Model output discussion 25th Jan onwards

[Biggin]

Best snow chances from the GEFS this morning for London: 

 

 

Best chance but little precip IDO ??

[nick sussex]

Quite surprised to see the ECM dropping its trend from last night, the UKMO now jumps to another solution! Very difficult to have much confidence in any of the outputs past T120hrs.

 

The ECM postage stamps have many different solutions on offer at T120hrs in terms of whether those would go onto show a more slider scenario:

 

http://www.ecmwf.int/samples/d/inspect/teasers/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!120!pop!od!enfo!enplot!2014010912!!/

[The PIT]

Pretty well broad agreement for a return to zonal stormy conditions in deep FI. In the reliable time a cold spell be it brief to go through. May even bring bring the first snow of the winter too us overnight. After that cold and wet until mid week when we get the dew points back.

Edited January 26, 2014 by The PIT

[shedhead]

You forgot to show UKMO and GEM?

UKMO does not go out that far, as for the GEM, if you have a point to make please post some charts to support your views. Tks.

[IDO]

Best snow chances from the GEFS this morning for London: 

 

 

Best chance but little precip IDO ??

 

 

I know its sad, even light showers is better than the winter down in the SE. The mean precipitation for around then:

 

 

About 10-18 hours potential for some light wintry stuff. Things could change, for the better (or worse). eg the op is a lot less keen.

[TEITS]

Ha Ha so the UKMO changes its mind from last nights awful 12Z and goes back to having the block further W than the ECM/GFS. Before anyone says the ECM/GFS is more likely to be correct then lets cast our minds back a bit.

 

At +72 all models agree with the LP sinking S. However it was the UKMO that modelled this consistently, whilst I recall the ECM & GFS especially flapped around with this. I should add the JMA was also consistent with this.

 

Trying to base a forecast on the output is a nightmare to be honest. Now like I said yesterday I wasn't convinced of a classic type E,ly i.e cold uppers, snow showers because the block would not be far enough W. However I certainly don't buy the W-E movement of LPs and SW,ly winds like the ECM is showing. I still feel the likely outlook is the block will prove more resistant and LPs will be sliders which will increase the risk of snowfall and keep the UK on the cold side.

 

The GEM is my favourite this morning as we see a slider followed by the block advancing W!

 

http://modeles.meteociel.fr/modeles/gem/runs/2014012600/gem-0-240.png?00

 

.

[shaky]

Quite surprised to see the ECM dropping its trend from last night, the UKMO now jumps to another solution! Very difficult to have much confidence in any of the outputs past T120hrs. The ECM postage stamps have many different solutions on offer at T120hrs in terms of whether those would go onto show a more slider scenario: http://www.ecmwf.int/samples/d/inspect/teasers/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!120!pop!od!enfo!enplot!2014010912!!/

and there are quite a few which look more favourable and colder than the op!!!might see an upgrade later I think!!

[karlos1983]

The GEM is EPIC!!

 

 

disagreement at +6 if you look at the 3 models and the center of the low

[Johnp]

UKMO does not go out that far, as for the GEM, if you have a point to make please post some charts to support your views. Tks.

I think you'll find this chart does existhttp://www.wetterzentrale.de/pics/Rukm1441.gif.My point is quite obvious, I disagree with your post about the Atlantic rolling in and am stating that if you look at all the model output instead of cherry picking charts you will see it isn't so cut and dried.

[Severe Siberian icy blast]

Pretty well broad agreement for a return to zonal stormy conditions in deep FI. In the reliable time a cold spell be it brief to go through. May even bring bring the first snow of the winter too us overnight. After that cold and wet until mid week when we get the dew points back.

Not really, the gfs and ECM yes , but how reliable is anything past t144? Not worth the time to even look at to be honest at the minute. Not sure why but the ECM is wild recently with its inconsistency , which is not like the ECM , but I do feel we are about to see yet another flip in the models to a much more blocked pattern, with the scandi high much more prominent , this week there will snow about . Also there is good wave 1/2 activity in the next week and that will be the final blow to the vortex I think.

[Gibby]

Good morning. Here is this morning's report on the midnight outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Sunday January 25th 2014 taken from my website at http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm

 

All models show a deepening depression moving towards NW Scotland with fronts crossing quickly East across the UK with yet another spell of heavy rain and strong winds. This moves away quickly East followed by clearer and showery weather. Temperatures will fall too with showers turning wintry with snow in places, even on low ground in Southern areas with hail and thunder also possible. This showery theme will continue through tomorrow and Tuesday as the Low pressure area responsible moves only slowly South across Britain reaching Southern areas by Wednesday. As it moves to the South winds swing Easterly and enhance the chill with further wintry showers and as winds become lighter after midweek the greater incidence of night frosts look likely.

