Winter Model Discussion 12Z 22/1/13 onwards.

[Djdazzle]

SSW's are by no means fully understood, and as was mentioned before, they are no guarantee whatsoever that cold will result in the UK. I do hope, however, that the people who promised the HLB a few weeks ago will now have a long hard look at the theories behind what they said, and why HLB has failed to materialise. Of course, there is time still. I can't believe that somebody in this thread has already written off February. Pathetic!

[stewfox]

Exactly and how depressing is it that we are searching yet again in deep F.I. That has been the theme this winter. We have constantly sat awaiting some mega blocking to arrive based on GPs forecast and may I say some of your posts in the Stratosphere thread. For example when the SSW occured on the 6th Jan many members including yourself said the end of Jan is when we could see some epic HLB. Now look at the chart below at +168.

http://www.wetterzen...s/Rtavn1681.png

That is a shockingly poor chart from a coldies perspective and completely opposite to what some predicted earlier this month.

Lets not confuse our recent cold spell with what was predicted by some. For starters our current cold spell started on the 12th Jan only 6 days after the SSW. Our current cold spell did not consist of blocking over Greenland or Scandinavia. We were frankly lucky that the wedge of HP positioned itself where it did and that a SW did track S instead of NE. If this SW had of tracked NE then our current cold spell wouldn't of occured. Now was the SSW responsible for the SW tracking S? My answer is no it wasn't.

My negative attitude is nothing to do with our current cold spell coming to an end. This winter has been so frustrating because much was promised and yet very little has delivered from a N blocking point of view. The Greenland HP has been elusive and the NAO has rarely even dropped below -1 on the index scale. So forgive me if my patience is running thin and why I have little faith in future predictions of blocking occuring in Feb!

This is why im recent days i've been saying to members that promising signs from the Stratosphere or the MJO or whatever else mean absolutely nothing if this isn't being shown on the actual NWP.

I can usually follow you but not this time. What are you saying is SSW going to give us barbeque summer or not ??

[stratty]

From the point of model discussion, this cold spell has been one of the most interesting to watch pan out in my 9 years of viewing on here. As always with a breakdown, we will now search for the next attempt at bringing cold to our island. Just a good job i've had lieing snow here for nearly 2 weeks, as it would have been similar to winters when I first joined this site, where even the whiff of snow was a rare beast!

Play nicely all and have patience! Afterall it is only the weather and we can do bugger all about what we end up getting anyway!

[ChartViewer]

Exactly and how depressing is it that we are searching yet again in deep F.I. That has been the theme this winter. We have constantly sat awaiting some mega blocking to arrive based on GPs forecast and may I say some of your posts in the Stratosphere thread. For example when the SSW occured on the 6th Jan many members including yourself said the end of Jan is when we could see some epic HLB. Now look at the chart below at +168.

http://www.wetterzen...s/Rtavn1681.png

That is a shockingly poor chart from a coldies perspective and completely opposite to what some predicted earlier this month.

Lets not confuse our recent cold spell with what was predicted by some. For starters our current cold spell started on the 12th Jan only 6 days after the SSW. Our current cold spell did not consist of blocking over Greenland or Scandinavia. We were frankly lucky that the wedge of HP positioned itself where it did and that a SW did track S instead of NE. If this SW had of tracked NE then our current cold spell wouldn't of occured. Now was the SSW responsible for the SW tracking S? My answer is no it wasn't.

My negative attitude is nothing to do with our current cold spell coming to an end. This winter has been so frustrating because much was promised and yet very little has delivered from a N blocking point of view. The Greenland HP has been elusive and the NAO has rarely even dropped below -1 on the index scale. So forgive me if my patience is running thin and why I have little faith in future predictions of blocking occuring in Feb!

This is why im recent days i've been saying to members that promising signs from the Stratosphere or the MJO or whatever else mean absolutely nothing if this isn't being shown on the actual NWP.

TEITS this was your quote in the Strat thread a while back.......

