Model Output Discussion - mid Autumn

[MattStoke]

9 minutes ago, bluearmy said:

At day 5 into 6  it’s less cold at the surface further south than the 00z run with widespread rain (and some snowfall nw mids and broadly manchester area 

Doesn’t really matter - we all know what we mean on here 

Don’t shoot the messenger!

It’s more convenient to call 850hpa temperatures ‘uppers’ and I know people in here know what that’s referring to it’s just not technically correct, that’s all.

[Mcconnor8]

Just now, nick sussex said:

ECM hits the buffers by day 8 . Once again the models have overdone the Greenland blocking at longer range .

That’s still a way off but the trend hasn’t been great . 

Still just 1 run the UKMO would have us colder for longer still and it really is minor adjustments to the Icelandic shortwave that will.make all the difference down the line

[bluearmy]

Found around half a dozen members of the 00z suite like this  op - too different on this run compared to the 00z but don’t be surprised to see the eps head the same way - a strange op is sometimes reasonably supported on the suite before flipping back again on the next run 

[Cambrian]

Worth taking a moment in awe of the underlying evolution over the next week or so.

Donation of two low pressure systems by the east Canadian trough to the European trough during the coming week on the 12z GFS ensemble mean, day 1-7, draws the European trough west before it itself then links up with a renewed Arctic trough dropping down through Svalbard. 

   

The first wave of poleward amplification heads up through Svalbard cutting off the European trough, freeing it to wobble west, while the second surges up through Greenland leading to the dropping of the Arctic trough - the two waves of amplification working one after the other to bring cold air progressively further southwest through the UK and Ireland. 

A third low sets off from the eastern seaboard, moving east along the southerly tracking jet stream to engage in the ensuing days with the cold air by then entrenched over Northwest Europe.

A great evolution for what will no doubt be a week (and more!) of avid model watching!

[weathercold]

A definite downgrade today for longevity of cold- not seeing any lowland snow for most of England. Heights weaker than 2 days ago - can’t spin this - this is no deep freeze, temps a little below average.

[MJB]

Just now, weathercold said:

A definite downgrade today for longevity of cold- not seeing any lowland snow for most of England. Heights weaker than 2 days ago - can’t spin this - this is no deep freeze, temps a little below average.

A deep freeze has never been on the cards 

[Southern Storm]

16 minutes ago, Met4Cast said:

What's 500hPa then? Upper uppers? What about higher? Upper upper upper uppers? The term is meteorologically incorrect and doesn't really make a whole lot of sense. 

Anyway, very good ECM 144!

In the 17 years that I've been visiting this forum, 850 temps have always been referred to as "uppers" 

I get where you are coming from, but uppers have to start somewhere, there are more than just two levels to the atmosphere! 

[Captain Shortwave]

It seems quite common in these Greenland high evolutions that the models underestimate how far west the cold pooling can extend out of Scandinavia and as such the models can flip from blocked to effectively a flat pattern with wind and rain returning. This may not happen this time but obviously if it does, then you will need be looking to where that Atlantic system could track, a southerly track could deliver frontal snow and of course keep the UK cold for longer. 
The usual wish would be that this occurred later in the season where we would probably have conditions that were more conductive for low level snowfall rather than middle single figures where everything is on a bit of the knife edge.

Edited November 25, 2023 by Captain Shortwave

[Decemberof2010]

Well it’s been an interesting couple of days

 

[weathercold]

4 minutes ago, MJB said:

A deep freeze has never been on the cards 

Lowland snow and strong heights around Greenland were under 24 hrs ago…not now.

[I remember Atlantic 252]

4 minutes ago, weathercold said:

A definite downgrade today for longevity of cold- not seeing any lowland snow for most of England. Heights weaker than 2 days ago - can’t spin this - this is no deep freeze, temps a little below average.

GFS and EC both bring milder air in from the Atlantic on 4th Dec, hopefully only a milder blip though

[Mcconnor8]

2 minutes ago, weathercold said:

Lowland snow and strong heights around Greenland were under 24 hrs ago…not now.

