The Weather Outlook

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roger63
  • roger63
  • Advanced Member Topic Starter
06 November 2013 17:02:03

There have been a variety of posts saying that it is impoosible to forecast what winters will be like.

The truth of this statement depends on what level of detail is being sought.I'm happy enough to have some idea of whether winter is likely  to be  either  cold or warm.

Went last year to a symposium run by Met Soc on winter forecasting.Met Office (Adam Scaiffe I think) went through their latest models and reckoned that they could forecast winter temperature anomaly sign to just below 70% accuracy.That's good enough for me!

As far as this coming winter is concerned one of the inputs I look at is pattern matching,seeking the types of season which produce frequency of warm/cold winters that are outsid the normal 50:50 split.

So far this year our very cold,dry spring type has a 75% chance of being followed by a cold winter.The very warm,very dry summer  does not produce a strong signal either way.

Just looked at October rainfall for Central England which in October was 104.4 mm 41.3mm above average.However as September had  a rainfall that was 14.6 below average this gives a total anomaly so far for autumn of 26.7mm which puts it in the wet ,but not very wet category.on th edtepertaure side the mean anomaly for sSept an dOctober is around 1.3c which puts it in the very warm category.

So the autumn  season todate is very warm wet.Such aurtumns have been followed by warmer than average winter in 100% of cases.Ofcourse if November tuns out to be extremely wet and cold then the categorisation for autunm could still change.

but currently we have cold signal (75%) from spring and a warm signal (100% ) from Autumn to date.in this situation one would choose the strongest signal which is the warm winter.But I stress this is only one of the inputs......

 

Gooner
06 November 2013 17:08:24

Toss a coin then Roger ?

Remember anything after T120 is really Just For Fun



Marcus

Banbury

North Oxfordshire

378 feet A S L



Solar Cycles
06 November 2013 17:49:40

There have been a variety of posts saying that it is impoosible to forecast what winters will be like.

The truth of this statement depends on what level of detail is being sought.I'm happy enough to have some idea of whether winter is likely  to be  either  cold or warm.

Went last year to a symposium run by Met Soc on winter forecasting.Met Office (Adam Scaiffe I think) went through their latest models and reckoned that they could forecast winter temperature anomaly sign to just below 70% accuracy.That's good enough for me!

As far as this coming winter is concerned one of the inputs I look at is pattern matching,seeking the types of season which produce frequency of warm/cold winters that are outsid the normal 50:50 split.

So far this year our very cold,dry spring type has a 75% chance of being followed by a cold winter.The very warm,very dry summer  does not produce a strong signal either way.

Just looked at October rainfall for Central England which in October was 104.4 mm 41.3mm above average.However as September had  a rainfall that was 14.6 below average this gives a total anomaly so far for autumn of 26.7mm which puts it in the wet ,but not very wet category.on th edtepertaure side the mean anomaly for sSept an dOctober is around 1.3c which puts it in the very warm category.

So the autumn  season todate is very warm wet.Such aurtumns have been followed by warmer than average winter in 100% of cases.Ofcourse if November tuns out to be extremely wet and cold then the categorisation for autunm could still change.

but currently we have cold signal (75%) from spring and a warm signal (100% ) from Autumn to date.in this situation one would choose the strongest signal which is the warm winter.But I stress this is only one of the inputs......

 

Originally Posted by: roger63 

So an average winter it is then. 

glenogle
06 November 2013 19:34:40

There have been a variety of posts saying that it is impoosible to forecast what winters will be like.

The truth of this statement depends on what level of detail is being sought.I'm happy enough to have some idea of whether winter is likely  to be  either  cold or warm.

Went last year to a symposium run by Met Soc on winter forecasting.Met Office (Adam Scaiffe I think) went through their latest models and reckoned that they could forecast winter temperature anomaly sign to just below 70% accuracy.That's good enough for me!

As far as this coming winter is concerned one of the inputs I look at is pattern matching,seeking the types of season which produce frequency of warm/cold winters that are outsid the normal 50:50 split.

So far this year our very cold,dry spring type has a 75% chance of being followed by a cold winter.The very warm,very dry summer  does not produce a strong signal either way.

