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Model output discussion - heading into 2018


Paul
Message added by Paul

Please only post model discussion in here. 
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Posted
  • Location: Peterborough N.Cambridgeshire
  • Location: Peterborough N.Cambridgeshire
8 minutes ago, bluearmy said:

The eps clusters back up my musings - anyone predicting what the second half of week 2 and into week 3 will deliver is tossing a coin. There are some that are contracted to do so - good luck! 

Most accurate post of the morning.

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Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth
1 minute ago, TEITS said:

Sorry but I cannot let this one go.

If we read back to around Xmas we will see explainations from GP and others why an E,ly was now unlikely towards Xmas & New year. You will also note rather dire predictions for January of a mild, zonal spell. Should the current model output be proved correct then in my opinion it is wrong to say the predictions from GP & others weeks back are now correct.

The same was said to me many years ago when I was always predicting E,lys. The same rule applies!

I must have missed that update from GP - but yes I have seen some of the others who've thrown in the towel over an easterly, fair enough!!

Anyway - this morning is the first time the models have looked even slightly confident in the NE heights rise, and really we need a few more runs like this before we can start building a forecast :)

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Posted
  • Location: Banbury
  • Location: Banbury
33 minutes ago, blizzard81 said:

I agree based on the current modelling and forecasts. Looks like this winter could be a case of plenty of cold spells but rather short lived affairs. Nothing disruptive over a long time period. 

Totally agree ,the only thing I would say the snow we had on Dec10th gave MBY 20cm and forced work to close on the Monday .

I think we could see more like this anywhere in the BI in the coming weeks 

Edited by Banbury
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Posted
  • Location: Camborne
  • Location: Camborne
1 minute ago, Man With Beard said:

I must have missed that update from GP - but yes I have seen some of the others who've thrown in the towel over an easterly, fair enough!!

Anyway - this morning is the first time the models have looked even slightly confident in the NE heights rise, and really we need a few more runs like this before we can start building a forecast :)

But height rises to the north east are a long way from a surface high cell plonked over Scandinavia. If care is not taken this will take on the same mythical properties of the now famed 'Greenie High'. :shok:

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Posted
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.
  • Weather Preferences: Winter synoptics.Hot summers.
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.
11 minutes ago, TEITS said:

Most accurate post of the morning.

It cannot be accurate at that range:crazy::D

Edited by winterof79
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Posted
  • Location: Lincolnshire - 15m asl
  • Weather Preferences: Frost and snow. A quiet autumn day is also good.
  • Location: Lincolnshire - 15m asl
7 minutes ago, knocker said:

But height rises to the north east are a long way from a surface high cell plonked over Scandinavia. If care is not taken this will take on the same mythical properties of the now famed 'Greenie High'. :shok:

Strongly agree. Expectations need to be kept in check...

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Posted
  • Location: Tyrone
  • Location: Tyrone

Lets be frank about it not one person foreseen what is happening with models as we head into first half of Jan quite a few experts wrote it off altogether and that ain't there fault as mother nature makes a fool of us all from time to time, but one thing that has been the trend setter this winter that is the jet running south and when that happens there is always a chance of white stuff.:spiteful:

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Posted
  • Location: st albans
  • Location: st albans

Re scandi high - the eps do show up to 40% support of a surface high up there in the extended period and we can see that there is a small upper ridge on the means and not surprisingly more notable on the clusters. Point is that at the moment, it seems to be fairly transient in nature if it does pop up. but we also know from experience that the nwp generally fails to model a scandi ridge very well - mind you, the upgraded models have had precious little experience ! 

All leads back to the uncertainty 

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Posted
  • Location: Wyke regis overlooking Chesil beach.
  • Weather Preferences: Snowfall
  • Location: Wyke regis overlooking Chesil beach.
Just now, knocker said:

But height rises to the north east are a long way from a surface high cell plonked over Scandinavia. If care is not taken this will take on the same mythical properties of the now famed 'Greenie High'. :shok:

Very true Knocker. Genuine Greenie And Scandie highs are rare creatures indeed. Fortunately for the cold and snow lovers amongst us we know that we don't always need a stonking scandi high for snow chances sometimes just a wedge of hieghts in the right place will suffice.

Edited by Broadmayne blizzard
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Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth
31 minutes ago, knocker said:

But height rises to the north east are a long way from a surface high cell plonked over Scandinavia. If care is not taken this will take on the same mythical properties of the now famed 'Greenie High'. :shok:

I appreciate that is technically true but on this occasion, when looking at the individual ensemble members at T240, there are a lot of high pressure areas to the NE in various positions/shapes/sizes (not all centred over Scandi tbf) - many linked to heights through the Atlantic - perhaps 50% causing an influence on the UK that is eastern rather than western at that time

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Posted
  • Location: Hertfordshire
  • Location: Hertfordshire
1 hour ago, TEITS said:

Classic example of what I mean.

