Model Output Discussion - Christmas week and beyond

[northwestsnow]

1 minute ago, Mucka said:

ECM rubber stamping a rough day for cold weather fans.

Starting look difficult to see cold and snow to low levels in England for the big day on that basis but lets be honest there is still plenty of variability and scope for change for the better in the output, it just needs to happen soon

And!

There is always the pub run!

Let's hope tomorrow sees the cold return and UKMO give us some hope as we are running out of time now.

Agreed.

GFS aside not a good evening.

[Kasim Awan]

Just now, northwestsnow said:

Agreed.

GFS aside not a good evening.

To me ecm looks almost decent with more tendency for Atlantic ridge 

My standards are obviously a bit different for altitude reasons lol

[That ECM]

Just now, northwestsnow said:

Agreed.

GFS aside not a good evening.

I would disagree. I’m talking past Christmas but gfs continues with heights nw ecm has made a small step in that direction and met seem to be favouring a return to cold. All opinions of course.  

[Kasim Awan]

Just now, That ECM said:

I would disagree. I’m talking past Christmas but gfs continues with heights nw ecm has made a small step in that direction and met seem to be favouring a return to cold. All opinions of course.  

Definitely a tendency for northerly attempts it needs to be clear that big flashy synoptics are not needed this time of year

[Tim Bland]

2 minutes ago, Kasim Awan said:

Definitely a tendency for northerly attempts it needs to be clear that big flashy synoptics are not needed this time of year

I think even high peak would struggle to get much settling snow with these Synoptics wouldn’t it? 

[TSNWK]

Would a decent forecast be by blending the todays models as I see currently ~ white Christmas Day chances trending north then for next week a settled and chilly week for most as uk high settles upon us.

[Kasim Awan]

3 minutes ago, Tim Bland said:

I think even high peak would struggle to get much settling snow with these Synoptics wouldn’t it? 

Pretty sure the ECM would give me atleast 10cm. We'll see when the precip charts are released.

Edited December 19, 2022 by Kasim Awan

[northwestsnow]

EC NH plot day 1

day 10

can the NEG AO really collapse thst quickly ?

[LRD]

ECM 240

Aside from some half-hearted attempts to ridge into Scandinavia, this wouldn't look out of place in many of the rank, mild winters we've had this last decade or so

This is far from sorted, however, aside from the Met Office update and two GFS ops, it's been a 'meh' day

Unfortunately, Christmas cold and even a little bit of snow now looks off the menu for my area for yet another year. Ho hum

Edited December 19, 2022 by LRD

[Tim Bland]

Just now, Kasim Awan said:

Pretty sure the ECM would give me atleast 10cm.

Wow ok. Keep me posted on that as I’m looking at where to book for a week from 26th. I guess it’s that time of year where we don’t need amazing Synoptics for the places like the peak district to get snow

[Kasim Awan]

1 minute ago, Tim Bland said:

Wow ok. Keep me posted on that as I’m looking at where to book for a week from 26th. I guess it’s that time of year where we don’t need amazing Synoptics for the places like the peak district to get snow

 

[tight isobar]

 states the notion.. separation of the lows is now pinpoint for advancement!.. getting “binocular sync “- dictates the forward of rolling the Iberian orange arm to pastry.. and the commence of heights allowance into the mid latitudes b4 we could become struggling with Jetstream placement! Anyway whichever way your bid ya head- we are slowly getting jigsaw management!! .. but .. we need to look for the pieces in the kitchen draw... and put them together... !!! 

[IDO]

ECM D10 is JFF but hopefully we are not heading in that direction, as D10 on the 12z flattens the NH profile and offers little short term blocking:

Thankfully we have yet to resolve the Atlantic lows at D5 yet, so not really a concern ATM. It has been clear for a while that models struggle with setups like the upcoming lows interaction and for the UK they have dramatic impact on what follows. My rule of thumb for GFS is three runs of the same then we can take it seriously. So the 18z is BIG tonight for my POV. 

No one knows what will be the outcome when the music stops, and the 2m temps for London highlight how D6-16 could play out for us down in the south:

Cold or mild and anything in between!

 

[Cloud 10]

1 minute ago, tight isobar said:

 states the notion.. separation of the lows is now pinpoint for advancement!.. getting “binocular sync “- dictates the forward of rolling the Iberian orange arm to pastry.. and the commence of heights allowance into the mid latitudes b4 we could become struggling with Jetstream placement! Anyway whichever way your bid ya head- we are slowly getting jigsaw management!! .. but .. we need to look for the pieces in the kitchen draw... and put them together... !!! 

 

I think that just about sums it up.

[tight isobar]

The ecm intrigue continues- it’s finds a way.. not to .. “ find a way through probable evolution “.. And it’s upper air overheads- are bordering abysmal!.. dynamics against the 12z op.. just don’t make much sense!!