Just looked at October rainfall for Central England which in October was 104.4 mm 41.3mm above average.However as September had  a rainfall that was 14.6 below average this gives a total anomaly so far for autumn of 26.7mm which puts it in the wet ,but not very wet category.on th edtepertaure side the mean anomaly for sSept an dOctober is around 1.3c which puts it in the very warm category.

So the autumn  season todate is very warm wet.Such aurtumns have been followed by warmer than average winter in 100% of cases.Ofcourse if November tuns out to be extremely wet and cold then the categorisation for autunm could still change.

but currently we have cold signal (75%) from spring and a warm signal (100% ) from Autumn to date.in this situation one would choose the strongest signal which is the warm winter.But I stress this is only one of the inputs......

 

Originally Posted by: Solar Cycles 

So an average winter it is then. 

Originally Posted by: roger63 

I dont know if it would be average.  If you take what Roger has said above and mix it with the hurricane info, it is possible that it will be more likely to lean to warm OR cold, other than something in between?

UserPostedImage LLTNP 105m asl 
nsrobins
06 November 2013 19:41:24

 

I dont know if it would be average.  If you take what Roger has said above and mix it with the hurricane info, it is possible that it will be more likely to lean to warm OR cold, other than something in between?

Originally Posted by: glenogle 

An honest question, but what deviation from the mean who constitute a warm or cold tag?

Neil

Fareham, Hampshire 28m ASL (near estuary)

Stormchaser, Member TORRO

roger63
  • roger63
  • Advanced Member Topic Starter
06 November 2013 20:35:32

 

I dont know if it would be average.  If you take what Roger has said above and mix it with the hurricane info, it is possible that it will be more likely to lean to warm OR cold, other than something in between?

Originally Posted by: nsrobins 

An honest question, but what deviation from the mean who constitute a warm or cold tag?

Originally Posted by: glenogle 

Neil answer to your question.In the classification I am using  for sprimg summer amd autumn seasons anything above mean is warm,above 0.7C variation is very warm  below mean is cold,greater than - 0.7c variation is very cold.For winter season split between warm and very warm is + 1.1C ,for cold /very cold split -1.1c.

Solar Cycles
06 November 2013 21:13:31

There have been a variety of posts saying that it is impoosible to forecast what winters will be like.

The truth of this statement depends on what level of detail is being sought.I'm happy enough to have some idea of whether winter is likely  to be  either  cold or warm.

Went last year to a symposium run by Met Soc on winter forecasting.Met Office (Adam Scaiffe I think) went through their latest models and reckoned that they could forecast winter temperature anomaly sign to just below 70% accuracy.That's good enough for me!

As far as this coming winter is concerned one of the inputs I look at is pattern matching,seeking the types of season which produce frequency of warm/cold winters that are outsid the normal 50:50 split.

So far this year our very cold,dry spring type has a 75% chance of being followed by a cold winter.The very warm,very dry summer  does not produce a strong signal either way.

Just looked at October rainfall for Central England which in October was 104.4 mm 41.3mm above average.However as September had  a rainfall that was 14.6 below average this gives a total anomaly so far for autumn of 26.7mm which puts it in the wet ,but not very wet category.on th edtepertaure side the mean anomaly for sSept an dOctober is around 1.3c which puts it in the very warm category.

So the autumn  season todate is very warm wet.Such aurtumns have been followed by warmer than average winter in 100% of cases.Ofcourse if November tuns out to be extremely wet and cold then the categorisation for autunm could still change.

but currently we have cold signal (75%) from spring and a warm signal (100% ) from Autumn to date.in this situation one would choose the strongest signal which is the warm winter.But I stress this is only one of the inputs......

 

Originally Posted by: glenogle 

So an average winter it is then. 

Originally Posted by: Solar Cycles 

I dont know if it would be average.  If you take what Roger has said above and mix it with the hurricane info, it is possible that it will be more likely to lean to warm OR cold, other than something in between?

