Model Output Discussion - moving into Winter

[Allseasons-Si]

1 minute ago, sheikhy said:

Ecm control looks like the op!!good support it seems!!!

Ecm control looks like the op!!good support it seems!!!

YES,...all good so far.

and the main ext'd EPS cluster follows the op/control

[Kentish Snowman in Yorks]

8 minutes ago, phil nw. said:

Yes Blue it's been forecasted for a while.

There's usually a lag effect of a 10/14 days hopefully we have time to see a decent cold spell.

Is the MJO really that much of a significant driver of our weather?  I am sure I remember on a number of occasions in recent years where it has moved into some apparently favourable phases (for cold weather) but that its failed to have the expected impact?

[TSNWK]

4 minutes ago, sheikhy said:

Ecm control looks like the op!!good support it seems!!!

Ecm control looks like the op!!good support it seems!!!

Yes this is a positive. As I understand that if the control is close to the op then more confidence can be applied..

[Cheshire Freeze]

1 minute ago, Kentish Snowman in Yorks said:

Is the MJO really that much of a significant driver of our weather?  I am sure I remember on a number of occasions in recent years where it has moved into some apparently favourable phases (for cold weather) but that its failed to have the expected impact?

I think it can be fairly easily overridden from what I remember

Edited November 29, 2022 by CreweCold

[TSNWK]

Just now, Kentish Snowman in Yorks said:

Is the MJO really that much of a significant driver of our weather?  I am sure I remember on a number of occasions in recent years where it has moved into some apparently favourable phases (for cold weather) but that its failed to have the expected impact?

That's an easy question to answer;) it's called sods law

[Bogman]

9 minutes ago, TSNWK said:

What is Cod?  

Call of Duty.

[Skullzrulerz]

17 minutes ago, CreweCold said:

We don’t want it lingering there for too long. It’s perhaps why the GFS wants to try and flatten things somewhat compared to earlier runs.

It's something to look at out, you never know GFS could be onto something.

Edited November 29, 2022 by Skullzrulerz

[Eagle Eye]

2 minutes ago, Kentish Snowman in Yorks said:

Is the MJO really that much of a significant driver of our weather?  I am sure I remember on a number of occasions in recent years where it has moved into some apparently favourable phases (for cold weather) but that its failed to have the expected impact?

Favoured just means an increased chance of cold, theoretically, Atlantic driven is still our main driver. I think the fact that we have a Nino AAM has meant that that combined with the MJO phase lag has significantly driven our recent and forecasted weather.

[bluearmy]

13 minutes ago, CreweCold said:

Any idea when we might climb out of it blue?

Ec46 has it fairly stuck in there - certainly not looking like much amplitude if it does reappear in 4 or 5 

[Vikos]

All I can say after nearly 15 years of model-watching is (about GFS): If it wiggels and wobbels within short time it doesn't really have a clue...

[chris55]

3 hours ago, Ali1977 said:

UKMO at T168 looks fine to me

When the trop PV is split, displaced and half the NH is loaded with high pressure then we all know times are good.

Tamara can post as many big words as she likes (and underline odd letters) but @Ali1977 will always post the charts  

Edited November 29, 2022 by chris55

[Rain All Night]

17 minutes ago, Allseasons-si said:

YES,...all good so far.

and the main ext'd EPS cluster follows the op/control

Looks like the Azores high trying to shield us from cold at the end of that largest cluster?

[Allseasons-Si]

Surely this is homing on looking more like a 2010 chart

[Battleground Snow]

Not sure if posted or not, but ukmo 168 did come out eventually

[Valleyboy]

1 hour ago, damianslaw said:

Short term - a sustained easterly flow up to the weekend, slightly colder uppers will be dragged in by then and it will feel very raw for most, possible wintryiness in any showers down to modest levels in the north I would think. Quite a bit of cloud, but in any breaks further west always threat of frost and fog.

Its from the 5th, that date again things become more interesting. Weak shallow trough/shortwave feature to our south notwithstanding the main theme is the transferal of heights to Greenland and the PV locked on the N Asian side wanting to move away and drop some of its energy. This is a much bigger force than the weak lower pressure feature to the south, and the way GFS develops this against the greenland high and PV looks very suspect to me. ECM shows a clean transition to somethign substantively colder and wintry from the north - Dec 09/10 redux anyone?

