Model Output Discussion - Staying cold into the new year

[sheikhy]

Is it me or has the gfs op gone further south with the high near iceland at 120 hours!!!!ldid that on the 00z now its 06z as well!!cant ignore it!!!!

[Tim Bland]

Still going with the nationwide snow events

[Ice Day]

The Control is showing another version of the northerly incursion at 192

  

A very cold set of short GEFS for my location - a cold week ahead is pretty much set in stone which is very much part of the battle for us in the UK.  Next up, snow watch!

[Tim Bland]

We saw on the ensembles yesterday that warming trend mid month was a lot more prevalent in the south than the north.  The signal for a battle lines to be drawn across the Uk somewhere is quite strong...So is the possibility of significant snow somewhere. It’s high risk high reward but I’d rather roll the dice than stay dry and pray for a light snow flurry! 

Edited December 30, 2020 by Tim Bland

[MATTWOLVES 3]

I quite like the UKMO this morning,looks like large parts of the North under -8 850s.

Matt Hugo saying 5th of Jan looking like the big day,and the trop vortex being in such a state that an SSW was not needed to bring it down,and its more than likely just gonna increase -NAO situation. So I would say get ready for some crazy output to start showing some time next week...perhaps its best to view the current runs with a very relaxed and open mind..a lot is about to happen...Closer to home im being told by the met to expect light snow tonight and tomorrow...what happened to that 500m snow line...lots of changes and dramas coming I reckon.

Edited December 30, 2020 by MATTWOLVES

[IanT]

17 minutes ago, Steady Easterly said:

I think its obvious the models are struggling with various factors, ssw being the obvious one, cannot be taken seriously given the stark run to run differences, probably better off finding some old wallpaper to draw your own charts on.

An alternative explanation is that many differentiated evolutions are possible from the present set of initial conditions, and the models are reflecting this accurately.

[I remember Atlantic 252]

hate far away charts, but childhood setup, huge snow dump here, rain S of M4, nowadays usually just M4 south

[Methuselah]

What a stonker! I haven't seen many stalling battleground snowbands like that, since the glory days of the 1960s and '80s!

    

Warning... FANTASY ISLAND!

[Froze were the Days]

6 hours ago, CreweCold said:

Much much better foundations for a prolonged cold spell on the 0z GFS, rather than the boom bust type charts we saw yesterday. The slower build, Scandi-Greenland is much more assured in terms of a transition than a quick wham bam thank you mam flash in the pan Greenland HP.

Couldn't agree more...exactly what I was thinking this mornings UKMO, ECM and GFS 0z (though slightly strange early on) all look more promising for a prolonged cold spell and possibly getting colder.

[Matt H]

Cherry picking here but the control run certainly looks good at t216 with a polar low sinking south within cold air and bringing non-marginal snowfall for many. Fantastic model runs this morning though, glad everything still looks so positive!

[Speedbird]

2 minutes ago, pureasthedriven said:

And completely hopeless for southern counties of England. ‘Nationwide’ snow event that ain’t - I appreciate London is like a different country but still part of the UK last time I looked!

Much like tomorrows 'miss' with the snow heading into the Channel, we could do with this correcting about 100 miles south

[I remember Atlantic 252]

9 minutes ago, General Cluster said:

What a stonker! I haven't seen many stalling battleground snowbands like that, since the glory days of the 1960s and '80s!

    

Warning... FANTASY ISLAND!

90's! could produce snow days here, where places like Penzance sweating at 13 degrees

[Kent Clipper]

This is the 500Hpa convective snow chart the Kent Crew have been waiting to see.  A kink in the ENE flow on the NW convective quadrant of a deeper more discreet cold pool over NE France.

 Its getting into the semi reliable now, 120 hours.

Finally after what feels like weeks of waiting we can finally start pinning the tail on the donkey here in the snow starved SE.

