again this year that these pressure profiles will be replicated & we will have a bitter winter, & it seems again that 'some' have jumped on this band wagon producing these early forecasts- however as already mentioned we HAVE to wait.-

Why?

* ENSO State- The prediction is Neutral- we are odds on for this to varify, however with 10 weeks to Winter we are not there yet.....

* Dataset + sample size- The sample size I believe at 10 years isnt long enough to be able to firmly say that the trend will continue - even though the data suggest it will- so whatever forecast is produced this year- I would emphasize that anyone using Arctic ice loss as a weighted variable should add the caveat around sample size being small in terms of its effects on the AO phase.

* The other variable that will not come online until mid November is the stratosphere- this is still a big player- & because ENSO is neutral this year it perhaps becomes CRITICAL to our D J F weather- especially December.

Let me explain-

Using this link:

http://www.cpc.ncep....re/temperature/

& these 70 HPA charts for 65N-90N like this

I have crudely catagorised the last 11 Winters into a sample set of Warm, Cold or Average types of Stratopheric temps with the biggest weighting to my decisions applied for December-

For clarity this is what I arrived at :

4 warm, ( 2009,2005,2003,2001,)

3 ave ( 2010,2008,2007,2002)

3 cold (2011, 2006 , 2004)

As I mentioned the stratosphere at the START of Winter has a bigger effect on the patterns than at the end of the winter when the thermal lag has caught up in terms of net gradient from equator to pole.in other words in the COLD years December patterns can be poor for vold & snow but it doesnt rule out better patterns in jan & feb just at a lower probability.

So the Stratospheric temp for 2012 for late november through December is critical for the 500 MB profiles for the start of Winter-

to prove this recall the anomaly for 2001-2010 in terms of pressure-

now look at what happens in December in COLD stratospheric years-

WOW- no thanks- Cold lovers wont want that-

So against a strong background polar signal the Stratosphere has ruled the roost- its also worth pointing out that these 3 years had strong ENSO Signals- X2 EL NINO & STRONG LA NINA

http://www.cpc.ncep....ensoyears.shtml

None of the 3 years had neutral Signals.

Also compounding the problem further was the QBO was in its westerly phase- ( or for 2011 coming out of the westerly phase)

http://www.esrl.noaa...lation/qbo.data

The westerly phase of the QBO will enhance the brewer dobson circulation which in turn usually enhances the mean westerly zonal wind upwards-

Working along the warming years for December- 2001,2003, 2005 & 2009-

Look at the difference-!! thats good!-

Also the QBO was mostly easterly on these 4 years - ENSO was neutral for 2 & Strong for 2-

However its important to include the Average Stratosphere years as well - this is because if the stratosphere is warm it supports the blocking, however if its average it doesnt MUTE the Arctic signal-

The december chart for ALL years ave & warm-

Conclusion for December then-

Ideally a Neutral ENSO, Easterly QBO & negative Artic ice anomaly SHOULD set the scene for a GOOD 500 MB profile over the NH ( namely a -AO) what we need at worst is an average temp stratosphere or better still a warmed stratosphere to paint the perfect picture condition.

Conclusion for D J F-

As for the rest of the winter the early signal of the stratosphere does get muted out- for the aforementioned reason of thermal lag & also because of warming events that can suddenly occur-

However if we start cold in the stratosphere the rest of the winter doesnt match the 10 year signal-

where as the average - warm starters do with much more negative anomalies across europe!

My Summary & early thoughts-

Im excited, very excited - ( obviously concerned at the long term effects of the arctic ) - but in the short term ALL the measured teleconnections seem to working in our favour-

ENSO neutral, Arctic ice anomaly, SST's around greenland, Easterly QBO & so on-

Its VERY understandable why some forecasters are jumping on the media bandwagon- however their is one large hurdle to overcome which could knock us down- which is of course the strat.-

I will be monitoring it daily from one of the many sources-

If you are viewing then this is timeline & area for focus-

we need to be above the brown line in the blue circled area- the higher the better- if we are then my forecast for December will be cold- possibly very cold depending on the location of the mean trough relating to where the -NAO anomaly is ( west or east based)

if its below I would be very conservative to say average or above.