The problem is, it won’t be substantially colder from the north.  Too much sea to cross which will modify temperatures.  We really need cold pools developing from the east.  09/10 was mostly continental cold, not northerlies.

[TSNWK]

Here is this afternoons late ukm168 looks very good to my eye.

[Eagle Eye]

Taking it on the face of it and a complete turn around from the GWO. We get one more round of +VE (Nino-esque) AAM. An increasing chance of another -VE NAO in late December after this potential one.

Beyond that we go back through phase 8 and a loss of frictional torque before a significant loss of mountain torque. Eventually northwards momentum transport, probably helping to also increase the southerly drag and an increased zonal wind suggests that on this run the Atlantic will end up having more influence going into January. A highly -VE AAM, very Nina-esque in terms of phases.

Based off the latest run, December will probably end up favouring cold but January may end up being a lot more Atlantic dominated as a return back to a more normal pattern in recent years.

It's only 1 run and will likely change next run but I'd like to remind you that this chance needs to be taken as if its the last chance this Winter because it might end up being just that.

[Eastern Scotland WX]

1 minute ago, Allseasons-si said:

Surely this is homing on looking more like a 2010 chart

Its good but follow the air flow and the source is from Central Europe rather than Scandinavia and Russia, unless if your in Scotland where the flow is more easterly sourced.

[sheikhy]

Ukmo looking very good at 168 hours!!!not as amplified as ecm but the cold air is further south than the ecm throughout!!!

[Cheshire Freeze]

1 minute ago, Eagle Eye said:

Taking it on the face of it and a complete turn around from the GWO. We get one more round of +VE (Nino-esque) AAM. An increasing chance of another -VE NAO in late December after this potential one.

Beyond that we go back through phase 8 and a loss of frictional torque before a significant loss of mountain torque. Eventually northwards momentum transport, probably helping to also increase the southerly drag and an increased zonal wind suggests that on this run the Atlantic will end up having more influence going into January. A highly -VE AAM, very Nina-esque in terms of phases.

Based off the latest run, December will probably end up favouring cold but January may end up being a lot more Atlantic dominated as a return back to a more normal pattern in recent years.

It's only 1 run and will likely change next run but I'd like to remind you that this chance needs to be taken as if its the last chance this Winter because it might end up being just that.

Yeah, it was always suspected that December would offer the best chance this winter unless we could somehow trigger a SSW.

It'd be nice, for once, to get a really cold January rather than dregs either side of the core winter period.

[January Snowstorm]

I haven't seen anyone mention how the ukmo has upgraded its cold uppers.... minus 8 uppers over us at 168hrs under a slack Easterly is more than sufficient for snowfall imo

[bluearmy]

8 minutes ago, Allseasons-si said:

Surely this is homing on looking more like a 2010 chart

-  

 
 

mid nov 2010 8/14. Note the low anomoly to our sw on current output engulfs the U.K. - it needs to be further south as per 2010 to allow the CAA to get across the country 

Edited November 29, 2022 by bluearmy

[Allseasons-Si]

3 minutes ago, Eastern Scotland WX said:

Its good but follow the air flow and the source is from Central Europe rather than Scandinavia and Russia, unless if your in Scotland where the flow is more easterly sourced.

That's too much micro detail that far out,what it shows is +ve heights to our NE -ve heights to our S/SE.

[Singularity]

Anybody know if ECM still has much of an edge in terms of number of vertical layers?

Higher vertical resolution in the stratosphere would be a very plausible reason for the model being so resolutely different to GFS & GEM, to a lesser extent UKM.

Reason being, it’s a troposphere-lower stratosphere-troposphere interaction that drives the polar vortex split. The more efficient and fluent that process is, the greater and more sustained the split.

[Rain All Night]

3 minutes ago, Allseasons-si said:

Surely this is homing on looking more like a 2010 chart

In case anyone missed @mushymanrob pointing out a couple of days ago that the CPC publishes the ingredients for its "height blend" each weekday...

https://www.cpc.ncep.noaa.gov/products/predictions/610day/fxus06.html

"The official 8-14 day 500-hPa height blend consists of: 15% of Today's 0z GFS Ensemble Mean centered on Day 11, 20% of Today's 6z GFS Ensemble Mean centered on Day 11, 50% of Today's 0z European Ensemble Mean centered on Day 11, and 15% of Today's 0z Canadian Ensemble Mean centered on Day 11"