Model Output Discussion:

[D KARLSON]

http://www.knmi.nl/e...agse/index.html

The day 5 ECM ensembles are starting to show what would reasonably be expected given what's going on with momentum transports across the Pacific Ocean in particular with signals for a mean ridge to develop across Canada and western Greenland and, a probable transient eastern extension of the ridge towards Iceland helping to draw colder air situated over Scandinavia towards the UK mid month.

It certainly looks that way ,the idea of the trough of low pressure systems pushing their way across the bristish isles with cold air to the north milder to the south,and of course details and exact modelling of this situation over the coming week is going to be impossible ,so only read modelling for 2 days ahead as things could change drasticly from run to run and exactly where the cold mild boundary will be.

I think as we run through next week the first milder weather of the winter will start to push into eastern europe western russia ,but scandinavia will hold onto the cold air and i think as all this happens, it will be the cue for another cold out break for britain ,but i think this time the emphasis will be on snow rather than cold although cold enough anyway certainlt thr possibility of a very snowy end to february ;filldyke;

[Matty M]

And at 144hrs the GFS has us on the brink of the intensiest easterly matching 1987!

[Nick L]

Something is seriously wrong with the models. There is no happy medium at the moment, it just keeps switching from one extreme to another! Although saying that, I wouldn't mind a bit of this...

http://www.wzkarten3.de/pics/Rtavn1501.png

[snowmadchrisuk]

This is now just getting silly.

http://www.wetterzentrale.de/pics/Rtavn1321.png

Going back to my earlier post and it seems the Met O know the models have been wrong which is why the forecasts differ so much. However this doesn't explain the discrepancy between the Fax and the forecast.

Can't wait for there 6-15 day forecast . I agree with you that something is a miss and it appears to have been for a few days. I know the UKMO is not on the Cold wagon just yet , but it has been hinting at it at around +96 for quite a while. I am guessing the UKMO Ensembles that we don't see have been hinting at Cold as well.

[Iceberg]

-12 850s enter the UK on the 9th....

This is obviously a much better run, but the ECM EPS members for London will be important when we get to see them in an hr's time.

Also this is probably as good as it gets, with only a little WAA distruption we would end up with a much messier affair with the high closer to the UK, less cold and probably the colder air not arriving until T240 IMO.

[Matty M]

Can't wait for there 6-15 day forecast . I agree with you that something is a miss and it appears to have been for a few days. I know the UKMO is not on the Cold wagon just yet , but it has been hinting at it at around +96 for quite a while. I am guessing the UKMO Ensembles that we don't see have been hinting at Cold as well.

Well this morning we see from the ECM ensembles

A split of 55% cold and 45% milder with the milder section including the op and control runs.

So it shows the uncertainty.

[Weather-history]

Remember unless the UKMO comes on board then anything the GFS shows is very suspect, that still has to perform a big backtrack to get close to this.

It has got to be said UKMO has hardly foolproof, we have seen that with last week's easterly it showed and also it has swung somewhat, this week. Remember how much the Atlantic was suppose to break through according to UKMO? So yes, it didn't go for a continental flow but an Atlantic one but then again it overegged it. UKMO had an Atlantic low around the north of Scotland for Thursday and as we see that isn't going to happen.

Edited February 3, 2010 by Mr_Data

[snowmadchrisuk]

You have to love the GFS ... I Know let's replace all the low pressure with High pressure :

[Slinky]

This has been a most interesting week so far wrt the model outputs, I have never seen so much variation at short range between runs! Can honestly say I am enjoying it greatly, although I think we should have a wager thread, where we can place our bets on which model will prove correct (if any)

My other punt is the 9th Feb

Sorry slighlty off topic

Ps- Thanks for all the great posts from the more knowledgeable members on here such as GP, JohnH, NickS, Teits, IanB ect..... (its a great help)

Edited February 3, 2010 by Slinky

[TEITS]

Can't wait for there 6-15 day forecast . I agree with you that something is a miss and it appears to have been for a few days. I know the UKMO is not on the Cold wagon just yet , but it has been hinting at it at around +96 for quite a while. I am guessing the UKMO Ensembles that we don't see have been hinting at Cold as well.

Does anyone know what range the MOGREPS ensembles go out to?

I know I keep harping on about this but I do think its significant. Here is the E Midlands forecast which was written last night at 3.34am.

"Milder with occasional rain and strong winds on Friday. Cloudy Saturday and Sunday, with a few light sleet or snow flurries."

However the fax chart shows mild S,lys with zero chance of snow flurries!

http://www.wetterzentrale.de/pics/brack4.gif

So if the Met O disbelieve the models then why does the fax chart show S,lys.

[Eugene]

As early as T+72 hrs i knew this run was looking like a stonker and the ensembles did have some runs like it so you can't write it off completely, remember this hasnt come out of nowhere, runs were showing it earlier this week/late last week, the last two weeks have bene cold just we were so used to very cold most got used to it so i can see it staying cold mostly throughout February into March, i think GFS has settled on the eventual outcome now.(maybe less cold though in actuality)

ECM and UKMO has showed this kind of outcome just a day or two ago so whose to say it won't again.