 

GFS then shows a new Low approaching from the West with a front moving slowly East over Britain with rain preceded by snow moving West to East over the UK towards next weekend clearing away East by Sunday with slightly milder air especially in the West. The second half of the run then shows a very inclement and wet period as further deep Low pressure areas continue to run into the UK from the Atlantic with rain and strong winds at times and temperatures returning close to normal offset by the wind.

 

The GFS Ensembles show good support for the somewhat colder period this week slowly giving way to more average temperature levels with rain at times through the amounts of rain stated by the operational run later is not as well supported.

 

UKMO closes it's run at the start of next weekend with a strong High pressure block to the East with a front moving into Western areas later on Saturday threatening rain and snow in what will be a cold and breezy day next Saturday with a strengthening SE wind.

 

GEM also shows this block holding firm and indeed intensifying over Scandinavia by the close of the run. Through next weekend fronts will push against the block giving a strong threat of significant snow in places before things dry up but become very cold in a strengthening Easterly flow by the end of the run.

 

NAVGEM too shows an active trough moving very slowly East across Western Britain with a band of significant snow edging slowly East while shearing SE into Europe later as the cold block to the NE holds firm.

 

ECM's operational run pushes the cold block further East with the net result being an easy win for Atlantic Low pressure next weekend bringing rain West to East over all areas, preceded by a short spell of snow in places and followed by less cold and changeable weather with rain at times, this becoming more pronounced towards the North and West as pressure rises to the South.

 

The ECM 9 and 10 Day Mean Charts show the chances of the Scandinavian High holding as relatively weak as the Low pressure to the NW shows a bias of allowing SW or South winds more likely to be across the UK with no doubt rain at times with a pressure rise over Southern Europe responsible for this with the most rain across Western areas.

 

The Jet Stream based on the GFS model Ensemble group show a preference to a strong flow across the Atlantic either crossing the UK on it's route to Southern Europe or being to the South of the UK at times.

 

In Summary the very interesting synoptics persist as Low pressure areas continue to run up against a cold block across NE Europe. We have GFS and ECM on the one side of the fence today pushing the block away with ease later this week and maintaining largely unsettled and sometimes wet weather across the UK in temperatures returning to more average levels after the cold week this week. On the other hand we have UKMO, GEM and NAVGEM show a much more bullish attitude to the block next weekend resulting in the very real chance of a significant snowfall somewhere across Britain dependent on the resting position of the push of Atlantic air from the West. What complicates matters today is that both the GFS and ECM ensembles support their operational runs to some degree of certainty which sets the other groups from which we have no such ensemble data to hand, more standalone in nature but despite this I feel that GFS and ECM push the block away too easily later this week and my thoughts lean more towards a UKMO, GEM or NAVGEM type solutions but of course I could be wrong..so more runs needed.

[shedhead]

I think you'll find this chart does exist

http://www.wetterzentrale.de/pics/Rukm1441.gif.

My point is quite obvious, I disagree with your post about the Atlantic rolling in and am stating that if you look at all the model output instead of cherry picking charts you will see it isn't so cut and dried.

Perhaps if you read my post properly you will understand the point I made...

 

This has been the consistent evolution for several days now; whether it actually happens or not remains to be seen, but that is what the charts suggest and charts are what we're supposed to be discussing.

 

Re UKMO, that is a 144hr chart, but for the record it also shows the Scandi block moving towards becoming a Kazak block, though it is a little better placed to hold up the Atlantic... 

 

 

GEM is a model that is only really taken seriously when it shows to coldest evolution...as per now.

Edited January 26, 2014 by shedhead

[Man With Beard]

Ah the folly of being swung by every run ... UKMO returns with a run that both maked sense of its recent output and indeed the shifting trends in all output - a slightly stronger east block resulting in a slightly more prolonged easterly from T72 to T120, followed by a battle of rain preceded by snow from the west at T144, the Atlantic possibly getting through for the moment but still cold evenso. Seems a fair forecast based on what we have - Azores high now too strong to allow a clean slider I would think.

[weather eater]

Quite surprised to see the ECM dropping its trend from last night, the UKMO now jumps to another solution! Very difficult to have much confidence in any of the outputs past T120hrs.

 

 

My thoughts exactly, post 120hrs we have a mish-mash of solutions which should suggest to all on the forum little confidence in any of them is advisable. Its real wait and see job, a bit of a heavy weight contest, the scandi block as Ali on the ropes, playing dope-a-rope and the PV as Foreman, big strong and powerful, wanting to batter its way in, could go either way at this stage. ding ding next round starts just before ten.

[cooling climate]

Very disappointed with the ECM this morning not for what it is showing but

for its complete lack of consistency.You just can not trust its output

anymore.I did wonder yesterday that if the GFS and ECM had overdone the

distruption to the west of the UK the cold scenario would implode and I just

don't by it. I think the mid term to extended range the pattern should be

amplifing to the north which is the opposite to what these two models are

showing.

As for the UKMO I did say yesterday that it was just one run and sure enough

it has reverted back to something more inline (although not as cold) as what

it was showing in previous runs.