'Absolutely BA.

However cold it becomes or however much snow I may see this thread has been the highlight of the winter so far. During Christmas the model output was truly shocking but thankfully we had this thread to keep our hopes up. The current model output really is showing how influencial the Stratosphere is especially this mornings ECM. If it wasn't for this thread we would of been amazed at the turnaround in the model output but really very few of us are surprised thanks to this thread.

Before anyone says im putting a jinx on the model output and I would say no because we can clearly see the effects early on. A big thanks to all those who contribute to this thread and I just wish I had more intelligence to understand the Stratosphere and contribute myself.'

Just that things do change quite quickly due to SSW but not always. Who knows if/when the output may change to HLB quite quickly.

[Snowman.]

lol this cold spell was picked up in mid term not long term whose to say it wont happen again?

Just take a snap shot of feb 1st currently predicted by 18z then match and see if your right if you are good for you, if not well some people are going to look silly!

[TEITS]

I am sorry but at this point I will bow out gracefully to your better analysis and opinion, as it is now becoming quite clear to me that the stratosphere has not contributed to the tropospheric pattern at all over these last few weeks as you suggest, and it is quite obvious that we will not get any high latitude blocking throughout the rest of winter.

I should know better than to spend a lot of time reading research to the contrary and I will contact the metoffice and BBC immediately to inform them that they have been misleading the public in saying as much that the SSW may have contributed to the cold spell.

Thanks for clearing that up.

You really can't take any critical remarks can you?

Like I have said many times I am a firm believer that the Stratosphere affects the weather patterns lower down. However it is only one jigsaw puzzle amongst many others and unfortunately many ignore these other pieces and assume the Stratosphere dictates everything. So the reason im sceptical isn't because I doubt the influence of the Stratosphere but our understanding of this jigsaw puzzle amongst all the others.

The problem with this forum in recent years is the Stratosphere has become the new trend and some of the other factors like SSTs in the Atlantic have been completely ignored. So many members now assume that a SSW equals HLB. This clearly isn't the case because we have yet to see a GH in the model output and yet in Dec 2009, 2010 we were treated to a 1070mb GH without a SSW!!

[Snowy Liverpool]

SSW's are by no means fully understood, and as was mentioned before, they are no guarantee whatsoever that cold will result in the UK. I do hope, however, that the people who promised the HLB a few weeks ago will now have a long hard look at the theories behind what they said, and why HLB has failed to materialise. Of course, there is time still. I can't believe that somebody in this thread has already written off February. Pathetic!

HLB has occured, just not in our tiny corner of the world. Much of America+Canada is suffering from intense cold due to high pressure in the arctic linking up to high pressure in the North Pacific/West America. If they promised HLB exclusively to the UK then I take it back, but I'm sure they didn't.

[Cheese Rice]

It's worth taking into account other models rather than just the GFS you know! A complete disregard of the UKMO and ECM by some on here which is rather surprising as I'd of thought they'd know better.

Anyway the GFS is projecting a significant spell of snow on Friday. It's great to see us going out on a high rather than the usual light rain spreading in from the west. As some have suggested the Meto will need to release an Amber warning soon as the GFS points to significant accumulations for the twelve hour period. We are looking at over 20mm for some places on top of what we already have, northern areas in particular like here have over 30cm with the potential for 10-20cm.

BBC estimates for low ground

Edited January 23, 2013 by Cheese Rice

[chionomaniac]

You really can't take any critical remarks can you?

Like I have said many times I am a firm believer that the Stratosphere affects the weather patterns lower down. However it is only one jigsaw puzzle amongst many others and unfortunately many ignore these other pieces and assume the Stratosphere dictates everything. So the reason im sceptical isn't because I doubt the influence of the Stratosphere but our understanding of this jigsaw puzzle amongst all the others.

The problem with this forum in recent years is the Stratosphere has become the new trend and some of the other factors like SSTs in the Atlantic have been completely ignored. So many members now assume that a SSW equals HLB. This clearly isn't the case because we have yet to see a GH in the model output and yet in Dec 2009, 2010 we were treated to a 1070mb GH without a SSW!!

