Model output discussion - into the start of Winter

[Allseasons-Si]

Ok we are starting to see a drop off in the 850's around the 4th Dec>

my local and London

it would be interesting to see if these cold 850's get extended or colder from the date i mentioned above

night all.

 

Edited November 27, 2020 by Allseasons-si

[SMU]

Morning - the GFS pigeon steps continue with the retraction west of the atlantic with the ENS also catching on-

Could we go full on send it !

Edited November 27, 2020 by Steve Murr

[swfc]

25 minutes ago, Steve Murr said:

Morning - the GFS pigeon steps continue with the retraction west of the atlantic with the ENS also catching on-

Could we go full on send it !

Is that one of the said ens Steve. Tia it's early

[northwestsnow]

Ruddy UKMO playing up on WZ this morning, and the 120hr chart is missing on meteociel too,absolutely typical when interesting model periods occur.

Have to say we are probably not even going to register a frost from this High pressure locally,the wait for a single frost continues...

 

 

Edited November 27, 2020 by northwestsnow

[swfc]

8 minutes ago, northwestsnow said:

Ruddy UKMO playing up on WZ this morning, and the 120hr chart is missing on meteociel too,absolutely typical when interesting model periods occur.

Have to say we are probably not even going to register a frost from this High pressure locally,the wait for a single frost continues...

 

 

Yes noticed that nw. Maybe its a good omen

[West is Best]

I usually come out of hibernation around now and it has been tempting once or twice with recent model runs. However, I'm not yet salivating. My hunch is that the Atlantic hasn't given up its blow just yet and that we are in for two or three phantom easterlies until Christmas. The GFS is backing away from anything particularly exciting, although we may have something meridional around c. 3rd December. 

The ECM is the main source of hope and it makes me wary that there isn't much backing from the other big two. I may be wrong!

Edited November 27, 2020 by West is Best

[northwestsnow]

GEM possibly brings something wintry for High ground in the North ...

By day 10 the jet is sending low pressure into Europe so we stay on the colder side ...

Not cold enough for snow for the majority though I dont think..

[KTtom]

Summing up the trend at the moment, well gfs trend anyway, is for a continuation of the dry theme for another 5 days or so but becomming murcky from the south over the weekend. A trough sinks over the uk to bring a period of cold damp conditions before the Atlantic reopens its doors courtesy of the Azores high. Signs of a northerly or easterly diminishing due to stalemate Between Russian and Mid Atlantic high, neither seem close enough to the UK to give a favourable pattern.

Northern hemesphere profile ecm 168, beggers belief how we ended up wet and windy out of this set up! Potential moving foreward, yes, but this sums up our luck!

Edited November 27, 2020 by KTtom

[carinthian]

Morning all, the European models in the shorter term making more of a feature of the short wave moving down the North Sea early next week. Looks like introducing a cold gusty wind into the SE during Tues into Wednesday. See how this feature develops over the next couple of day. Longer term look like having low pressure wanting to move into the British Isles but trough distrupts towards the west of the British Isles. Best leave it there with a complicated pictures but think a colder outcome is 60/40 favourite now as we head into earlt December.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Griff]

Total agreement that they don't agree... Tbc

(UKMO looks closer to ecm if it went out that far) 

Edited November 27, 2020 by Griff

[northwestsnow]

Lots of cold rain on EC ....

Positive being a lot of energy dropping into Europe ...

Can we get any help upstream? Downstream looks good for a little while...

[sheikhy]

Who gona be right!!!ecm explodes the low again!!ukmo not as flat across america but looks very ecm like!!i just dont understand how a low explodes like that over the uk between 144 and 168 hours!!could it be down to that mini cold pool over the continent at 144 hours joining forces with troughing to the northwest giving it a bit more umph?

[northwestsnow]

By day 9 there is an intense 1045mb anticyclone across Western Russia ...can it assist force the Jetstream SE?

[sheikhy]

8 minutes ago, northwestsnow said:

Lots of cold rain on EC ....

Positive being a lot of energy dropping into Europe ...

