Model Output Discussion - 1st - 7th January

[Craigers]

Nice cold member from the suite

[ChartViewer]

Nice cold member from the suite

Come on craigers I was called to task last night for misleading members over SST's over the North Sea....You are doing just the same for coldies!!!!

Edited January 7, 2012 by ChartViewer

[mulzy]

Isn't the "control" run at the same resolution as the other ensembles?

Edited January 7, 2012 by mulzy

[Backtrack]

You can't make those assumptions - a Strat cooling WILL lead to zonality and low heights at Northern Latitudes but a warming event is not so clear cut and mid-latitudes on the other side of the globe can be the beneficeries.

But the stratosphere is warming.

I've no idea if the warming in its current modelled position will have any effect on us at all, but there is a strong correlation between warming of the stratosphere, and what the weather is doing in the troposphere.

Strat cooling? It's not forecast to cool, but afterall, after the warming, it's highly likely to cool, if the models are correct, it'll be 88C above the average for the time of year, there's not really more room for warming. After such an epic increase in temperature, the only way is down.

Come on craigers I was called to task last night for misleading members over SST's over the North Sea....You are doing just the same for coldies!!!!

No, not really.

Uppers of -7C is hardly spectacular. What's misleading about cold uppers from an Easterly? The models suggest cold pooling over Europe around that time frame.

That chart is perfectly plausible.

[phil nw.]

Poor old UKMO has been reduced to a sideshow as any possible changes to the vortex are not likely to show by T144.

Just to ensure he`s not left out here is his last chart.

http://www.meteociel...44-21.GIF?07-17

as expected the UK still under the influence of the mild Euro High at that stage.

Edited January 7, 2012 by phil n.warks.

[mcweather]

Lets hope the GFS 12Z operational is as much of a mild outlier as so many other have been recently. lol

[ChartViewer]

But the stratosphere is warming.

I've no idea if the warming in its current modelled position will have any effect on us at all, but there is a strong correlation between warming of the stratosphere, and what the weather is doing in the troposphere.

Strat cooling? It's not forecast to cool, but afterall, after the warming, it's highly likely to cool, if the models are correct, it'll be 88C above the average for the time of year, there's not really more room for warming. After such an epic increase in temperature, the only way is down.

No, not really.

Uppers of -7C is hardly spectacular. What's misleading about cold uppers from an Easterly? The models suggest cold pooling over Europe around that time frame.

That chart is perfectly plausible.

Because it is 1 of many ensembles...Matty M sums it up above...no need to say anymore. I could pull out many ensemble members showing a Bartlett over the last 8 weeks when any cold potential showed....Lets have a bit of realism in this thread...As soon as cold is shown someone digs out an ensemble from the suite....

Regards

PS - Blimey if things do work out for cold go on GP/Netweather forecast...as much as i dislike cold im rooting for their forecast as this site beats others hands down

Edited January 7, 2012 by ChartViewer

[Paul]

Isn't the "control" run at the same resolution as the other ensembles?

Yes

[Backtrack]

Because it is 1 of many ensembles...Matty M sums it up above...no need to say anymore. I could pull out many ensemble members showing a Bartlett over the last 8 weeks when any cold potential showed....Lets have a bit of realism in this thread...As soon as cold is shown someone digs out an ensemble from the suite....

Regards

Realism?

I'm not being realistic because I highlighted the fact that the chart posted above was perfectly plausible?

The ensembles are there for a reason, and regardless of what anyone says, we all use them for spotting trends on a daily basis. They have an input of data just as the operational runs do, so why should I ignore them? If they were completely useless, then do you really think they would continue to operate?

People may be singling out single charts from one particular ensemble, but the models are flipping around all over the place at the minute, especially in the latter parts of the runs, so right now, I'm open to many solutions, whether this be winds from the east, or winds from the south.

Can you tell me exactly what the weather will be like on the exact date of that chart? No? Didn't think so.

[phil nw.]

If individual members wish to disagree with each other and can`t keep on topic then please use the PM system.

[Weather Boy]

Well, there can be no doubt that the 12z is an interesting run with bags of potential, but I think that it's important not to get carried away with just run, especially as we are not even aware of the ensembles yet.

I can see why people would want to get carried away, because there are all sorts of other signs (most notably the strat warming) suggesting potential for a change to cold. However, even the 12z only shows potential - no blizzards and the like on that chart. In fact it looks quite similar to the set up we had in the autumn (although obviously the different season would give different conditions) by which I mean a Scandi/East Europe high dragging southerly winds to the UK, rather than an easterly as many would like. But no-one can deny the potential.

You don't have to be a seasoned model watcher to be aware that surely the models are going to pull the rug from under us before they have even show a chart that, if it verified, would actually give the cold that many are looking for.

My feeling is that it will either get there eventually, or we will just miss out. Zonal is not the long-term look IMO.

Edited January 7, 2012 by Weather Boy

[johnholmes]

I wonder how many of you really believe the GFS output post T+168 hours?