Can you not just have a consistent opinion instead of changing day to day?

I can take constructive criticism that will help better our understanding of the stratosphere and it's interaction with the troposphere and welcome it.

I don't think that destructive criticism serves any purpose whatsoever and I will always fight my corner against that.

[TEITS]

TEITS this was your quote in the Strat thread a while back.......

'Absolutely BA.

However cold it becomes or however much snow I may see this thread has been the highlight of the winter so far. During Christmas the model output was truly shocking but thankfully we had this thread to keep our hopes up. The current model output really is showing how influencial the Stratosphere is especially this mornings ECM. If it wasn't for this thread we would of been amazed at the turnaround in the model output but really very few of us are surprised thanks to this thread.

At the time I didn't realise we would now be looking at such awful output.

Whether members like it or not the much promised severe cold spell at the end of Jan is now looking extremely unlikely.

http://modeles.meteociel.fr/modeles/gens/graphe_ens3.php?x=308&ext=1&y=89&run=18&runpara=0

Coldest GEFS member from the 18Z is only -3C.

So why should we believe this HLB will appear in Feb? I won't until it actually appears in the model output at a sensible timeframe.

[stratty]

BBC estimates for low ground

10.30pm weather on BBC1 was a massive upgrade on that pic. 5-10cm over most of central and eastern UK

[Cloud 10]

I keep reading about how HLB has failed to happen,and yet when i look at the 500mb

anomalies for the first 3 weeks of January.....

[Jason M]

It's worth taking into account other models rather than just the GFS you know! A complete disregard of the UKMO and ECM by some on here which is rather surprising as I'd of thought they'd know better.

Anyway the GFS is projecting a significant spell of snow on Friday. It's great to see us going out on a high rather than the usual light rain spreading in from the west. As some have suggested the Meto will need to release an Amber warning soon as the GFS points to significant accumulations for the twelve hour period. We are looking at over 20mm for some places. On top of what we already have, northern areas in particular like here have over 30cm with the potential for 20cm.

BBC estimates for low ground

The GFS ensembles are very odd again tonight in the sort term. Considerable disagreement even at 60 hours. Especially in relation to the SE re the breakdown. The ensembles then converge very strongly on a deep SW flow and are strongly zonal right out to the end f high res.

As mentioned earlier the record levels of entropy seem to be slowly clearing.

It seems to me that some in here have unrealistic expectations. The SSW was well forecast by GP, Chio etc and no doubt had a massive influence on our weather. The fact that the northern blocking doesn't look like happening doesn't alter the fact that a lot of skill was involved in forecasting the SSW in the first place.

My own feeling is that th SSW impact was fast and hard but has been quick to wane. Rather thn people moaning at each other I'd be more interested in Chio / GP thoughts there? Do they feel the impacts are working out of the system now?

Jason

[chionomaniac]

I keep reading about how HLB has failed to happen,and yet when i look at the 500mb

anomalies for the first 3 weeks of January.....

It doesn't count C10 though, if that type of anomaly dramatically reduces zonal flow which leads to cold air being forced westwards because the block couldn't be seen clearly. Apparently.

[Mark Bayley]

Further to my post the other day. Given the strong MJO signal, GWO progression and continued influence of the reduced zonal winds/strat warming then this is the pattern i would expect the models to start showing as we progress through first half of February (i.e. mid Atlantic ridge and possible height rises over Greenland).

Edited January 23, 2013 by Mark Bayley

[TEITS]

Can you not just have a consistent opinion instead of changing day to day?

I can take constructive criticism that will help better our understanding of the stratosphere and it's interaction with the troposphere and welcome it.

I don't think that destructive criticism serves any purpose whatsoever and I will always fight my corner against that.

