Model output discussion - here comes the beast!

[Man With Beard]

3 minutes ago, Summer Sun said:

Reload at the end

Minus 12 uppers over the UK on 6 consecutive days, freezing weather from all directions, a mega cold low ... have we just seen the run of the century??

[beng]

Ignoring the detail since that'll change, I think the idea a system droping down from the North after the Easterly is quite plausible. 

Edited February 21, 2018 by beng

[Johnp]

At the end the Greenland high drifts west, as if taken by the reverse zonal flow.

Wouldn't be surprised to see a Scandinavian high reappear afterwards.

[pandit-scholar]

After the model drama today, the ECM has come up with an excellent run with a deeper cold and lots of snow potential.  As many have said before me, the GFS, ECM, UKMO, show just one option in their respective models, and best not to hung up on one particularly run. Although the GFS shows a breakdown much later on, some on here tend to forget that it's way into FI, and the odds of that happening is less than 10%. Once the cold sets in it I think will be very difficult to shift. After all these are predictive models, and it's the weather that dictates itself. 

 I think many of you saw what was on offer today from the main models a week ago, in reliable, you would have said BANK. Being a snow lover I am happy with what the output has to offer from the main models in reliable and semi reliable, and sit back and see what the weather does outside thereafter. Well I am happy, at least inside the head (?), although the rest of the body probably will be cursing the head being a psoriasis sufferer.

[bradymk]

Great run.

that snow on Tuesday moving across country with snow showers for the south east! 

 

[Purga]

2 minutes ago, The Eagle said:

Latest high res NMM 850 hpa temperatures to Monday 1 pm

 

Nice chart - thanks Eddie

[Staffordshire]

34 minutes ago, I remember Atlantic 252 said:

certainly a damn sight better than 00Z, kink too, maybe organised ppn moving in

Yes, a better ECM 12z, hopefully putting the brakes on the southwards shift.

The kink in this chart is of great interest to me, and everyone else in Central/Southern England as well as wales

[Frosty.]

Great finish to the Ecm 12z.. the cold and snow would go on..and on.. and on!

 

[kold weather]

4 minutes ago, beng said:

Ignoring the detail since that'll change, I think the idea a system droping down from the North after the Easterly is quite plausible. 

I agree and the models have been playing about with the idea of shoving shortwaves SW from Norway for some time now. Of course the GEM/ECM one is more significant as its changing the airmass we have to some extent. Hopeful that we get that evolution.

[Timmytour]

3 minutes ago, Weather Wonder said:

Feel like im peeing in the wind, im just being realistic here.. the reason half the newbies go wtf is that there is no reason and balanced discussion.

People commenting on what the models showing is getting you down?

A very disappointing ECM.... the cold gets in far too quickly and would be better being delayed until saturday week.

That's what we* need and that would mean we wouldn't miss out on what could be some really unforgettable weather for the UK while we are away for the week .

*we = me and a couple of mates who go skiing to Austria this saturday! 

 

[kold weather]

Amazing looking ECM for snow.

2 shortwaves give a fair chunk of the country a decent covering of snow, maybe a BIG snow event, especially for the west on this run. Also LOTS of showers coming into the east constantly and the Thames streamer looks like it sets up on the 12z ECM which is impressive on a global model and suggests probably very conducive set-up for a streamer will be in place.\

[Man With Beard]

OK here's the snow details on the ECM:

Monday - snow showers on the east coast from the off, pushing well inland, even to western areas

Tuesday - a trough from the NE crosses the UK affecting all except the SE and perhaps sheltered NW area - has cleared Wales and the SW by teatime. Snow showers carry on for the SE all the while

Wednesday: convective snow showers bubble up as the day goes on, particularly SE but could be anywhere

Thursday: Possibility of more organised troughs over central/northern areas, bringing snow

Friday: the trough becomes a very active front, much of central/western/northern areas would be absolutely buried in snow today. 

Saturday: The front heads east but fizzles out before reaching the east coast. Looks like more snow about the approach from the SW (perhaps rain in the extreme SW by this time)

[Mike Poole]

Having drawn breath, time to rerun the key part of the ECM 12z, starting at T144, though to T216.  I'm astonished at the 'speed' that the high scoots across from Scandinavia to Gfeenland, and even beyond, dragging oodles of instability in it's wake, of course with freezing cold air over the UK in place.  Charts:

I'd like to see some intermediate charts between these!

Edited February 21, 2018 by Mike Poole

[stodge]

Evening all

JMA is very disappointing with the cold air gone by Thursday in the south:

As for 12Z ECM, it ends up not unlike the morning models with a large complex trough covering much of northern and western Europe. The westward movement of the HP takes us toward west-based negative NAO territory but is useful in stopping the PV remnant setting up in its usual place:

The models this morning were hinting strongly at a second pressure rise over Scandinavia well into FI. That ought to happen in the absence of heights anywhere else and IF it does it should prolong the cold for western Europe. The deep cold pool over Scandinavia should promote height rises - it may be we'll have a milder interlude before cold returns or we may not.

