Model output discussion - Winter has arrived and the hunt for cold is on

[snowray]

12 minutes ago, markw2680 said:

Which will completely change next run, why bother even looking when there’s so much inconsistency between each model early on

Yes of course it will change but the point is that the ensembles seem to trending colder from around Christmas onwards. This is for East Anglia, those for the NE are similar so colder air from the east maybe?

Edited December 12, 2019 by snowray

[Tim Bland]

Some snow on the ECM run for next week

[Methuselah]

Not IMO, the most exciting set of GEFS ensembles I've ever seen; but, at least the scrag-end 'trend' is now downward!

    

    

A question for @Glacier Point, if I may: Having never before never heard of the Indian Ocean Dipole, until very recently (it wasn't even important enough to be included in any of the teleconnection bumph, I've downloaded!) I'm wondering whether Nature has found another, more efficient/additional, way of dissipating heat toward the North Pole....? (I know that the current unusual situation may simply be a one-off.) TIA.

[jules216]

44 minutes ago, Glacier Point said:

Recent uptick in easterly zonal winds across the Equator was pathetically weak and transient. No way there's going to be any settled spell of the back of that, so current drift in op GFS and ensemble guidance suggesting a more unsettled theme look on the mark to me.

That tropical wind profile suggests a return to low frequency Indian Ocean Dipole forcing. Expect troughing centred over the UK and near continent to be the key feature, in tandem with a -AO regime with moderate +ve height tendencies to the north - but not enough to properly displace Arctic airmasses. 

@Glacier Point isn't there a slight weakening forecast of IOD by looking at VP forecast? The profile to me looks similar to late November which combined with cyclonic wave break in Atlantic caused a short term flip in NAO. 

[feb1991blizzard]

Is the IOD that anomalous blue blob of cold just below the equator?

 

[jules216]

Just now, feb1991blizzard said:

Is the IOD that anomalous blue blob of cold just below the equator?

 

I think so and the cold water is killing prospects of MJO wave to propagate through eastwards in decent amplitude in order for it to generate wave train which can aid advection of blocking patterns I believe if not mistaken

[Glacier Point]

12 minutes ago, jules216 said:

@Glacier Point isn't there a slight weakening forecast of IOD by looking at VP forecast? The profile to me looks similar to late November which combined with cyclonic wave break in Atlantic caused a short term flip in NAO. 

Still seeing convective centres 60W, 170E, 60E, which is symptomatic of the base state since the late part of the summer. The latter centre does look like weakening, but how much faith do you place in that persistent low frequency stuff fully disappearing ? Plus, atmosphere will be imprinted to a degree with this signal.

[Premiere Neige]

7 minutes ago, jules216 said:

I think so and the cold water is killing prospects of MJO wave to propagate through eastwards in decent amplitude in order for it to generate wave train which can aid advection of blocking patterns I believe if not mistaken

I'm sure I read somewhere yesterday that the cold area is expected to warm over the next couple of weeks....

[jules216]

8 minutes ago, Glacier Point said:

Still seeing convective centres 60W, 170E, 60E, which is symptomatic of the base state since the late part of the summer. The latter centre does look like weakening, but how much faith do you place in that persistent low frequency stuff fully disappearing ? Plus, atmosphere will be imprinted to a degree with this signal.

@Glacier Point,so to a degree suggestion of similar pattern that we had in Autumn? Stuck through in vicinity of UK and subsequent Sceru high pressure?That would indeed lock the door to any attemp of Arctic air via North East pathway,perhaps more of temporary cold zonal north westerlies? Your seasonal anomaly for January had the through more inland in Europe rather then centered over UK,this would tie with -AO notion and NW-SE jet stream

[mb018538]

1 hour ago, snowray said:

Yes of course it will change but the point is that the ensembles seem to trending colder from around Christmas onwards. This is for East Anglia, those for the NE are similar so colder air from the east maybe?

If that mean line starts getting close to -5c then we might be in business. At -1c it's just nothing but average winter weather, and at 10+ days out then it's as good as worthless.

[Ali1977]

29 minutes ago, mb018538 said:

If that mean line starts getting close to -5c then we might be in business. At -1c it's just nothing but average winter weather, and at 10+ days out then it's as good as worthless.

It’s the direction of travel and an increase in colder ENS that’s more important in FI, nothing may come of it but the key word often used in here is - trend  - for the next few hours anyway!! 

Edited December 12, 2019 by Ali1977

[swfc]

1 hour ago, Ali1977 said:

It’s the direction of travel and an increase in colder ENS that’s more important in FI, nothing may come of it but the key word often used in here is - trend  - for the next few hours anyway!! 

trend,potential oh dear.nearly as bad as the word "moist" anyway the ens are a mixed bag but who knows? Think Stewart"GP"kind of summed things up.think it's a case of sit and wait up to Xmas and new year.must admit I've slightly negative on this thread but that's 50years of watching weather and hopefully having a bit of exp.im a glass half full guy but I do appreciate people's thoughts and comments.they do seem optimistic looking at the background signals etc and mo.respect for keeping hunting however bad it looksbtw the charts look rank hahaha

Edited December 12, 2019 by swfc

[blizzard81]

Nice updates today. AO tanking and NAO going in the right direction as well. 

