The Hunt for Cold continues 02/01/19

[Eastnorthwest]

We've had the SSW ,we are now waiting to see if it will reverse the winds and create blocking which should start happening from the 15th to the 20th,if not it will be a huge disappointment for all ,but we are still 9 to 14 days away yet so still plenty of time for things to change with the models ,

I personally don't take the forecast models very seriously beyond 5 to 7 days as they always change on each run beyond 7 anyway ,I am still very confident of reversal happening but like you guys it will be a great dissappearment if it doesn't happen this time round

[Frosty.]

A chance of coldish zonality on the way? in such situations the north is more favoured but that's life, unfortunately those in the south will more likely say the output is cr*p which kind of makes it more difficult for newbies to get a true picture but I welcome the expected change from the mostly abysmal benign winter so far..we need change don't we?!! 

[Kirkcaldy Weather]

I will be looking to do a another update on the 8th Jan as that was my date to look out for but here is a summary from my POV 

If I had to give percentages with most likely outcomes for the next 2 weeks (again starting from the 8th Jan) so that would be up until the 22nd Jan here are my percentages

(overall 85%- low pressures starting to take a more NW - SE track and perhaps struggling to get much past the UK, a few from the  06z GEFS not far off the mark)   

45% - Northerly   > North easterly   (possibly then an easterly) 

35% -  above average heights get into the right position and take us straight into an easterly  

20% - the above average heights end up more of a west based - NAO / fail to develop over Greenland , scandi or the arctic or low pressures become too deep and head through the UK aka "zonal" 

My key things to look out for over the next 2 - 7 days 

1.Above average heights and where they are heading - Arctic / Greenland    

Iceland / Scandi  

Possibility of more of a west based -NAO   

2. Teleconnections (AO/NAO) and other background factors strat, MJO etc (more knowledgeable posters than me for these, @Bring Back1962-63 @Catacol @Singularity @Glacier Point @lorenzo @Tamara apologies if I missed anyone)

 https://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/teleconnections.shtml          http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml  

3. Other models coming on board with the blocking signal, ECM, JMA, NAVGEM, GEM etc could be another few days before they begin to pick it up simply due to the fact they dont go to the same +hr as the GFS, GEFS

 

 and hopefully this will be the UK within the next 2-3 weeks  

[jules216]

7 hours ago, Weather-history said:

I thought that any changes that might occur would be during the second half of January? That chart you posted is mid January. 

NAO is just a measurement of the pressure difference  between two points again I thought any changes that might occur would be during the second half of January?

 

 

I am aware that teleconective analysis are pointing now for cold signal second half of January - UK related cold,not before that. Lets just go back to the beginning of winter. There were certain posts that raised expectations far too much beyond considerate measured level headed analysis:

1. I wont name him, but certain cold ramper that excites great audience and popularity which ultimately led to the fact that @Tamara stopped posting here.

2. @Roger J Smith seasonal forecast -For verification, I expect the average temperatures to run as much as 1.5 to 2 degrees below recent normals and for this winter to be one of the colder ones in the past thirty or even fifty, and colder even than the longer-term averages which run almost a degree below modern 30-year averages. I respect Roger very much and of course we can get our forecasts wrong and also I am aware, that we have second part of winter left. 

3. GP's December musing in Stratosphere thread:  

So timing looks like this:

Stratospheric (displacement) warming 27-29th December. First tropospheric response would on that basis be around 10th January, peaking on first wave response 15th-25th January. Second wave early to mid Feb, potentially very interesting if split vortex occurs.

Bear in mind, this doesn't take into account troposheric forcing. MJO cycles suggest mid latitude ridges early January, but GWO lagged impact of westerly inertia being deposited as of 9th December suggests more -NAO variant to this. Either way here, January and early February hold the greatest cold weather potential for this winter (and has been the case for some time).

 

Now lets look at London ensembles which cover period up to 22nd January - this suggests that there is about 80% probability that January will not be a cold month in UK.

Now lets look at NAO forecast:  clearly no -NAO in sight 

 

I have great respect and admiration for Roger and Stuart and they have made some amazingly accurate seasonal forecasts, some parts of this winter have already gone different way. We see what happens next.

I do not hold much teleconective expertise myself but know that predicting NAO 2 weeks + is almost impossible, even ED Berry (GSDM) pointed out this at his presentation. Also I believe that we are missing a tripole signature in Atlantic SST which we had in 2009/10, this is being overlooked and much more weight is being given to other teleconections which effect CONUS more then Europe  and get ineffectively used here as USA seems to have so many experts and cold rampers which filter down to UK forums. 

