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

[AO-]

42 minutes ago, blizzard81 said:

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. 

Good Morning,

Agree. Not a good one, but not surprising either. There still is little support for a colder type of weather even though the synoptics are okay. In the EPS there aren't any members like the Control of GFS. But It is still 10 days ahead, so it is to soon to draw any conclusions. The agreement is something which is great, which leaves a window of opportunity.  The details will come, either in our advantage or not.

[AO-]

At this moment, the GFS seems beter in FI than EC. Let's hope GFS is picking up the signals from background drivers a little better again this time. 

[LetItSnow!]

GFS once again showing a nasty windstorm for Sunday. It’s slightly less intense and a little more south with the strongest of the winds compared to this time yesterday but still packs a punch. These are moisture laden southwesterly winds so there will be plenty of rain. Sunday indeed looks to be a day to stay at home if you can with very strong winds and torrential rain. Not the most welcomed after such a long, wet period. “At least it will be mild” with temperatures in the 8-12C range. 

The GFS 0z shows an imbedded low on Monday the 22nd so further heavy rain likely. We import less mild uppers and while the raw data is suggest 2-3C maxes for some reason, I imagine more around around the 7-10C region and a bit higher in the extreme south.

Weather enthusiasts of a cold persuasion may want to look away at the 23rd. A positively balmy flow of exceptionally mild southwesterly winds. More heavy rain will be associated with this, time time more in the northwest. Temperatures look exceptionally mild. Raw data shows 13-14C in multiple spots but I wouldn’t be surprised if 15-16C was reached, couldn’t even rule out 17C. 

However, by the 25th the idea is toyed with yet again for a raise of pressure from the south which will introduce settled and more normal temperatures, particularly if the ridge builds high enough for clear nights. There is the suggestion that the mild weather, at least for the south, may not last too long. Now exactly what the high does afterawards on this run isn’t of too much importance in terms of exacts, though it does show the signal yet again for height rises over Scandinavia. This is important as there does seem to be a signal that this could be our next chase. 

There’s no guarantee of this happening and not every model agrees but with telecommunications favourable I do think it is a possibility that this could just be an unfortunate spell egged on by an intensification of the Atlantic flow due to extreme, record breaking cold in America, and that the building blocks could be in place for a cold set up to return and this could be how we get there. Not anything Id like to make a bet on, but there *is* a signal even if it’s not unanimous… yet!

Hope this was informative as I’m still a novice forecaster!

[MJB]

Before anyone moans " why the charts" Just looking for any signs of hope moving forward. Certainly it isn't all doom and gloom eh?

Will look again Sunday and see if the 5 days makes a difference with regards what's on show .

[ANYWEATHER]

This morning ,we are far away as can be from a Proper cold spell happening. As long as we keep high pressure over mainland Europe, then it's game over for the forseable future. Charts at day ten ,I've posted ,yes the unrelable time frame, but looking at the synoptic pattern right now and the days ahead ,I cannot see any deep cold reaching the UK ,for at the very least another two weeks and then we are into February. ....by which....... time is starting to tick along....

[TEITS]

2 hours ago, mountain shadow said:

Ah well. Back to the drawing board.

I think a month end change is less probable now.

Why because of just one set of runs and not forgetting the period of interest being 13 days away!

I am optimistic we shall be chasing the next cold spell very soon for the period between end of Jan/Early Feb. The ensemble below is an indicator that we could soon be seeing the classic battle between the Siberian High and the Polar Vortex over Greenland.

However when it comes to potential E,lys I rarely use the ensembles. For now I shall just keep an eye on the GFS operationals especially towards the latter part of the run.

I shall just finally add that I am not saying an E,ly will occur. Like I  say you cannot assume anything for a tiny island such as ours for a period that is 13 days away.

[Rain All Night]

13 hours ago, RainAllNight said:

An overview of this afternoon's model outputs.

Deterministic runs to day 7, Tue 23rd

It seems we may be affected at least indirectly by storms on both Sunday and Wednesday.

