Model output discussion - Jan 3rd onwards

[Paul]

While everyone is waiting on the 18z, @Nick F's latest blog is well worth a read - looking at the SSW and what may happen next. 

Sudden Stratospheric Warming today, but will this bring the Beast From The East?

WWW.NETWEATHER.TV

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A look at the Sudden Stratospheric Warming that officially occurred today and how this may impact our weather for the rest of this winter. It doesn't guarantee the Beast From The East.

 

[bluearmy]

1 hour ago, steveinsussex said:

But the ssw reaction wouldn’t yet be showing in the models. It’s going to take at least 14 days or so to show

if it doesn’t propagate then yes, the initial downwelling could take a couple weeks but the ec op and gfs zonal flow charts are showing the reverse flow getting down to the trop within a week or so . No certainty how far south that will get. The very end of the gfs 12z run shows a further reversal wave headed down through the upper strat .... 

[Man With Beard]

Right, time for my most sobering report on the ECM individual ensembles to date 

I looked through all 51 ensembles for T360, and there was next to nothing wintry. Either a line of lows through the Atlantic aimed at the UK, or a line of high pressure from the Azores through southern Europe keeping us in westerlies. 

Just a few breakaway north Atlantic highs but not particularly impressive attempts.

Has the SSW actually broke winter, or was this coming anyway? Or will we get a massive surprise?

 

 

[ICE COLD]

There’s  definitely a trend today to re amplify the pattern over are neck of the woods around day 8 . ECM, JMA , ICON and GFS // all on the same page . 

[Vikos]

Well, this is still 00z... but still...

 

[ALL ABOARD]

7 minutes ago, Man With Beard said:

Right, time for my most sobering report on the ECM individual ensembles to date 

I looked through all 51 ensembles for T360, and there was next to nothing wintry. Either a line of lows through the Atlantic aimed at the UK, or a line of high pressure from the Azores through southern Europe keeping us in westerlies. 

Just a few breakaway north Atlantic highs but not particularly impressive attempts.

Has the SSW actually broke winter, or was this coming anyway? Or will we get a massive surprise?

 

 

Maybe the clusters are a day behind and haven't factored in the SSW reversal yet....

[Malcolm Edwards]

3 minutes ago, Man With Beard said:

Right, time for my most sobering report on the ECM individual ensembles to date 

I looked through all 51 ensembles for T360, and there was next to nothing wintry. Either a line of lows through the Atlantic aimed at the UK, or a line of high pressure from the Azores through southern Europe keeping us in westerlies. 

Just a few breakaway north Atlantic highs but not particularly impressive attempts.

Has the SSW actually broke winter, or was this coming anyway? Or will we get a massive surprise?

 

 

Maybe just maybe it will be one of the biggest snowlercoasters of all time. Let's hope the SSW (stupid sodin weather) helps rather than hinders. 

 

 

[Man With Beard]

1 hour ago, feb1991blizzard said:

I have to say i have never ever seen an Easterly pop up at short notice on ops without any ensemble signposting of it in all my years, so not sure why it would happen now although to be fair we have seen some members already shown one but not enough yet, not enough showing a potent one anyway.

100% true. Look back any almost any easterly and I bet you'll find a sniff of an easterly on the D10 ECM mean chart. I challenge anyone to find one that showed westerlies at D10.

Edit - ok I had a quick look and found some that did. I take it back

Edited January 5, 2021 by Man With Beard

[stodge]

Evening all :)

It's that time of day when I look at some of the medium and longer term trends on the output. The key development over the last few days has been the growing consensus for an end to the current cool/cold non-event /spell (delete as appropriate) and an evolution to a more anticyclonic spell with HP initially to the south or south west of the British Isles promoting mild W'ly or SW'ly winds but with the Atlantic sluggish to moribund, the opportunities for amplification at higher latitudes seem to be there but will they work for the British Isles?