I think the UKMO 12z chart is better than any chart from 24 hours ago lol

Edited November 25, 2023 by Mcconnor8

[January Snowstorm]

So it looks like the 06z run this morning by gfs was not a bogey and had latched on to weaker heights up North. The gfs is going well lately after a dreadful 12 months. Its kind of turning into cold zonal as the block isn't holding out. In general a week of below average temps with lucky spots seeing some wintriness at times. No lying snow is evident right now

[MattStoke]

1 minute ago, I remember Atlantic 252 said:

GFS and EC both bring milder air in from the Atlantic on 4th Dec, hopefully only a milder blip though

GEM similar but shows lows running further south, so potential for some battleground marginal snow maybe.

Edited November 25, 2023 by MattStoke

[MATTWOLVES 3]

Doesn't end to badly tbh..and I feel we pull in a Ntly towards towards the end...a little model volatility creeping in right now which is to be expected...would very much like to see the ens and clusters before making full judgement.

[weathercold]

9 minutes ago, weathercold said:

A definite downgrade today for longevity of cold- not seeing any lowland snow for most of England. Heights weaker than 2 days ago - can’t spin this - this is no deep freeze, temps a little below average.

Interesting to see many disagreeing - must be looking at different charts. 
a lot of hopecasting going on here - reality is they have downgraded aside from an isolated UKMO run.

[Kasim Awan]

25 minutes ago, Met4Cast said:

What's 500hPa then? Upper uppers? What about higher? Upper upper upper uppers? The term is meteorologically incorrect and doesn't really make a whole lot of sense. 

Anyway, very good ECM 144!

500hpa is 500hpa. 850hpa temperatures are referred to as uppers as 850hpa is the general geopotential height above ground level that is used for forecasting near surface phenomena such as snow as it is a level that shows a nice blend of mid and lower tropospheric conditions. 850hpa temperatures are more useful than 950hpa and 700hpa temperatures for snow forecasting and indication of air mass as it is largely unaffected by surface anomalies like 950hpa is whilst still indicating the general temperature of the near ground air mass which 700hpa+ may not do very effectively due to elevated baroclinic processes.

[mbrothers]

1 minute ago, weathercold said:

Interesting to see many disagreeing - must be looking at different charts. 
a lot of hopecasting going on here - reality is they have downgraded aside from an isolated UKMO run.

Or maybe most never expected a month long deep freeze 

 

2 minutes ago, weathercold said:

Interesting to see many disagreeing - must be looking at different charts. 
a lot of hopecasting going on here - reality is they have downgraded aside from an isolated UKMO run.

 

[smith25]

1 minute ago, weathercold said:

Interesting to see many disagreeing - must be looking at different charts. 
a lot of hopecasting going on here - reality is they have downgraded aside from an isolated UKMO run.

I was expecting a downgrade over the weekend.  This is pretty common but beware this is also just one variation of many possibilities and so far only one run.

[weathercold]

Just now, mbrothers said:

Or maybe most never expected a month long deep freeze 

 

 

But many have discussed lowland England snow and a two week cold spell…not seeing either.

[Kasim Awan]

As far as I can see the ECM is an upgrade in the 120-168hour timeframe which is where focus should be for establishing blocking around southern Greenland.

[Big Gally]

I’m hoping to see a return of the cold weather as we approach Christmas. 
It’s great start to winter considering the dross the uk has endured the last few years.

Many more twists and turns to come.

 

[smith25]

1 minute ago, weathercold said:

But many have discussed lowland England snow and a two week cold spell…not seeing either.

Which was a possibility and still could happen.

[ItNeverSnowsInWindsor]

The GFS control is the correct one for next week

[MattStoke]

It’s inevitable low pressure will try to make inroads and introduce milder air at some point. It’s rare that blocked conditions with entrenched UK cold last much longer than a week.

BUT

We know models often are too progressive with such a breakdown of cold air, and this can bring marginal snowfall for some which is the best chance we’ve got for lowland snow this early in the season.

Not much for cold weather and/or snow fans to be despondent about.