Ensemble means at day 10, Fri 26th

Drier for many by the end of next week?

Ensemble means at day 13, Mon 29th

Any further progress into the following week looks very uncertain... but other posters here have pointed out that we have reasons to be optimistic about this.

An overview of this morning's runs.

Deterministic runs to day 7, Wed 24th

Some strong and long-fetch south-westerly winds for us on Sunday, and renewed strong winds by Wednesday.

Ensemble means at day 10, Sat 27th

We still have that signal for southern Britain to be drier later next week, thanks to the swelling high to our south...

Ensemble means at day 13, Tue 30th

...and, for the moment, that is all we seem to have.

Edited January 17 by RainAllNight

[adrianh]

Good time for a model break till after the weekend for those feeling fatigued by another chase! - This one hasn't been a bust, it's just that most of us just haven't had any luck with where the precipitation ended up falling. 

There's signs of potential from the 25th January with models showing a push of heights up through the UK and still plenty of time left in winter for another cold spell. 

[Cambrian]

Over the last day or two we’ve begun to see some very interesting charts in FI, but it’s worth emphasising the exceptional degree of build in heights that will “cut it” for a Scandinavian high far enough north to bring a surface easterly flow and cold into the UK and Ireland, and the kind of build that might look quite impressive on the charts but won’t cut it. 

All taken from yesterday’s output - 

First of all, builds that are not quite there, i.e. some that won’t cut it….

12z ECM ensemble mean at day 10, good build of heights but clearly too far south. Euro high.

 

12z ECM op at day 10, very impressive northward push of heights…

 

…even 12z GEFS at day 14

 

So don’t let the anomalies tease you! Both attain heights over southern or central Scandinavia, with the PV centred over Greenland, and even though the trough is angled favourably north-south, this setup is still not good enough, the trough is too far east in the Atlantic and at the western periphery of Europe we are again pulled into an Atlantic flow. 

Some that will cut it (this type of output is what I’ll be looking out for)…

12z GFS at day 16

 

PV centred to the northwest of Greenland, trough heading down further west into Newfoundland, very strongly anomalous heights over the far north of Scandinavia into the Barents Sea / Arctic Ocean, allowing lower heights to pool over Europe that can bring us into a long fetch easterly.

Now something like that should do it nicely! However, it is an exceptional and relatively rare setup with just the right amount of PV energy needed in just the right places to pull it off. 

Moreover, we are in exciting times where it is possible to connect atmospheric developments over the Pacific with weather patterns on the other side (our side) of the world. 

The trick is to temper our expectations of these teleconnections, and their advanced interpretation in these pages, with respect to their translation to the weather in our local geographical regions, and outside our even more local windows. 

The level of self and mutual congratulation is at times far too high as is the level of criticism by others of those learned and brave enough to give it a go and share that with us. If there is one place on the planet where those delicate intellectual balances can be struck, it is this forum. 

[Lukesluckybunch]

Morning guys..I'm just wondering if we can make something out of that surge of heights..that was there on the 0z ..around day 8 time,behind that low moving through?

[Mcconnor8]

Well Sunday looks like a fun day on the GFS 06z!

Edited January 17 by Mcconnor8

[Daniel*]

Newest to oldest for 12z 25th still a very mild position but the base seems to be gaining more height. If these trends continue SE parts especially will start seeing cooler flows from near continent.

[Methuselah]

I think this stuff relates to weather models, though the moderators might disagree.

Some peeps blame 'faulty software', others cite all sorts of problems arising from a human perspective; but, ultimately, it's mostly down to good old Chaos; simple equations (be they weather-related or not) involving feedback can create an almost unimaginable degree of complexity.

I wonder whether the next generation of AI-/Machine Intelligence-based models will ever 'cut the mustard'. 

 

[booferking]

Can't see anything wintry until after mid February atleast the modo this winter has been a delayed response once we first start seeing in the charts a 15 day lag or so enjoy the chase leave but I'd leave it a good week or so meanwhile watch out for these nasty buggers.