Destructive criticism is a bit OTT. I am simply saying that I don't feel as though we can use the Stratosphere alone to predict whether HLB will occur. We need to use all the variables and this is where us humans come stuck. We don't fully understand all these variables and more importantly understand how they interact with each other.

Basically in my opinion long range forecasting is a waste of time especially for the UK in winter.

[chionomaniac]

The GFS ensembles are very odd again tonight in the sort term. Considerable disagreement even at 60 hours. Especially in relation to the SE re the breakdown. The ensembles then converge very strongly on a deep SW flow and are strongly zonal right out to the end f high res.

As mentioned earlier the record levels of entropy seem to be slowly clearing.

It seems to me that some in here have unrealistic expectations. The SSW was well forecast by GP, Chio etc and no doubt had a massive influence on our weather. The fact that the northern blocking doesn't look like happening doesn't alter the fact that a lot of skill was involved in forecasting the SSW in the first place.

My own feeling is that th SSW impact was fast and hard but has been quick to wane. Rather thn people moaning at each other I'd be more interested in Chio / GP thoughts there? Do they feel the impacts are working out of the system now?

Jason

Jason,

I have gone to lengths in recent days to try to explain exactly what has occurred ( stratospherically) to lead us into a more zonal flow. And I have also suggested that this doesnt mean that the effects of the SSW are over. The ridge following the SSW has been trapped in the mid strat in the Pacific sector and it will take time now to establish whether this can eventually squeeze through to the Atlantic side. There are signs that this could occur from day 10 onwards - in the meantime, we are trapped with the Polar vortex based on the Atlantic side.

[nick sussex]

EITS at this rate you're going to make me seem like Mr Happy! lol

Strangely I feel quite optimistic going forward! Especially when you view the trend of the ECM in recent runs, initially when the models decided on the PV remnants moving out of Canada they dished up flat as a pancake upstream patterns, now we have a deep low crossing as the pattern becomes more amplified.

Its easy to see the effect this has on the PV lobe in northern Canada. The saviour low as I put it in an earlier post could well end the imminent mild mush quite quickly.

We'll just have to see what happens over the next few days if this verifies.

Regarding the SSW I have to disagree with you, without that reversal in zonal winds IMO this cold spell had no chance of occuring, as for HLB's lets just wait and see what occurs.

Of course theres still alot to learn re SSW's, perhaps we'll never have a complete understanding because there are so many variables in play at any one time.

Its very complex but certainly the strat thread has been incredibly interesting especially in those dark days of relentless zonal dirge on offer in the models.

[Catacol]

The PV is expected to set up north of Hudson Bay and not be ejected into the Atlantic so the lower resolution GFS is unlikely to verify.

Are you sure? That doesnt look right to me - ECM ensemble at 96 here shows the ejection very clearly:

and then at 144 as the ensemble picture gets a bit wooly we still have a clear ejection signal into the mid atlantic

This is now a consistent forecast for the last 4 / 5 days and, I believe, is at the heart of the pessimism from some interpreters in the last few days, including me. I keep looking for signs of a blocking pattern returning, but they remain elusive. The 10 day ensemble forecast today is interesting - not only has the vortex solidified again - it has parked over Canada again ready to fire more energy over the atlantic at us while the vortex shard that we have been assured by some will drop down from Scandinavia looks (on the basis of the ensemble) to have disappeared.

I'm just saying it as I see it. Not wanting to upset anybody... certainly not Chio! I am not suggesting by the way that the SSW has had nothing to do with all this - my view of the next 2 weeks is what it is precisely because of the SSW we have had. Maybe I have it all wrong and the atlantic energy will just dissipate and allow height rises - but right now I dont see it.

Here is the ongoing Canadian Warming that will shunt the energy out into the atlantic:

and here is the current GFS op run at 240 that almost exactly matches the ECM ensemble forecast:

Still got a lot to learn, and still looking for cold... but not having much luck. Dont want to get involved in a slanging match, but would gratefully accept anyone that can unpick my analysis a bit here. It seems as though we are having to take a lot on faith here about greenland blocking approaching?