[snowray]

28 minutes ago, blizzard81 said:

Nice updates today. AO tanking and NAO going in the right direction as well. 

Lovely stuff. I mean this is the hunt for cold thread after all and it's all about trends and what the charts show, whether they verify or not is entirely a different matter.

So looks like coldish weekend with snow chances for some, particularly in the Midlands and North of the country, then milder in the week or so before Christmas. After this possibly something colder as we head towards New Years but all a long way off of course so caution required, this idea of colder would fit in nicely with the AO/NAO going negative. 

Edited December 12, 2019 by snowray

[Mucka]

8 hours ago, KTtom said:

Not sure im getting the enthusiasm some are seeing with the GEM? Yes synoptically its nice to see some greens to our north but for the uk it doesnt mean muc. The uk is in possitive uppers. ECM is similar at 144 the atlantic low tilted favourably but troughs to the north of the uk form a wall preventing any cold uppers getting to the uk.

  

If you can't see what a good chart GEM is then you need to take another look, use NH charts for this, and take into account how the pattern is developing rather than take single snapshot and be disappointed in a lack of cold air over the UK.

When I posted it was stuck on 228 but from the NH chart the blocking and cold for the UK is already assured because the low is undercutting and high pressure is being drawn NW to reinforce strong Arctic blocking, the low has nowhere to go but to disrupt SE from there.

Ideally the upstream would be more amplified but it is good enough because the low stalling backs the pattern and Atlantic ridge will further strengthen Arctic high pressure with the next low stalled well out in the Atlantic.

From 240 the low over Ireland would disrupt toward Italy with the high pressure coming SE SW (sorry) since the Atlantic is blocked off and would orient perfectly to pull in very cold NE winds with the cold uppers over Scandi racing toward the UK within 48hrs

You would see boom charts day 12.

Unfortunately it is all FI and one model which is not reliable but that is the best case scenario synoptic we are currently shooting for. Usual caveat, it is still not the favoured outcome at this time but then nor is the GFS.

 

 

Talking of GFS, people saying it could be right, it is already wrong and has been wrong for a few days because it cannot model Arctic high pressure. 

Here are the last 3 00z runs

 

And the last 3 12z runs

 

 

Other than run to run variance what are the corrections GFS is making?

The Atlantic trough is being held back further and further W and the ridge is getting stronger and more vertical

The pressure over the pole is very slowly being raised.

 This is still a long way from the Euros and even further from the GEM undercut but look how hopeless it has been and even while it has moved a long way it is still miles from the Euros.

That is why I say GFS is already wrong because it has moved so far already, even if the ridge gets overrun it will still have been wrong.

BUT, that does not mean we will get blocking or cold and not quickly return to a more typical zonal pattern after a brief respite, it just means that currently looking at GFS for guidance over the Euros is counter intuitive, even illogical. A better way to use it is to compare rotten apples to rotten apples and compare it against itself, run to run is okay , but preferably 12z V 12z and 00z V 00z to see if ti is still correcting toward the Euros. If it stops then it may be time to give it more attention but while it is still correcting and not modelling the Arctic region anything like the other models even at shorter time-frames then it worthy of a shrug at best.

I know that if we don't get a spell of blocking or cold people will still post,"haha GFS was right," forum life, but it wasn't  Eventually it will of course catch up to a middle ground solution which may be correct but for the last few days it has been trash and that is coming from someone who sticks up for it from time to time because it has its uses, but modelling Arctic high pressure and unexpected halts of the zonal train are just not chief among them.

And one more time, none of that means we will get a pattern change to blocking or Arctic flow.

 

Edited December 12, 2019 by Mucka

[Mucka]

ICON less than great this afternoon it has to be said, let's hope it is just a blip. All about UKMO and ECM this evening.

[Paul_1978]

May be of interest.....

 

[Ali1977]

1 minute ago, Paul_1978 said:

May be of interest.....

 

Definitely of interest, especially coming from one of the chief forecasters at the METO

[swfc]

2 minutes ago, Ali1977 said:

Definitely of interest, especially coming from one of the chief forecasters at the METO

wonder when that will show on the output if at all 

[Ali1977]

Just now, swfc said:

wonder when that will show on the output if at all 

In time for Xmas you’d hope, but I imagine IF it does happen it’ll prob be nearer New Year. 

[booferking]

Sliding under?

[booferking]

Gfs 12z v 06z trending.

[northwestsnow]

3 minutes ago, booferking said:

Sliding under?

That wretched high pressure across SE Europe is an absolute pain ..

Everything else about the 144 chart looks great for coldies.

[TSNWK]

2 minutes ago, booferking said:

Sliding under?

Not so sure! - would the trough to our West / South west not bump into, be slowed down by the High-pressure over Greece ( if anything the trough might pump it up a little ) for balance it would certainly ramp up the interest if it did with what is a promising profile to our north.

 

 

[northwestsnow]

UKMO 144-

If only the low to our west could dive SE.. that would open the door to cold ..