Winter Model Discussion 06Z 10/01/13>

[Bobby]

But there is NO middle road with this Bobby...

It either goes over the top, or underneath...both with very different outcomes.

Yes I know and looking at the ensemble means and individual runs I find useful in determining which outcome it will be. It's best to look at all the information available and combine it into a big picture instead of limiting yourself to this or that. Op runs, GFS ensembles means, individual peturbations, ECM ensembles, anomalies etc. Then put it all together and try and make sense of it all.

Edited January 10, 2013 by Bobby

[Rocheydub]

I can't see how looking at the mean will help here at all... Maybe I'm missing something.

[mulzy]

The same could be said for the ECM ensemble mean at the same timeframe.

HUGE difference between GFS and ECMWF ensemble means there (even though as stated above, the use of ensemble means when solutions diverge radically is probably flawed).

Edited January 10, 2013 by mulzy

[Dean E]

06z GFS is again, so consistent, its completely mind blowing. You've got to had it to the GFS, it's out on its own still and has been since Tuesday evening, amazing! Sadly, more worrying, there's hardly any support for the GFS and ECM, UKMO, GEM ect. Are in agreement once again.

From the 06z, there are some small changes that its slowly starting to shift in a slightly different direction, but that's not fully shown as of yet.

SSW still on going at them moment, but starting to show some signs of some sort of slowing trend/ peak rise.

Someone did say that Met Office had no clue to what is going on... I wouldn't say that, they are probably trying to get some 'middle ground' of what's going to happen and I would of thought, they would not be discounting the GFS just yet.

I think we all need a break today!!

SM

Edited January 10, 2013 by SnowMania

[rory o gorman]

The ens are still far to spread on the gfs to give up hope of a descent cold spell . The 06z op has backtracked slightly in the medium term and is close to a warm outliner. seems to be a major uncertainty beyond the 16 th in all models this morning. an upgrade for me personally.

[Weathizard]

The same could be said for the ECM ensemble mean at the same timeframe.

Exactly, this just proves how really, we have no clue where this is going because the ECM is going one way and the GFS is going the other, the difference in the mean charts is quite frankly astonishing, I know in setups like this they are pretty useless but this is STILL ECM vs GFS, both models have HUGE divergence even at T96-T120, Its the big derby and its coming up to crunch time now 2-2 going into the last 10, lets hope the ECM is Man United.

Anyone got the full De Blit/London ENS please?

[Timmytour]

A Couple of days ago we were waiting for the ECM to climb aboard. Does anyone know what it was showing for what is now T72...so I guess around T144 before it did climb aboard, and whether there is any similarity to what the GFS is now, or has been showing?

[SP1986]

There actually is a potential middle ground, but only in a dynamic sense, you would have a middle ground scenario. There has to be a point in the model output that will achieve a middle ground, but it won't be the end product or the outcome. I'm thinking the middle ground will occur when the Azores High starts ridging towards the UK, a middle ground scenario would be high pressure slap bang over the UK at that point. I think realistically that's as far as we can go for the moment with any great certainty

Edited January 10, 2013 by SP1986

[Frosty.]

The ECM 00z Ens Mean maps show a cold to very cold cyclonic pattern for next week and beyond with bitter winds (light to moderate) from the east and northeast and combined with low pressure it means a potent mix of heavy snow and severe frosts, the GEFS 06z mean in comparison becomes less cold from around midweek with winds from the north atlantic rather than northeast europe, so it's very messy and will the gfs emerge victorious and scupper cold prospects for the rest of january apart from the cold blip it shows for this weekend and early next week or will we have our first proper cold spell of longer duration.

[IDO]

I think we are all in the dark here and we just have to wait for the models to sort it out.

All I know is that GFS are now even downgrading the snow event for most this weekend. Lucky there is only 36 hours to go otherwise we may see the Atlantic by Saturday.

Of course GFS could be wrong but hopefully eureka will be the 12z's tonight, either way.

Although the GFS looks right to me we have to respect the "pros" on this site who suggest a closer solution to ECM. Least we should know which model(s) to favour next time as one or more will be shamed in the next 24 hours.

[Summer Sun]

06z GFS ensembles

So its clear either GFS is going to be very very wrong or ECM and UKMO are going to be the big winners of this

I would hate to be a forecaster during this spell

The last sudden stratospherics warming events were in 2009-10 and 2010-11 both of those brought big snow events to parts of the UK.............