Originally Posted by: roger63 

I was being mischievous glenogle and highlighting how difficult this winter is to call with so many long range models going for different scenairos, even Matty's flip of a coin stratergy is as good a call as any. IMO which means diddly squat, I think we'll have a mixed December with any prolonged cold spell coming from mid January onwards.

Gooner
07 November 2013 08:00:15

CFS throws up the cold January ......................again

http://modeles.meteociel.fr/modeles/cfs/run/monthly/runs/2013110606/cfs-8-1-2014.png?06

Remember anything after T120 is really Just For Fun



Marcus

Banbury

North Oxfordshire

378 feet A S L



nickl
07 November 2013 13:15:46

Is the first wintry spell of the season coming into view ? (whoops - should be in the autumn thread!)

 

Gavin P
07 November 2013 13:53:57

Hi all,

Here's my latest seasonal update looking at NASA's experimental model;

http://www.gavsweathervids.com

Seems to be going for quite a cold late winter period, though the Dec-Feb anomaly comes out slightly colder than average as well.

I didn't know NASA had a seasonal forecasting model TBH.

Rural West Northants 120m asl

Short, medium and long range weather forecast videos @ https://www.youtube.com/user/GavsWeatherVids

John S2
07 November 2013 14:58:30

An honest question, but what deviation from the mean who constitute a warm or cold tag?

Originally Posted by: nsrobins 

One method is to split a sample into 5 groups of equal size. For winters the warmest fifth could be referred to as mild, second fifth 'milder than average', third section 'average' etc, or alternatively very mild/mild/average/cold/very cold.

Using this type of method 'average' means close to average, not the precise value of the mean or median. A similar classification can be used for precipitation. 

roger63
  • roger63
  • Advanced Member Topic Starter
07 November 2013 15:45:57

An honest question, but what deviation from the mean who constitute a warm or cold tag?

Originally Posted by: John S2 

One method is to split a sample into 5 groups of equal size. For winters the warmest fifth could be referred to as mild, second fifth 'milder than average', third section 'average' etc, or alternatively very mild/mild/average/cold/very cold.

Using this type of method 'average' means close to average, not the precise value of the mean or median. A similar classification can be used for precipitation. 

Originally Posted by: nsrobins 

John have looked at this approach.Couple of observations.With 5 groups of equal size there  are 25 different combinations of temerature and precipitaion types compared to 16 on the simple very warm,warm,cold,very cold and similar for precipitation.This means smaller numbers of years in each classifcation type.Second there is clear understanding of anomalies versus mean ie warmer/colder.I,am not sure that  the inclusion of "average" band makes things clearer-although I know that the Met Offoce use this quintile approach in their contingency planning seasonal forecast.

JACKO4EVER
07 November 2013 17:10:12

CFS throws up the cold January ......................again

http://modeles.meteociel.fr/modeles/cfs/run/monthly/runs/2013110606/cfs-8-1-2014.png?06

Originally Posted by: Gooner 

Fixed

Gooner
07 November 2013 18:00:36

Hi all,

Here's my latest seasonal update looking at NASA's experimental model;

http://www.gavsweathervids.com

Seems to be going for quite a cold late winter period, though the Dec-Feb anomaly comes out slightly colder than average as well.

I didn't know NASA had a seasonal forecasting model TBH.

Originally Posted by: Gavin P 

Good vid Gav

Cheers

Remember anything after T120 is really Just For Fun



Marcus

Banbury

North Oxfordshire

378 feet A S L



Gooner
07 November 2013 18:04:08

http://modeles.meteociel.fr/modeles/cfs/run3/cfsnh-0-894.png?12

JFF JFF JFF

A cold flow mid December

 

Remember anything after T120 is really Just For Fun



Marcus

Banbury

North Oxfordshire

378 feet A S L



Chiltern Blizzard
07 November 2013 20:53:16

http://modeles.meteociel.fr/modeles/cfs/run3/cfsnh-0-894.png?12

JFF JFF JFF

A cold flow mid December

 

Originally Posted by: Gooner 

About as far as you can get from snow for Santa though!

