Model Output Discussion - Cold spell ending - what next?

[Met4Cast]

5 minutes ago, feb1991blizzard said:

The whole of feb or just the first half?

Given a lag of 20ish days in terms of momentum driving pattern changes, at least the first half but probably longer, by which time the MJO will likely have become unfavourable again. 

So.. eeek. 

That’s not to say colder spells/snaps won’t happen but i’m really struggling to see anything supporting sustained high latitude blocking, the type that had been favoured previously through February. 

Edited January 22, 2024 by Met4Cast

[jules216]

3 minutes ago, Met4Cast said:

Given a lag of 20ish days in terms of momentum driving pattern changes, at least the first half but probably longer, by which time the MJO will likely have become unfavourable again. 

So.. eeek. 

Not surprising that change if it comes will be well in to second half of February. The winter analog blends despite being cool on the seasonals did not look very interesting anyway for February with exception being 2004/05 but thats falling away now as 2005 had a big -SOI boost that reignited ENSO coupling just in time to bring cool February and March, however that is now not happening a crucial disconnect from base state is happening with strong MC convection and then COD which will diffentiate this year outcome from likes of 2004/05 or 2017/18 with  this winter,early spring now looking closer to a blend of years like 2020,1998 etc. Most likely outcome here is cold March which is sadly looking more and more on the cards.

[Ali1977]

So everything was looking good for late Winter and now signals aren’t so good - well personally the long range signals are clearly worth toffee - so with that February is still very possibly going to be wintery - so far I’ve had no snow what so ever living on a pretty decent hill - sad times, so everything is crossed for Feb and early March. Mid March onwards , I’ll be ready for the heat

[Mike Poole]

14 minutes ago, Met4Cast said:

Given a lag of 20ish days in terms of momentum driving pattern changes, at least the first half but probably longer, by which time the MJO will likely have become unfavourable again. 

So.. eeek. 

If, indeed, the MJO ever becomes favourable in the first place…

 

[Jacob]

The jet is further south on the GFS run and the PV is still disintegrated. There's also a blocking high heading into west Canada

6z:  0z:

Edited January 22, 2024 by Jacob

[northwestsnow]

Just now, Ali1977 said:

So everything was looking good for late Winter and now signals aren’t so good - well personally the long range signals are clearly worth toffee - so with that February is still very possibly going to be wintery - so far I’ve had no snow what so ever living on a pretty decent hill - sad times, so everything is crossed for Feb and early March. Mid March onwards , I’ll be ready for the heat

Yeah it's really hard being a coldie in this country Ali   

I looked at the 00zs and felt dejected straight away  ..

While we have cluster 1 we have hope but others probably feel as dejected as us.

MJO might be our wildcard yet, let's hope things turn for the better ..

 

[jules216]

3 minutes ago, Ali1977 said:

So everything was looking good for late Winter and now signals aren’t so good - well personally the long range signals are clearly worth toffee - so with that February is still very possibly going to be wintery - so far I’ve had no snow what so ever living on a pretty decent hill - sad times, so everything is crossed for Feb and early March. Mid March onwards , I’ll be ready for the heat

There is very little point in putting that much interest in seasonal models anyway. If you go with previous experience with them in winter. Sadly these days there is a bunch of people, self aclaimed forecasters what seek and use every single bit of information that would support claims of deep freeze/cold. Them people share it with a snowball effect. Like I said before there are very few out there that would look at their own forecast, instead they just vanish and re-appear in November again etc. Like with this SSW, too much focus on the fact about zonal wind reversal/weakening and very little on detailed analysis as absolutely no one mentioned a very close analog of SSW,near split of winter 2006/07  what has a great resemblance with this winter warming. We could go a lot in details about which years are/were very good analogs for different reasons but they all had about the same or similar outcome. First being a very good signal for cold/blocked second half of november in to early december, then possibly another 2 potential spells of colder outbreaks dependant on timing of course but overall being very mild. This is general for most of Europe and looks like its not far off. Also there is a good chance that March will end up cold with a good signal of Euro troughing as usual timing is yet to be decided but a signal is there. We will re-visit this later once close to date.

[Met4Cast]

8 minutes ago, Mike Poole said:

If, indeed, the MJO ever becomes favourable in the first place…

 

Ha, quite.. 