12Z GEM: T+120 takes us to Sunday and by then the British isles is under a ridge of HP from the Atlantic with a significant LP in the Norwegian Sea. 850s are around zero but milder air is moving in across Ireland and into western parts of the United Kingdom. Moving forward, the LP over the Norwegian Sea fills as it moves SE into Scandinavia while the HP over the British Isles eases south but with the Atlantic still sluggish, weak heights are trying to form over or just to the north. 850s continue around zero in slack or even calm conditions. From T+180, the HP moves into Iberia and around its western, northern and eastern flanks a succession of LP move to the north of the British Isles and down into eastern Europe. Mild air covers the British Isles in a benign weather environment. 

12Z GFS OP - for those of us who like interesting and unusual synoptics, GEM was ditchwater-like in its dullness. I'm not expecting much better tonight if I'm honest but let's see what GFS OP has to offer - at T+120 a ridge from the Canaries through the west of Biscay to south-west England leaves a flow of WSW'ly air over the British Isles while LP remains to the north. 850s are still zero to -4 at this time.  By T+180 not too different from the GEM with a weak ridge of HP covering the British Isles. Some colder air has infiltrated the north and east behind a trough over Scandinavia but milder air is encroaching from the west across Ireland once again. From there, a new LP from lower latitudes swings NE well to the west of Ireland throwing a ridge into Iberia and mile or very mild SW'ly winds over the British Isles by T+240. The PV lobe looks to be over eastern Scandinavia with some very cold air. 

12Z Parallel: - GFS OP keeps the mild theme but Parallel still has a residual NE'ly for the far south of Britain at T+120 with the trough more influential than on other models. Uppers are generally zero to -4 but some colder air close to the south coast. The evolution to T+180 isn't too surprising with a weak ridge of HP extending north from Iberia through western Britain to Iceland while the trough digs down over Scandinavia. Colder air to the north and east of Scotland once again as milder air returns from the west. From there, it gets more interesting as the LP from lower latitudes swings NE but fills as it does so and keeps further to the west allowing the ridge of HP to persist in tandem with heights building to the north of the British Isles. Milder air has come in but cold air is very close to the east coast with -4 850s over East Anglia.

12Z ECM - an intriguing Parallel but I'm not expecting anything from the mildie's friend, ECM.  No real surprises at T+120 - perhaps the LP a smidgen further south than on other models. By T+192 weak heights over Greenland with the main HP over Biscay and the Scandinavian trough away over the Baltic States. Milder air for all by this time as you would expect.  From there, a bit of a surprise as heights build to the north at T+216 before the anticyclone re-centres over the British Isles at T+240 with a slack Atlantic and a small LP north of the Canaries helping to prop up the new HP. Colder air is pushing back into the south-east on a light NE'ly breeze.

Looking ahead, I will, as usual offer the OP and Parallel output at T+312 and T+384 respectively for direction of travel/casual interest/waste of space (delete as appropriate).

Confused? That makes two of us.

Looking elsewhere, 12Z Control also ends very messy. The 10 HPA charts all show the PV recovering from the initial split/displacement ongoing but coming under further attack after mid month and being shoved around a prize boxer having a bad night.

Conclusion: - signs of more interest in tonight's output with both ECM and Parallel hinting at the anticyclone setting up near or just to the north of the British isles keeping any milder interlude fairly brief.  Both GFS OP and GEM keep the mild theme going and the GFS suite into far FI is just all over the place so I suspect those claiming the models are struggling with the impacts of other events may have a point and certainly I have no clue much beyond mid month tonight. In the medium term, a milder 3-5 days looks likely but cold air is never far away and we aren't looking at anything too dramatic - indeed, next week could be quite benign and quiet before it gets more "interesting" again.

 

 

[damianslaw]

In the short term, further cold conditions through rest of the week and into the weekend, hard frosts in places especially tonight and tomorrow, chance of further snow in the north Thursday.

Models continue to show a change this weekend, we cut off the colder flow as heights sink and sit in situ to our SW, a less colder flow off the atlantic but we are not talking anything especially mild. There are then indications heights want to build to the north, lower heights digging down to our east eventually and the heights to our SW probably amplifying again through the UK. GFS longer term shows a west-based NAO scenario with strong Greenland heights but low pressure to our SW, and the UK at the margins between cold and much milder atlantic air.

