Model Output Discussion - Deeper into Autumn

[kazaddress]

8 hours ago, Kirkcaldy Weather said:

I believe that's the closest we've seen that severe cold pool get to the UK on an operational thus far.

Why do I call it severe well you've got to take into consideration just how early those dates we see it modelled are in the season but mostly even in our most memorable cold snowy setups we rarely have seen the 510 dam or below get into the UK.

Even when we had the TPV lobe pay us a visit in December 2010 we were within 528 dam air 

The snow that cut London off in 2009 again 528 dam

The peak of the most recent beast in February 2021... 528 dam 

January 2013 ... 528 dam 

March 2013 was 528 dam

December 1981 also 528 dam 

December 1962 also 528 dam 

Similar for Jan 1962 with the 510 close to our east 

So how extreme would 510 and below dam air be?

Dates we've seen that reach the UK 

February 1991(small circular area)

2018 Beast 

December 1978

February 1979

If there are other dates that anyone would like me to get for reference ..please let me know, as I'm only 26 obviously I don't know the dates of all the snowiest synoptics we've had.

 

I find this so interesting.   I was born during the Feb 1979 snow (my poor mum was stuck in an ambulance in the snow for hours).  Then my eldest was born during the 09 snow (good job we had planned on a home birth as we had no choice when the snow came).  Looks like we were born to be coldies.

I wonder how much effect the hunga tonga eruption is having on the models. The amount of water and rock fired into the atmosphere must be a tricky data to enter. 

I feel like there have been lots of volcanic activity this year.  It would be interesting to see the weather charts compared to the most volcanically active years.

I do feel more positive towards the charts this year compared to the last few years.  Last year I didn't even bother getting the kids snow toys out... but this year they are located and on hand  

 

Let's hope we don't end up chasing day 10... all winter long  

Edited November 26, 2022 by kazaddress

[Lukesluckybunch]

It's nice to know that from Wednesday next week..temps will be struggling 5-8c max,and this is likely to continue for next two weeks at least..so very seasonal feeling and with the chance of something very cold developing..let's see.ready for 6z!

[Skullzrulerz]

3 hours ago, jules216 said:

Never seen so much hype when ensemble mean is showing -2 uppers, what is clear to an unbiast viewer there are 2 issues. 1. Trough that slides down to Portugal pushing ahead high pressure from Greece-Turkey to central/east Europe cutting of Easterly pronto. 2.Attempt at -NAO later engages Scandi trough with Portuguese one forcing west based -NAO later putting America in to freezer yet again!

Agreed, I have seen yet again comparisons to 2010 along other years, as well as "Beast From The East" 

I can assure that this upcoming cooler spell isn't that.

If you're expecting widespread snowfall, ice days and the like I hate to say that you will be disappointed.

At the same time, we have got some good building blocks so we will have our chances of getting more colder weather.

[blizzard81]

16 minutes ago, northwestsnow said:

That's exactly where I am mate ..

Nothing worse than wind and rain this time of year..

Certainly will feel colder next week I'm on FOG watch..

Me too mate. We've already had 2 fog days the weekend before last. Very rare these days and always a good harbinger for proper wintry weather a few weeks later imo. 

18 minutes ago, IDO said:

Same here, getting rid of the Azores ridge, punctured by a wave of westerly Atlantic storms, was getting a bit repetitive and boring. A slack easterly/SE'ly will make a nice change, and that looks nailed on. 

Those worried about the ECM op, that was an outlier early on, and it is the usual ECM op deja vu of overplaying heights in setups like this:

London Oz ECM:  

Yesterday's 12z: 

Yep, you are so right about ecm and over amplification bias. 

[Uncertainty]

At 330 hours, The mean charts from the eps

and geps 

Are hugely supportive of a north easterly flow even at this extended time frame. This means op runs that follow this theme, like the frankly preposterous gfs para, are both plausible and possible.

 

Al aboard the Kamchatkan Express?

As early as day 11, the JMA is preparing our air from Alaska!

In the meantime, the UKMO continues to annoy and frustrate, planting seeds of doubt. Yes it might end well, but we never see that bit and it’s different from other output so that adds uncertainty.

You can’t discount it, but the amount of times even in the last two weeks it’s been on its own and later found wanting is telling. 
 