GFSOPEU06_312_1.png

Based on some of the comments over recent days with regards to the  Strat the GFS should not be showing these charts!

Also look at the difference between the 06 & 0Z. If a supercomputer can churn out such a massive difference then what hope do us humans have in making an accurate LRF!

GFSOPNH00_336_1.pngGFSOPNH06_336_1.png

I wrote a post yesterday hoping to show that there is still residual downwelling from wave breaking, warming at the 10mb level around 9th of December. This can be traced using the ESRL mean and anomaly composite charts. I think some have perhaps forgotten that there is normally a lag time with these warmings as they propagate down through the layers.

I to very much doubt we will see a Scandi high at least not in the time frame that the 0z gfs was showing. In fact the 06z run proves how uncertain the models are with regard to modelling this downwelling with a completely different pattern to its previous run. There will I think be some amplification in the pattern ahead but how much and exactly where it will manifest itself is still very much up for grabs.

Edited by comet
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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.
3 minutes ago, TEITS said:

Nothing to do with one upmanship. I just disagree with how Teleconnections are used on here.

Personally I feel Teleconnections are useful for seasonal forecasting. They are useless when I see posts trying to predict an E,ly for the UK via a Scandi HP. You simply cannot put that amount of detail for such a tiny Island like the UK. The same rule applies if you're trying to predict a N,ly or SW,ly.

Let me put it another way. Why is it at +384 the GFS runs can vary so wildly? The simple answer is despite these supercomputers working out a massive amount of equations, the runs end up different due to slight changes much earlier which only increase as the run progresses. The chaos theory will always be troublesome for long range forecasting. So if a supercomputer struggles with these slight changes then how on earth can teleconnections compensate for the chaos theory. The simple answer it can't!

So sorry but I would rather use seaweed than rely on teleconnections for the next few weeks. if someone made a post in the Autumn about the possible trends for the winter then I would take more note. So nothing to do with one upmanship. I am more interested in accuracy than who can make the most technical post by using as many abbreviations as possible!

Finally didn't you say in a recent post that "winter might be over"?

FWIW TEITS, I think that teleconnections only predispose the NH to take up certain, overall  patterns; they don't (and never have) comprise a forecast, as such...they merely imply that the overall NH pattern will be statistically more (of less) likely to conform to any particular said pattern - than would (all other factors being equal) otherwise be the case...?

But - all other factors are never equal? :cc_confused::D

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Posted
  • Location: Camborne
  • Location: Camborne
16 minutes ago, Man With Beard said:

I appreciate that is technically true but on this occasion, when looking at the individual ensemble members at T240, there are a lot of high pressure areas to the NE in various positions/shapes/sizes (not all centred over Scandi tbf) - many linked to heights through the Atlantic - perhaps 50% causing an influence on the UK that is eastern rather than western at that time

Well I'm no great fan of taking a single day, in fact I'm not a fan at all,  but taking the surface analysis for the det run at T240 with some ridging in mid Atlantic towards Iceland and the clusters for the same time I still do not see any justification in suggesting relevant  high pressure over Scandinavia,

ecm_mslp_uv850_natl_11.thumb.png.0b5636e1de2e551b3cd53baf98b96ab0.pngclusters.thumb.png.6ae3bd447b26f426d30e28d809b6ddc0.png

 

Edited by knocker
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Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl

Models continue to show a very unsettled outlook, but with hints of some weak amplification in the predominant atlantic westerly flow, and the jetstream taking a more southerly path, which would help aid frontal and trough feature on a more NW-SE path at times than SE-NE path, possible runners, secondary low developments, stalling features etc, which will make forecasting quite difficult.

I don't foresee any significant height rises to the NE, but yes a possibility we may see a wedge of heights to our north and north east, later next week, which would allow a possible snow event again, a battleground scenario, with the north locked in cold air, a bit like we have now.

An interesting outlook, with a bias more to cold zonality than mild.

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Posted
  • Location: Hernia Bay
  • Weather Preferences: Heavy Snow
  • Location: Hernia Bay
6 minutes ago, damianslaw said:

Models continue to show a very unsettled outlook, but with hints of some weak amplification in the predominant atlantic westerly flow, and the jetstream taking a more southerly path, which would help aid frontal and trough feature on a more NW-SE path at times than SE-NE path, possible runners, secondary low developments, stalling features etc, which will make forecasting quite difficult.

I don't foresee any significant height rises to the NE, but yes a possibility we may see a wedge of heights to our north and north east, later next week, which would allow a possible snow event again, a battleground scenario, with the north locked in cold air, a bit like we have now.

