Winter 2012/13 - Chat

[johnholmes]

So Met has flipped, its ONE model folks and as I bore all constantly, one model and one run do not always make a correct forecast.

Trends and how does each model fit in with trends from other models are what we have to look at to try and arrive at as unbiased a summary of this as possible. So head not heart when it comes to assessments!

[Cheshire Freeze]

Yes the alarm bells are starting to ring a little, hopefully GP's musings last week will be nearer the mark than some of these horror shows. On the plus side how many times are these LRF actually right, every straw to clutch counts.

To be honest there's plenty to be disheartened about. I think without the cold strat a -NAO would have been odds on; GP lists all the factors in his vid. However, I suspect when the last UKMO run (which incorporates strat temperatures) was published, the strat temp was nothing out of the ordinary. Hence the model picked up on the favourable factors and ran with the idea the strat would remain average. However, over the last month the strat temps have falle to well below average levels and against this the favourable factors suggesting -NAO have been overridden........hence the flip to zonal and low pressure at high latitudes. I could be wrong but this is what could have happened.

[UV-RAY]

So Met has flipped, its ONE model folks and as I bore all constantly, one model and one run do not always make a correct forecast.

Trends and how does each model fit in with trends from other models are what we have to look at to try and arrive at as unbiased a summary of this as possible. So head not heart when it comes to assessments!

But it's not just one model now John, of course it doesn't mean they are right but right now the models make for grim reading.

[UV-RAY]

To be honest there's plenty to be disheartened about. I think without the cold strat a -NAO would have been odds on; GP lists all the factors in his vid. However, I suspect when the last UKMO run (which incorporates strat temperatures) was published, the strat temp was nothing out of the ordinary. Hence the model picked up on the favourable factors and ran with the idea the strat would remain average. However, over the last month the strat temps have falle to well below average levels and against this the favourable factors suggesting -NAO have been overridden........hence the flip to zonal and low pressure at high latitudes. I could be wrong but this is what could have happened.

Possibly and that in itself could be our saving grace as I feel that this years Stratospheric profile is rather different to previous ones. Chio will be able to put far more meat on the bones regarding this.

[Met4Cast]

GP and Chion are still calling for decent winter synoptics, Chion after being cautious for a while seems to be coming on board with the cold potential too so I don't think we have too much to worry about.

[Cheshire Freeze]

Possibly and that in itself could be our saving grace as I feel that this years Stratospheric profile is rather different to previous ones. Chio will be able to put far more meat on the bones regarding this.

Yes, one possible straw to clutch is that stratospheric forecasting is tricky at best (as hinted by Chiono) and that the models are failing to take into account any warmings etc which may allow other, more favourable factors to come into play.

[Ice BIast]

What's to say the 850 charts aren't wrong? As you say, the pressure charts were also consistent with progging Northern Blocking up until today.

500hPa chart also looks more zonal rather than blocked

Not saying it WILL happen. Just saying what it shows

I know its a long way out, but I find this chart a bit concerning.

If you look at the forecasts of this model from previous years, the temperature forecasts have been, IMO, very poor, at least for our latitude anyway. However, looking at the forecasts of the 500z geopotential height, they are significantly better than the temperature ones.

The model correctly predicted the blocking that occured in 2009/2010 from as early as September:

and the November to December 2010 blocking:

as well as the lack of 2011/2012 blocking:

However, the temperature forecasts arent so great, for example, 2009/2010 again at the same time as the first chart:

So I do think that this model has performed well at modelling heights, just take no notice of those temperatures!

Edited November 12, 2012 by lce Blast

[Vertical Limit]

To be honest there's plenty to be disheartened about. I think without the cold strat a -NAO would have been odds on; GP lists all the factors in his vid. However, I suspect when the last UKMO run (which incorporates strat temperatures) was published, the strat temp was nothing out of the ordinary. Hence the model picked up on the favourable factors and ran with the idea the strat would remain average. However, over the last month the strat temps have falle to well below average levels and against this the favourable factors suggesting -NAO have been overridden........hence the flip to zonal and low pressure at high latitudes. I could be wrong but this is what could have happened.

My thoughts are exactly this. The models start at T=0 and so based on current data /strat temps (perhaps the last week or so) then the seasonal updates etc are not unsurprising. We seem to be getting to an interesting point with plenty of wave 2 activity being progged to happen over the next couple of weeks - as per GP's thoughts yesterday, I think we really need to see what happens here and some patience is required.

Just my thoughts anyway.