Also, on the ice front ( assuming the strat plays ball) the impact of the WORST ive melt anomaly ever recorded will help sharpen up the anomalies over greenland & over Europe even further-

with this in mind you would expect the extent if the cold to be able to penetrate further South & WEST from the pole & siberia...

thanks for your time.

Steve

[Cheshire Freeze]

Evening All Im going to paste this on here & on TWO-

thanks for your time.

Steve

Wow, I bet that took some time to write Steve.....thank you for that informative post.

I do agree with you, the strat is a major consideration just as we saw last year. An above average strat temp should do the trick but the question is will that be a reality this winter? I really don't know; only time will tell.

Edited September 18, 2012 by CreweCold

[SMU]

One last stat-

If you take try & make an Analogue Excluding the Strat ( as data only does back to 1979)-filter QBO to most negative december in rank order then & use eliminate Non Enso NEUTRAL years & take PDO to negative years the analogue for this year is

1962 -1963 Winter.........

S

Edited September 18, 2012 by Steve Murr

[johnholmes]

the last post is ? perhaps a wind up Steve but thanks for the main post, very interesting with a lot of thought obviously gone into it.

[Excitable_Weatherwatcher]

Evening All Im going to paste this on here & on TWO-

My time these days is limited, reserved for the one liners & jesting around the far reaches of FI from the GFS & at this early juncture the CFS 9 month runs...

This winter has generated a lot of hype - already the seasonal rampers are beginning to come out of hibernation- but whether logged on or not most are lurking in some guise across the year.

Ive seen a fair amount of commentary across this last 10/15 days around Winter & even some long range forecasts dropping in from some- its important to disinguish between winter thoughts/ideas V a forecast- Anyway more of that in a moment-

Autumn is getting a lot of coverage now- not least because of the record ice melt in the arctic- but also because people are searching for that connection between Autumn patterns & Winter weather-

The bottom line IMHO is that you cannot take surface obs over the UK Sept- Nov & correlate them to some form of signal for winter-

Reason: The mean location of the polar front is still generally north of the UK & because of this- a background signal of a +VE 500 height anomaly over the pole with a weak -AO signature doesnt always land a specific weather pattern for the UK because we are not close enough to the margin of the polar front- This sort of anomaly will have a greater effect along 60-70N where the jet flow is more amplified.

As Autumn wears on especially mid to late November then there would be some applicable data to correlate polar anomalies V the UK obs because we are then in the realms of where the mean location of the polar front is moving towards the UK ( or shall I say closer to 50N)

If the jet is higher in amplitude in Autumn then what I would say the UK will see northerly incursions of colder air at earlier dates, however in the 'mean' its probably not enough to distort the overall temperaure CET, maybe shave some off the NET plus anomalies we have seen in the last decade.

Its also worth mentioning at this stage the ice anomaly & how this teleconnects to Autumn- more specifically NOVEMBER.

This is a month where the stratosphere doesnt have a massive effect on the mean Westerlies - this is because the range of temps in the stratosphere doesnt get cold enough to propergate down before we reach December - so essentially the Stratospheric profile in november is MUTE.

The dataset since 2001 ( remember this date ) suggests that because of the reduction in ice cover the feedback into the atmosphere produces a weaker thermal gradient & a weaker jet-

You will note the 10 year MEAN average for the NH for November.

Note the Anomalous +VE profiles over the central atlantic- now for the UK at the weaker end of the scale this is a cool & unsettled flow, & if you get a stronger anomaly the UK will be cold with winds prevailing from the North.

As we know, excluding 2012 the lowest arctic ice cover anomaly for the summer melt in September is 2007- so if there is really a strong correlation between Arctic ice coverage & atmospheric 500 MB signatures then really instead of looking at WINTER D,J,F the key month is November- ( not just for the Uk but more the NH picture)

Below we have November anomalies for 2001 > 2006-

As you can see not much in the way of Anomaly-

Now look from 2007- 2011-

WOW look at that height anomaly in the west atlantic- For the UK because that anomaly is so far west it doesnt correlate to a cold UK- because again we are still not close enough to the mean location of the polar front & it appears to be more of a west based -NAO

However what it does illustrate the mean westerly flow is WEAKER-

illustrated another way-

note the massive negative anomaly in the mean westerly flow across the atlantic.

My commentary for this autumn- Bearing in Mind we are ENSO Neutral & have the BIGGEST arctic ice anomaly on record will mean that we should see a NET reduction in the 50-60 N zonal Wind.