My view tonight is there is plenty of confusion from as early as this time next week - JMA is one extreme but ECM offers an extended cold period.

[Summer Sun]

JMA has a low early next week which gets closer by mid-week shifting the colder air a bit further north plenty of snow here but more marginal for the south as the milder air pushes in

Edited February 21, 2018 by Summer Sun

[Timmytour]

5 minutes ago, Man With Beard said:

OK here's the snow details on the ECM:

Monday - snow showers on the east coast from the off, pushing well inland, even to western areas

Tuesday - a trough from the NE crosses the UK affecting all except the SE and perhaps sheltered NW area - has cleared Wales and the SW by teatime. Snow showers carry on for the SE all the while

Wednesday: convective snow showers bubble up as the day goes on, particularly SE but could be anywhere

Thursday: Possibility of more organised troughs over central/northern areas, bringing snow

Friday: the trough becomes a very active front, much of central/western/northern areas would be absolutely buried in snow today. 

Saturday: The front heads east but fizzles out before reaching the east coast. Looks like more snow about the approach from the SW (perhaps rain in the extreme SW by this time)

Actually I've seen people refer to Jan 1987 before and this reminds me of it a bit.  In Herts we had an inch of snow.  I would go into work in London and have to double up on work because some living south of the river couldn't get out of their houses for the amount of snow they had had!  (and this is the days when there was no capability to work from home). It felt great to have the synoptics but at the same time disappointing without getting the potential amount of snow associated with them!

Edited February 21, 2018 by Timmytour

[Southender]

Any punts on where the ECM Det sits amongst the Ensemble pack then? I will go for below the mean, perhaps significantly so at times, but not without good support. Hopefully it’s on the high side of the mean ????

[Summer Sun]

GFS and UKMO extended at odds with the pressure pattern for the UK GFS has the high a lot further north than UKMO

Edited February 21, 2018 by Summer Sun

[Snowjokes92]

Btw what is an omega block! Its one thing i never remember or how it looks on a model chart thanks!

[Summer Sun]

2 minutes ago, Snowjokes92 said:

Btw what is an omega block! Its one thing i never remember or how it looks on a model chart thanks!

Bit of info here https://www.metoffice.gov.uk/learning/learn-about-the-weather/how-weather-works/highs-and-lows/blocks

[stodge]

The more I look at the UKMO the more I like it. The T+168 posted by Summer Sun above confirms there's absolutely no route in for milder air from the south or south west. The Atlantic LPs are over the Azores and Portugal. The airflow over the UK looks from the north and we can only speculate on any disturbances in the colder air over Scandinavia.

I know a lot of people want deep snow but I'd prefer extended cold so for me UKMO is far superior to GFS and ECM this evening.

[phil nw.]

That was a phenomenal ECM.

Easterly then north easterly as the Canadian vortex is first pushed aside then is forced around the top of the block to join with the Siberian sector and then the whole shooting mmatch heads towards Scandinavia and Europe at the end.

Of course it's only for fun beyond day 5 but shows what is possible with such a dramatic warming and the typical evolution of a Scandinavian high moving west or north west towards Greenland as the clockwise movement of the shredded vortex continues.

In the short term early Monday sees the Russian cold hit the east coast and spread west through the following 24hrs.

UK T96hrs                                                UK T120hrs

Let there be no doubt next Monday for the real cold to arrive has been bookmarked in modelling for some days now.

The gefs are showing the 12z op was a notable mild run from 1st March -these for C.England 2m temp.on the right(second image)

with such deep cold running across the warmer North sea there is every chance of minor troughs/disturbances developing in the flow next week but there is no point in speculating further on snowfall until much closer to the introduction of the deeper cold.

There is certainly nothing to be downbeat if you are a coldie with the best synoptics on view for years and indeed the block is already forming with a continental chill already in the air.Time to prepare the real deal coming our way in only 5 days!

[Stuie]

What the hell has the JMA picked up on? I suppose it is an evolution which is plausible, Greeny/Scandi HP block with no shortwaves dropping into Iberia.

GFS:

Not a million miles away

ECM:

Having none of it

GEM:

Can`t see the UKMO but akin to the last 2 charts IMO after looking at T144. 

GFS/JMA are deffo worth watching closely in the next 48hrs (as they all are but...)

[Freezing-Point]

The last few days have been just sensational synoptics.  All kinds of scenarios are coming out now and there will be more to come in the coming days.

What seems certain, is that a deep cold pool is going to be placed over the UK for a long period which has not happened for a very long time.  The chances for snow are very high just about anywhere, with the windward coasts in favour, but not necessary getting the most.  Who will get lucky?  I think some are in for a real pasting.

If there is one thing I have learnt in all my years of snow watching, is that we will now know until is actually happening!

[karlos1983]

ECM mean looks a good match at 120 to the OP

Same can be said at 144

Edited February 21, 2018 by karlos1983