http://modeles.meteociel.fr/modeles/cfs/run3/cfsnh-0-1164.png?12

Rendlesham, Suffolk 20m asl
Gooner
07 November 2013 21:02:53

http://modeles.meteociel.fr/modeles/cfs/run3/cfsnh-0-894.png?12

JFF JFF JFF

A cold flow mid December

 

Originally Posted by: Chiltern Blizzard 

About as far as you can get from snow for Santa though!

http://modeles.meteociel.fr/modeles/cfs/run3/cfsnh-0-1164.png?12

Originally Posted by: Gooner 

http://modeles.meteociel.fr/modeles/cfs/run4/cfsnh-0-1266.png?18

JFF JFF JFF

Some wintry stuff soon follows

Remember anything after T120 is really Just For Fun



Marcus

Banbury

North Oxfordshire

378 feet A S L



John S2
07 November 2013 21:57:28
Italian researchers are predicting a mild winter for the UK. Arctic Oscillation expected to be positive based on correlation with the October Pattern Index [OPI]. Long term correlation said to be to be at least +0.83. OPI value for October 2013 is +1.6

Plenty reading below for those interested:

http://www.centrometeotoscana.it/forum/index.php?topic=7371.0 

http://www.centrometeotoscana.it/forum/index.php?topic=7473.0 

http://www.americanwx.com/bb/index.php/topic/41379-october-pattern-index-predicting-winter-ao-from-october-with-90-accuracy/ 

http://www.americanwx.com/bb/index.php/topic/41639-seasonal-winter-20132014-forecast-based-on-opi-index/ 

Solar Cycles
08 November 2013 09:14:21
It's fairly new research is this though they did call last winter right if my memory serves me right, again with any LRF there are just far too many variables to come up with an accurate forecast time after time.

roger63
  • roger63
  • Advanced Member Topic Starter
08 November 2013 10:03:11

Interesting pattern matching October to the AO.Although the time series is short 1979-2013 the correlation is high.

The next question is how well does the AO link to European winter temperatures?I dont know the answer for the AO but the Met office work  for the NAO suggests that the correlation between the NAO and winter temperature is r =0.6 meaning that the NAO alone accounts for c40% % of winter temperature.Also was involved in a paper published in Weather magazine (March 2013) which demonstrated that across much of Europe there is  a closer link between NAO and winter temperature in NAO + years than  NAO -ve years.

Andy Woodcock
08 November 2013 23:31:35

The MetO very confident prediction of a warm November issued on its website just 8 days ago is going horribly wrong with temps during the first 8 days below average especially in the north where its been particularly chilly with night frosts and hill snow.

Now the MetO have dropped the warm November forecast all together with an updated MRF indicating a cool month, all this with such high Atlantic SST's

Confidence significantly decreases regarding which weather type is most likely to dominate through this forecast period. There are currently no strong signals indicating significantly above or below average temperatures or rainfall. However, the projections suggest that precipitation amounts are more likely to be just above the seasonal average than below. This would suggest that the weather remains changeable with spells of showers or longer spells of rain, particularly in the north and west, interspersed with drier and clearer periods, giving a greater threat of overnight frost and fog. Temperatures are also more likely to be just below average than above, and this would give a greater threat of wintry precipitation, particularly over hills.

Updated: 1201 on Fri  8 Nov 2013

Model output continues to show cool zonality which again is surprising given the high SST's, where is the cold air coming from?

Its back to the drawing board with any winter forecast IMO.

Andy

Andy Woodcock

Penrith

Cumbria

Altitude 535 feet

"Why are the British so worried about climate change? Any change to their climate can only be an improvement" John Daley 2001

Andy Woodcock
08 November 2013 23:34:32

The MetO very confident prediction of a warm November issued on its website just 8 days ago is going horribly wrong with temps during the first 8 days below average especially in the north where its been particularly chilly with night frosts and hill snow.

Now the MetO have dropped the warm November forecast all together with an updated MRF indicating a cool month, all this with such high Atlantic SST's

Confidence significantly decreases regarding which weather type is most likely to dominate through this forecast period. There are currently no strong signals indicating significantly above or below average temperatures or rainfall. However, the projections suggest that precipitation amounts are more likely to be just above the seasonal average than below. This would suggest that the weather remains changeable with spells of showers or longer spells of rain, particularly in the north and west, interspersed with drier and clearer periods, giving a greater threat of overnight frost and fog. Temperatures are also more likely to be just below average than above, and this would give a greater threat of wintry precipitation, particularly over hills.

