Model output discussion - after the beast, what next?

[feb1991blizzard]

Unfortunately the GFS op is a clear outlier.

[ItNeverSnowsInWindsor]

Not much support currently for the GFS 6z op run, but hopefully better ensembles come the 12z run.

[SMU]

Afternoon- 

Its a difficult call this - However the operationals working towards the very solution could hold the key-

The last beast the other day the Ensembles were 24-36 hours behind the operations in delivering the deep cold, the operationals were there / thereabouts by day 5-

But prior to that the model tendancies were to drop the high pressure & undercutting further SE at day 6 & 7 (144 & 168 )

Heres a great example of 'bias' from the ECM

I we compare the 168 chart with the actual chart we see the high pulled back but also significantly more troughing to our East-

Taking todays ECM 168

 

It doesnt take much of a leap of faith to forecast that theres a higher probability of the cold being curved Further west if the ECM is applying the same bias -

Of course we cant assume it be the same again, however considering its very similar synoptics at a ver similar timescale then we could almost forecast a westward correction in the next 24 hours....

 

S

[johnholmes]

9 minutes ago, Steve Murr said:

Afternoon- 

Its a difficult call this - However the operationals working towards the very solution could hold the key-

The last beast the other day the Ensembles were 24-36 hours behind the operations in delivering the deep cold, the operationals were there / thereabouts by day 5-

But prior to that the model tendancies were to drop the high pressure & undercutting further SE at day 6 & 7 (144 & 168 )

Heres a great example of 'bias' from the ECM

I we compare the 168 chart with the actual chart we see the high pulled back but also significantly more troughing to our East-

 

Taking todays ECM 168

 

It doesnt take much of a leap of faith to forecast that theres a higher probability of the cold being curved Further west if the ECM is applying the same bias -

Of course we cant assume it be the same again, however considering its very similar synoptics at a ver similar timescale then we could almost forecast a westward correction in the next 24 hours....

 

S

An interesting post there Steve

Personally I would prefer a warmer option from now on but as they say, 'beggars can't be choosy' so we have to accept whatever the weather gives u.

[nick sussex]

The set up looks tantalizingly close to something exceptional for the time of year with some remarkable cold to the ne.

The depth of cold for the end of March is extremely rare which means the stakes are high for coldies .

The GEFS have loads of different solutions in terms of trough set up which really reduce confidence in the outlook.

The main issue at present is the hang back of low heights to the nw and the depth of low pressure near the UK, and also the amount of trough disruption, there’s a reluctance to drive sufficient energy into central southern Europe.

A lot to be resolved but the early timeframe is important as it sets the boundary for the initial cold, in terms of how close that is to the UK.

It could still go either way.

Edited March 22, 2018 by nick sussex

[Frosty.]

There's plenty of support from the GEFS 6z for a cold / very cold wintry Easter with overnight frosts, ice and a risk of snow, there is also some support for further cold weather into early april.

[Summer Sun]

00z NASA has intensified the low to our west significantly compared to yesterdays 00z this results in the coldest air staying further east away from the UK as we move closer to the start of the Easter break

00z today

00z yesterday

 

Edited March 22, 2018 by Summer Sun

[Frosty.]

8 minutes ago, Summer Sun said:

00z NASA has intensified the low to our west significantly compared to yesterdays 00z this results in the coldest air staying further east away from the UK as we move closer to the start of the Easter break

00z today

00z yesterday

 

Am I right in thinking that NASA isn't the most reliable respected model?..anywhoo, plenty of support for an increasingly rather cold run up to Easter next week with rain and hill snow and then potentially a colder than average Easter with frosts, ice and snow showers, especially further north.❄❄❄⛄⛄⛄

Edited March 22, 2018 by Frosty.

[MR EXTREMES]

GFS will bring more cold for Easter with further backing from gem ECM and ukmo JMA.

The Greenland area is really gaining ground.

[stodge]

Afternoon all

Apologies for the late running of today's update and the 12Z output will be on us shortly so I'll keep it a little briefer than usual.

Looking at the medium term for Sunday April 1st and whether the weather will be making fools of us all by that time:

ECM 00Z at T+240 has an E'ly covering most of the British isles with an area of LP just to the west of Biscay and the trough extending into the English Channel. The British isles is directly in the battleground between the warm air-mass over France and the much colder air over northern Scotland. I suspect therefore plenty of rain or showers with snow for northern hills.

GFs 06Z OP at T+234:

A ridge is moving across the British Isles from north to south. Pressure is high to the west and south west and lower to the NE but the previous colder spell has mitigated somewhat. Further into FI heights remains strong to the west and north so while for many it would be dry we're a long way from spring warmth and further retrogression at the end of FI hints at renewed Arctic outbreaks.