This is just my 50 pence worth of analysis and by no means I intend to offend anyone and apologies if it comes across that way

[Catacol]

31 minutes ago, WhiteFox said:

For the moment we have to accept that forecasts beyond a week cannot offer much more than probabilities of an overall pattern based on an imperfect set of inputs. Last year's forecasts following the SSW were the best I've ever seen (I remember following the BFTE from as far out as three weeks based on the musings of the knowledgeable members on here), and even then we still had variations in the NWP models. We will never have perfect information being input and the current setup introduces huge new and rarely modelled complexities to the NWP models.

All we can be sure of is that at some point the pattern will change; probability seems to favour an outbreak of cold at some stage, indeed GEFS ensembles are hinting at just such a change. I'll sit back and enjoy the ride!

Good, thoughtful post. I think we have certainly come a long way - though at the same time I think changing global conditions are also challenging the tools we have available. Already there are plenty of wise gurus who reject any data gathered pre approx. 2006 because it no longer fits the template of our changing world, and personally I continue to think that arctic sea ice melt is going to continue to challenge our forecasting ability, particularly in the crucial autumn/winter transition phase of the refreeze.

However in broad terms using data above 144 hours is now much more possible than it was 15 years ago. Back then anything above 144 was dreamland really....but now we can probably push that back to 192, and microscale prediction has also become much better. As a cricket coach I can vouch for the ever improving accuracy of the predictive MetO rainfall radar every summer! It  is really pretty good now out to 48 hours.

The macroscale stuff - and by that I mean above and beyond 2 weeks, continues to be a challenge. We know much more about the whole weather system and how it interacts (this is the baseplate for GSDM theory) and modelling of stratospheric impacts is getting better...but really we are a long way from accuracy. It is one of the key reasons why there is a lot of shoulder shrugging going on now - we talk about SSW impacts in a 1 - 3 week window without real certainty as to what will occur within that 14 day bracket, and in the meantime ongoing issues in accurately predicting MJO strength and passage are impacting on accuracy. Understanding of torques and how to read them is much more possible - but on its own frictional and mountain torque cycles are only part of a much bigger picture.

Enthusiasts will keep striving to improve - and for sure will get it right sometimes! Feb/March 18 was one such moment as the mists cleared and a roadmap was possible to mark out 2 weeks or so before the event. Right now such a roadmap for Jan 18 remains shrouded in heavy fog because the strat impacts are still evolving and pacific signals have yet apparently to fire. It's frustrating - but that's part of the fascination.

Edited January 6, 2019 by Catacol

[jules216]

53 minutes ago, Catacol said:

 

Sounds simple enough - though the extra tropical factors in GSDM theory lie outside of the MJO as a single factor, and the nature of the ongoing SSW is certainly wreaking havoc with modelling and predictions. I hope people on here are trying to learn about these processes as much as they are hunting gold plated charts - and learning for me doesn't equate with moaning when things don't sit right. Those who wish to moan are best doing so to the mirror. From a learning angle the sense that the MJO acts in lag times of a few days is wrong, both from evidence of past events and also common sense. How could a tropical signal in the equatorial pacific change pressure patterns in the north atlantic within 96 hours?

 

@Catacol I have not been stating to have a great knowledge of teleconections as you have and have read only some of the research papers, the one I was using as reference is perhaps wrong in stating the lag for -NAO. But regardless:

1. Even with longer LAG now lets look at the facts - MJO phase 7 was on 04/01/19 - attached ensemble forecast goes to 20/01 - that is 16 days LAG and at best neutral NAO.

2.MJO and tropical weather forecast - perhaps as fragile as other NWP? As we use these MJO etc for our teleconective musing as if their forecast verification is a given. 