One final point - I agree that we have had height anomalies in our favour to the north, but in December some excellent cpc charts pointing to this were proven to be absolute tosh in terms of getting us cold air, and the weather we have just had has been great for some parts to see snow, but has not really tapped into a strong easterly or north easterly feed because the block has been so weak. It has almost been more of a cold zonal setup with positive or neutral NAO. I dont want anyone to take offence... but it doesnt really look to me as though we have had blocked weather at all so far this winter. Am I way out in my analysis here?

Edited January 23, 2013 by Catacol_Highlander

[TEITS]

I keep reading about how HLB has failed to happen,and yet when i look at the 500mb

anomalies for the first 3 weeks of January.....

Rather than using those charts lets have a look at the ACTUAL recorded SLP.

Tells a different story!

Edited January 23, 2013 by THE EYE IN THE SKY

[Jason M]

Jason,

I have gone to lengths in recent days to try to explain exactly what has occurred ( stratospherically) to lead us into a more zonal flow. And I have also suggested that this doesnt mean that the effects of the SSW are over. The ridge following the SSW has been trapped in the mid strat in the Pacific sector and it will take time now to establish whether this can eventually squeeze through to the Atlantic side. There are signs that this could occur from day 10 onwards - in the meantime, we are trapped with the Polar vortex based on the Atlantic side.

Cheers for the response.

To be fair there is a degree of support in the very long range ensembles. The weather will do as it will in the meantime and I still think there are a number of issues for the models to resolve at 60 hours at the moment. There could be some interesting developments there I feel.

Jason

[chionomaniac]

Rather than using those charts lets have a look at the ACTUAL recorded SLP.

Tells a different story!

Does it?

[nick sussex]

Catacol Highlander heres the extended discussions from NOAA:

http://www.cpc.ncep....day/fxus06.html

CH the current ejection of the PV is inline with the forecasts, this is caused by the strat warming in the Canadian sector, thats not in dispute, its the next PV lobe in Hudson Bay.

The PV at this point located north Hudson Bay initially, a trough in the eastern USA for 8 to 14 day with some movement of the PV but not as the GFS does ejecting it too far east.

The ECM still holds the main lobe further nw. The key is the eastern USA troughing, much depends on the tilt and shape of that but if its amplified its likely game over for mild in the UK.

We'll see in the coming days whether we can get that amplification but overall the ECM is a marked improvement on previous runs.

Edited January 24, 2013 by nick sussex

[Catacol]

... and while I am burbling the MetO update of long term drier to the north and wetter to the south surely suggests they see an atlantic dominated picture for the south with some height rises to the north to deflect the systems south. That sounds like a weaker version of what we have just had. No big high lat block?

[GrangemouthBairn]

SSW's are by no means fully understood, and as was mentioned before, they are no guarantee whatsoever that cold will result in the UK. I do hope, however, that the people who promised the HLB a few weeks ago will now have a long hard look at the theories behind what they said, and why HLB has failed to materialise. Of course, there is time still. I can't believe that somebody in this thread has already written off February. Pathetic!

Nobody ever promised HLB for this time a few weeks ago. All they said was that HLB was more likely. I don't think there us much doubt that a SSW does make HLB more likely but that doesn't mean that it always happens.

The question is whether the SSW did play a part in the current cold spell. I personally think that it did because before the SSW, there was no sign of any high pressure to our north at all since mid December. Then all of a sudden six days after the SSW an area of high pressure drifted north from the south and stayed to our north for about 2 weeks. I know it wasn't a strong area of high pressure but it was still strong enough to keep the Atlantic at bay for about 2 weeks.

But who knows what the lag time is? I don't think anybody really does. And although I have said I think the SSW did play a part in this cold spell, that could be wrong. Maybe the real effect if the SSW won't be felt until February. Or maybe come the end of this winter we will look back and people will think that there has been no effect. We won't know until we look back on the winter as a whole to see if it has had an effect.