We really do have such rotten luck in this country. To have the cold spell just gone cut short (in part) by a SSW really is the peak of UK weather irony 

[Froze were the Days]

Amazing just how consistent the ECM det runs have been over the last few days...you can almost guarantee out to D10 will come to fruition, shame we can't say that about more blocked -NAO conditions, lucky to feel confident of anything over 5 days!

If you're a coldie it looks pretty bleak...but that's looked the way since the breakdown in my opinion.

[jules216]

1 minute ago, Met4Cast said:

Ha, quite.. 

We really do have such rotten luck in this country. To have the cold spell just gone cut short (in part) by a SSW really is the peak of UK weather irony 

I dont think its bad luck only for UK as the pattern is very un-conductive for most of Europe and the same can be said about various dates this winter where you can say things gone wrong in worst times where enso coupling didnt happen. Speaking of IMBY the only positive was the fall of -AAM/MJO in November which finally brought good bit of snow at the back of falling momentum and La Nina type of pattern,which is quite interesting because 3 seasons in a row there was AAM rise in November and atmosphere wasnt typical of Nina yet it was like Nina this year with strong Nino in place  Make your own mind up knowing for future that what can happen with taking the typical ENSO response which is not happening at all. That is why seasonal forecasting job is so hard

[mountain shadow]

35 minutes ago, Met4Cast said:

What did previous look like a good chance of sustained high latitude blocking during February is rapidly fading. 

Despite an increasingly favourable MJO signal into the western Pacific, we’re missing a vital ingredient & that’ poleward propagating +AAM (westerly momentum). 

The arrow shows the previous “starting pistol” of +AAM anomalies propagating poleward through December & indeed into early January, this along with the MJO helped to support & sustain the recent blocking we’ve seen around the UK/over Greenland. 

Did we really get Greenland blocking last week? Maybe for a day, possibly two, I would hardly call it sustained.

As for next month, the Met Office remain confident so they maybe have access to something we don't.

[jules216]

6 minutes ago, Met4Cast said:

Ha, quite.. 

We really do have such rotten luck in this country. To have the cold spell just gone cut short (in part) by a SSW really is the peak of UK weather irony 

When doing re-analysis or even seasonal analogs I come to a lot of conclusions where SSW actually cut the good promising patterns. Its like a double edge sword. That is why best winter here in years was 2016/17 where zonal winds were kept just below average and no dramatic swings, the pattern was steady cold in Slovakia. How often the SSW completely re-shuffled good patterns here you would be surprised, quick example January 1987 or January 2015.

[Met4Cast]

Just now, mountain shadow said:

Did we really get Greenland blocking last week? Maybe for a day, possibly two, I would hardly call it sustained.

As for next month, the Met Office remain confident so they maybe have access to something we don't.

We've just had a 2 week period of below average temperatures across the UK with many areas last week recording the coldest nights for a good number of years, that's pretty sustained in my book. We might not have seen widespread heavy snowfall but it was still a notable cold spell & period of blocking.

[Gowon]

Back to where we started:

[Stephen W]

Yes, the background signals for a cold February have been diminishing over the last few days. I think I’m more confident of believing that we are looking at an early taste of Spring in the next 10 days or so than anything wintry especially with those strong heights persisting over central/southern Europe giving the potential for a long fetch south or southwesterly wind.  February hasn’t felt like an especially wintry month for some considerable time. 

Edited January 22, 2024 by Stephen W

[Gowon]

26 minutes ago, Ali1977 said:

So everything was looking good for late Winter and now signals aren’t so good - well personally the long range signals are clearly worth toffee - so with that February is still very possibly going to be wintery - so far I’ve had no snow what so ever living on a pretty decent hill - sad times, so everything is crossed for Feb and early March. Mid March onwards , I’ll be ready for the heat

Gonna have to look for a new hobby until something decent shows up.

Might be gone for a while

[Stephen W]

5 minutes ago, mountain shadow said:

Did we really get Greenland blocking last week? Maybe for a day, possibly two, I would hardly call it sustained.

As for next month, the Met Office remain confident so they maybe have access to something we don't.

Do they remain confident? I think we all know how quickly their longer term forecasts can change and if they are seeing the same background signals change as we are at the moment, I would expect their forecast to be updated.  We shall see..

