The hunt for cold - Model discussion (late November)

[phil nw.]

Just viewing the ECM clusters comparing yesterdays 00z with today's 00z for 13/12- now day 10,yesterday day 11.

I chose this time as this looks like the potential tipping point as to whether the block holds or is pushed se by any attack from the Atlantic.

I would say on today's lot the largest clusters show a stronger block, at that point further north, with the second cluster more in favour of an easterly and with low anomalies to our south.

Today's first with yesterday's second.

Based on these this could still go either way with still just over half of the clusterings showing some Atlantic inroads to westerlies.Still it is a move away from that today with a better looking block to bring cold in,compared to yesterday. 

 

[SMU]

Today has been a good day in terms of modelling of what may well be a great Scandi high-

Cold in place over the UK @150 now but the ridge developing about 132 - so beginning to get better agreement

 

The 06z is better because the initial ridge has uninterupted movement Ne where as the 00z tried to push energy through eastwards into the block impeding it-I remember this occuring a lot in 2012 Easterly only to be ushered away nearer the time...

The run up to christmas looking very festive - note the return of ridging straight away if the first one collapses day 10- The atmosphere is primed this winter !!

Edited December 3, 2018 by Steve Murr

[Man With Beard]

Viewing the EC clusters this morning, the general guidance seems to be:

Dec 7-10: Pressure rises through the N Atlantic (consistently advertised for a week now)

Dec 11-14: A split between a quick topple and a NE ridge supported by Euro trough (the latter scenario leading to a cold easterly)

Dec 15-17: Where ridging to the NE had been established, it starts to lose influence over the UK - but in the meantime, positive height anomalies start to appear in the W Altantic, potentially leading to a west-based or east-based negative NAO soon after. One to watch!!

My main headline would be this, though: Whatever happens in the next two weeks regarding cold/snow for the UK, it is becoming clear to me that the polar vortex is struggling - big time - to achieve a long-term influence over the weather in the UK - in a period when you would expect it to be close to its peak.

[Iceaxecrampon]

Clasic battleground 12th 13th

Bring it on.

[Mike Poole]

1 hour ago, s4lancia said:

Interesting,.that would be very early indeed for an SSW, Where do you get this from? I can't find it

I always thought Hannah tends to use 65 deg N. 60N is of course correct in terms of it being an offical SSW.

Latest ECM running a bit higher at around 35 m/s at D10

http://www.atmos.albany.edu/student/hattard/realtime/u_60N_10hpa_gefs.png 

Or load the 65N chart, then change the '65' to '60' in the URL.

[Duane S.]

9 minutes ago, Mike Poole said:

http://www.atmos.albany.edu/student/hattard/realtime/u_60N_10hpa_gefs.png 

Or load the 65N chart, then change the '65' to '60' in the URL.

Cheers Mike. 65N, naturally, makes even better viewing

[turkishfella]

yes wxcharts.eu indicates that as well:

 

[Wilxy]

06z ensembles are a bit colder in the mid to longer range than the 00z so the trend is on are side still for now  

[Paul_1978]

1 hour ago, frosty ground said:

Ensembles not looking that great with 3 in 4 clappsing the high and the rest only a few showing anything like the operation.

 

1 hour ago, snowray said:

06z far better run, just been looking through the ensembles, very much an upgrade compared to 00z. Sorry can't post any charts right now

Consecutive posts completely at odds with one another. Which is it then chaps?!!

[ArHu3]

3 minutes ago, Paul_1978 said:

 

Consecutive posts completely at odds with one another. Which is it then chaps?!!

First one unfortunately 6z oper is much better but ensembles are very similar 

Edited December 3, 2018 by ArHu3

[Radiating Dendrite]

1 minute ago, ArHu3 said:

First one unfortunately 6z oper is much better but ensembles are very similar 

Given the lower res that the ensembles run at this is not surprising. They always take a few runs to come onboard with the op, especially in a blocking scenario such as this.

 

Stick with the hi-res runs for now.

[northwestsnow]

13 minutes ago, ArHu3 said:

First one unfortunately 6z oper is much better but ensembles are very similar 

6z are colder ?

