257 replies to this topic

[Liam J]

Heres an example of the drastic changes FI can bring from run to run, below are charts from the GFS @ 300hrs on the 12z and then again on the 18z.

The 945mb low has been replaced with a 1025mb high!!

Attached Thumbnails

• 
• 

[BLAST FROM THE PAST]

Looking at other methods.
Solar cycle 24 although 'perked up' is still at a low level, way below most 20th century cycles and is mirroring closely cycle 5 which I think was Dalton period.
Perturbation cycle [solar driven] is about 36 yrs in length. It alternates the 'dominant' phase of ENSO and we have entered the La nina phase. It doesn't mean that there'll be no El Ninos, just that La Ninas will be longer lasting and more frequent over the period. PDO is in -ve phase cycle and both these cycles enhance chances of -ve NAO. As C mentioned it doesn't mean permanent -ve NAO, we will get +ve phases.
Lunar and solar cycles directly linked pointing to longterm shift of jetstream southward again. Research seperate to this has shown that the ITCZ had been 'spreading out' over last 150+ years and thus forcing PFJ polewards. This stopped in around 2002 and a reversal [albeit slow but sure] now seems apparent.
So this year what are we seeing again...a -ve NAO prevalent, return of La nina, a jetstream that is certainly overall more south and meridional than 'suffered' over many years. Responses IMO....thats IMO.... expected to be seen and are seeing under the solar and lunar cycles. Those are the building blocks.
What am I looking for? Over next 5-6 weeks if we get stuck with PV stuck over Greenland and storm after storm going through the GIN corridor then they are gone but I think that is the least likely scenario.....but to be sure I don't expect continued northern blocking and constant early cold.
-ve NAO doesn't guarantee cold for UK as we have seen if it is too west based but it does along with a jet tracking south greatly increase chances.

BFTP

Edited by BLAST FROM THE PAST, 18 October 2011 - 23:32 .

[mushymanrob]

tbh i think people only see 'building blocks' when the runs show something they want to see, i wonder how many people would be so keen to spot early signals for cold, if the runs only showed mild.... would continuous mild runs still be regarded as building blocks? or ignored?

[stewfox]

Liam J, on 18 October 2011 - 20:27 , said:

We all need to chill a little here, it's only mid October and for now winter will arrive as ever on the 1st of December, and winter weather will arrive when I see cross model agreement within T96 hours or less and not 300 hours+

We could have a cold winter, we could have an average winter or we could have a mild winter.

Bottom line no one can predict with any real accuracy what the weather will be like in Dec,Jan or Feb in mid October.

If someone was 90% accurate in mid Oct for their 2011 ,12,13,14 forcasts then people would take note.

We know there is no correlation bewteen CET october and following winter. Wider global correlations ?

Would I like to know that we have 98% confidence that CET for Jan 2012 will be 6.4c probably not !

[BLAST FROM THE PAST]

mushymanrob, on 19 October 2011 - 06:29 , said:

tbh i think people only see 'building blocks' when the runs show something they want to see, i wonder how many people would be so keen to spot early signals for cold, if the runs only showed mild.... would continuous mild runs still be regarded as building blocks? or ignored?

No not all.
BFTP

[johnholmes]

BLAST FROM THE PAST, on 18 October 2011 - 23:23 , said:

BFTP

thanks Fred
In there you have given your views on the main teleconnections that you look at, and where you feel they are, along with a very balanced view as to their likely resultant weather pattern.
More like that post would be beneficial to this site rather than some of your posts from last winter.
thanks again.