Its almost like 2 seperate models, one to T+168 and one beyond it.

Of course it may turn out to have picked up a trend but equally it may be a load of whatever you want to call it.

Treat it with a huge amount of caution even if ECMWF and GEM show similar ideas on their 12z outputs at T+192-T+240.

Edited January 7, 2012 by johnholmes

[Cheshire Freeze]

I wonder how many of you really believe the GFS output post T+168 hours!

Its almost like 2 sepearte models, one to T+168 and one beyond it/

Of course it may turn out to have picked up a trend but equally it may be a load of whatever you want to call it.

Treat it with a huge amount of cation even if ECMWF and GEM show similar ideas on their 12z outputs at T+192-T+240.

Sensible words John, I refuse to get suckered in just yet.

[bluearmy]

theme from the past two gefs runs is a growing number of members that want to dive the troughing to the sw. plenty of other cold runs now showing but with the mean jet now running out of steam on each of the past two ens runs in fi, the fact that we start to see these troughs diving towards iberia/w france is a superb development. it is one op run but the trending of the ensembles is what i'm watching and its all there to see (at the moment)

I wonder how many of you really believe the GFS output post T+168 hours?

Its almost like 2 seperate models, one to T+168 and one beyond it.

Of course it may turn out to have picked up a trend but equally it may be a load of whatever you want to call it.

Treat it with a huge amount of caution even if ECMWF and GEM show similar ideas on their 12z outputs at T+192-T+240.

very true john although high res stops at T192. the 00z run looks to be the 'odd run out' so far. the ens are full of interesting trends. i think i noted the first scandi highs being shown yesterday. plenty more today and now the diving trough. maybe an op run will pick that out soon in fi.

[Cheshire Freeze]

theme from the past two gefs runs is a growing number of members that want to dive the troughing to the sw. plenty of other cold runs now showing but with the mean jet now running out of steam on each of the past two ens runs in fi, the fact that we start to see these troughs diving towards iberia/w france is a superb development. it is one op run but the trending of the ensembles is what i'm watching and its all there to see (at the moment)

One thing I noticed is the Pacific high being more robust fairly early on in this run, I assume this plays a key role in disturbing the jet enough for the high to get a hold further downstream as seen on the 12z?

[Grimsby Snow Lover]

Best set of ensembles I seen for a while

http://www.wetterzentrale.de/pics/MT8_London_ens.png

http://www.wetterzentrale.de/pics/MT8_Manchester_ens.png

http://www.wetterzentrale.de/pics/MT8_Aberdeen_ens.png

A definate cooling trend there would you not agree?

[Cheshire Freeze]

Best set of ensembles I seen for a while

http://www.wetterzen..._London_ens.png

http://www.wetterzen...chester_ens.png

http://www.wetterzen...berdeen_ens.png

A definate cooling trend there would you not agree?

Not brilliant but some colder runs starting to appear at an earlier timeframe

[sn0wman]

I have been through all the 12z GFS ensembles, and I could only count 5 out of 20 which didn't show some brilliant cold synoptics and even most of these showed a cold zonal theme! :smilz38:

[mcweather]

Interesting that at the end of the run the op is the 4th warmest solution of the 20.

Edited January 7, 2012 by mcweather

[Catacol]

There are countless synoptic set-ups I could run through where the Arctic High emergences but fails to influence matters at mid-latitude, the one massive exception being Jan 87.

I deal in probabilities from the proposed synoptic set-ups going forward. And where we are at the end of the reliable timeframe is historically poor for cold fans going forward. Anything else is straw clutching when you look at the NAO set-up.

The US guys are often quick to spot amplification and how they see things in the Pacific. They see a flattish jet going forward and an SE ridge.

I agree that we deal in probabilities - of course. How can weather forecasting really be anything else? I doubt the science will ever be there to predict more than a few days ahead the specific synoptic setup because there are too many variables that contribute to a system of chaos.

However I'll still stick to my guns here and suggest that you are being rather one sided. For as long as the vortex remained strong and undisrupted the probability of sustained cold weather for the whole UK was very slim indeed. Now that we have a vortex on the wobble, and possibly about to be splintered by warming, the probability of cold weather increases substantially. An arctic high is a by-product of a a vortex under pressure, and it cannot be right to move from a position of arguing (correctly) that cold weather is unlikely in a westerly scenario, to then stating that now the westerlies are likely to fade and higher latitude blocking is likely to emerge somewhere that cold is still not going to happen and that Jan 87 was an exception. Smacks of wanting to have your cake and eat it.

On topic - and the ECM shows greater amplification at T144, an attempt at high pressure to our NE at T216 and a trough sinking south at T240. To me it looks like a computer struggling to cope with mixed signals and an uncertain calculation as to what the final product will be from next weekend onwards. Cold weather not probable? Looks a darned sight more probable than 3 weeks ago.

[Matty M]

How many times must it be reiterated, the ensembles are very fickle things and are only useful during certain

set ups and this one certainly is not one of them.

I think im gonna go order 100 sleds!