[Met4Cast]

8 minutes ago, Penguin16 said:

But is it categorical that it was cut short by the SSW? or is it just a case of selective revisionism as to way to explain why the background signals were a major fail once again? Only 10 days ago we were hearing about a 1978 pattern from a god and to ignore the models breakdown. I’ve never seen one of the background zealots on here actually hold their hands up and say actually guys I got it wrong. There’s always an excuse.

"Background signals" haven't failed, though. They only take you so far and micro details are important, shorter range changes are important. There have been several rounds of strat warming and it seems the most recent one "reflected" if you like, this helped to draw the Canadian PV eastwards towards Siberia which flattened out what previously should have been a more promising pattern for cold. 

Things change, forecasts evolve. Anyone expecting snow outside their front door or cold in a small area such as the UK purely based on teleconnections doesn't understand them, or is placing far too much emphasis on their ability to predict the micro pattern. Broadscale pattern they've done incredibly well this winter. 

Unfortunately, short-term prospects that simply cannot be forecasted at range (such as the SSW) can disrupt and change expectations. That doesn't make the teleconnections/background drivers useless.

The background drivers (GSDM, MJO etc) should be used as diagnostics of possible broadscale patterns and to provide context to NWP modelling, they cannot be used to say "London will see snow in 2 weeks". Forecasts constantly evolve and unfortunately on this occasion, unforecastable consequences have disrupted expectations. It's not about being right or wrong, it's about analysing the situation based on the evidence you have available and forming a conclusion, when the evidence changes or shifts so must too the formed conclusion, that's just the nature of this game.

Edited January 22, 2024 by Met4Cast

[jules216]

Just now, Penguin16 said:

But is it categorical that it was cut short by the SSW? or is it just a case of selective revisionism as to way to explain why the background signals were a major fail once again? Only 10 days ago we were hearing about a 1978 pattern from a god and to ignore the models breakdown. I’ve never seen one of the background zealots on here actually hold their hands up and say actually guys I got it wrong. There’s always an excuse.

I think the reason being at a certain time the tools used by some long range forecasters were showing something different. The issue with GSDM is better for re-analysis or diagnostics but its quite prone to error in forecasts, almost as like with models showing 500mb on meteociel.fr  

There might be a hangover that is lasting almost a decade now since likes of GP(Stuart Rampling) managed to use this GSDM as forecasting tool sucesfully in 2012/13 but the other failed attempts to use GSDM tend to get quickly forgotten,sadly.

[Penguin16]

6 minutes ago, Met4Cast said:

"Background signals" haven't failed, though. They only take you so far and micro details are important, shorter range changes are important. There have been several rounds of strat warming and it seems the most recent one "reflected" if you like, this helped to draw the Canadian PV eastwards towards Siberia which flattened out what previously should have been a more promising pattern for cold. 

Things change, forecasts evolve. Anyone expecting snow outside their front door or cold in a small area such as the UK purely based on teleconnections doesn't understand them, or is placing far too much emphasis on their ability to predict the micro pattern. Broadscale pattern they've done incredibly well this winter. 

Unfortunately, short-term prospects that simply cannot be forecasted at range (such as the SSW) can disrupt and change expectations. That doesn't make the teleconnections/background drivers useless.

They haven’t failed? Reading over this forum this winter must have been a dream then. It’s amusing every time they go bust, they get downplayed by those who put most emphasis on how important they are and ramping it only to fall back to the micro vs macro argument. They never factor that in when ramping the prospects. All in all another major fail for the background signals, you can’t polish a turd.

Edited January 22, 2024 by Penguin16

[mulzy]

3 minutes ago, Met4Cast said:

"Background signals" haven't failed, though. They only take you so far and micro details are important, shorter range changes are important. There have been several rounds of strat warming and it seems the most recent one "reflected" if you like, this helped to draw the Canadian PV eastwards towards Siberia which flattened out what previously should have been a more promising pattern for cold. 

Things change, forecasts evolve. Anyone expecting snow outside their front door or cold in a small area such as the UK purely based on teleconnections doesn't understand them, or is placing far too much emphasis on their ability to predict the micro pattern. Broadscale pattern they've done incredibly well this winter. 

Unfortunately, short-term prospects that simply cannot be forecasted at range (such as the SSW) can disrupt and change expectations. That doesn't make the teleconnections/background drivers useless.