There does however seem little chance of snow here during the retrogression phase, thanks to those se euro heights that have thwarted coldies so often in recent years. The low to the sw too influential to suggest anything white and flakey manifesting before day 11. It’s almost back to its ‘heat pump’ position it took so often this summer. 
It’s clear to see the SE flow it’s causing on the eps mean at day 9

Recent years have seen this low struggle to progress SE. It could trend further se, but equally it could trend stronger or even further NW. one eps cluster has it close enough to bring rain to many in England late next weekend. The GEM representative of this scenario

This would bust many of the ‘settled weather returns’ forecasts that have understandably been made in recent days. 
It would be ironic if we end up with all this blocking and a low parked just to our sw throughout.

There is so much to be resolved, even with the initial trough disruption early next week. It’s ever so interesting synoptically  compared to most years - indeed it could be heading somewhere quite remarkable - but it still has all the same frustrations when following the models.

[mushymanrob]

Whilst the ops are all over the place, these Anomalies are consistent. The NOAA is centred on the 6th, the EPS is for the 6th... these are consistent and are in very good agreement. But will trough disruption spoil this promise of Wintry weather?

 

[Singularity]

The broad scale progression has an unusually tight spread thanks to a combo of MJO forcing & the lower stratosphere offering little resistance. It may even be adjusted by the troposphere pattern to align with it, prolonging the HLB episode.

So we have a rare level of confidence in a general retrogression of blocking high pressure toward Greenland, just a bit or uncertainty on how fast that happens.

Trouble is, the blocking high looks to be so vast that it’s not physically possible for the whole thing to head west. It must split in two at some point with low pressure dropping through Scandinavia or thereabouts.

Consequently we could well see a ‘milling about’ interlude such as the ECM 00z shows, should the split of the high place a lot of it to our east. It’s then a bigger ask, especially so early in the winter, for a lowland snow-conducive level of cold air to reach much of the UK. Still feasible, though.

Or, there might be less of a high to the east enabling a swifter transition with more efficient cold air import.

Or, the transition might be delayed but the high orientate such that we see something notably cold from the east for a time.

Or, the eastern high could dominate and orientate such that cold air gives the UK a miss.

All these options have featured in recent modelling & we can only guess which will actually unfold.

We can see the wood but the trees are shrouded in fog.

Edited November 26, 2022 by Singularity

[blizzard81]

12 minutes ago, bluearmy said:

It is cluster 2 on the extended 

all eps are freely available on meteociel 

Meteociel - Cartes Ensemble CEP/ECMWF ENS

WWW.METEOCIEL.FR

---

meteociel propose des rubriques météo temps réel, forums, modeles...

 

Many thanks mate. I didn't realise these were available on meteociel

[Kasim Awan]

I actually think this monster PV drop into eastern Europe is a possible outcome given the magnitude of the block & resultant inability for Atlantic advancements to break it down. If the PV energy pushing southwards exceeds the Atlantic energy then this will be the outcome.

[bluearmy]

5 minutes ago, Josh S said:

At 330 hours, The mean charts from the eps

and geps 

Are hugely supportive of a north easterly flow even at this extended time frame. This means op runs that follow this theme, like the frankly preposterous gfs para, are both plausible and possible.

 

Al aboard the Kamchatkan Express?

As early as day 11, the JMA is preparing our air from Alaska!

In the meantime, the UKMO continues to annoy and frustrate, planting seeds of doubt. Yes it might end well, but we never see that bit and it’s different from other output so that adds uncertainty.

You can’t discount it, but the amount of times even in the last two weeks it’s been on its own and later found wanting is telling. 
 

There does however seem little chance of snow here during the retrogression phase, thanks to those se euro heights that have thwarted coldies so often in recent years. The low to the sw too influential to suggest anything white and flakey manifesting before day 11. It’s almost back to its ‘heat pump’ position it took so often this summer. 
It’s clear to see the SE flow it’s causing on the eps mean at day 9

Recent years have seen this low struggle to progress SE. It could trend further se, but equally it could trend stronger or even further NW. one eps cluster has it close enough to bring rain to many in England late next weekend. The GEM representative of this scenario

This would bust many of the ‘settled weather returns’ forecasts that have understandably been made in recent days. 
It would be ironic if we end up with all this blocking and a low parked just to our sw throughout.