Edited December 19, 2022 by tight isobar

[Cheshire Freeze]

10 minutes ago, northwestsnow said:

EC NH plot day 1

day 10

can the NEG AO really collapse thst quickly ?

Yes it can...we've seen it in the past. It can happen very very quickly once the strat and trop couple, for example.

[carinthian]

1 hour ago, carinthian said:

UKMO extended seems to want to go tropical as does ICON.  GFS on its own at the moment. However, Met Office think it will be Mid -week before getting resolved . Time running out ! Big call from GFS  if it times the next cold spell correct !

C

ECM showing a fairly mild Christmas Day in the offering. So the main models continue to show a wide spread in outcomes for the Festive Period across Blighty , ranging from Cold/Mild/ Average.  Take your pick ! Think it will be Wednesday at the earliest before the forecast becomes more resolved.

C

[frosty ground]

6 minutes ago, IDO said:

ECM D10 is JFF but hopefully we are not heading in that direction, as D10 on the 12z flattens the NH profile and offers little short term blocking:

Thankfully we have yet to resolve the Atlantic lows at D5 yet, so not really a concern ATM. It has been clear for a while that models struggle with setups like the upcoming lows interaction and for the UK they have dramatic impact on what follows. My rule of thumb for GFS is three runs of the same then we can take it seriously. So the 18z is BIG tonight for my POV. 

No one knows what will be the outcome when the music stops, and the 2m temps for London highlight how D6-16 could play out for us down in the south:

Cold or mild and anything in between!

 

I think you need to reevaluate what is JFF that chart has sent @northwestsnowinto hiding like a scary movie.

but you are indeed correct everything and anything is on offer days 6-16 

[northwestsnow]

1 minute ago, CreweCold said:

Yes it can...we've seen it in the past. It can happen very very quickly once the strat and trop couple, for example.

The Euro heights are killing so much potential.

[damianslaw]

An observation but possibly not true, but always thought GFS better with developments to the NW - any signal for height rises, ECM better with euro/scandi highs - I suspect even stevens between the two at present which will verify, but they are wildly different and its rare to see such a difference. Can't remember if it was the ECM or GFS that last week showed low pressure blowing itself up and north, think it was ECM, it got that completely wrong... is it struggling at present?

 

[Cheshire Freeze]

5 minutes ago, northwestsnow said:

The Euro heights are killing so much potential.

It's how the dice have landed. I think we can blame the fall in AAM that occurred as we entered the cold spell...it provided an opportunity for the jet to get a look in and all of the shenanigans with the Azores storm. It was essentially rotten luck as we were on the cusp of locking in to an extended period of severe winter weather which would have seen us well into January (and possibly beyond). We needed all of another week or so to set us in to a feedback pattern whereby the amplified state of proceedings would have ensured there'd have been no coming back for the strat in the longer term.

Que sera. We've been desperately unlucky as ever.

We're now in a situation where the pressure on the SPV has been eased and we're staring down the barrel of an extended period of zonal crud rather than severe cold.

Edited December 19, 2022 by CreweCold

[Battleground Snow]

ECM op is towards the top for Xmas day, but the spread is narrowing, not many make it to -5 at 850 now.

Mogreps still give some hope, but you feel the tide is turning against snow for Xmas.

Edited December 19, 2022 by Battleground Snow

[Kasim Awan]

12 minutes ago, northwestsnow said:

The Euro heights are killing so much potential.

Thank climate change and Hadley cell expansion. Read this article with the knowledge that the Hadley cell is a direct modulator of the Azores high. Gives an insight into how climate change reduces our cold chances, by pushing the average latitude of the jet stream further north. This means that cold air to the north of the jet stream will not make it south as often as prior to the expansion. It also means that there could be more "failed" cold spells as modelling struggles to integrate how this change impacts jet stream behaviour in the north atlantic - specifically by underplaying the effect the Azores has on synoptics in the mid range.

Pinpointing Effects of Hadley Cell Expansion - Eos

EOS.ORG

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As a major atmospheric circulation system spreads farther poleward, some regions are drying out. But as time passes, will this drying be symmetrical across the globe?

 

Edited December 19, 2022 by Kasim Awan

[LRD]

MOGREPS still showing cold options

Let's see what ECM ensembles and the 46 say in about 30-45 mins

[nick sussex]

An underwhelming ECM op run.

There are opportunities for improvement however  . The day 5 into 6 looks dubious , low heights feed the low but with no deepening, it weakens by 5mb day 6 but the low almost heads north.

The low is then so far north and it’s a struggle from there . And then it blows up a shortwave on the western flank of the limpet low .

Even if you take this run at face value further down the line some trough disruption could cut the high off .

I’m placing the ECM op into the Suspicious Synoptic Evolution section .

Overall there’s huge uncertainty for the festive period.

More runs needed !