Model output discussion - Winter has arrived

[blizzard81]

4 minutes ago, sheikhy said:

Pretty big turnaround on the gfs!!flat as early as 96 hours!you just knew once ecm comes on board and the ukmo the gfs would go the other way!!

Yep, very progressive at very short notice. Good job I don't really give the gfs 06z too much attention as it always seems to 'wrongly' go against the grain. In fact, I like it when it goes mild as whatever the 06z shows, the opposite generally happens. 

[danm]

9 minutes ago, Kentspur said:

Very interesting you say this- here on the cusp of SE London and Kent we had rain and sleet mainly with nothing settling I remember seeing the models forecasting the cut off point of the snow line to be the Thames Estuary to my dismay

Yes it was more of a north London and northern Home Counties event. The infamous M4 corridor!

Edited December 5, 2020 by danm

[ICE COLD]

Unbelievable the 6z just switches at day 4 to the Atlantic ?? Just as the ECM and UKMO are a lot better this morning. What the hell is going on ? 

[snowlessayr]

2 hours ago, syed2878 said:

 scotland get more snow in winter most years even in the most crappy winters day have snowfall at least once so it’s nothing unusual you had lying snow yesterday

I live on the west coast of Scotland, the most snowless place in Scotland hence the name. Not everywhere in Scotland always gets lying snow. In my 21 years of my life most I have had is 10cm. Lucky if I get more than a cm covering on an average year so it is very unusual here. 

Anyway back on topic, as much as we are not in a proper cold scenario we are seeing a much different pattern than typical at this time of year. Hopefully we will eventually source some colder upper air temperatures if a similar pattern maintains. I think we can all agree that this winter has already much more enjoyment than last winter. Let's hope we can all get some snow at some point 

[Frosty_wsm]

4 hours ago, West is Best said:

You do need cold uppers for snow. What was 'produced' yesterday was mostly rain and sleet, especially at low levels. Many of us on here remember the days when snow would fall consistently out of the sky and pile up sufficient snow to wade through and sledge in, even in early December. That's snowfall and you roughly require -5C 850hpA for it to occur in the UK at low altitudes. 

Sorry but you're talking rubbish, think I'll use Dec '81 as an example, that was the most severe snowfall I've ever lived through, over a foot of level snow on the ground, couldn't even open the back door of the house due to a snow drift all the way up to the top of the door. 

I'm down south at sea level and just a few miles from the coast and looking back at the archive charts the upper air temp was only - 2/-3, if other factors are favourable then you don't need - 5 uper air temps. 

[damianslaw]

52 minutes ago, Bristle boy said:

The Russian High doing its Winter Worst, as the trough just sits right here at mo, giving cold rain. A sign of things to come this Winter for the UK? Oh, for a December 2015 right now.

 

Hope your jesting about December 2015, not a month many in Cumbria would like to see again, or anyone who got flooded out. It was a shocker. The Russian high is squeezing out energy in low pressure, so less likelihood of flooding.

Edited December 5, 2020 by damianslaw

[dragan]

classic gfuqhgfpjhing with each other, can only mean one thing, MILDER weather. Ok, it’s not going to get overly mild, but according to the gfs and ecm, after this milder colder blip, we have perhaps a touch below average temps to look forward to

[PiscesStar]

5 hours ago, northwestsnow said:

My first reaction to UKMO is positive ....

Looks very complex but hoping we see a Scandy High as 00z UKMO depicts...

Be nice to see that high expand and fill above u

[Froze were the Days]

What I want to know is what happened to the seasonal models i.e. dwd/ukmo/ec/gem that were in general showing mslp +heights to the north west or not far from the UK - that certainly hasn't materialised!

Looking at the medium term modelling just looks to me to be somewhat of a southerly jet which equates to rain at times but not overly mild = half baked cold synoptics.

Edited December 5, 2020 by Froze were the Days

[bluearmy]

Incidentally, the eps have no sign whatsoever of a positive AO or NAO out to the 20th .....not your normal December ......

[IDO]

6 minutes ago, ICE COLD said:

Unbelievable the 6z just switches at day 4 to the Atlantic ?? Just as the ECM and UKMO are a lot better this morning. What the hell is going on ? 

The balance of Atlantic -v- Russian block is difficult to prog further out than 4-5 days. It is quite possible that the models are over-estimating the force of the block and that the Atlantic would just brush it aside, so when the models get that eureka moment they will just power the Atlantic through.

To me, it looks like now the Atlantic wave has crashed we are left in a docile NH pattern that generally leads to a flatter profile:

D5>> 

Without any forcing upstream we are relying on a micro-synoptic to bring us something seasonal. Sadly there is simply no cold flow to maximise any undercutting or battleground scenario. This was a chance missed and now we are waiting on the next forcing pattern to see if we get a better landing site? No strat>trop link, good background signals and a NH prone to wave breaking suggest the wait will not be long after this pseudo-reset.

[mountain shadow]

1 minute ago, Froze were the Days said:

What I want to know is what happened to the seasonal models i.e. dwd/ukmo/ec/gem that were in general showing mslp +heights to the north west or not far from the UK - that certainly hasn't materialised!

Heights have been relatively higher to the North West though with the deep purple PV around Greenland mostly absent.

 

[Midlands Ice Age]

3 minutes ago, danm said:

Yes it was more of a north London and northern Home Counties event. 

Dan...

See my avatar!!!