This will manifest itself with increased blocking over high lattitudes- with a high chance of a big +VE anomaly situated close to Southern Greenland-

The central location of this high pressure will generally dictate our temps - however I would say in terms of Precipitation theres a greater chance of being drier than Normal, however temperatures look to be average to slightly above for Sept & above average again for October -

If you reanalyze the anomalies for Oct 2007-2011 & even 2001-2011 there is NO signal to colder temps for us-

I would say November will be below average this year because of the clear - NAO signal- its just how far east the 500MB anomaly stretches into iceland etc-

So then Winter-

Its Sept 17th & I can already see Winter forecasts arriving in the threads from different sources- For liable sake im not naming these people, however at this stage we need to differentiate between Winter thoughts & a winter forecast.

YOU CANNOT ISSUE A WINTER FORECAST IN SEPTEMBER..... WHY:- because the temperature & strength of the Stratospheric vortex for the winter is undefined at this date-

( We can guess what it might be- but real time data for November & right on the doorstep of Decemeber will always be the pinion for a forecast.)

What we can do at the moment is take the background signal & see whats been happening to the heights over the Northern Hemisphere-

Calling back on my date of 2001 I have chosen this date because it alligns with a study completed on the arctic ice coverage from 2001 - 2010-

This was published by the IMIS & heres an abstract part- ( thanks Nouska for the link)

http://www.tellusa.n...view/11595/html

there is a LOT of detail in this artical, feel free to browse & read at your leisure- however I will paste the summary below - & the Pressure anomalies highlighted from 2001-2010 ( low ice) V the pressure defined across 1990-2000 ( high Ice)

As you can see rather like November there is a consistent anomaly across Greenland & further East.- this is consistent with a shift of the observed phases of the AO & NOA to a more negative state-

Its also worth noting that 2010 ( the last year of the study) was the LOWEST year in recorded ice volume- ) with 2011 lower & 2012 looking to be lower still- the lowest ever infact.

Another way of illustrating the net effect is reanalysing the 2001-2010 500 ANOMALY data for D J F across the NH-

this is what it brings-

As we can see there is a considerable anomaly in the NH- its consistent with the IMIS report- that Southern Greenland has the biggest + VE Anomaly & there are some minor negative anomalies in central Europe.

It is very clear that the arctic ice study data is correct & that the last 11 years have earmarked a turning point in the pressure patterns over the pole- I guess you can call this 'man made' if you have a AGW agenda around what the human race does.

Its easy now just to assume that because this arctic Ice anomaly is here again this year that these pressure profiles will be replicated & we will have a bitter winter, & it seems again that 'some' have jumped on this band wagon producing these early forecasts- however as already mentioned we HAVE to wait.-

Why?

* ENSO State- The prediction is Neutral- we are odds on for this to varify, however with 10 weeks to Winter we are not there yet.....

* Dataset + sample size- The sample size I believe at 10 years isnt long enough to be able to firmly say that the trend will continue - even though the data suggest it will- so whatever forecast is produced this year- I would emphasize that anyone using Arctic ice loss as a weighted variable should add the caveat around sample size being small in terms of its effects on the AO phase.

* The other variable that will not come online until mid November is the stratosphere- this is still a big player- & because ENSO is neutral this year it perhaps becomes CRITICAL to our D J F weather- especially December.

Let me explain-

Using this link:

http://www.cpc.ncep....re/temperature/

& these 70 HPA charts for 65N-90N like this

I have crudely catagorised the last 11 Winters into a sample set of Warm, Cold or Average types of Stratopheric temps with the biggest weighting to my decisions applied for December-

For clarity this is what I arrived at :

4 warm, ( 2009,2005,2003,2001,)

3 ave ( 2010,2008,2007,2002)

3 cold (2011, 2006 , 2004)

As I mentioned the stratosphere at the START of Winter has a bigger effect on the patterns than at the end of the winter when the thermal lag has caught up in terms of net gradient from equator to pole.in other words in the COLD years December patterns can be poor for vold & snow but it doesnt rule out better patterns in jan & feb just at a lower probability.