[stratty]

How many times must it be reiterated, the ensembles are very fickle things and are only useful during certain

set ups and this one certainly is not one of them.

I think im gonna go order 100 sleds!

........this might help your point Matty, Bern Ensembles from earlier lol

[mcweather]

Posted Today, 09:31

bluearmy, on 07 January 2012 - 09:20 , said:

More confusion. The ECM op brings the trough closer to us (remember the spreads I posted last night?) . However its shallower and has no proper cold uppers in there as no decent low uppers have penetrated into the circulation. Maybe this is why we have seen few really cold options showing on the london ens. More importantly, the upstream flow is much flatter than yesterday's 12z showed. What is more significant for me is the gfs in high res. Forget the dross post t192. However, the desire of the ncep modelling to retain high heights close to the south of the uk pre T192 is a major concern for those wanting to see cold before the 20th.

Let's see if its a one run job or if high res continues to prog the mid lat high and keeps the euro trough further east.

Btw, the gem at day 10 isn't a bad tool and has, on occasion, flagged up a pattern that the others have subsequently latched onto.

Your last comment about the GEM is very true blue army especially in relation to cold scenarios . It has occassionally been a trend setter. IIRC it was one of the first to pick up the drop into the cold abyss at 240 last november. The evolution it shows is as likely as any of the others on offer at the moment.

The sucking of the euro high north then east into a scandi has been seen on occassion before and is not that unusual a development.

Edited by mcweather, Today, 09:33.

well well well

Edited January 7, 2012 by mcweather

[SMU]

Afternoon All-

Ians comments- are balanced tonight this is by no means a cert- HOWEVER,

'tentative' signs from the GFS & the earlier vaunted 00Z GEM that the Amplification of the jet mucg discussed over the last 5 days or so instigatingt he Aleution high is settling down in the models into the 140-170 timeframe,this is certainly disrupting the overall flow of the jet & its easterly propergation-

look at the pacific disruption here:

http://176.31.229.228/modeles/gfs/runs/gfsnh-2012010712-5-150.png?12

Once you get that weakness in the jet then the Easterly extent in terms of penetration across the atlantic into Europe becomes less overwhelming to the point that further eddies & blocks can start to form-

Also on a positive note- todays 12z's- thats the UKMO ( that looks good at 144) the Nogaps, SOME of the GFS ensembles seem to have resolved the path of the low in the atlantic at 144-

The Building ridge out of the azores looks to send this crashing into Southern greenland before getting Cut off- Which is perfect if you want Nortehrly ridging out a high to start linking up with a building Arctic high over the pole-

Shown here at 150-

http://176.31.229.228/modeles/gfs/runs/gfsnh-2012010712-0-150.png?12

That camels hump of high pressure over the UK is going to get drawn Northwards- now for those wondering what shape it needs to be to push for an easterly - it needs to build DIRECTLY North- if it does its showing the jet as a perfect NORTH SOUTH horse shoe which will carve out a high towards Scandi-

This is what the perfect camels hump of high needs to look like

http://176.31.229.228/modeles/gens/run/gensnh-8-1-156.png?12

However we will ALWAYS need to bits of the cherry to get the cold to the UK ( people might want to refer to 08/1/87> 12/1/87 for the perfect evolution-

Phase 2- which Ian alludes to is what follows on after the first amplification- & this currently sits in the timeframe 170-220

We will need continued Amplification with the jet as the Scandi high will not simply advect the Cold our way we need a trigger to 'prop' up the base of the high & funnel the cold along the northern flank- & its at this point we so often fail because if the jet rushes EAST or NE like Ian alludes to then the trigger low gues up against the western flank fo the high as opposed to under it- RE_ KETTLEY HIGH 2001-

We need another loop to get a shortwave to the South of the block-

So remember PH 1

http://176.31.229.228/modeles/gens/run/gensnh-8-1-180.png?12 Scandi high development

Phase 2-

trigger low moving SE into the low countries-

http://176.31.229.228/modeles/gens/run/gensnh-8-1-192.png?12

Cause by this Jet-

http://176.31.229.228/modeles/gens/run/gensnh-8-3-216.png?12

Which leads to-

http://176.31.229.228/modeles/gens/run/gensnh-8-1-228.png?12

& the holy grail

http://176.31.229.228/modeles/gens/run/gensnh-8-1-276.png?12

http://176.31.229.228/modeles/gens/run/gensnh-8-0-288.png?12

So what to look for Jet wise

PHASE 1

http://176.31.229.228/modeles/gens/run/gensnh-8-3-150.png?12 Camels hump over the UK

PHASE 2

http://176.31.229.228/modeles/gens/run/gensnh-8-3-204.png?12

This is what we DONT want PH2 to look like otherwise bye bye block-

http://176.31.229.228/modeles/gfs/runs/gfsnh-2012010712-5-240.png?12

eyes down for the ECM-

STEVE

[Mike Storm]

when Steve Murr starts posting....the snow be a coming.....hopefully

Edited January 7, 2012 by Mike Storm