3. Even bigger fail is CONUS and their cold rampers seasonal forecasts which pointed to cold season - yet they are torching mid December onwards.(east coast)

4. Even the greatest teleconective understanding has to account to the stochastic nature of atmosphere. 

Edited January 6, 2019 by jules216

[Guest]

Just before the 12z's roll out i really do think a reality check is needed, We here in the UK live in a country that as a norm we do not get harsh winters with massive amounts of Snaw, and lets face it if we knew we were going to get Snaw from October to April it would be boring, we would soon become so used to seeing that it would loose its magic and wonder, we wouldnt have this part of the forum so wouldnt have this social interaction every year for about 6 months, Snaw for me is a wonderful thing that still even at my age makes me smile inside and im gutted when it leaves, the joy it brings when my kids scream with joy when those first flakes start to drift down in the wind is something that would be missing if we were covered in Snaw 6 months of the year. so what im saying is this, enjoy the chase enjoy the hunt but most of all enjoy the Snaw when it comes, if you have kids share the wonder share the magic. go out in it and go crazy but please try to remember that Snaw for the UK is a gift from mother nature. she gives when she wants not when we demand. and also in the grand scheme of things is it really worth getting all worked up about and making your own life miserable worrying about it. life is short and for some of us its too short so just think about things before we get all moaning and snipping at one another. Peace Love and Respect.

[karlos1983]

57 minutes ago, Mike Poole said:

You can't get an elephant up a drainpipe.  

ICON 12z up soon, let's hope for a few pleasant upgrades, we need them...

We need the upgrades purely to stop the drab posts in here, because the squabbling & down beat posts are getting very tedious now! So let’s hope so Mike!

I'm looking for POST D7 (as in any time after D7) trends as we head into the 12z.

• signs of Height rises to our N/NW

• Jet digging South 

•agreement if possible Ok that’s probably a bit much to ask ....

 

Edited January 6, 2019 by karlos1983
Edited for clarification....

[Catacol]

6 minutes ago, jules216 said:

@Catacol I have not been stating to have a great knowledge of teleconections as you have and have read only some of the research papers, the one I was using as reference is perhaps wrong in stating the lag for -NAO. But regardless:

1. Even with longer LAG now lets look at the facts - MJO phase 7 was on 04/01/19 - attached ensemble forecast goes to 20/01 - that is 16 days LAG and at best neutral NAO.

2.MJO and tropical weather forecast - perhaps as fragile as other NWP? As we use these MJO etc for our teleconective musing as if their forecast is a given. 

3. Even bigger fails is CONUS and their cold rampers seasonal forecasts which pointed to cold season - yet they are torching mid December onwards.(east coast)

4. Even the greatest teleconective understanding has to account to the stochastic nature of atmosphere. 

Agree with all that. The factor not listed here is impact of the ongoing SSW. Each SSW is historically unique. The specific connections between arctic vortex shape/activity and the tropics are an area I cannot hope to understand yet. We will need to wait and see whether a neutral NAO is actually how things pan out by the 20th....but for sure events aloft are encouraging energy transfer between the 2 daughter vortices (I was personally slow to pick up on this as a likely impact and have made a mental note for next time....) and this looks to be overriding the pacific signal. However if/when we get clarity on a separation of this energy at tropospheric level then forecasts may ping back to a high lat block scenario very quickly. If that separation doesn't occur then all bets are off, particularly as MJO forcing will be declining by the 20th.

Edited January 6, 2019 by Catacol

[feb1991blizzard]

3 minutes ago, karlos1983 said:

We need the upgrades purely to stop the drab posts in here, because the squabbling & down beat posts are getting very tedious now! So let’s hope so Mike!

I'm looking for post D7 trends as we head into the 12z.

• signs of Height rises to our N/NW

• Jet digging South 

•agreement if possible Ok that’s probably a bit much to ask ....

 

I think it will be post day 7 for that but well post it, as long as we see it around D15 pretty soon i wont be to concerned.

[Duane S.]

Strange JMA take on the where the MJO is heading...

Surely a data error? Also, looking at GEFS / ECM, it seems very strange.

Mind you, I certainly didn’t see quite such a quick passage through the Pacific. A shame the passage through P4/5 wasn’t like that!  

Edited January 6, 2019 by s4lancia

[karlos1983]

2 minutes ago, feb1991blizzard said:

I think it will be post day 7 for that but well post it, as long as we see it around D15 pretty soon i wont be to concerned.

Agreed, to confirm I mean after D7, I don’t expect it by D7! 