Updated: 1201 on Fri  8 Nov 2013

Model output continues to show cool zonality which again is surprising given the high SST's, where is the cold air coming from?

Its back to the drawing board with any winter forecast IMO.

Andy

Originally Posted by: Andy Woodcock 

The key phrase in the MetO MRF sums up any winter forecast 'Confidence significantly decreases'.

That says it all!

Andy

Andy Woodcock

Penrith

Cumbria

Altitude 535 feet

"Why are the British so worried about climate change? Any change to their climate can only be an improvement" John Daley 2001

Solar Cycles
09 November 2013 08:40:45

The MetO very confident prediction of a warm November issued on its website just 8 days ago is going horribly wrong with temps during the first 8 days below average especially in the north where its been particularly chilly with night frosts and hill snow.

Now the MetO have dropped the warm November forecast all together with an updated MRF indicating a cool month, all this with such high Atlantic SST's

Confidence significantly decreases regarding which weather type is most likely to dominate through this forecast period. There are currently no strong signals indicating significantly above or below average temperatures or rainfall. However, the projections suggest that precipitation amounts are more likely to be just above the seasonal average than below. This would suggest that the weather remains changeable with spells of showers or longer spells of rain, particularly in the north and west, interspersed with drier and clearer periods, giving a greater threat of overnight frost and fog. Temperatures are also more likely to be just below average than above, and this would give a greater threat of wintry precipitation, particularly over hills.

Updated: 1201 on Fri  8 Nov 2013

Model output continues to show cool zonality which again is surprising given the high SST's, where is the cold air coming from?

Its back to the drawing board with any winter forecast IMO.

Andy

Originally Posted by: Andy Woodcock 

The key phrase in the MetO MRF sums up any winter forecast 'Confidence significantly decreases'.

That says it all!

Andy

Originally Posted by: Andy Woodcock 

Lol, I think they should stick to the 7-10 day timeline as I feel there longer range stuff is just as woeful as it's always been. Still at anything up to 10 days they are the best in the business.

TomC
  • TomC
  • Advanced Member
09 November 2013 11:49:12

The MetO very confident prediction of a warm November issued on its website just 8 days ago is going horribly wrong with temps during the first 8 days below average especially in the north where its been particularly chilly with night frosts and hill snow.

Now the MetO have dropped the warm November forecast all together with an updated MRF indicating a cool month, all this with such high Atlantic SST's

Confidence significantly decreases regarding which weather type is most likely to dominate through this forecast period. There are currently no strong signals indicating significantly above or below average temperatures or rainfall. However, the projections suggest that precipitation amounts are more likely to be just above the seasonal average than below. This would suggest that the weather remains changeable with spells of showers or longer spells of rain, particularly in the north and west, interspersed with drier and clearer periods, giving a greater threat of overnight frost and fog. Temperatures are also more likely to be just below average than above, and this would give a greater threat of wintry precipitation, particularly over hills.

Updated: 1201 on Fri  8 Nov 2013

Model output continues to show cool zonality which again is surprising given the high SST's, where is the cold air coming from?

Its back to the drawing board with any winter forecast IMO.

Andy

Originally Posted by: Andy Woodcock 

The key phrase in the MetO MRF sums up any winter forecast 'Confidence significantly decreases'.

That says it all!

Andy

Originally Posted by: Andy Woodcock 

It does and for time scales beyond 2 weeks it is very rarely more than 75%. In my view all the indications are for a mild winter in NW Europe but that obviously doesn't mean it will be mild just more likely than recent winters. Seasonal forecasts are useful for those who understand them and particularly for those who have weather dependent businesss where seasonal forecasts can be of value over a decade.

Charmhills
09 November 2013 11:55:40

As you said in the past Tom, the atmosphere is in constant chaos.

Loughborough, EM.

Knowledge is power.

Duane.

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