[Model Output Discussion - Spring Has Sprung]

I much preferred it when you could reply 'directly' to a post so people could see without having to trawl back at what is being replied to. 

[Model Output Discussion - Spring Has Sprung]

@uncertainty - could you please give us some more certainty in your next post

[Model Output Discussion - Spring Has Sprung]

Hmmmm.... Ecm and ens throwing an interesting curve ball this evening which is nice. Also in tandem with a fair few of those gfs ens. We haven't seen much (if any) upgrades in the modelling at relatively short range this winter. It would be nice to see this continue tomorrow and maybe even see Exeter revert back from their delaying of the cold in tomorrow's update. 

@Don That's from the 00z suite though.

[Model Output Discussion - Cold spell ending - what next?]

50 minutes ago, sebastiaan1973 said:

EC46 offers some hope, for those with patience.

Middle of Feb is exactly when those inflated southern Euro heights dissipate. Only then do we see the opportunity for the white stuff we are all craving. 

[Model Output Discussion - Cold spell ending - what next?]

1 hour ago, Bricriu said:

So have they dropped the idea of Easterly winds now? They had that as the direction of travel  for days. 

As others have already said, the Exeter update today is a slight upgrade for wintry potential but patience required. Isn't it always in the UK?

[Model Output Discussion - Cold spell ending - what next?]

1 minute ago, Mike Poole said:

Different outcome on GFS 12z, but the same big picture point, by the end of the run, the trop vortex has vacated Canada/Greenland and moved to the half of the hemisphere to our east.  

I just think we are now picking up on a theme, which will leave the door open to height rises in the Atlantic towards Greenland into February.  

In tune with Exeter's thoughts as well. 

[Model Output Discussion - Cold spell ending - what next?]

42 minutes ago, Gowon said:

Hmm, what's the GEM up to - it's a lot more amplified than the GFS :

 

 

 

 

GEM is very prone to doing this. It needs upgrading significantly. 

[Model Output Discussion - Cold spell ending - what next?]

17 minutes ago, Mike Poole said:

I read that blog, but one thing that confused me with that picture, is that the often quoted (on here, anyway) Ural high, Aleutian low combo, as a SSW precursor, isn’t one of the two main patterns. Instead the two patterns are Aleutian low, North Atlantic high (for wave 1) and Aleutian high, Ural high (for wave 2)?  In fact, the Aleutian low, Ural high is more similar to the left picture of what happened this year.  

Can anyone explain/reconcile this, please?  I am confused!

Indeed. Well spotted Mike. 

[Model Output Discussion - Cold spell ending - what next?]

2 hours ago, Mike Poole said:

ECM clusters T192-T240:

All show a ridge through the UK to Scandi, but this is much stronger on cluster 2 (20 members) than cluster 1, which has a more westerly influence. 

T264+:

The Scandi high option seems to no longer be on the table this morning, with a UK high being the destination in cluster 2, whereas the more mobile cluster 1 eventually puts up an Atlantic ridge.  This is the retrogressive option - and this seems to fit with the signal from the seasonals, and also the ECM 46 - which, as @blizzard81 noted earlier, was a stronger signal for heights to the NW yesterday than recent runs.  

I’m still not wildly optimistic that a cold spell is on the way in February, but all the evidence seems now to suggest that if it does materialise, it will be from height rises somewhere to the NW.  

Yep, I think we need to look north west through week 2 now. I thought there was going to be a more robust ridge into Scandi but that is a bust now. Gfs now joining EC46 with that trend to amplify to our north west as we enter the first week of Feb. Let's see if we can reel this in. It's a make or break situation for this winter as far as I am concerned. 

[Model banter and emotions]

Just now, Don said:

It certainly has.  I woke up to a dusting Monday and that was it!  Biggest let down imo was for the south with that low going through France!

Must admit... My empathy side came out there for them. Not often that happens

[Model banter and emotions]

Just now, Singularity said:

For broad patterns they have value if not taken too literally, more as a suggestion which way the weather patterns will attempt to go. After all, the MJO is one of many forcing factors. That’s why we don’t see forecast models just following MJO composites even at 7+ days lead time when there here & now becomes increasingly less relevant I.e. persistence of the near term pattern tendency becomes increasingly inaccurate.

Long story short, while I can see plenty of scope for a high to set up over Scandinavia by early Feb, I think it’s a lot more up in the air whether it’s positioned & orientated in a way that’s notably cold for the UK (let alone snowy). The HLB dominated seasonal modelling for Feb is very intriguing in this regard - it seems it must be tied to subsequent developments… but can we trust that those will come through? If only it was that easy!

I think everyone is clueless to be honest lol. 

[Model banter and emotions]

1 minute ago, Don said:

Most likely model fatigue!  I don't think it would be so bad if more parts of the country had experienced decent snow events this week! 

Absolutely mate. It really has been a disappointing cold spell on that front hasn't it? It deserved so much more. 

[Model banter and emotions]

23 minutes ago, Don said:

Yes, I thought tonight's update looked slightly better than recent runs.  However, need it to gain some traction.

You're right Don. Traction is a good word. A little surprised that nobody else has mentioned the improvement - model fatigue? . Where is the stamina these days? 

[Model Output Discussion - Cold spell ending - what next?]

The EC46 looks much improved to me compared to the last couple of days. More retrogression to the north west and leaning back towards the seasonals in terms of anomalies. 

[Model Output Discussion - Cold spell ending - what next?]