[CreweCold]

Just had a quick nosey at the CFS pressure anomoly charts for Nov-Feb and I must say that striking high anomoly over Greenland has been well watered down in just a few days! In fact there is now no signifficant anomoly showing anywhere in the world for next month really(when compared to the anomolies shown for other months).....this is odd and suggests that either there is likely to be little deviation from average pressure distribution, or there is wild deviation in the data with the median solution being fairly central and thus being reflected in the output. Either way, after months of the striking anomoly showing over Greenland, a fairly major shift has occurred.

http://www.cpc.ncep..../glbz700Mon.gif - Latest Update/Rolling average

http://www.cpc.ncep..../glbz700Mon.gif - As it was last week

Edited by CreweCold, 19 October 2011 - 12:12 .

[ribster]

Seeing as some of the more narrow minded (some of whom should know better) were adamant there are no such things as building blocks etc, I decided to contact the MET Office regarding the question of whether the weather today has any bearing further down the line, i.e. patterns establishing etc. The answer was yes sometimes the weather today will have a bearing/shape events weeks down the line, other times it will have no bearing whatsoever. An example cited was the cold snap last year, suggesting that not only would it occur, but that it would become established for weeks. So in my view, those suggesting building blocks are in place are not wrong in doing so, it is entirely plausible. Of course at the same time, a case can be argued against also, but to simply dismiss out of hand is clearly wrong.

Edited by ribster, 19 October 2011 - 21:44 .

[Liam J]

ribster, on 19 October 2011 - 21:42 , said:

Seeing as some of the more narrow minded (some of whom should know better) were adamant there are no such things as building blocks etc, I decided to contact the MET Office regarding the question of whether the weather today has any bearing further down the line, i.e. patterns establishing etc. The answer was yes sometimes the weather today will have a bearing/shape events weeks down the line, other times it will have no bearing whatsoever. An example cited was the cold snap last year, suggesting that not only would it occur, but that it would become established for weeks. So in my view, those suggesting building blocks are in place are not wrong in doing so, it is entirely plausible. Of course at the same time, a case can be argued against also, but to simply dismiss out of hand is clearly wrong.

A large percentage of the so called 'building blocks' were charts that were picked out of deep FI by a few members and ramped up because they spotted a potential set up for cold weather, the charts have subsequently vanished from the model outputs and this thread has gone very quiet.

I have no doubt that the current pattern will have a bearing on the weather further down the line - as it occurs quite often through autumn and winter and is highly likely to repeat itself many times. I dont' see what your point is on that one?

The arrival of the cold spell late November 2010 wasn't picked up months in advance by looking for building blocks in October, Long range forecasts can and have gone very wrong even for the most experienced forecasters who analyse many many sources of data to create them. The Met Office give up producing long range season forecasts to save their reputation after they went horribly wrong.

[Snowmad79]

This mornings 00z GFS chart again show a tendancy for height rises to our north east and the north/nw, with warm air advecting towards Greenland and HP gaining influece over a wider area, not just a little pool of low heights centred over GL and thus actually having the effect of a "weak" Greenland High Block. Only going back to last winter we saw similar things and even when the models dropped the idea they re-emerged later and came to fruition.

The run is mild in terms of UK weather but what the charts again show this morning is how a GL High block can form out of a seemingly atlantic dominated outlook and what we need to see more of as we head towards and into winter.

Edited by Paul, 20 October 2011 - 10:50 .
Removed response to an already deleted post

[Liam J]

I am not totally discounting the theory regarding the early signs and building blocks which can lead to cold and snowy weather in the coming months over winter, my point I was trying to get across was that perhaps experienced meteorologists would have picked up on this in the past and then have been able to identify early in the season what this actually meant in terms of weather we can expect in the near future.

Long range forecasts do still go wrong, so this theory needs much more investigation before anyone can can say with confidence that potential building block synoptics do have a bearing on the weather some months down the line. Equally at the same time nobody can claim with any confidence that no link exists.

I'm sure this thread will keep going through winter so we can keep the discussion on this subject open, the buidling blocks that we see appearing now may or may not come to fruitition - hopefully not as early as last year because the final two months of last winter were painfully boring and lacking in anything remotely interesting!!