[mountain shadow]

1 hour ago, TEITS said:

Why because of just one set of runs and not forgetting the period of interest being 13 days away!

I am optimistic we shall be chasing the next cold spell very soon for the period between end of Jan/Early Feb. The ensemble below is an indicator that we could soon be seeing the classic battle between the Siberian High and the Polar Vortex over Greenland.

However when it comes to potential E,lys I rarely use the ensembles. For now I shall just keep an eye on the GFS operationals especially towards the latter part of the run.

I shall just finally add that I am not saying an E,ly will occur. Like I  say you cannot assume anything for a tiny island such as ours for a period that is 13 days away.

Why?

Because there is no continuity. 

We all know Scandi Highs are rare beasts and the models have backed off today.

[Kasim Awan]

2 hours ago, TEITS said:

Why because of just one set of runs and not forgetting the period of interest being 13 days away!

I am optimistic we shall be chasing the next cold spell very soon for the period between end of Jan/Early Feb. The ensemble below is an indicator that we could soon be seeing the classic battle between the Siberian High and the Polar Vortex over Greenland.

However when it comes to potential E,lys I rarely use the ensembles. For now I shall just keep an eye on the GFS operationals especially towards the latter part of the run.

I shall just finally add that I am not saying an E,ly will occur. Like I  say you cannot assume anything for a tiny island such as ours for a period that is 13 days away.

One set of runs? It's not like the mild runs are in isolation.  All the runs show a lack of high pressure situated in a position conducive to cold in the UK. 

[AO-]

19 minutes ago, mountain shadow said:

Why?

Because there is no continuity. 

We all know Scandi Highs are rare beasts and the models have backed off today.

I disagree that Scandinavian hights are the holy Grail to look for atm. Yes, eventually for enduring cold, the Scandinavian block is what we want, but 2012 dids not have a Scandinavian block when winter set in. It started with a block over Kazachstan, ending up with a Northwest Russian block. A southeasterly van be very cold with the right setup. And writing off something that is in far FI, is just ridiculous. The Scandinavian block is still in the EPS (albeit minimal with 4 members, but that number is pretty constant), just not in the operational. Since when do we take one operational at day 11 seriously? 

Edited January 17 by AO-

[Jason M]

5 minutes ago, Kasim Awan said:

One set of runs? It's not like the mild runs are in isolation.  All the runs show a lack of high pressure situated in a position conducive to cold in the UK. 

Yes, focus of heights is to our south. We will probably see a gradual shift to a more 'mid lat' scenario over the next couple of weeks, but very hard to see a route to anything cold in the extended outlook IMHO. I reckon we will see some pretty charts in deep FI over the coming days but nothing convincing. Maybe 10% chance of a very cold easterly early next month.

[feb1991blizzard]

2 minutes ago, AO- said:

I disagree that Scandinavian hights are the holy Grail to look for atm. Yes, eventually for enduring cold, the Scandinavian block is what we want, but 2012 dids not have a Scandinavian block when winter set in. It started with a block over Kazachstan, ending up with a Northwest Russian block. A southeasterly van be very cold with the right setup. And writing off something that is in far FI, is just ridiculous. The Scandinavian block is still in the EPS, just not in the operational. Since when do we take one operational at day 11 seriously? 

I certainly don't take the ECM operational day 11 seriously!

[IDO]

As always, we should be wary of random cold charts in FI on the models, especially if they are outliers and contrary to solid means. The GFS 06z op falls more in line with the mean from D8-16 with the synoptic:

The control also follows this. 

The mean at D11:

An Iberian-centred Euro high. I am sceptical that we will see any blocking from the NE with this setup. That high is unlikely to move east due to the Siberian high & E Euro trough, so retrogression back to the Azores and more likely GH than a Scandi high.

 

[Severe Siberian icy blast]

1 hour ago, Daniel* said:

Newest to oldest for 12z 25th still a very mild position but the base seems to be gaining more height. If these trends continue SE parts especially will start seeing cooler flows from near continent.