Edited January 10, 2013 by Gavin.

[Catacol]

Can I just clarify this suggestion "UKMO never use GFS".... to be clear, they of course analyse each NCEP run in detail and indeed their last 6-15d briefing offered considerable comparative view citing NCEP ensembles, GFS 12 & 18z runs, etc, versus ECMWF.

Thanks Ian - I wasnt aware of that... past posts had suggested that GFS was pretty much a non feature at discussions in Exeter. Thanks for the clarity.

[pinball wizard]

So dissapointed in the models on what they were predicting to what they are now predicting, pretty rubbish if you ask me...

You have to bare in mind that a) its only one model that is not providing what you are looking for, and all models are just predictions - reality can be very different! We see this time and time again in winter in the UK, moral of the story is don't get your hopes up until ALL models are in agreement within 24 hours of an 'event'.

Many have spoken about the record levels of uncertainty within the models at the moment and so there is really no excuse for any of the surprise or melodrama currently on show in this thread.

Edited January 10, 2013 by pinball wizard

[Kentspur]

Not only does there appear to be uncertainty around the general synoptic outputs, but after the freak snow fall we had in the South East prior to the failed easterly when the whole precipitation band was forecast as rain with sleet on the hills possible, who can really rely on the precipitation models at this far out either?

[swilliam]

UK Outlook for Tuesday 15 Jan 2013 to Thursday 24 Jan 2013:

Sunny spells and wintry showers are expected to affect the UK on Tuesday and Wednesday. The showers are expected to be most frequent towards the east with snow likely to low levels, giving the risk of significant accumulations across some eastern counties. More prolonged rain, sleet and snow may spread into the southwest by Wednesday. It will be cold, locally very cold, with widespread overnight frost and ice. Thereafter, there is greater than average uncertainty, but central and western areas are likely to be mainly fine and dry although some rain and milder conditions may temporarily spread into the far west. Elsewhere, snow showers are expected and these spread further west at times. Generally cold with widespread frost, icy patches and freezing fog in places.

Updated: 1137 on Thu 10 Jan 2013

http://www.metoffice...st_weather.html

Seems the UKMO going with their model and not the ECM or the GFS although with the usual caveats about the uncertinty (who wouldn't)

[IanM]

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[Troubleatmill]

I think we are all in the dark here and we just have to wait for the models to sort it out.

All I know is that GFS are now even downgrading the snow event for most this weekend. Lucky there is only 36 hours to go otherwise we may see the Atlantic by Saturday.

Of course GFS could be wrong but hopefully eureka will be the 12z's tonight, either way.

Although the GFS looks right to me we have to respect the "pros" on this site who suggest a closer solution to ECM. Least we should know which model(s) to favour next time as one or more will be shamed in the next 24 hours.

Actually couldnt agree more, going crossed eyed ATM trying to look at different outcomes and we are none the wiser than a few days ago, the models will get a grip of things...they have to at some point because its nearly upon us. It does look ominous with the GEFS ensembles, but we do look too much at these as the GFS gives us all info for free, think even the most optimistic people are feeling a little heavy hearted with current outputs from the GFS, but ECM still playing ball, rather it be that way round than the other...perhaps

[SP1986]

The Met office forecast suggests to me, that they expect high pressure to ridge over, but not quite bringing the SWly flow that the GFS shows, this would be literally middle of the road. It would naturally be a little milder further west in this situation, with potential for an onshore light easterly drift further east. By no means suggesting a full on easterly blast though, and after the initial very cold air, the description of icy patches suggests it will never get too cold.

That said I suspect it is akin to tossing a coin at the moment.. not that I'm suggesting the Met-office have simply tossed a coin, they will obviously have put a lot of time and effort into this, but I suspect even within that forecast there is uncertainty.

[Timmytour]

Are the models useless? Depends what you want them for. if you expect them to deliver certainty, even in a short timeframe, then ask yourself if you'd be happy in such a boring predictable life!

Use them as guides for the potential as seen from different perspectives and you'lll have nothing to get frustrated about in what they are, maybe only what they show.

For my part, I looked at a GFS run back on 30Dec and posted up on facebook that the first weekend of the New Year would be mild and springlike if the sun came out, while the following weekend would be a very different kettle of fish!

I wasn't taking the GFS as gospel, especially out in FI, but I'm looking pretty guru-like with that prediction now!!