Edited by Paul, 20 October 2011 - 10:50 .
Removed response to an already deleted post

[johnholmes]

I suppose it depends on what you define as 'building blocks'.
I do believe that what the synoptic models are showing at the moment has nothing to do with how the 3 winter months MAY turn out.
It is true that certain weather types once set up do take quite some time to be changed. Remember last November into early Decemeber. The cold associated with that was not really broken until we were into january.
What caused the change?
Did any model predict the change to less cold some 3 months before hand?
Are we able to routinely predict what the weather pattern, as opposed to precise weather deatails, that far ahead?
Are there any links which do this on a better than 50% basis?
There is some discussion on how reliable could certain values in the AO and NAO for predicting what the winter may be in Britain-to me its far from proven either way about either of them.
Others disagree-that is fine-we are all entitled to our views so long as we respect each others' views.
I find the attempts on various sites including professional centres quite fascinating and am open to the various ideas, some mainstream meteorology others from viewpoints which do not yet have much if any support from that area.
It sure does make for interesting reading and research.

Edited by johnholmes, 20 October 2011 - 09:56 .

[shedhead]

If you buy into this 'building blocks' theory, which incidently I don't, you could argue that this time last year the blocks were already far more clearly in place....




Mind you, 2003's 'building blocks' looked pretty good too... how did Winter 03/04 turn out?

Edited by shedhead, 20 October 2011 - 10:46 .

[Paul]

I agree, charts in isolation surely can't be talked of as building blocks. A chart + some explanation of other longer term signals which perhaps tie in with it, then there's more scope for discussion.

[Coast]

Nice article on the upcoming Winter from Irish Weather online - I've copied some of the more interesting parts into the media thread here:

http://forum.netweat...ost__p__2147294

[Don]

Winter 2003/04 was mild overall, although it wasn't bad for the 1997-2008 period! The overall CET was 5.1C

Edited by Don, 20 October 2011 - 11:48 .

[Liam J]

UK Outlook for Friday 4 Nov 2011 to Friday 18 Nov 2011:

The early part of November is expected to be unsettled with Atlantic systems moving from west to east across the British Isles. Northern and western areas are expected to see the most persistent rain with strong winds and gales at times. The southeast will be most favoured for some drier and brighter interludes. Overall temperatures, rainfall amounts, and sunshine totals across the United Kingdom for this period should be around average for early November.
Updated: 1237 on Thu 20 Oct 2011

Meto continue to predict unsettled weather into Mid November, temperatures around average.
.

[ribster]

No, as someone has said, one chart in isolation cannot be defined as the building blocks. However, I have categorically had it from the MET Office that the state of the atmosphere today, can and sometimes does have an effect on the weather that we get weeks down the line. At the same time they advised that at other times it has no bearing at all. So I don't see what the argument is, only relaying what I was told by the professionals.

[bobbydog]

ribster, on 20 October 2011 - 12:08 , said:

No, as someone has said, one chart in isolation cannot be defined as the building blocks. However, I have categorically had it from the MET Office that the state of the atmosphere today, can and sometimes does have an effect on the weather that we get weeks down the line. At the same time they advised that at other times it has no bearing at all. So I don't see what the argument is, only relaying what I was told by the professionals.

of course todays weather has an effect weeks down the line! we all know that.
the art of forecasting is to predict how it evolves. days, weeks, months down the line

[Liam J]

ribster, on 20 October 2011 - 12:08 , said:

No, as someone has said, one chart in isolation cannot be defined as the building blocks. However, I have categorically had it from the MET Office that the state of the atmosphere today, can and sometimes does have an effect on the weather that we get weeks down the line. At the same time they advised that at other times it has no bearing at all. So I don't see what the argument is, only relaying what I was told by the professionals.

Do you have any replies from the Meto via e mail you can post out of interest with a bit more explanation? or was this a telephone conversation?

Thanks

Edited by Liam J, 20 October 2011 - 12:27 .