There is so much to be resolved, even with the initial trough disruption early next week. It’s ever so interesting synoptically  compared to most years - indeed it could be heading somewhere quite remarkable - but it still has all the same frustrations when following the models.

the good folk of the West Midlands would take that gem as the snow depth chart reveals …..
 

[That ECM]

Morning all. Lots of worry about details yet professionals have low confidence.  Broad scale themes for the time being is where I’ll sit.
 

im off to worry about individuals shoulder blades and the stress they must be under with all the self back slapping they are doing.

[Bradley in Kent]

8 hours ago, Kirkcaldy Weather said:

I believe that's the closest we've seen that severe cold pool get to the UK on an operational thus far.

Why do I call it severe well you've got to take into consideration just how early those dates we see it modelled are in the season but mostly even in our most memorable cold snowy setups we rarely have seen the 510 dam or below get into the UK.

Even when we had the TPV lobe pay us a visit in December 2010 we were within 528 dam air 

The snow that cut London off in 2009 again 528 dam

The peak of the most recent beast in February 2021... 528 dam 

January 2013 ... 528 dam 

March 2013 was 528 dam

December 1981 also 528 dam 

December 1962 also 528 dam 

Similar for Jan 1962 with the 510 close to our east 

So how extreme would 510 and below dam air be?

Dates we've seen that reach the UK 

February 1991(small circular area)

2018 Beast 

December 1978

February 1979

If there are other dates that anyone would like me to get for reference ..please let me know, as I'm only 26 obviously I don't know the dates of all the snowiest synoptics we've had.

 

Good morning @Kirkcaldy Weather,

A fascinating post especially useful when comparing to current outputs I.e., what do those uppers actually translate to.

I wasn't alive, but the one spell I'd love to see charts for has to be January 1987 between the 8th and 15th. It was, according to many, one of the coldest weeks ever with some serious sea affect snow. 

Thank you for sharing the above 

[Lukesluckybunch]

Slight westward correction on the parra..nice start!both look fairly clean from the gfs

[TSNWK]

6 minutes ago, Lukesluckybunch said:

Slight westward correction on the parra..nice start!both look fairly clean from the gfs

Current op and not run still being tested as is the //   a smidge flatter at 138… personally I’m reluctant to take anything from a model that is not released as live… on that point is there a go live?

[bluearmy]

Ec to our west looks quite isolated in the handling of the trough at day 6 

 

Edited November 26, 2022 by bluearmy

[That ECM]

Split pv on this run?

[sheikhy]

Ecm looks odd one out!!!

[TSNWK]

 00z had no energy and a nice gap south of green for heights to our west to build into.. will that energy block and flatten.. and unwelcoming development 

[IDO]

The op at D6 exploring another option with the disruption off the trough in the west, with the split occurring further east.

0z: 6z:

Not sure if that is good or bad or insignificant. The para keeps to the plan A.

[TSNWK]

On a positive the 06z  o 850 over line is over Paris. on the 00z it was around Cambridge so a 200 mile shunt south.. odd ax I thought looked worse.. learning all the time.

Edited November 26, 2022 by TSNWK

[Lukesluckybunch]

2 minutes ago, IDO said:

The op at D6 exploring another option with the disruption off the trough in the west, with the split occurring further east.

0z: 6z:

Not sure if that is good or bad or insignificant. The para keeps to the plan A.

Could be a nice run from the op!

[Blessed Weather]

5 minutes ago, TSNWK said:

Current op and not run still being tested as is the //   a smidge flatter at 138… personally I’m reluctant to take anything from a model that is not released as live… on that point is there a go live?

GFS // goes live on the 29th November, so only 3 days away. I can't see there being any changes made to algorithms at this late date. We should probably take more notice of what the // is suggesting now.

[Kasim Awan]

im gonna take a punt and say the initial easterly is highly unlikely to produce any noteworthy surface conditions in the uk. this means that the interest should be on both the long range integrity and magnitude of blocking and possibility for a pv split to produce a northerly.

[TSNWK]

2 minutes ago, Blessed Weather said:

GFS // goes live on the 29th November, so only 3 days away. I can't see there being any changes made to algorithms at this late date. We should probably take more notice of what the // is suggesting now.

Thanks.. but can we start on the next run please! Cut off low to west of Portugal pumping up milder air.. the current op does have this feature 

[Lord Baltimore]

Not convinced that the charts are showing us anything other than a cooler, drier period.