1 minute ago, bluearmy said:

The pub run has a bit of the 00z gem about it 

shove a ridge up and then undercut if so that there are heights around svaalbard waiting for that next push

and for good measure, the pub run rotates the Alaskan ridge to try and complete a cross polar ridge!

Anybody who knows me on here will know I'm certainly no fan of the pub run nor the gem (in it's entirety lol). However, I am also a great believer in the old adage 'every dog has it's day'.

[Model Output Discussion - Cold spell ending - what next?]

Just now, northwestsnow said:

GFS like a dog with a bone here.

Gfs really is gunning for 47.

[Model Output Discussion - Cold spell ending - what next?]

The most crucial part of this winter is upon us. There is significant potential at around day 7. Because the models are out of their comfort zone aka 'amplification' in the area of north west Europe, I feel we could see some quite mouth watering synoptics appearing in the next 24 hours. 

[Model Output Discussion - Cold spell ending - what next?]

My thoughts haven't changed. Things could develop quite rapidly at around day 7. The models won't be anywhere near getting a grip on that amplification yet at that timeframe. 

[Model Output Discussion - Cold spell ending - what next?]

1 minute ago, joggs said:

The GFS ops were fairly decent over the predicted breakdown of our current spell far out imo.

The ops, whether they be gfs or ecm tend to do much better at handling mild breakdowns. I suspect most know this. They find it much more difficult when there is a possibility of meridional/amplified patterns emerging. Gfs often spots these way out but only spasmodically. Ecm initially doesn't want to know, gfs roller-coaster ensues, ecm sort of jumps on etc etc. The amplified patterns are still obviously very difficult for the models to get a grasp of, hence my own advice of sticking to 7 days tops in situations like this. 

[Model Output Discussion - Cold spell ending - what next?]

I don't take any op seriously after 7 days tops, whether it be ecm, gfs etc. There's a reason why ukmo ops stop at 168hrs. Anything after is not really worth taking seriously. With this in mind, the ecm op run this evening is definitely an upgrade compared to yesterday's. Compare this evening's 168hr chart to yesterday's 192hr chart. Poles apart if you excuse the pun. After 168hrs, the ecm flattens again but let's see if this improvement grows as we get to the 5/6 day timeframe. Things could develop rapidly here - and in a very good way for those of a cold persuasion. 

[Model Output Discussion - Colder but how cold and for how long?]

The ecm op is disappointing this morning, flat in the later timeframe with no sign of the magnitude of amplification we will need to bring the cold back. Not overly concerned as quite frankly, the op has been a Grinch all winter in the 8 to 10 day slot when the gfs sniffs something close to interesting. 

[Model Output Discussion - Colder but how cold and for how long?]

1 minute ago, Scott Ingham said:

Yeah I thought that’s what you meant my own opinion is similar to yours ridging 25th leading to easterly winds by the 29th or a day or 2 after. All said and done if the broad evolution came off I couldn’t care less if the dates are before or after. The satisfaction comes from seeing the pattern play out so you know that you’re moving in the right direction as far as knowledge is concerned and interpreting the signals correctly and if not then not. Where did we go wrong and what can we learn from it for next time.

Let's hope it comes off - I think we both feel like it could well be the main course if it does

[Model Output Discussion - Colder but how cold and for how long?]

6 minutes ago, Scott Ingham said:

Yeah that’s also an option, models won’t have a grasp on this period, won’t have a full grasp on the momentum budget and consequently the level of poleward amplification. The next 5 days are a watching brief. Better to know we have a ticket to the raffle than no ticket at all. It will be another interesting period of model watching to come. As of now the evidence points to Febs analysis on dates but it doesn’t mean it’s right yet we’ll just have to watch for the trends and ensembles around the 25th as you suggest

Just to clarify. I'm not saying the start of any cold spell on the 25th. Rather more ridging by this date than what is being modelled at the moment - This then leading to a more rapid descent into cold. 

[Model Output Discussion - Colder but how cold and for how long?]

15 minutes ago, Scott Ingham said:

It could very well be early mate in all honesty. The date is just an educated guess that has more chance of being wrong than right for the start of a pattern change to one conducive to high lat blocking near scandi or Iceland. I do feel fairly confident of us being in a favourable pattern however by mid Feb at the very latest. Your opinion based on the ens suites at this moment in time is well founded. Evidence would suggest at this moment in time that your timings are more likely to be correct pal

I will add a bit of a curve ball to this. It could well be the ensembles in particular are underestimating the start of the amplification in around 9 days time - that's the 25th Jan. I say this because we have the gfs op and control and also the ecm control smelling the amplification route significantly today. It could well be one of those great ocassions when, if anything, the momentum could speed up and things brought forward a day or two. Quite the opposite to the present cold spell where the chase seemed to go on forever. 

[Model Output Discussion - Colder but how cold and for how long?]

4 minutes ago, Mike Poole said:

Plenty of uncertainty early doors on the ECM clusters this evening, then - from a point of view of looking for what might come after the Atlantic spell, here’s T192 onwards.  

Pretty much 3 shades of zonal until the extended, where once again, the signal is for a build of heights to the NW, most notably cluster 2.

I was struck by the 46 Hovmoller plot tonight actually, there are clear changes suggested:

You can see the Greenland block (upper B) collapse, to be replaced with a zonal period Z where things are clearly moving (diagonally on the diagram) east to west.  But then there is a second blocked phase (lower B) which is transitioned to around the 25th January, with blocking just to our E.  This is the next opportunity for a chase into February, looks a bit earlier on the 46 than suggested by the EPS.  

But for now, enjoy the cold weather this week before the wind and rain returns.  

Cluster 1 looks awful right until the end.