Model Output Discussion - Winter arrives

[Eagle Eye]

Acknowledging the very small model support for the GFS output at the moment, I know only 1 thing that could or couldn't have an effect on this, (this information is off a relatively old ECM site article)

Full quote 

"

Although the basic physics of the QBO is well known, the quantitative details and balances of the different processes are still rather unclear. Worse, many of the models used for numerical weather prediction (NWP) or climate modelling are unable to produce a QBO, or they produce a QBO which looks very different from observations. For example, only 4 of more than 30 models used for the last IPCC report have any sort of QBO.

At ECMWF, the IFS does have sufficient vertical resolution and physics to allow a reasonable simulation of the QBO, for example as seen in ECMWF’s ERA-20CM, a set of extended model runs covering the 20th century. Our seasonal forecasts also have skill in predicting the future evolution of the QBO signal. However, we would like to improve the accuracy and skill of the IFS, so we are working with other members of the international scientific community to better understand and model the processes driving the QBO."

Hence why almost all of the models at times, have majorly different outputs.

like I said this is old and could have changed but to me it's quite likely that this is at least partly the reason for poor model agreement 

[Nick F]

18 minutes ago, Mike Poole said:

Hey, I bet @Nick F is hastily rewriting his Netweather winter forecast - it’s due out in a couple of days

Yes, perhaps a more interesting start to December for coldies than I originally thought a week ago. Starting to snow lightly here in NE Surrey too.

[JBMWeatherForever]

GFS seems to have been very consistently in modeling of a scadi high for a little while now. This signal is continuing to strengthen.   

Significant cold building to are North East, and an increasing signal for the weather to start to come from that direction fairly soon, what's not to like !!!

[Battleground Snow]

UKMO at 168. 1030mb in scandi

[rwtwm]

On 28/11/2021 at 16:58, Mike Poole said:

Yes, it is a good point.  In recent years if an easterly had even been threatened by the models there would have been nothing there to deliver - a toothless easterly.  Now, thanks to the previous pattern that eventually set up the northerly, and with the location of the strat vortex, both easterlies and northerlies could deliver on day 1 of winter!

No if about it. We had a few easterlies in January this year, and they were cold without ever being bitter.

With all eyes to the north-east I wonder if we might be sleeping on Thursday's event. Short ens posted above show the mean at around -6 even down this way. The low doesn't look particularly deep, but could be snow on the front.

 

[Mike Poole]

6 minutes ago, tight isobar said:

Exactly it’s a firm step in that direction! And the form horse is advection to/toward Scandinavia, as per knee jerking setting in...let’s see where the euro heads

Yes, I said before the 12s I was looking for a UKMO and GFS hold - they have, in fact doubled down.  GEM has moved towards them.  All we need from ECM is a move towards UKMO and GFS, and then I think we can be pretty sure of the evolution, even if it takes the 0z to confirm.  

[TSNWK]

On 28/11/2021 at 17:27, Battleground Snow said:

UKMO at 168. 1030mb in scandi

Better or worse than this mornings ukm168?

[Lukesluckybunch]

i really cant wait for the ECM lets hope it shows somthing great! i have a feeling it will continue to go against the gfs,but i do hope i am wrong!

[Battleground Snow]

1 minute ago, TSNWK said:

Better or worse than this mornings ukm168?

Broadly similar, the shortwaves around the UK may delay the cold initially though

[marksp]

1 hour ago, Mike Poole said:

UKMO T144 and it is good:

First step - a UKMO hold!

Thats a chart full of promise, I too have waited watching the Atlantic this past few months, not really livened up much , more knowledgable could probable explain.

This weekends storm came down from the north, not west or south westerly very  unusually. Todays snow fest appeared short term.

I will be watching the ECM with some optimism looking for some height rises North East, as long as the Atlantic can be kept quite, theres some hope.

[pages]

18 minutes ago, Battleground Snow said:

UKMO at 168. 1030mb in scandi

I am not sure why everyone getting excited. there won't be any boom charts/long deep cold from the east this early.

Why? Yes the deep cold is there but the North sea of the Scandinavian coast is too warm in contrast to the air moving west. 

This causes a weakness in the block between the shetlends and Faroes. It's on the ukmo at 168 and GFS and it always happens when there is serious cold in that region with warm sea.. The mentioned weakness then results in lack of forcing and lows stall to South west dragging up warm uppers from South. 

