Model output discussion - another cold spell on the horizon?

[icykev]

2 minutes ago, Jason M said:

GFSP isn't buying it and goes zonal again. Still lots of uncertainty and nothing is nailed on.

The biggest risk looking at the output now is our old friend the west based -NAO. The GEFS are sniffing this out around 192 hours.

Much to be decided though and in a sense I'm actually pleased that we are not seeing the perfect charts at present because the odds of them making it from days 9/10/11 plus to day 1 are tiny.

They all have to start counting down from somewhere! With 240 being peoples markers along with many peoples "its always @ 10 days" remarks something is going to give soon. Trending v/cold to me. If it continues tomorrow I'd say we are nearly there.

[Howie]

The day 10 mean is quite impressive 

[That ECM]

Has there ever been such an interesting, fascinating time to watch output? The volatility run to run is incredible. 18, 10 and to a certain extent 2013 were reasonably signposted. This is on a different level.
 

 

[chris55]

This SSW is producing some of the most insane synoptics for the NH we have seen in many years. The turmoil it is producing in the operational runs is crazy.

But the underlying trend is extremely interesting if you like cold weather and snowfalls blocking your front door! We are endlessly looking for at least a 'chance' of something noteworthy/historical and that chance is certainly apparent with the current circumstances!

As ever nothing is set in stone and we have the lesser trend of the Azores ridge/Euro high remaining and scuppering any really cold feed, however that is most definitely in the minority, but has to be factored in.

Another real positive is that the main 'spill out' of Arctic air (as a consequence of the SSW) looks to be heavily trending to be heading to our third of the globe. Often we say that a SSW will bring the cold down to the mid lats but never know quite where it will head, well recent modelling says it is firmly heading towards the Europe/Atlantic sector.

This is just me digressing so to be taken with a pinch of salt, but overall Id say as 'cold weather hunters' we are climbing that ladder at pace and hopefully we'll eventually get to the top and all be happy with the view

 

 

Edited January 10, 2021 by chris55

[Matt H]

Evening everyone. A fantastic set of GEFS 12z ensembles once again that average around -5C from the 15th onwards. The momentum is definitely behind the colder air winning now, at least for a time. I’m hopeful for a better ECM 12z tonight now.

Edited January 10, 2021 by Frosty Winter

[Jason M]

2 minutes ago, icykev said:

They all have to start counting down from somewhere! With 240 being peoples markers along with many peoples "its always @ 10 days" remarks something is going to give soon. Trending v/cold to me. If it continues tomorrow I'd say we are nearly there.

Hope your right, but its not a done deal yet both in terms of anything half decent occurring or depth of any cold. GFS opp is a pig in lipstick and looks far more dramatic than it is. GFSP goes the full Bartlett in FI and if that came off we could kiss the rest of January goodbye (not that I'm convinced by that either).

To be clear, I'm not saying it won't happen, just that nothing is yet modelled in a convincing way. I certainly won't be saying anything to my kids at this stage as I remain to be convinced. The old rule in here used to be broad model consensus for three runs before getting interested. We haven't even achieved the first half of that yet.

I feel like the Grinch this year on here, but I can only say it as I see things. 

 

[northwestsnow]

Excellent GEFS...

UKMO leaves a bit of a sour taste, that has the hallmarks of an Atlantic high with energy going over the top moving forward, IMO..

We are fast approaching that crucial 120-168 timeframe now ...

[phil nw.]

6 minutes ago, Frosty Winter said:

Evening everyone. A fantastic set of GEFS 12z ensembles once again that average around -5C from the 15th onwards. The momentum is definitely behind the colder air winning now, at least for a time. I’m hopeful for a better ECM 12z tonight now.

Interesting to see the cold uppers(-5c) are back by day 5 and the op in the middle of the pack on that. 

[That ECM]

Just now, phil nw. said:

Interesting to see the cold uppers(-5c) are back by day 5 and the op in the middle of the pack on that. 

Not overly surprised when looking at the location. Cardiff for example would look different I would guess.

[ALL ABOARD]

6 minutes ago, northwestsnow said:

Excellent GEFS...

UKMO leaves a bit of a sour taste, that has the hallmarks of an Atlantic high with energy going over the top moving forward, IMO..

We are fast approaching that crucial 120-168 timeframe now ...

I don't see that tbh.. 

Not with that new area of heights of the eastern seaboard at 144. 

Can only see it linking with the azores high and a push towards Greenland. 

Edited January 10, 2021 by ALL ABOARD

[Battleground Snow]

5 minutes ago, northwestsnow said:

Excellent GEFS...

UKMO leaves a bit of a sour taste, that has the hallmarks of an Atlantic high with energy going over the top moving forward, IMO..

We are fast approaching that crucial 120-168 timeframe now ...

I think we would be okay NWS, there isn't much energy upstream of the ridge. Things could pop up at short notice and scupper it though. A nervous countdown awaits us.

[phil nw.]

2 minutes ago, That ECM said:

Not overly surprised when looking at the location. Cardiff for example would look different I would guess.

Not really

A little colder further east but it's lurking. 

 

 

[Matt H]

Should have waited to post the ensembles as by the 22nd there’s a decent cluster of runs that breach -10C...

[Allseasons-Si]

CAUTION,...ADULTS ONLY!!!

the control is very similar to the op run synoptically...

great 12z so far except the parra,now come on ECM give us a BOOM!!! run.