ECM has raised an eyebrow it shows high pressure ballooning through the UK and with a deep cold trough moving down through Eastern Europe a shot of cold easterlies would most likely then verify followed by heights retrogressing to Greenland and we and then exposed to a very cold NE flow. That's how I would see the next couple of frames going if they went out that far.

I suspect the models are struggling to get to grips with developments in the Stratosphere at present and modelled arctic heights, so not surprised to see large variance in the longer range. What is a common theme is no suggestion of low heights setting up shop to our NW anytime soon.

[Snowman.]

Conclusions to 2013 Jan are looking pretty good atm, both featured SSW and both saw a very difficult period for the models as they came to grips with it. Make no mistake these models have improved over the 7 years and are more likely to handle situations and pick up on them sooner.

10th of Jan 2013

ECM 

GFS 

That's at 7 days out, ECM was in dreamland and the GFS was almost there maybe as per GFS fashion a little too much gas on the atlantic. 

Take it D5 we get the UKMO which has seen better days in the office. 

ECM 

GFS  (really well done here)

UKMO 

 

Clearly see the GFS was very close to on the money, ECM and UKMO not having any of it. This was all at D5 they started to "get it" the next day but this was merely the start of Jan 2013 as the model drama continued due to a second trigger low dropping south. 

Either way I expect some very interesting charts and lots of chopping and changing.

[nick sussex]

Easterlies are normally led by the operational runs . The ensembles only move on mass nearer the time .

Thats my experience from that type of set up. The lower resolution ensembles often find problems with plotting the associated cut back sw of the jet into the Low Countries .

This will also be more of an issue for the GFS as its past performance with easterlies tends to be last to that jet cutback .

Also once any easterly if it does count down when this comes into the day 6 range the UKMO needs to be onside .

That in the past has dealt the fatal blow to an easterly .

It’s encouraging to see some better solutions showing up , the ECM op though does need a bit more amplitude day 9 and 10 but it’s a start .

Lets hope this can evolve even more favourably over the next few days.

With that likely deep cold pool setting up to the east and ne , it looks tantalizing and might finally allow me to give a green light to my crunchy snow and ice day alert system if things could fall nicely ! 

[bobbydog]

Hemispheric patterns are something to watch for...

I've just seen the ECM at 240 (yes ... I know...)

It immediately reminded me of this...

Just saying...

[ALL ABOARD]

2 minutes ago, nick sussex said:

Easterlies are normally led by the operational runs . The ensembles only move on mass nearer the time .

Thats my experience from that type of set up. The lower resolution ensembles often find problems with plotting the associated cut back sw of the jet into the Low Countries .

This will also be more of an issue for the GFS as its past performance with easterlies tends to be last to that jet cutback .

Also once any easterly if it does count down when this comes into the day 6 range the UKMO needs to be onside .

That in the past has dealt the fatal blow to an easterly .

It’s encouraging to see some better solutions showing up , the ECM op though does need a bit more amplitude day 9 and 10 but it’s a start .

Lets hope this can evolve even more favourably over the next few days.

With that likely deep cold pool setting up to the east and ne , it looks tantalizing and might finally allow me to give a green light to my crunchy snow and ice day alert system if things could fall nicely ! 

Not in 2013 nick according to snowmans brilliant post above. 

Anyone want to do a 2018 ten day and 5 day? 

 

[Griff]

Good to see icon hasn't backed off (yet) 

[feb1991blizzard]

2 minutes ago, Man With Beard said:

100% true. Look back any almost any easterly and I bet you'll find a sniff of an easterly on the D10 ECM mean chart. I challenge anyone to find one that showed westerlies at D10.