An interesting outlook, with a bias more to cold zonality than mild.

Nicely balanced and my take on the models in a nutshell. At least periods of interest 

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Posted
  • Location: Rotherhithe, 5.8M ASL
  • Location: Rotherhithe, 5.8M ASL
41 minutes ago, karyo said:

This is indeed the saving grace of this winter so far and may be the result of low solar activity. Hopefully a sign of winters to come as we head towards minimum.

Easterly QBO probably the reason why it’s been missing in recent winters...

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Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts
1 hour ago, Paul_1978 said:

Surprised at the downbeat post Nick. Yes it's not as mouthwatering as the previous run, but taking the general theme overall without the inter-run dissection, then overall things are looking pretty good IMO. 

This chart is at T+180 for example. I'm not suggesting it's snow laden, but this time last year we'd have been jumping up and down with excitement seeing a chart like this at that time range. 

GFSOPEU06_180_1.png

I think the reason for Nick's apprehension is that this time last year on too many occasions we WERE jumping up and down looking at charts even better than that at T180+

And we remember how it turned out

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The models continue to show an exciting prospect.

The meridional / cold zonal will have ongoing snow potential over the next week. What will particularly wet the appetites of cold lovers, however, are the repeatedly clear hints of something much more exciting evolving in 10 days time. We're seeing this now across models and within runs and ensembles. Whereas the 0z operational had little support in FI, this is not true of the 6z which shows some exceedingly cold members.

I continue to be very encouraged. Yes yes yes ... it's FI. But I like the way this is evolving. It looks to me to be plausible. It fits the patterns seen so far this winter and there is good support within and outwith models. Keep hoping oh ye cold lovers.

5a4639d34270c_ScreenShot2017-12-29at12_45_31.thumb.png.679ac39d0e855371648701f0c16fef8a.png

5a4639ddae618_ScreenShot2017-12-29at12_45_47.thumb.png.e0443836b2b0b43c3759a8f58befcbaa.png

5a4639e7dbff7_ScreenShot2017-12-29at12_46_13.thumb.png.c558d919a5d1f2a5e4e0e4bb240f4747.png

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6 minutes ago, Timmytour said:

I think the reason for Nick's apprehension is that this time last year on too many occasions we WERE jumping up and down looking at charts even better than that at T180+

And we remember how it turned out

We didn't start the winter like this, though. I've seen two big snow events this side of New Year and I can't remember that happening for many many years. I'm not naive enough to think one colder month makes the other two cold, and there have been some infamous examples of that, but I do tend to think colder winters show their hand and start as they mean to go on.

A touch anthropomorphic but not without meteorological backing. The signs looks good to me.

Edited by West is Best
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Posted
  • Location: winscombe north somerset
  • Weather Preferences: action weather
  • Location: winscombe north somerset

npsh500_192.thumb.png.5513ef5df0d38cf299d0d638750c5daf.pngnpsh500_192.thumb.png.5513ef5df0d38cf299d0d638750c5daf.png

Edited by legritter
my post is further down the page .
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Posted
  • Location: Hertfordshire
  • Location: Hertfordshire
32 minutes ago, TEITS said:

Nothing to do with one upmanship. I just disagree with how Teleconnections are used on here.

Personally I feel Teleconnections are useful for seasonal forecasting. They are useless when I see posts trying to predict an E,ly for the UK via a Scandi HP. You simply cannot put that amount of detail for such a tiny Island like the UK. The same rule applies if you're trying to predict a N,ly or SW,ly.

Let me put it another way. Why is it at +384 the GFS runs can vary so wildly? The simple answer is despite these supercomputers working out a massive amount of equations, the runs end up different due to slight changes much earlier which only increase as the run progresses. The chaos theory will always be troublesome for long range forecasting. So if a supercomputer struggles with these slight changes then how on earth can teleconnections compensate for the chaos theory. The simple answer it can't!

So sorry but I would rather use seaweed than rely on teleconnections for the next few weeks. if someone made a post in the Autumn about the possible trends for the winter then I would take more note. So nothing to do with one upmanship. I am more interested in accuracy than who can make the most technical post by using as many abbreviations as possible!

Finally didn't you say in a recent post that "winter might be over"?

Good post. A cold forecast was made only to be replaced by a much milder zonal pattern but just like the NWP models, forecasts are changing all the time.  Trying to put to much detail into a long range forecast will probably lead to failure. Rather than trying to pin point where highs and low pressure areas for our little Island will be surely it would be better to give a broader brush idea of what to expect ie colder, milder, wetter, dryer, etc.

Their is amplification to be had in the northern hemisphere weather pattern over the next few weeks which may be conducive for us but as always the models are struggling with the amount and location of such.

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