[cooling climate]

I know its the 06z run and should be treated some caution but its funny that at

t162 it is now showing similar chart to what was being shown a week ago.

The more extensive blocking is down to the energy over Scandinavia that was being

modeled incorrectly.

Fantastic run though it must be said.

[thegreat316]

And just to tease us more the GFS at +180 gives us a channel low. hmmm......

[Matty M]

Check out snowmageddon on the GFS around 192hrs, just for the laugh! Brilliant. A few feet of snow!

[Nick L]

GFS FI wouldn't be a GFS FI without a potent low pressure....

http://www.wzkarten3.de/pics/Rtavn2161.png

[Totoro]

As early as T+72 hrs i knew this run was looking like a stonker and the ensembles did have some runs like it so you can't write it off completely, remember this hasnt come out of nowhere, runs were showing it earlier this week/late last week, the last two weeks have bene cold just we were so used to very cold most got used to it so i can see it staying cold mostly throughout February into March, i think GFS has settled on the eventual outcome now.(maybe less cold though in actuality)

ECM and UKMO has showed this kind of outcome just a day or two ago so whose to say it won't again.

Indeed. Time will tell. Although now the 'getting colder' output is in a more reliable timeframe.

I think it could be said that the only consistency in the models of late has been their inconsistency.

[Iceberg]

You just knew this run would throw up a mega snow storm 10.11.12 of Feb.

No crazy run would be complete without one.

[Matty M]

So in conclusion, lets look around 96 hours and this is where the key change is.

The trough over Scandy is almost wiped out and allows big height rises to its west.

This IMO is the best chart of the output.

[bluearmy]

HELP!!

the only thing worth saying at the moment is to note the similarity between the NOAA cpc anomoly chart 6/10 days from yesterday and the GEM/ECM op runs from this morning. given that the ecm ens seem to want to take the trough further south as per gem (lower temps in holland), i am keen to see todays cpc chart as i think it may well extend the trough further se and drop the whole pattern a little futher south at the same time.

certainly not a time for picking apart individual runs. it'll just make you look silly within 6 hours!!

[swfc]

Crazy run this past 120,watch that low move across the uk and deepen.?????

[sandstorm2]

Think I will just start looking at one chart per day and that will probably be the 0600 and the previous nights UKMO and ECMWF otherwise I will go bonkers.

TEITS said a few days ago that easterlies have a habit of disappearing off the chart and then return in the 72 hr timeframe, that is what is happening now.

SS2

Edited February 3, 2010 by sandstorm2

[snowmadchrisuk]

I like what 6z is saying until +120 but after that although amazing it is totally gone off the wall Crazy . A 980 deepening low over Northern England with -10 uppers and 60 MPH winds . 6z FI is near on impossible to develop like that so I suggest we just try and look to getting the initial pressure rise and Easterly and go from there .

[TEITS]

Although it will be silly to pin your hopes on the 06Z there is a factor that needs to be taken into account. Due to these changes in the relatively short time frame the latest models runs using the latest observational data need to be taken into account. Due to how volatile the model output is at the moment a model run that is 6hrs old i.e ECM/UKMO becomes ancient in these situations.

Have to say im loving this uncertanity which is providing more drama than the TV. The game of tug of war has suddenly seen a pull towards cold.

[Guest North Sea Snow Convection]

Stephen P said last night:

Whatever anyone thinks about the GFS it's still the best model at introducing trends. Furthermore if the GFS re-introduced a raging easterly tomorrow it would become everyones favourite model again.

I don't think it's the models here that have the problem, it's probably the assessment of the models in the near time frame, which given the current lack of certainty is not surprising.

No one can be blamed for being confused, but for me GFS is still as good a model as the ECM/UKMO, every model has it's ups and downs from time to time.

I replied:

In a situations like this it would be unreasonable to say a models wrong when they're all finding it difficult to deal with the situation.

No Stephen, it wouldn't neccesarily. At least speaking personally - although obviously I would like what it showed!

But by illustration of not always going along with it because it shows what I want it to - last week when the GFS persisted with showing a perishing easterly (you remember the first saga over the easterly?) I was continually voicing doubt over it and pointed to the euros who had dropped the idea. I was also sceptical about all the ultra OTT cold that the model was churning out only a few days ago that lots of people were speculating about.

I have only seen the easterly as most likely, strangely enough, in the last couple of days or so!

What can I say!!

It isn't a surprise though really to see another twist though is it - I'll say no more about the latest GFS .

That post t96 time period is the trip wire yet again here for the models. How many more times are they going to stumble over it!??

Uniform agreement on this tonight please - and put everyone out of their misery!

[Iceberg]

I thought it would be interesting to see the major differences at T72 between the METO and GFS 06Z, I know that the 06Z is 6 hrs ahead, but it will help to judge the 12's as the differences are huge.

Firstly the direction of the WAA, has a much better tilt on the GFS.

Secondly as Matty pointed out the SW over Scandy, GFS has pressure about 5mb higher and doesn't make anything really of the weakness.

Thirdly the HP over GH is much more pronounced on the GFS with a much better ridge from it towards Scandy.

Nobody should expect the METO to tick all 3, but it should come into a line a little bit as T72 is hardly FI.