Can't 100% vouch for that but no reason to disbelieve you, but what you will nearly always see when an Easterly does verify, is at least a few members even in the 336-384 range, i would go as far as to say if on the GEFS, it gets to 240 and less than 5 are showing it, forget it, and once you get to 192, if its going to be a potent Easterly you need a majority cluster outright flatlining around -10 or below, by majority i mean 51%, not a small cluster with loads of other even smaller ones, also the Easterlies that ticked down like clockwork (2018 an example), were showing an Easterly on both the eps and GEFS mean at around 240, not necessarily every single run of every single day but enough to suggest evidence was overwhelming. The only one i remember being a bit flaky was the Ian Brown 2013 moment, but there were still plenty of individual members showing it, plus that was not really what i class as a rip roaring E'ly, more battleground setups that.

[booferking]

Just now, Griff said:

Good to see icon hasn't backed off (yet) 

That would be a cold Northerly in the a day or two if it went further.

[Cheshire Freeze]

8 minutes ago, nick sussex said:

Easterlies are normally led by the operational runs . The ensembles only move on mass nearer the time .

Thats my experience from that type of set up. The lower resolution ensembles often find problems with plotting the associated cut back sw of the jet into the Low Countries .

This will also be more of an issue for the GFS as its past performance with easterlies tends to be last to that jet cutback .

Also once any easterly if it does count down when this comes into the day 6 range the UKMO needs to be onside .

That in the past has dealt the fatal blow to an easterly .

It’s encouraging to see some better solutions showing up , the ECM op though does need a bit more amplitude day 9 and 10 but it’s a start .

Lets hope this can evolve even more favourably over the next few days.

With that likely deep cold pool setting up to the east and ne , it looks tantalizing and might finally allow me to give a green light to my crunchy snow and ice day alert system if things could fall nicely ! 

Exactly, operationals always always lead the ensembles with these pop up easterlys. First you see a few stragglers and then a couple of runs later the entire suite shifts.

[bluearmy]

17 minutes ago, Man With Beard said:

100% true. Look back any almost any easterly and I bet you'll find a sniff of an easterly on the D10 ECM mean chart. I challenge anyone to find one that showed westerlies at D10.

 

6 minutes ago, ALL ABOARD said:

Not in 2013 nick according to snowmans brilliant post above. 

Anyone want to do a 2018 ten day and 5 day? 

 

I just did - the ens were on it at day 10 ....... I think tomorrow is v important if we are going to see any wintry consequence from the SSW before the 20th 

[Matt H]

55 minutes ago, ALL ABOARD said:

Not in 2013 nick according to snowmans brilliant post above. 

Anyone want to do a 2018 ten day and 5 day? 

 

Just had a look at 10 days away in 2018 on both the 00z/12z runs.

Actual:

GFS:

ECM:

GEM:

Edited January 5, 2021 by Frosty Winter

[bluearmy]

 

the eps was progressive with the pattern and probably a few days ahead rather than behind! 

Edited January 5, 2021 by bluearmy

[Snowman.]

3 minutes ago, CreweCold said:

Exactly, operationals always always lead the ensembles with these pop up easterlys. First you see a few stragglers and then a couple of runs later the entire suite shifts.

TEITS would also go on about this. Always say that OPs lead the way and ensembles would follow.

[damianslaw]

2 hours ago, Kasim Awan said:

We have high pressure slap bang over the Azores at 144-168h. Strangy enough this is quite a common pre-SSW response pattern. 

Quite a few examples I think of cold spells developing from azores high, a sudden amplification takes place, cold air advection on east side, warm air advection west side. I remember we saw a transferal of azores high through UK around 9-10 Dec 2009. A sudden shift usually indicates a major change.

[Cheshire Freeze]

2 minutes ago, bluearmy said:

That was hardly a pop up E'ly though Nick...it was signposted for weeks, it was a jugonaut.

I'm on about instances that sit on a knife edge e.g instances where any drop in the zonal flow can tip the balance towards Scandi blocking...

Edited January 5, 2021 by CreweCold

[Froze were the Days]

13 minutes ago, bobbydog said:

Hemispheric patterns are something to watch for...

I've just seen the ECM at 240 (yes ... I know...)

It immediately reminded me of this...

What could go wrong from that?...Oh I forgot a shortwave blowing itself up near Greenland in situ.