 

 

 

Edited December 30, 2020 by Kent Clipper

[bluearmy]

Both the op and para showing a QTR signature later week 2. ( look at the NH profile and see the ridge headed into the pole, splitting the tpv).  It could be argued that a wave around mid month isn’t that quick and could be seen as a standard 2/3 week later (given that the strat is already reversing above 75N in the upper strat as we begin the new year ....

Whether this wave will be of assistance to bringing deep cold to nw Europe is a moot point ..... it may remove what we have and lead to a relaxation of a week 

Edited December 30, 2020 by bluearmy

[Chesil View]

8 minutes ago, pureasthedriven said:

And completely hopeless for southern counties of England. ‘Nationwide’ snow event that ain’t - I appreciate London is like a different country but still part of the UK last time I looked!

Assuming the front get that's far north. 

[blizzard81]

Happy with the output today so far. What's not to like with mean charts like this showing

[Eskimo]

The thing is, once cold becomes entrenched over the next week or so effectively supercooling our little nation down, anything that comes from the Atlantic, whether it be a temporary slider or a full return to westerlies, someone somewhere, will be buried. 

It's one of those situations where when a breakdown of the cold does eventually happen, it may even be better than the main course. 

Edited December 30, 2020 by Eskimo

[carinthian]

I have a bit of an update from the Central European team of forecasting experts. Their charts currently show a strong alignment to the UKMO at 144t.  Looking a head for period 144t -240 they expect a two pronged attack to affect the British Isles during the first third of January. Firstly ,pressure falls in Biscay expected to transfer towards Low Countries with increasing tightening of the isobar flow ( easterly component ) especially for Southern England. Secondly, later in the period pressure falls from the North with a NEly becoming more widespread. The snow computer outer parameter results flags up a increasing snow risk for SE England during this period, marginal at first but becoming more definite later in the period ( possible due to a much colder source of Scandinavian getting established ). Hope this helps.

C

Edited December 30, 2020 by carinthian

[Stu_London]

morning runs keep it on the cold side through to about 5th Jan, pretty much guaranteed. 

beyond that - no point looking - events in the strat clearly stressing the supercomputers.

 

[Met4Cast]

The GFS could forecast the next ice age and air cold enough to freeze the English channel and some in here still wouldn't be happy. Beautiful GEFS mean at T192.

You'd struggle to find a better mean at that range.

 

[pureasthedriven]

1 minute ago, Met4Cast said:

The GFS could forecast the next ice age and air cold enough to freeze the English channel and some in here still wouldn't be happy. Beautiful GEFS mean at T192.

You'd struggle to find a better mean at that range.

 

Oh, I’m all about the mean. That’s excellent. Good alignment with Exeter, too. 

[phil nw.]

A couple of posts have been removed. 

Please keep moaning about personal snow chances to the regionals or indeed the moans thread. 

Ta. 

[Howie]

4 minutes ago, Met4Cast said:

The GFS could forecast the next ice age and air cold enough to freeze the English channel and some in here still wouldn't be happy. Beautiful GEFS mean at T192.

You'd struggle to find a better mean at that range.

 

That's a bit of me! Looks like we could really be close to something special 

[nick sussex]

A very good GFS run with the high boxed in and a more shallow feature heading s/se.

A very good  alignment with the cold heading south and then turning sw into the UK .

The low to the sw will head towards the Scandinavian troughing and then you get that strong ne flow developing .

This is why you need the block sufficiently east, low heights act as a magnet for each other so any low to the sw will move ne to meet those . As long as that happens to the east se of the UK you stay in the cold .

As for the post day ten output really not worth worrying over especially given the GFS tendency to not disrupt energy when it should , more likely some shortwave energy will head se feeding the low heights over Southern Europe.

 

[SMU]

Morning Just topping off the morning runs which have been excellent

 

I posted the GEFS table the other day showing the layers of cold

If you note the 4th of Jan just a couple of -8s with the piste being -5/-6c

Now today a couple of -10s & -9s with the piste being close on -8c

 

Thats a crucial upgrade for England & could be the crucial difference between convective  rain / sleet or snow...

For me we need to come in under -7.5c ....