[IDO]

Ten members in the 12z gefs at d11 within that op cluster including the control, and that control looks the best solution:

That is a similar amount as to previous runs, the main difference is that the op and control have joined. We have been expecting that for a while (excluding pub run) so even if there are some flip-flopping op runs, we want to see this more regular in the next 2-3 days. There is a cluster with an Atlantic ridge that may go onto develop a Greenland block.

Nearly all members have the Scandi trough stretching back to Asia. That is a solid a signal as you can get at d11. We would expect heights to rise in the Atlantic as the trough drops, just need it to be as clean as possible, maybe helped by troughing/cut-off low? 

We will worry about how far west this possible pattern sets up when we have more data, but atm it is unclear. Need ecm to now get on board. I would not worry about the 12z gfsP as it has poor verification on that run. The 0z is the one to note. 

[MATTWOLVES 3]

Come onnn you beauties...its GAME ON,the ens are onto this cold snap like a rat up a drainpipe...let the drama continue.

Edited January 10, 2021 by MATTWOLVES

[Jason M]

10 minutes ago, northwestsnow said:

Excellent GEFS...

UKMO leaves a bit of a sour taste, that has the hallmarks of an Atlantic high with energy going over the top moving forward, IMO..

We are fast approaching that crucial 120-168 timeframe now ...

GEFS are actually surprisingly good given the opps tonight. The control run is interesting as its really cold but you can also see how close it gets to having a very unhappy ending!! Some really cold GEFS though and its good see these.  

[KTtom]

So, I assume we are looking at UKMO to be the key model, as it happens i think 144 is ok tonight regarding the high. Ecm, I thought was number 2, but noone seemed concerned about this mornings run as GFSp was the one, now its gfs operational and not much interest in gfsp?...we can also chuck in the GEM....so, basically we can find what we want in these uncertain times...can someone please explain the hirachy of models? Its very difficult to look, for trends when this place switches constantly as to which model is king? 

Edited January 10, 2021 by KTtom

[Singularity]

Casting an eye over the various model runs including ensembles, it seems the deterministic runs are just picking random routes out of the hat, but the content of that hat is increasingly skewed toward outcomes that move some very cold air in from the northeast.

We can see the favoured direction of travel but have little idea how many bumps in the road there will be on the way there. We can't even be sure that the truck won't get overturned and leave us out in the... less cold or milder!

None of the models are putting in a great performance but it's a bit like if someone switched the round ball for a cube in a football match - the level of challenge is a bit unreasonable!

[Daniel*]

This is partly why Atlantic/Greenland blocking is more likely to feature SSTs have warmed somewhat, warmer waters increase likelihood of high pressure formation -NAO, contrast with how cool waters were in November which experienced strong +NAO and very mild conditions across Europe.

[BLAST FROM THE PAST]

17 minutes ago, ALL ABOARD said:

I don't see that tbh.. 

Not with that new area of heights of the eastern seaboard at 144. 

Can only see it linking with the azores high and a push towards Greenland. 

Agreed 

 

I can’t see what NWS is seeing. The 12z ukmo imo is much better than the 00z

 

BFTP

[Tim Bland]

No sign of that GFSp in the GEFS...it would be a massive outlier ! Let’s hope for a good ECM...interested to see if it has a snow Thursday in the east (like the GEM ) and if it still has the snow next weekend

[Allseasons-Si]

I have only just viewed the ECM 00z,...how did i miss that!!! ha ha ha

i do hope the 12z is a lot better than that,...it was sheeeeet!!!!

 

[BLAST FROM THE PAST]

1 hour ago, Roger J Smith said:

I had a look at temperature analogues from CET and found among those 1881, in fact the mean temperature now is a bit lower than it was on the 10th of that famous cold/snow month (1.2) ... blizzards hit the southern counties in a very similar looking evolution around the 16th to 20th of that month and severe cold followed. 

Another interesting factoid is that the only January which ever managed a 2 deg CET increase after the 10th before dropping to a lower end point was 1947 (2.6 to 4.6 to 2.2). Those numbers are all higher than this month's potential numbers, but the severe cold did not start until the 22nd and it did get very mild (probably milder than we'll see mid-week) for a few days after quite a cold start.

I like to see cases where unusual synoptics on model runs have actually happened in the past, shows that nature can accommodate them. 

If I had to guess how this particular evolution might actually work out instead of what's shown, it would be a faster drop in the jet stream and for the channel low scenario to push more into northern France but with less slack flow over Britain, in other words getting the full extent of severe cold into the UK faster. It would mean the main mechanism for snowfall would have to be sea effect rather than synoptic however. 

A little ramp Roger

 

 

BFTP

[icykev]

19 minutes ago, Jason M said:

Hope your right, but its not a done deal yet both in terms of anything half decent occurring or depth of any cold. GFS opp is a pig in lipstick and looks far more dramatic than it is. GFSP goes the full Bartlett in FI and if that came off we could kiss the rest of January goodbye (not that I'm convinced by that either).

To be clear, I'm not saying it won't happen, just that nothing is yet modelled in a convincing way. I certainly won't be saying anything to my kids at this stage as I remain to be convinced. The old rule in here used to be broad model consensus for three runs before getting interested. We haven't even achieved the first half of that yet.

I feel like the Grinch this year on here, but I can only say it as I see things. 

 

Thanks Chris, I wouldn't say grinch .

Gfs p just having a wobble hopefully, wouldn't call any chart or model to be correct at this time either, as you said.

Just looking for trends and its heading cold imo.

Looks like its lining the uk up, even better in animation!

Cross model agreement should come soon.