So the Stratospheric temp for 2012 for late november through December is critical for the 500 MB profiles for the start of Winter-

to prove this recall the anomaly for 2001-2010 in terms of pressure-

now look at what happens in December in COLD stratospheric years-

WOW- no thanks- Cold lovers wont want that-

So against a strong background polar signal the Stratosphere has ruled the roost- its also worth pointing out that these 3 years had strong ENSO Signals- X2 EL NINO & STRONG LA NINA

http://www.cpc.ncep....ensoyears.shtml

None of the 3 years had neutral Signals.

Also compounding the problem further was the QBO was in its westerly phase- ( or for 2011 coming out of the westerly phase)

http://www.esrl.noaa...lation/qbo.data

The westerly phase of the QBO will enhance the brewer dobson circulation which in turn usually enhances the mean westerly zonal wind upwards-

Working along the warming years for December- 2001,2003, 2005 & 2009-

Look at the difference-!! thats good!-

Also the QBO was mostly easterly on these 4 years - ENSO was neutral for 2 & Strong for 2-

However its important to include the Average Stratosphere years as well - this is because if the stratosphere is warm it supports the blocking, however if its average it doesnt MUTE the Arctic signal-

The december chart for ALL years ave & warm-

Conclusion for December then-

Ideally a Neutral ENSO, Easterly QBO & negative Artic ice anomaly SHOULD set the scene for a GOOD 500 MB profile over the NH ( namely a -AO) what we need at worst is an average temp stratosphere or better still a warmed stratosphere to paint the perfect picture condition.

Conclusion for D J F-

As for the rest of the winter the early signal of the stratosphere does get muted out- for the aforementioned reason of thermal lag & also because of warming events that can suddenly occur-

However if we start cold in the stratosphere the rest of the winter doesnt match the 10 year signal-

where as the average - warm starters do with much more negative anomalies across europe!

My Summary & early thoughts-

Im excited, very excited - ( obviously concerned at the long term effects of the arctic ) - but in the short term ALL the measured teleconnections seem to working in our favour-

ENSO neutral, Arctic ice anomaly, SST's around greenland, Easterly QBO & so on-

Its VERY understandable why some forecasters are jumping on the media bandwagon- however their is one large hurdle to overcome which could knock us down- which is of course the strat.-

I will be monitoring it daily from one of the many sources-

If you are viewing then this is timeline & area for focus-

we need to be above the brown line in the blue circled area- the higher the better- if we are then my forecast for December will be cold- possibly very cold depending on the location of the mean trough relating to where the -NAO anomaly is ( west or east based)

if its below I would be very conservative to say average or above.

Also, on the ice front ( assuming the strat plays ball) the impact of the WORST ive melt anomaly ever recorded will help sharpen up the anomalies over greenland & over Europe even further-

with this in mind you would expect the extent if the cold to be able to penetrate further South & WEST from the pole & siberia...

thanks for your time.

Steve

This has shown me some things to look out for when it comes to looking at the charts when looking for cold weather.

[Excitable_Weatherwatcher]

Waw 361 comments and still going in less then 8 days. LET KEEP GOING!

To A cold winter

Edited September 18, 2012 by Excitable_Weatherwatcher

[chionomaniac]

A very good post Steve.

I would agree entirely with your thoughts and was looking this weekend at the 2009/10 30Hpa temp graph, thinking that is what we would like to see this year (from October). I am opening the strat thread a little earlier this year to monitor this aspect.

One thing of importance that you highlight is that we are far better starting winter with warm stratospheric conditions rather than cold and hoping for a SSW later. If there is one thing that I have learnt these past few years is that with a warm strat we are much more likely to get wave breaking up through the centre of the polar vortex, rather than over the top breaking through the surf zone later in the season. It is in these conditions that we are more guaranteed prolonged cold spells rather than fleeting snaps.

c

Edited September 18, 2012 by chionomaniac

[Excitable_Weatherwatcher]

A very good post Steve.

I would agree entirely with your thoughts and was looking this weekend at the 2009/10 30Hpa temp graph, thinking that is what we would like to see this year (from October). I am opening the strat thread a little earlier this year to monitor this aspect.

One thing of importance that you highlight is that we are far better starting winter with warm stratospheric conditions rather than cold and hoping for a SSW later. If there is one thing that I have learnt these past few years is that with a warm strat we are much more likely to get wave breaking up through the centre of the polar vortex, rather than over the top breaking through the surf zone later in the season. It is in these conditions that we are more guaranteed prolonged cold spells rather than fleeting snaps.

c

Dose this mean that having warmer weather before winter is good news?