Whatever the pros and cons of teleconnections and background signals, if (a big if) February doesn't deliver, it will be another exceptionally poor winter viz. wintry nirvana.  With all the hype that has been flying around, it could be one of the most disappointing winters in NW history.

[jules216]

2 minutes ago, Met4Cast said:

"Background signals" haven't failed, though. They only take you so far and micro details are important, shorter range changes are important. There have been several rounds of strat warming and it seems the most recent one "reflected" if you like, this helped to draw the Canadian PV eastwards towards Siberia which flattened out what previously should have been a more promising pattern for cold. 

Things change, forecasts evolve. Anyone expecting snow outside their front door or cold in a small area such as the UK purely based on teleconnections doesn't understand them, or is placing far too much emphasis on their ability to predict the micro pattern. Broadscale pattern they've done incredibly well this winter. 

Unfortunately, short-term prospects that simply cannot be forecasted at range (such as the SSW) can disrupt and change expectations. That doesn't make the teleconnections/background drivers useless.

It is a bit of "excuse finding" when saying about bad UK microscale luck if things are turning mild for most of Europe not just UK and for a very long duration. Its not a micro scale error in my view, just look at T2m shading on the whole Europe map next two weeks. The analogs of this winter we were using - 2004/05, 2006/07 and 2014/05 out of 3 winters 2 had a SSW or near SSW that correlated with date in which a very promising cold snap was in place and after SSW everything collapsed, its a very very good match of overall what is happening now.

[Met4Cast]

1 minute ago, Penguin16 said:

They haven’t failed? Reading over this forum this winter must have been a dream then. It’s amusing every time they go bust, they get downplayed by those who put most emphasis on how important they are and ramping it only to fall back to the micro vs macro argument. They never factor that it when ramping the prospects. All in all another major fail for the background signals, you can’t polish a turd.

Evidently you've not been reading the forum very much, then. 

Highlighting potential based on the evidence available isn't "ramping". Things didn't evolve as expected and it's important to know why & what changed. Simply saying "well that didn't happen ah well lets move on" doesn't teach you anything, it doesn't provide any context as to why. 

The teleconnections produced the Greenland blocking & two week colder spell we've just seen across the UK, this was well advertised weeks in advance, indeed, talks really started to pick up on this in early December! Goings on in the troposphere & changes have meant that the February period (still 2 weeks away, by the way) has evolved to show different weather patterns. 

What has "failed" there, precisely?

[Penrith Snow]

22 minutes ago, jules216 said:

There is very little point in putting that much interest in seasonal models anyway. If you go with previous experience with them in winter. Sadly these days there is a bunch of people, self aclaimed forecasters what seek and use every single bit of information that would support claims of deep freeze/cold. Them people share it with a snowball effect. Like I said before there are very few out there that would look at their own forecast, instead they just vanish and re-appear in November again etc. Like with this SSW, too much focus on the fact about zonal wind reversal/weakening and very little on detailed analysis as absolutely no one mentioned a very close analog of SSW,near split of winter 2006/07  what has a great resemblance with this winter warming. We could go a lot in details about which years are/were very good analogs for different reasons but they all had about the same or similar outcome. First being a very good signal for cold/blocked second half of november in to early december, then possibly another 2 potential spells of colder outbreaks dependant on timing of course but overall being very mild. This is general for most of Europe and looks like its not far off. Also there is a good chance that March will end up cold with a good signal of Euro troughing as usual timing is yet to be decided but a signal is there. We will re-visit this later once close to date.

Agreed,

However, the surprising thing is that tge MetO were taken in by all the cold signals as their MRF has been for colder than average conditions since early January and laughingly still is!

The MetO aren't known for cold ramping so some signals must have been clear, to me it demonstrates that all those teleconnections are useless as a forecasting tool, conditions over the next two weeks being the exact opposite to those predicted.

I would have had more success asking the Cat to point to the correct NH pressure anomaly for late January!

Andy

[StretfordEnd1996]

Relentless 

GEM Control would be nice




Amongst the low mood regarding colder options this morning, even with milder background signals and synoptics we can still "fluke" a brief push of heights W or NW to bring in something even if it was brief, something like that can pop up any time, however unlikely it may be

Edited January 22, 2024 by StretfordEnd1996