Model Output Discussion - Winter arrives

[london-snow]

9 minutes ago, Updated_Weather said:

A very wise Ian Fergusson

This was my point last night expect a backtrack westward correction regarding the block. 

[Mapantz]

The other thing worth mentioning here, is that we don't need an Atlantic onslaught to give copious amounts of rainfall. That was evident last year, particularly here, with twice the winter rainfall average which caused flooding in many places.

So, while we keep getting reminded of a quiet Atlantic, that doesn't mean it cannot turn wet and horrid.

[tight isobar]

On 01/12/2021 at 21:01, damianslaw said:

I know some bemoan the Met Office updates.. and I have many a time.. but generally they go for milder conditions beating colder.. however yesterday there was an about turn and the forecast by them resolutely remains colder rather milder.. milder pushed back, and possibly brief.. winter in the north. The la Nina base state I think is the key driver and this should promote heights to our west for a good while.. NW- SE jet and heights to our NE. No surprise to see ECM in line with this..  GFS as ever sends Atlantic on turbo change it's been doing it all year.. and it has never come to avail.. 

The Nina consequence has always been the driver- and continues in that theme, I’m keeping close folds on every updated format. And we could be ona gold road- the way it’s shaping

[Mark wheeler]

Well the mighty Navgem is certainly more ecm than Goofus .

[Battleground Snow]

Missed the ECM earlier, was out chasing Santas sleigh with my 4 year old daughter

Icon looking much more blocked compared to the 12z and moving towards the ECM solution.

What will the pub run bring

Edited December 1, 2021 by Battleground Snow

[Ali1977]

ICON looks good at day 4

[Allseasons-Si]

Talking of the 18z ICON,...there could be some front edge snow from tomorrow evening into Fri morning...

[Jordan S]

Evening

A few sleet/snow showers possible later tonight for few areas of Wales and England.

The possibility of snow on the leading edge of the band of rain on Friday for Eastern and especially northern areas though this will be mostly rain for many.

Big differences of course between some models but frontal systems coming into the west early next week may be preceded by a period of sleet/snow in eastern and especially northern areas, before moving in a east or southeasterly direction accompanied by strong winds in some places.

Then during the middle part of next week we see low pressure over some of the country keeping things unsettled with any snow probably mostly for hills in the north, but not to be ruled out for other areas further south for example northern England, as the low is likely to hang around the UK instead of moving swiftly through.

The end of next week more likely than not remaining unsettled and although temperatures may rise, it isn't likely to be particularly mild, but with a more mobile set up perhaps taking place then wet and possibly very windy conditions may arrive, more for the west and north, a fairly high chance of snow for high ground in the north even then.

[sheikhy]

4 minutes ago, Allseasons-si said:

Talking of the 18z ICON,...there could be some front edge snow from tomorrow evening into Fri morning...

Ecm looked identical!!!

[minus10]

 

It never ceases to amaze me how different the models can be 7 days out or so, as seen so clearly with the GFS and ECM 12z's.

I know that the GFS has known tendencies to power up the Atlantic and blow up lows in its often noted flattening of the pattern and move to +NAO whereas ECM has a better handle on European weather / blocking. However in the light of Nick's excellent winter forecast and explanation of the many different winter drivers influencing our weather, I wonder how much of these other factors are taken into account by the models. Do they all take them into account?...or different models take different factors into account or is it more geographical based depending on where the models are produced.? I suppose what I am saying is why are there so many differences sometimes within 7 days when, don't they all have kind of the same base data and /or data feeds? This has always interested me and is often seen on occasions where channel lows are forecast. I know that slight differences upstream can lead to major differences downstream...perhaps thats it. Also obviously further out into FI differences are of course understandable. Anyway it is certainly interesting model viewing at present and as others have said I think the GFS is underestimating the power of the ne block once it forms. 

[stodge]

Evening all

Well, I'm none the wiser.

The questions seems to be whether the rapidly deepening Atlantic LP at T+120 either does the traditional and swings NE aligning everything positively, sweeping away and heights and sending us off down the zonal highway or slows and sinks SE as heights rise to the NE.

I don't know - really, I don't.

[stodge]

All I can offer is:

[Dennis]

A little winter update from Norway:

Its cold to very cold in big parts here ; in my area here (called Vestlandet) it is snowing since 25nov and the cum. are near 30cm here at my house

I hope charts will show more and more MJO 7 soon 

[Mike Poole]

So to the pub run then.  Obviously it could go on off on one glorious snowfest, as it sometimes does.  But the ECM put down a marker on the 12z run, I don’t expect the GFS to fall in line yet, but a shift towards it is what I’ll be looking for. 

[Dennis]

Come on

 

Edited December 1, 2021 by Dennis

[Mike Poole]

GFS T90 vs 12z:

Just a bit more amplified at this stage.  Early doors…

[fromey]

Update from bbc weather, Darren bett has just said about the low pressure and how the models differ, the preferred solution is for the low to go south and for us to remain on the cold side of things, so I assume they are following the ECM

[sheikhy]

Gfs looks a snooze fest again!!so different to the ecm!!

[Mike Poole]

Huge shift in the area that matters GFS T108 v 12z T114:

[Updated_Weather]

Interesting to see quite a number of 12Z ECMWF and JMA members with the NAO dipping significantly negative again by this time next week - but only 3 of 31 GEFS members jumping on this scenario.

[Allseasons-Si]

The gfs is starting to hit the buffers,...OK not too drastic but a little step in the right direction

18z 108 vs 12 114..

@Mike Poole,...snap.

Edited December 1, 2021 by Allseasons-si

[sheikhy]

The gfs just doesnt know whats goin on!aint got a clue!!its chalk and cheese compares to ecm!!

[Battleground Snow]

1 minute ago, sheikhy said:

The gfs just doesnt know whats goin on!aint got a clue!!its chalk and cheese compares to ecm!!

Yep, amazing really, hope we don't get a half way house

[topo]

ECM 850mean for next Tuesday for southern Norway -15.

GFS +2 !!!

No Comment!!

[bluearmy]

2 hours ago, Neilsouth said:

As this IS related to the models, do the BBC Weather forecasts use the GFS models as I notice they keep chopping and changing with every weekly update. Just yesterday they were forecasting south westerly winds next week

At the moment I would be predicting a stand off and thereafter the Atlantic winning out by day 12 ……that’s the sensible forecast for someone who has to give one. 

no surprise that gfs is struggling - it never does well with split flows