[BLAST FROM THE PAST]

Round about which time would you expect the cold to first make inroads then?, the end of December, beginning of Jan etc? I'm not asking you for a diirect forecast btw as that would be silly at this early stage, just a rough estimate based the info we currently have on hand.

Early thoughts are early winter kick off. QBO is very much on cue to be -ve.

An incredible post by Big Steve Murr and some very interesting pointers. ENSO is promising,El Nino as yet just aint taking off and that is a good thing but not the be all and end all. Reason? During the 20th century the overall hit rate of cold winters or mild winters with mod to strong El Ninos was 50/50. However, during the last 30 years of the 20th century the hit rate was very heavily favoured towards mild winters. Difference being that in last 20-25 years or so we were in +ve PDO and we had very strong solar cycles with very high sunspot numbers. We are now seemingly heading towards a grand minima and we are strongly in a -ve PDO phase....ENSO very useful but not be all and end all.

1905 PDO turns positive -

1946 PDO turns negative -

1977 PDO turns positve -

2007 PDO turns negative -

Interesting to see dates that Steve has used 2001 to present and also particularly to 2007-present. Why do they interest me? Well as you can see we entered -ve PDO officially BUT also the perturbation cycle changed in feb 2007. This is a solar driven cycle where we see La Nina becoming more dominant/prevalent than El Nino and the pattern fits snugly with the PDO. remember dominat/prevalent NOT exclusive. As one has seen in my signature the PDO/peturbation cycle 'encourage a -ve NAO signature, particularly winter time, it isn't fool proof as NAO will go -ve and +ve but anomaly wise the pattern is most certainly there.

Remember dates of 1905, 1946 and 1977 thats +ve PDO -ve PDO and +PDO

Just look at the phase times and not global cooling for next 30 years....that's another discussion...

Now look at the winter NAO...

1905 to Early 40s we see positve NAO dominat, 40s to mid 70s negative dominant, mid 70s to 2007 positive dominant. These are cyclic indicators.

Since 2007 we have seen a more meridional and south shifting jetstream and to me its no coincidence. Last winter showed as I mentioned that it isn't exclusively so but the -ve NAO signal is enhanced.

Is it the arctic ice as per study shown by Steve. Or is solar driven and oceanic cycles? Is the low ice a direct link?

As I mentioned the jetstream, I cannot find the research paper but it was done by Canadian female scientist. Her research showed that the ITCZ [also known as the doldrums] had been spreading polewards from mid 1800s until 2002 when it stopped and showed signs of retreating [we aren't talking gigantic movements but even an anomaly of a few hundred miles makes a big difference]. In turn this would see the knock on effect of seeing the poleward movement of the PFJ which was at its furthest the decades upto 2002. Ian Brown's view of MW? Its why I posted in past years that I did not wholly disagree with him re jetstream/GIN corridor etc BUT that it was his assertions of permanency was where I disagreed. Recent years both winters and summer have see our jet move south, we have seen major -ve NAO phases, we have had monster cold spells and poor summers.

This is why I believe that colder winters are much more achievable now and indeed may become more likely but it won't be linear downward trend, as last winter proved. Chuck in the potential grand minima solar cycle and bingo.

Just to add, we need many pieces of jigsaw to fall into place but as they say...every little helps. These are all 'indicators' I use.

BFTP

Edited September 18, 2012 by BLAST FROM THE PAST

[chionomaniac]

Dose this mean that having warmer weather before winter is good news?

No, EW.

We are talking at a whole new level - the stratospheric level where conditions and temperatures have a delayed effect at the ground level (the troposphere) - the level that we recieve the weather.

It is important to get a full grasp of the factors and how the weather occurs at this level before moving onto the worldwide factors that influence the local factors (we call these teleconnections).

Have you found the guides section yet?

http://forum.netweather.tv/forum/5-the-netweather-guides/

[Excitable_Weatherwatcher]

No, EW.

We are talking at a whole new level - the stratospheric level where conditions and temperatures have a delayed effect at the ground level (the troposphere) - the level that we recieve the weather.

It is important to get a full grasp of the factors and how the weather occurs at this level before moving onto the worldwide factors that influence the local factors (we call these teleconnections).