It's why we see so few convective easterlies in December, we need the initial high further south to the real cold over land rather than north sea but then the increased pressure reduces convection. We need to be very lucky to get the high in the ideal zone 

Edited November 28, 2021 by pages

[Uncertainty]

Fear not, @sheikhy, they build stronger heights into Scandi after day 10, low heights over C euro better defined too.

12z

6z

GFS has had some good moments in the past year or so. This would be another big coup. I’m never sure about Scandi highs though I’ve seen so many not verify. 
 

it’s an option going forward though and it wasn’t a few days ago. The broader signal, including on the EPS, for a big N Russian high is even more important in the wider context of this winter. 
 

[Allseasons-Si]

Afternoon all and what a fantastic set of 12z runs bar the GEM and whoever said that the UKMO at 144 wasn't that good then i suggest you take another look at it again,

ridging in the Atlantic: check

surface high to the northeast: check

low diving SE into Europe: red arrow

possible easterly from there: yellow arrow

in fact,the the UKMO looks better than the gfs for that time period and then the gfs a few frames on goes to show this at 168

the short gefs ens show another cold plunge as we go into Dec after a mild blip,the gfs is on the cold side of the pack but with some support

 

and finally another unexpected surprise snowfall "(not forecast)" here this morning with another 3 inches,...that's 6 inches in two days and also next doors telephone cable came down with the weight of the snow

sorry for the crappy images,...took on crappy phone.

C'mon ECM we need you on board...

 

 

Edited November 28, 2021 by Allseasons-si
added info

[ScottSnow]

15 minutes ago, Allseasons-si said:

Afternoon all and what a fantastic set of 12z runs bar the GEM and whoever said that the UKMO at 144 wasn't that good then i suggest you take another look at it again,

ridging in the Atlantic: check

surface high to the northeast: check

low diving SE into Europe: red arrow

possible easterly from there: yellow arrow

in fact,the the UKMO looks better than the gfs for that time period and then the gfs a few frames on goes to show this at 168

the short gefs ens show another cold plunge as we go into Dec after a mild blip,the gfs is on the cold side of the pack but with some support

 

and finally another unexpected surprise snowfall "(not forecast)" here this morning with another 3 inches,...that's 6 inches in two days and also next doors telephone cable came down with the weight of the snow

sorry for the crappy images,...took on crappy phone.

C'mon ECM we need you on board...

 

 

Yes if this weekend has shown anything is get the cold in first and the snow possibilities will follow. Here in Gateshead we have had three days of falling snow and two days of lying snow. Some areas in the Pennines have had a really good dumping.

The signs are good and it seems we are seeing a gradual increase in the forecast severity of the next cold snap.

 Interesting model watching for sure. 

[TSNWK]

Up and down the land as the ECM rolls out !

[Dennis]

Goodevening all

 

Winter start soon - all have FUN to follow the charts

[Updated_Weather]

Here we go folks! Seatbelts on.. ECM is next...

[Mucka]

ECM finally sniffing the ridge to the NE though not as strong as UKMO and GFS yet

[ANYWEATHER]

Plenty of snow options available from late week onwards...the trend from the Gfs is still showing after several days now of blocking to our Northeast in about 5 to 6 days. Obviously it's a trend but for coldies it's a great trend to be looking at, details will change ,but the name of the game is on the cards....

[Ali1977]

Looking better around there

[Mike Poole]

ECM T144, compared with GFS, and GEM.

What are we looking for here? 

ECM somewhere between the two, moving towards GFS, yes, will it go this time, in the mix, let’s see:

 

[Lukesluckybunch]

dont think the ECM is going to make it,doesnt look great at t144

[Ali1977]

1 minute ago, Mike Poole said:

ECM T144, compared with GFS, and GEM.

What are we looking for here? 

ECM somewhere between the two, moving towards GFS, yes, will it go this time, in the mix, let’s see:

 

I’d say ECM looks better than the GFS between Iceland and Svalbard 

[Updated_Weather]

3 minutes ago, Lukesluckybunch said:

dont think the ECM is going to make it,doesnt look great at t144

It's fine.. 

[Lukesluckybunch]

Just now, Updated_Weather said:

It's fine.. 

ok wait and see then.think will end up like GEM