Can we get any help upstream? Downstream looks good for a little while...

I know your pain mate!!ensembles were rock solid for 5 degrees by day and 0 by night here for the next 10 days but they have now flipped to 8 or 9 degrees by day and 4 degrees at night

[joggs]

Just now, northwestsnow said:

By day 9 there is an intense 1045mb anticyclone across Western Russia ...can it assist force the Jetstream SE?

All I can make out from that is the energy to the nw of us will just barrel around keeping us in a westerly flow of sorts.

Positives are pressure dropping in EU and main vortex on opposite side of hemisphere.  Hope I'm wrong on the first instance.

Edited November 27, 2020 by joggs

[West is Best]

The ECM evolution is now basically a fast exit from the amplified shortwave into an Atlantic pattern, thus falling into line with the GFS.

 

There's no blocking where we need it. As mentioned above by KTtom, the relevant high pressures are too far away and in the wrong position to halt the UK's default south-westerly flow.

 

To borrow from W.B. Yeats, 'the centre cannot hold.'

[cyclonic happiness]

I this a famous 'pre cold spell wobble' or is it a garden path?  I'm not biting this time.

Although it look promising for cold weather, it could never be as bad as last year with zero lying snow and only one observable snow falling spell, which lasted all of 20 minutes.

Do your worst weather!!!

[swfc]

16 minutes ago, West is Best said:

The ECM evolution is now basically a fast exit from the amplified shortwave into an Atlantic pattern, thus falling into line with the GFS.

 

There's no blocking where we need it. As mentioned above by KTtom, the relevant high pressures are too far away and in the wrong position to halt the UK's default south-westerly flow.

 

To borrow from W.B. Yeats, 'the centre cannot hold.'

I'd agree with that summary altho possibly told I'm wrong. Over the last7-10 days there has been a lot of chopping and changing but never really landed what's needed to get what folk want in the UK. Onto winter proper hopefully 

Edited November 27, 2020 by swfc

[dragan]

gfs, indicate a much cooler period coming up, this followed by a lifting of temps to near or above average with the usual souther westerly pattern

[IDO]

The problem we have is that ECM and the new-GFS (AKA ECM #2) overdo heights and we cannot trust them until we get to circa D5. The seemingly inevitability of the downgrade in the Atlantic ridge may not solely be due to to that model bias but that is a fundamental piece of the puzzle that makes a big difference where UK cold is concerned. 

It was always a hit or miss close call due to where the upstream amplification was, more US west than the normal Pacific ridge, so the accompanying trough on the east conus had the potential to scupper the westerly wave. This is the outcome on the 0z:

D9-16>>>   London ens 2m>>>  

The wide trough over the East US makes it hard for a further trough to dig down due to the winter spoiler of the Russian high. That block is my pet hate and for me a winter killer for the UK in trop terms, as it rarely leads to that easterly rarity.

The ensembles have moved towards the op but still some scatter around that D6-7 mark, but even the best case scenario is uninspiring. Maybe a false dawn as to anything wintry but def a cooler than normal early Decembers from of late. ^^^

As for the ECM op, it has lost the plot of late. The ECM mean from last night is relative to the GFS NH profile:

d10 ecm 12z>> 

[Tim Bland]

GFS is an outlier (thankfully) around the time it blows up the PV around Greenland. liking the UKMO tho morning..

[Frosty.]

Just had a look through the GEFS 0z and for sure there is some wintry interest in there at times!..and yes that means snow / snaw!  

[DavidS]

What are the chances of the monster Russian high, present at the end of the ECM, pushing west?

[nick sussex]

As early as T72 hrs there’s a difference between the models in terms of how far east the low sw of Iceland is.

After that the Euros take a good start with the trigger shortwave being further sw then the ECM repeats its blown up low , the UKMO is less progressive than last night .

Still a lot of uncertainty with the detail moving forward even though the overall evolution has cross model support .

[Anthony Burden]

Lots of uncertainty regarding low pressure track from the northwest southwards.

Models only agree on that,but will the Atlantic win over continental air still very

uncertain.Monday should tell us the answer.