[gottolovethisweather]

42 minutes ago, Kirkcaldy Weather said:

I will be looking to do a another update on the 8th Jan as that was my date to look out for but here is a summary from my POV 

If I had to give percentages with most likely outcomes for the next 2 weeks (again starting from the 8th Jan) so that would be up until the 22nd Jan here are my percentages

(overall 85%- low pressures starting to take a more NW - SE track and perhaps struggling to get much past the UK, a few from the  06z GEFS not far off the mark)   

45% - Northerly   > North easterly   (possibly then an easterly) 

35% -  above average heights get into the right position and take us straight into an easterly  

20% - the above average heights end up more of a west based - NAO / fail to develop over Greenland , scandi or the arctic or low pressures become too deep and head through the UK aka "zonal" 

My key things to look out for over the next 2 - 7 days 

1.Above average heights and where they are heading - Arctic / Greenland    

Iceland / Scandi  

Possibility of more of a west based -NAO   

2. Teleconnections (AO/NAO) and other background factors strat, MJO etc (more knowledgeable posters than me for these, @Bring Back1962-63 @Catacol @Singularity @Glacier Point @lorenzo @Tamara apologies if I missed anyone)

 https://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/teleconnections.shtml          http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml  

3. Other models coming on board with the blocking signal, ECM, JMA, NAVGEM, GEM etc could be another few days before they begin to pick it up simply due to the fact they dont go to the same +hr as the GFS, GEFS

 

 and hopefully this will be the UK within the next 2-3 weeks  

9

Thank you, a most informative and well-measured post right there. Monday's 12zs onwards will bring back the colder scenarios to the NWP outputs after these weekend wobbles, you mark my words! I agree on the increasing signal of the NW-SE tracking lows, the first of which on Monday/Tuesday should see wintry showers in its wake. Look NW. Look N and eventually E come the final third of January if not before is what I think will happen, with a big switch around first being consistently highlighted within the reliable by w/c 14th January. Patience once again necessary, especially so, if we really want deep cold to show up within D4-D5 timescales.

Edited January 6, 2019 by gottolovethisweather

[jules216]

1 minute ago, Catacol said:

Agree with all that. The factor not listed here is impact of the ongoing SSW. Each SSW is historically unique. The specific connections between arctic vortex shape and activity and the tropics are an area I cannot hope to understand yet. We will need to wait and see whether a neutral NAO is actually how things pan out by the 20th....but for sure events aloft are encouraging energy transfer between the 2 daughter vortices (I was personally slow to pick up on this as a likely impact and have made a mental note for next time....) and this looks to be overriding the pacific signal. However if/when we get clarity on a separation of this energy at tropospheric level then forecasts may ping back to a high lat block scenario very quickly. If that separation doesn't occur then all bets are off, particularly as MJO forcing will be declining by the 20th.

I have been "fighting" against weather followers in Slovakia who have heard zilch of GSDM and other post 10 days forecasting tools on various forums since my move back home, their response is: Sure that is interesting but the weather will always do its own thing.

Luckily we in Slovakia have at least had intermittent cold snaps which at least gave some credence to my musing about potentially cold Europe this winter. UK being on the periphery of the cold EU most of the times has the margin far too narrow and chances often too utopistic in the most recent warming clime where Arctic is much warmer and supply of cold air is more limited. Anyway enough out of topic posts, lets hope we get at least 1 prolonged high lat blocked period within next 4 weeks.

[shaky]

Icon 12z an absolute yawn fest!!over to you gfs and ukmo!!!

[swfc]

5 minutes ago, shaky said:

Icon 12z an absolute yawn fest!!over to you gfs and ukmo!!!

Can't see up to the 180hr mark much change on any runs atm imo

[Leon1]

Just now, swfc said:

Can't see up to the 180hr mark much change on any runs atm imo

We are looking fro mid-Jan onwards for snow/cold in the model output now.

[shaky]

6 minutes ago, Leon1 said:

We are looking fro mid-Jan onwards for snow/cold in the model output now.

Yup 15th onwards i hear!!lets see !!

[swfc]

5 minutes ago, Leon1 said:

We are looking fro mid-Jan onwards for snow/cold in the model output now.

Yes I know.was just replying to shaky in regard to today's 12z

[northwestsnow]

UKMO..

Looks very interesting to me..

Edited January 6, 2019 by northwestsnow

[jules216]

We are flirting with a very dangerous pattern on ICON12Z if the displaced Azores High gets pushed to continent. That would drain all the cold air present and the patter would basically reset.

Edited January 6, 2019 by phil nw.
removal of ot comment

[Leon1]

13 minutes ago, shaky said:

Yup 15th onwards i hear!!lets see !!

Hope so.

[swfc]

2 minutes ago, northwestsnow said:

Better run but look to the nw  yet again !!!

Edited January 6, 2019 by swfc

[Mike Poole]

And then this happens, certainly potential from here:

UKMO T 144:

[Guest]

2 minutes ago, northwestsnow said:

UKMO..

Looks very interesting to me..

Very interesting chart that. could open up the floodgates sorry Snawgates...