Have you found the guides section yet?

http://forum.netweat...weather-guides/

this definitely not the easiest this to learn about.

Edited September 18, 2012 by Excitable_Weatherwatcher

[Coast]

this definitely not the easiest this to learn about.

We are all still learning every day E_W

[johnholmes]

hi EW

I did post the link a few pages back but you may have missed it.

If you have any questions don't be afraid to ask, I'm always happy to help via pm if you prefer to chat privately.

Don't take this the wrong way but as we all learnt to walk before running the same apllies to understanding the highly complex subject called meteorology.

Its fascinating but a bit mind boggling to start with.

enjoy the site and the weather

[Excitable_Weatherwatcher]

hi EW

I did post the link a few pages back but you may have missed it.

If you have any questions don't be afraid to ask, I'm always happy to help via pm if you prefer to chat privately.

Don't take this the wrong way but as we all learnt to walk before running the same apllies to understanding the highly complex subject called meteorology.

Its fascinating but a bit mind boggling to start with.

enjoy the site and the weather

I am glad of the help from this forum and website and am getting a vague understanding of one or two aspects.

[Gavin Hannah]

I am glad of the help from this forum and website and am getting a vague understanding of one or two aspects.

I've been on here for a year and although I only really visit in the Autumn/Winter, trying to understand what a lot of the tele-connections mean and how they work still mystifies me. My advice is research research research and then examine an idea from all points of view. Things like La Nina/El Nino, +/- NAO etc all have certain effects on the weather patterns we experience but I don't think you can bet your mortgage on what the outcome is because there are so many other factors.

If you tried to balance them all out in your head it might just explode lol. As I mentioned in another thread, I don't believe there is a computer big enough or powerful enough to factor every single weather driver/influencer and churn out a 100% accurate forecast, especially LR forecasts.

Edited September 18, 2012 by IBringTheHammer

[Mark Neal.]

Some fantastic posts on this thread, very informative post from steve, certainly i now know other factors to consider when looking out for a cold winter. Cheers.

[Excitable_Weatherwatcher]

I've been on here for a year and although I only really visit in the Autumn/Winter, trying to understand what a lot of the tele-connections mean and how they work still mystifies me. My advice is research research research and then examine an idea from all points of view. Things like La Nina/El Nino, +/- NAO etc all have certain effects on the weather patterns we experience but I don't think you can bet your mortgage on what the outcome is because there are so many other factors.

If you tried to balance them all out in your head it might just explode lol. As I mentioned in another thread, I don't believe there is a computer big enough or powerful enough to factor every single weather driver/influencer and churn out a 100% accurate forecast, especially LR forecasts.

have been looking at a couple of sites that have been useful, this is one of them http://ukweather.wor...weather-guides/

[BornFromTheVoid]

And with Steve Murr's superb post, the winter excitement on netweather gets upped to a new level!

Edited September 18, 2012 by BornFromTheVoid

[manx_mick]

Morning

I am very new to this site, i found it by accident when i searched for Winter 2012/13 predictions.

I love all the banta and also all the well researched information and will be monotoring it all very closely.

I live on the Isle of Man and usually the snow we get here comes one day and is gone the next, but back in December 2010 during the well recorded cold spell it lasted for nearly 10 days with hardly any melt. It was the first time my 5 year Old Son (Now 7) had seen serious snow and he keeps asking me will we get it again this year.

Here is hoping!!!

Keep the posts coming Guys and thanks

[Radiating Dendrite]

Great posts from Steve and BFTP.

When these big guns come out to play we know that winter is just around the corner!

Fingers crossed that in 6-7 weeks we could be in our first cold spell!

[AWD]

http://t.co/dAccIUTS

Another good read from Matt Hugo regarding early signs for the coming winter. Similiar to Steve Murr's earlier post and both in agreement that so far, at this early stage, its looking promising for cold conditions.

[johnholmes]

have been looking at a couple of sites that have been useful, this is one of them http://ukweather.wor...weather-guides/

Yes you need to read as much as you can that explains things as simply as possible, be it the Net Wx Guides or others you will find on the web.

The site below is a first class site for explaining all manner of things in as simple a way as possible. It also has the added benefit that most of the data on it has been provided by ex senior meteorologists with UK Met.

http://weatherfaqs.org.uk/

[snow raven]

this definitely not the easiest this to learn about.

All you need is a lamp post and a window