GFS 06Z Control at T+240:

Weak heights across the UK with areas of LP to the north and south so a light WNW'ly airflow for Scotland and an E'ly flow for southern England. Further into FI the Control goes more zonal but not terribly warm.

The GEFS at T+240:

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240

As with yesterday, no sign of anything warm. The mid-Atlantic ridge is a strongly-signalled feature but its strength and orientation very much up for grabs at this time. The question is whether it builds far enough north to anchor the trough over or just to the east of the British Isles or whether we can retain any milder Atlantic component.

In summary, this weekend's brief unsettled spell will be as nothing compared to the descent into colder conditions likely as Easter approaches. I'll leave others to talk about "Beast 3.0" and certainly ECM would only be beast-like for parts of the far north. The strong signal for heights to the west or north west of the British Isles isn't good for those wanting warmth - much more likely is we will continue to source our air from the north or east so it's likely to remain below average for temperatures (and possibly significantly so) and quite likely to be wet at times especially for southern regions though I see snow only as a problem for hills in the south though obviously for lower ground in the north it will be possible on occasion and for the Scottish mountains the snow keeps on coming.

[Summer Sun]

ICON 12z is keeping the coldest air further east from the UK

12z                                                                   00z

[feb1991blizzard]

Yes, the Icon is showing how easily this can go wrong, Met Office update also isn't bullish on a deep freeze.

[Connor Bailey Degnan]

Quite a downgrade on all 12z models in terms of depths of cold and snow. 

Unsettled and dreary for most with snow limited to northern hills.

[John Michael How]

10 minutes ago, feb1991blizzard said:

Yes, the Icon is showing how easily this can go wrong, Met Office update also isn't bullish on a deep freeze.

The met update says the same from what I've read? A lot of uncertainty. Anyway not looking like a deep freeze as you say. For the South anyway but things could change 

[Summer Sun]

GEM showing more of a north-south split around Easter temps around 8c to 10c in the south but always that bit cooler/colder the further north you go

[lassie23]

Haven't we been here before when everything downgrades, hasn't this happened with the last two cold spells and then eventually everything upgrades and BOOM before you know it, it's snowing in your back yards

[Summer Sun]

Just now, lassie23 said:

Haven't we been here before when everything downgrades, hasn't this happened with the last two cold spells and then eventually everything upgrades and BOOM before you know it, it's snowing in your back yards

From what I remember the last 2 had fairly unanimous agreement almost daily on the flow from the east the only thing that altered was just how low the 850's would get

[cobby]

2 minutes ago, lassie23 said:

Haven't we been here before when everything downgrades, hasn't this happened with the last two cold spells and then eventually everything upgrades and BOOM before you know it, it's snowing in your back yards

Was just going to post the same

[Johnp]

I'm surprised at the downbeat mood in here. We've just had two beasts and we're now heading towards April.

I'm literally sitting back and watching events unfold without stressing (for a change)- any further snow would just be a ridiculous bonus in my eyes!

[Frosty.]

There's actually plenty of snow in the north next week on the Gfs 12z op, and not just on high ground either as it looks cold further north..or doesn't that count!!?

Edited March 22, 2018 by Frosty.

[DIS1970]

Those latest charts look interesting, from 240hrs, but again they will look different again in the 18hrs.

Edited March 22, 2018 by DIS1970

[Tim Bland]

Tweet from BBC / Meteogroup suggests they buy ECM route perhaps with the low a bit further SE. talk of snow in the south over Easter 

[phil nw.]

Probably no point in debating details beyond day 5 to strongly as we need to see which way the mean jet flow ends up as we go into next week.

This pattern has always looked 50/50 wrt getting the cold far enough south and for now this is still the way to look at it.OK so far the 12's are disrupting the Atlantic trough further north which keeps us chilly but not the cold required if looking for a late snowfall apart from higher levels further north.

We can see how a little more dig south of the jet would make a difference-day 5 GFS

Still time for an adjustment south again as shown in some earlier runs,let's see if ecm goes down that route in a while.

Day 6 UKMO

Showing a colder west/North westerly coming in but at this late stage of the season for meanifull cold we really need to get those winds around to the ne by seeing those lows further south.

 

[Frosty.]

Looking at the GEFS 12z mean, the further north you are, the colder it would become during the course of next week (especially scotland) where snow could fall, and not just with elevation either,  and this is just based on the GEFS, we can't rule out more widespread cold towards / during the Easter period.

Edited March 22, 2018 by Frosty.

[Bristawl Si]

1 hour ago, feb1991blizzard said:

Yes, the Icon is showing how easily this can go wrong, Met Office update also isn't bullish on a deep freeze.

"Deep freeze" at end of March/early April in the UK!?? I think you need to lower your expectations.