That's why I love the GFS.... it's why I'm disappointed in what it shows but not disappointed in what it is

Edited January 10, 2013 by Timmytour

[bradymk]

The Met office forecast suggests to me, that they expect high pressure to ridge over, but not quite bringing the SWly flow that the GFS shows, this would be literally middle of the road. It would naturally be a little milder further west in this situation, with potential for an onshore light easterly drift further east. By no means suggesting a full on easterly blast though, and after the initial very cold air, the description of icy patches suggests it will never get too cold.

That said I suspect it is akin to tossing a coin at the moment.. not that I'm suggesting the Met-office have simply tossed a coin, they will obviously have put a lot of time and effort into this, but I suspect even within that forecast there is uncertainty.

Sort of disagree, they mention the risk of "significant accumulations", "cold, locally very cold". Then "snow showers are expected and these spread westwards". To me like you say an uncertain outlook definitely but a stronger easterly flow than you describe especially if showers are moving inland. Still a good outlook (not so much for me) but considering the uncertainty, they still seem more confident of colder outcome.

[kold weather]

Hard to have faith in any model at the moment really.

I've just had a good look through the GFS ensembles for THIS weekened and there is huge uncertainty about the track of the front. Everything from it totally missing us to alot of rain faling right up to the N.Midlands...

Anything beyond that is going to highly uncertain.

[Uncle_Barty]

You have to bare in mind that a) its only one model that is not providing what you are looking for, and all models are just predictions - reality can be very different! We see this time and time again in winter in the UK, moral of the story is don't get your hopes up until ALL models are in agreement within 24 hours of an 'event'.

Many have spoken about the record levels of uncertainty within the models at the moment and so there is really no excuse for any of the surprise or melodrama currently on show in this thread.

OK, next week......

What would concern me (if I were a coldie) is that One, there is not cross-model agreement at D5+, and Two, that the fly in the ointment is the GFS. Being an American model and therefore probably more focussed on what happens Stateside, and what happens there is likely to affect us downstream. Three, the 'default'/most common setup is Atlantic and zonal.

For those reasons, i think that the most likely outcome is that the rest of the models will fall into line with GFS in time and that the GFS is most likely to verify at the moment. I know that there are those will say "..but the Strat events go against what GFS are showing...." but that is for beyond the end of next week.

I'm not saying it's "game over" after Tues, I could be proved completely wrong, of course. but gut feeling (for the reasons I've explained above) tells me we are likely to have a repeat of the December shenanigans, but without the rampant zonality that followed for the rest of that month.

Whatever, we live in interesting times.

[Captain Shortwave]

OK, next week......

What would concern me (if I were a coldie) is that One, there is not cross-model agreement at D5+, and Two, that the fly in the ointment is the GFS. Being an American model and therefore probably more focussed on what happens Stateside, and what happens there is likely to affect us downstream. Three, the 'default'/most common setup is Atlantic and zonal.

Nick Sussex posted the NAM model prediction, it seems to show that the American high res disagrees with GFS, of course that might be wrong and GFS might have made a stonker of a decision, but whose to say. I think the 12z will make things a little clearer (hopefully)

[Snowfan50]

OK, next week......

What would concern me (if I were a coldie) is that One, there is not cross-model agreement at D5+, and Two, that the fly in the ointment is the GFS. Being an American model and therefore probably more focussed on what happens Stateside, and what happens there is likely to affect us downstream. Three, the 'default'/most common setup is Atlantic and zonal.

For those reasons, i think that the most likely outcome is that the rest of the models will fall into line with GFS in time and that the GFS is most likely to verify at the moment. I know that there are those will say "..but the Strat events go against what GFS are showing...." but that is for beyond the end of next week.

I'm not saying it's "game over" after Tues, I could be proved completely wrong, of course. but gut feeling (for the reasons I've explained above) tells me we are likely to have a repeat of the December shenanigans, but without the rampant zonality that followed for the rest of that month.

Whatever, we live in interesting times.

Im wondering that with greenland being effected with weather coming east out of USA it might model the weather better around greenland than the ECM and UKMO.

[rory o gorman]

Agree totally uncle barty , the gfs has been so bullish in its last 4/5 runs ,That its hard to look past what appears to be a fast break down.long term zonal if SST is to be accounted for is unlightly though and typical of low res F.I