[feb1991blizzard]

I really do not think that there is justification for the LEVEL of negativity on SOME on here, SOME of the LR models have flipped to mild but conversely, the medium range modelling has looked more promising the lst 24 hours, there are going to be many more swings like this before anything remotely long range is nailed, nothing wrong with CreweCold's view as he has stuck to his guns for a while, rather than just changed his mind because of one seasonal run, nothing wrong with calling a mild winter if your sticking to it, could the prognosis be better?, yes, could it be worse?, definately.

Are these charts for instance really that bad???

Remember, that is not a limpet trough centred to our South West for the whole month, these are mean representations, that is a fairly good chart IMO, could be better, could have the deep reds further North and stretching across toward scandi, and the core of negative heights would be better stretching from W to E across france rather than NEwards.

low height anoms do look in a bad positioning for Jan, again though, with + anoms across the North, we might still get the odd cold spell.

And feb!!!

Edited November 12, 2012 by feb1991blizzard

[feb1991blizzard]

If that post in the strat thread is correct thought, that does sound worrying, even then thoughs it till does not mean it will stay that way the whole winter.

[UV-RAY]

I really do not think that there is justification for the LEVEL of negativity on SOME on here, SOME of the LR models have flipped to mild but conversely, the medium range modelling has looked more promising the lst 24 hours, there are going to be many more swings like this before anything remotely long range is nailed, nothing wrong with CreweCold's view as he has stuck to his guns for a while, rather than just changed his mind because of one seasonal run, nothing wrong with calling a mild winter if your sticking to it, could the prognosis be better?, yes, could it be worse?, definately.

Are these charts for instance really that bad???

Remember, that is not a limpet trough centred to our South West for the whole month, these are mean representations, that is a fairly good chart IMO, could be better, could have the deep reds further North and stretching across toward scandi, and the core of negative heights would be better stretching from W to E across france rather than NEwards.

low height anoms do look in a bad positioning for Jan, again though, with + anoms across the North, we might still get the odd cold spell.

And feb!!!

I've been trumpeting the MetO probability charts since June, up until now they have been consistent whilst others have been inconsistent. It's worrying now that the MetO chart has flipped somewhat, but I don't take any model or chart that seriously unless it's in the +24 range, so they maybe worrying but I won't be losing any sleep over them.

[Barry12]

Negativity from the usual suspects..December will be average, January below or well below, february below.

[UV-RAY]

Negativity from the usual suspects..December will be average, January below or well below, february below.

And your reasoning for this is?

[Barry12]

And your reasoning for this is?

A SSW will occur in December which will result in a well below January.

[UV-RAY]

A SSW will occur in December which will result in a well below January.

How do you know one will occur?

[feb1991blizzard]

I dont think you can call a bitter winter at this stage, if people think another 1963 is nailed they will be disappointed, i just cannot see another rubbish one like last year, slightly below average is my view but with some good snow events, snow events view being based on the law of averages that if we get a slightly below winter overall then a good chance of some decent events, I will wait though before casting final judgement, until G.P and other respected people / organisations issue their final forecasts, even then though, if every model / forecaster went for a 3 month Bartlett setting up, i would still watch the models, forecasts can be wrong!! if they could not, it would be a boring subject!!.

[Met4Cast]

A SSW will occur in December which will result in a well below January.

Can you tell me the lottery numbers for next week?

[I remember Atlantic 252]

Can you tell me the lottery numbers for next week?

Hope he is right though, not seen much snow since 2010, a bit snowstarved

[shotski]

How do you know one will occur?

Its his forecast, he was asked for a reason and thats what he gave. Lets see how it pans out.

[UV-RAY]

Its his forecast, he was asked for a reason and thats what he gave. Lets see how it pans out.

What he said isn't a forecast. it's a statement.

[shotski]

What he said isn't a forecast. it's a statement.

Ok maybe so, so lets see

[johnholmes]

thanks IB a very observant post. 500mb heights are easier to predict than msl and also the 2m temperatures. On any model on any time scale.

[UV-RAY]

Ok maybe so, so lets see

Ok on that basis here's my forecast/statement, January will be mild because over the last ten years most of them have been mild.

[shotski]

Ok on that basis here's my forecast/statement, January will be mild because over the last ten years most of them have been mild.

Ok have you got any data to back that up

[I remember Atlantic 252]

Terry Michael Wood = TMW = The Modern Winter...how very drole Ian...not.

Actually you could be right, also noticed 'this mobile weather' in his sig, although I would have thought it would be TME