[Paul_1978]

16 minutes ago, ArHu3 said:

First one unfortunately 6z oper is much better but ensembles are very similar 

You always have a very cautious outlook...

[Catacol]

42 minutes ago, Paul_1978 said:

 

Consecutive posts completely at odds with one another. Which is it then chaps?!!

Running the EPS just now ensemble means are good all the way. Transfer of heights from the Azores to Scandy ending in this

I dont tend to spend that much time now dissecting every set of runs (it can drive you completely and utterly insane) - but there is nothing at all wrong with this. Ties in with next pacific cycle and fits the well advertised timescale of winter starting mid month - will try and do a more detailed analysis later.

 

EDIT - and note this is an absolutely corking pattern if an unhappy vortex is what you are after. Signals for this winter continuing to get better all the time...... (if you like it cold.....)

Edited December 3, 2018 by Catacol

[Purga]

18 minutes ago, ArHu3 said:

First one unfortunately 6z oper is much better but ensembles are very similar 

There is a shift towards the cold clustering with the 06z - compare

00z

06z

 

[nick sussex]

You can’t beat an easterly for drama in here !

In an ever changing world good to see some things never change !

Thankfully the GFS06 hrs run pulls back from the less than inspiring 00hrs run. I still think we’re lacking sufficient trough disruption , so the bowling ball shaped lows moving east are still sending too much energy ne.

We want to see these more elongated digging more energy south/ south east  into the mid Atlantic .

The ECM does disrupt more energy se which is what you want to see.

The UKMO looks the pick of the big 3 , for its upstream pattern at day 6 and at day 7 is has more trough disruption .

 

Edited December 3, 2018 by nick sussex

[ArHu3]

3 minutes ago, Paul_1978 said:

You always have a very cautious outlook...

I've seen too many modeled cold episodes getting postponed and then downgraded. For a real cold spell we need cross model and almost all the ensembles on board

 

I want to see something like this 

 

 

[nick sussex]

7 minutes ago, ArHu3 said:

I've seen too many modeled cold episodes getting postponed and then downgraded. For a real cold spell we need cross model and almost all the ensembles on board

 

I want to see something like this 

 

 

You don’t want much!

The thing with easterly type set ups is the ensembles take longer to come on board . Because the jet cut back in towards the Low Countries and upstream trough disruption are much better handled by the higher resolution op runs. Even then as we’ve seen from previous easterly traumas they can still get it wrong . 

I’d advise newer members to hold off ordering the ear muffs and scarves for at least another day !

Edited December 3, 2018 by nick sussex

[summer blizzard]

15 minutes ago, Purga said:

There is a shift towards the cold clustering with the 06z - compare

00z

06z

 

Can you post the control, that looks epic.

[Pajcov]

Not model related so will probably be deleted... encouraging none the less,particularly for us coldies

[Iceaxecrampon]

1 hour ago, tomjwlx said:

06z ensembles are a bit colder in the mid to longer range than the 00z so the trend is on are side still for now  

GFS has an E and potential battleground - these ensembles all on the rise for mid Dec - but all agreement for cold dip at 8/12 though

[Spanish Dani]

58 minutes ago, ArHu3 said:

I've seen too many modeled cold episodes getting postponed and then downgraded. For a real cold spell we need cross model and almost all the ensembles on board

 

I want to see something like this 

 

 

Yes I remember folowing the forum a few years ago in December, there was a huge let down I think it was 2012

[snowray]

52 minutes ago, summer blizzard said:

Can you post the control, that looks epic.

But can we see more improvement on the 12z ENS, them pesky milder members keep turning up and need to naff off....I'm feeling lucky!

[ArHu3]

22 minutes ago, Spanish Dani said:

Yes I remember folowing the forum a few years ago in December, there was a huge let down I think it was 2012

Incidentally, though I did not follow the forum at the time, that came to be the coldest I have seen in a long time over where I live. It broke quite a few cold long standing records 

[snowray]

Poor ICON 12z, even worse than its 00z run. Hoping for a lot better from the other models this afternoon, UKMO will be all important.