Well the core of the heights have gone from Spain/Italy to Belgium/Denmark so a definite movement north.

All models were pointing toward a lengthy cold spell with flatliners on the ensembles now a wk later we're looking at a lengthy mild sleep and i dont believe it will go on any longer than a wk. The models will change over the wkend as the models get to grip with the pattern change and the fact we've just had a reversal the last day or so or at least very close.

So think more changes are on the way

[bluearmy]

4 minutes ago, IDO said:

As always, we should be wary of random cold charts in FI on the models, especially if they are outliers and contrary to solid means. The GFS 06z op falls more in line with the mean from D8-16 with the synoptic:

The control also follows this. 

The mean at D11:

An Iberian-centred Euro high. I am sceptical that we will see any blocking from the NE with this setup. That high is unlikely to move east due to the Siberian high & E Euro trough, so retrogression back to the Azores and more likely GH than a Scandi high.

 

Heights into Greenland for more than a fleeting ridge at best look troublesome to me within the next 16 days. 
unless we see the Canadian vortex relaxing itself markedly across the end week 2 ens, then i think we could be looking towards week 4 approaching mid feb to get that to stick.  It really wouldn’t surprise me to see the nwp trying to repeat the last couple weeks with a mlb that eases north to Orkney ish latitude  and then retrogresses slowly. if upstream plays ball then we can then get a griceland high to follow. If split flow plays ball then we can possibly advect something notable around the south of an Orkney high. 

 

 

[feb1991blizzard]

14 minutes ago, bluearmy said:

Heights into Greenland for more than a fleeting ridge at best look troublesome to me within the next 16 days. 
unless we see the Canadian vortex relaxing itself markedly across the end week 2 ens, then i think we could be looking towards week 4 approaching mid feb to get that to stick.  It really wouldn’t surprise me to see the nwp trying to repeat the last couple weeks with a mlb that eases north to Orkney ish latitude  and then retrogresses slowly. if upstream plays ball then we can then get a griceland high to follow. If split flow plays ball then we can possibly advect something notable around the south of an Orkney high. 

 

 

That's what i see as well.

But following on from failed attempts at an out and out scandi.

And i'd prefer it to a GH, we all know where they end up in recent years, either a W based setup or a magic roundabout, both caused by iberian heights.

Edited January 17 by feb1991blizzard

[IDO]

1 minute ago, bluearmy said:

Heights into Greenland for more than a fleeting ridge at best look troublesome to me within the next 16 days. 
unless we see the Canadian vortex relaxing itself markedly across the end week 2 ens, then i think we could be looking towards week 4 approaching mid feb to get that to stick.  It really wouldn’t surprise me to see the nwp trying to repeat the last couple weeks with a mlb that eases north to Orkney ish latitude  and then retrogresses slowly. if upstream plays ball then we can then get a griceland high to follow. If split flow plays ball then we can possibly advect something notable around the south of an Orkney high. 

 

 

Yes, if it is a replay of the last cold spell; the UK high being eased west/NW is a better option and a possibility, bearing in mind it is a repeating pattern that can be noticeable in a trop-driven regime. But so far, looking at the modelled jet, we are less favoured by the split jet versus this recent cold spell UK high. That may change with further runs, but the northern arm is being modelled to be stronger than earlier in January before the UK high developed. That may make it more difficult to sustain higher pressure at higher latitudes.

[AO-]

15 minutes ago, feb1991blizzard said:

That's what i see as well.

But following on from failed attempts at an out and out scandi.

And i'd prefer it to a GH, we all know where they end up in recent years, either a W based setup or a magic roundabout, both caused by iberian heights.

The problem with the synoptics atm is that if we get a Scandinavian high, there won't be any cold left to put on transport towards Northwest Europe. Thats why I would prefer retrogressing of the Siberian high into Russian. I see that as one of the few options left to get a proper cold spell on short notice.