Interesting the differences between the 2 situations. 

I  recorded 22 cms here in Solihull. All snow. The snow 'migrated' south into the Home Counties and parts of London from the Central Midlands as the sliding low passed towards the East,  and produced  the chart you have provided..

I had to visit in hospital that day (1 mile away!). I used the wife's Corsa. Had to stop after 100yards on a very slight incline,  as the snow had piled up at the front against the front grill from the number plate, and I could gain no forward momentum.. 

In the end gave up and returned home and walked. Fantastic walk in heavy snow.

The sliding low entered England via Central Wales, moving ESE off the Atlantic. Perfect angle for us.

Similar 850 temps to yesterday but the low did not intensify and drag in the slightly warmer uppers from the south.

The angle yesterday  came more from the south west, developing as it came.

The 'colder' air did not have the same chance to infiltrate the low pressure, hence local falls  caused by heavy precipitation, but no wide-spread snow fall.

MIA

 

[johnholmes]

14 minutes ago, johnholmes said:

 

sorry about the repeat, I was just trying to alter a word, can the team pse sort it for me ?

Edited December 5, 2020 by Polar Maritime
Ok John, All is 'well' now☺️

[bluearmy]

2 minutes ago, Froze were the Days said:

What I want to know is what happened to the seasonal models i.e. dwd/ukmo/ec/gem that were in general showing mslp +heights to the north west or not far from the UK - that certainly hasn't materialised!

1) it’s the fifth 

2) Greenland and the W Atlantic look like returning higher than normal returns

the persistent lw trough axis nw/se into Europe is certainly not what was predicted though - but it could be that it isn’t a mean feature come the end of the month ....the Russian ridge certainly looks like it will be ! 

[Froze were the Days]

2 minutes ago, mountain shadow said:

Heights have been relatively higher to the North West though with the deep purple PV around Greenland mostly absent.

 

If so they have only been minutely and the redeeming feature has been of low heights close to the UK and a number of those mslp seasonal's simply weren't showing this (closer to the reverse). Anyway if this has been the case as you state it's very easy to misconstrue these mslp thumbnails to something us 'coldies' think is 'boom time'.

[jules216]

And suddenly GFS chart fot the middle od December does not look too different to last year. The period around a week before Christmas in recent years always suddenly brought Atlantic to life despite semi promising long range charts,when they flipped they did it big tíme.

[Froze were the Days]

5 minutes ago, bluearmy said:

1) it’s the fifth 

2) Greenland and the W Atlantic look like returning higher than normal returns

Yes still early days but out to near mid-month I'm not noticing much impactful...but again those higher than normal returns aren't really indicative of making that much of an impact on these shores (yet, crossing fingers), just not the raging low pressure we usually experience to the north west.

[Weathizard]

Advice for anyone wondering about the GFS 6z... don’t look at it, total eyesore, even Stevie wonder can see it’s utter rubbish.

 

Stalled Atlantic systems against the usual eastern block, my least favourite winter weather of all, cold, windy and dull.

 

[That ECM]

[Frosty.]

WOW I cannae keep up, such a hot topic ..anyway, this is probably obsolete already but just my observations of the GEFS 0z mean...and to me it indicates a predominantly cold outlook, cold enough for snow at times and it should go without saying there would be plenty of scope for frosts, ice and freezing fog too!..I wouldn’t anticipate anything other than short-lived milder interludes and I think the emphasis would be on variable / varying degrees of cold rather than anything mild as such...I think that covers all bases!  ️ 

[alexisj9]

4 hours ago, carinthian said:

Morning all, cold lovers have reasons to be joyful this morning. All main models have put the break through of the Atlantic back towards the end of the medium term forecast period( 6-10 day) . Thats all ways a good sign. The picture below from ECM shows a build up of upper height values towards the Greenland Sea area with the Russia block still in place. As time goes on the surface cold and lower layers will only get colder in NE Europe and should even help to strengthen heights. How will this to affect the weather for the British Isles during the coming week I ask ? The view from a foreign field is still 60/40 in favour of extension of the colder conditions lasting in your part of the world. Its towards next weekend that a more active front comes up against the colder block that could become interesting but out of reach of most snow prediction models but certainly the risk of snowfall remains in the developing stand off (ie ) Atlantic v Russian  and you guys in the potential battle ground.

C

 

 

Yep the classic snowy battle, but will the front win, or the high. Which ever, it will be an interesting day of weather for sure. It's been a long time since a high won out, this may well be it, this time. Anyway it's to far out to speculate, but I'm rather happy.

[Tim Bland]

Hmm not looking great is it. Certainly no Beast From the East that some are predicting  

[alexisj9]

3 hours ago, mountain shadow said:

The question I have is  where is the really cold air?

By mid month the Russian high will have been in place for about a month and a Southerly jet stream with low pressure into Southern Europe. The British Isles will have been on the cold side of the jet for a considerable period. 

Yet, the air in Europe is still only cool as opposed to cold and the really cold air still 1000 of miles away. 

I'm not worried at all. The cold will come.

[bluearmy]

14 minutes ago, Tim Bland said:

Hmm not looking great is it. Certainly no Beast From the East that some are predicting  

I don’t mind it - descending arctic upper high of sorts and the strat split almost to 10hpa ........all before Xmas ! 
 

and who has predicted a BFTE in the next couple weeks ????

Edited December 5, 2020 by bluearmy