[Johnp]

Perhaps if you read my post properly you will understand the point I made...

 

This has been the consistent evolution for several days now; whether it actually happens or not remains to be seen, but that is what the charts suggest and charts are what we're supposed to be discussing.

 

Re UKMO, that is a 144hr chart, but for the record it also shows the Scandi block moving towards becoming a Kazak block, though it is a little better placed to hold up the Atlantic... 

 

 

GEM is a model that is only really taken seriously when it shows to coldest evolution...as per now.

I know that is a 144hr chart. So were the two charts you posted?

[EML Network]

As ha already been pointed out the way things currently stand there looks to be a range of options on the table post + 96 , but there a very few options that paint a picture that includes an extension of an Easterly feed. 

 

Here IS our Easterly. 

 

 

GFS really is not interested in dropping the 2nd low some time around Friday, instead it wants it to take the same route every other Low pressure this Winter has taken and knock our block out of the way....

 

this chart is + 138 so isn't inside the reliable zone, but here's the end of the block from the GFS perspective. 

 

 

 

ECM at + 144 looks very similar

 

You can see both models want to bring in a North Westerly feed afterward with some cold air entrenched and then both models are now in agreement about flattening everything out and back to stormy conditions. 

 

It's been the trend to flatten the pattern out and put us right back where we started in December for the past 4 or 5 days now. 

 

Not welcome news for those who are looking for an end to the wet weather IMO.

 

IF THIS COMES TO PASS, then I really can't see where another shot at cold would come from.

 

Due to the ECM evolution over the past few days IMO the 2nd nail in the coffin has been firmly nailed down for Winter 2013 / 2014. 

 

let's enjoy what next week brings and hope things change over the next few days / runs. 

 

But when both the ECM and GFS fall very much in line with the Met Office's outlook for Feb, you have to admit it's not looking good after this week. 

Edited January 26, 2014 by EML Network

[phil nw.]

The switching of modeling emphasis between the block and the Atlantic continues for the period after the low moves to our south around T96hrs..

ECM and GFS want to move it away but the UKMO holding firm as the next system comes in for Friday hitting the cold air.

I think this could still result in a snow event for quite a few if the UKMO is correct,especially for areas away from the sw.

T144hrs on that model shows every sign of rebuild of heights to our north as the approaching trough hits the brick wall.

 

http://www.meteociel.fr/ukmo/runs/2014012600/UN144-21.GIF?26-06

 

of course until we get nearer and agreement beyond T96hrs amongst the other models this is only one option.

What raises my expectations on a more UKMO type of setup though is looking at the GFS?ECM means for T144hrs

http://www.wetterzentrale.de/pics/Rz500m6.gif

http://www.wetterzentrale.de/pics/Reem1441.gif

 

We can see the trough inclining se and held back further west compared to the op runs.This would draw the surface flow off the continent with consequently lower dew points.

Thurs/Friday looks like the days to watch to see if the block has more life in it.If it holds then i can see the pattern really changing for a colder spell.

[Captain Shortwave]

Going to echo the thoughts of many on the ECM, well I just want to slap it senseless. After around 10 days of that high being in situ to our north east, I don't buy the ECM/GFS evolution of it simply sinking away in 24 hours allowing a south westerly flow back into the UK for the foreseeable.

That leaves the other models which frankly want to not only keep the high but phase it with further pulses of heights being delivered from across the pole with the GEM developing a Scandi high on steroids

Game over for the Atlantic here with further pulses incoming to feed the high and a wall of cold marches westwards.

 

Probably the correct solution is probably in between with the battlefront draw somewhere across the UK, but more runs needed.

[shedhead]

I know that is a 144hr chart. So were the two charts you posted?

No, they were the T+192hrs from GFS and ECM, which despite the overall confusion in the short/medium term looked very much alike.

 

So as Gibby summerised there is something of a split in the longer term evolutions between GFS/ECM on one side and GEM/NAVGEM on the other, with UKMO probably floating somewhere in the middle. Again as I said there is nothing to suggest the former will be correct, but they have shown a fairly consistent trend towards the Scandi block slipping SE, so for now if I had to put money on it I'd back them over GEM/NAVGEM. However, and this is the main point (reiterated several times yesterday) this DOES NOT MEAN MILD WEATHER, so any talk of the Atlantic coming back in should not automatically be viewed in this way.

[It Might Snow]

No, they were the T+192hrs from GFS and ECM, which despite the overall confusion in the short/medium term looked very much alike.

 

So as Gibby summerised there is something of a split in the longer term evolutions between GFS/ECM on one side and GEM/NAVGEM on the other, with UKMO probably floating somewhere in the middle. Again as I said there is nothing to suggest the former will be correct, but they have shown a fairly consistent trend towards the Scandi block slipping SE, so for now if I had to put money on it I'd back them over GEM/NAVGEM. However, and this is the main point (reiterated several times yesterday) this DOES NOT MEAN MILD WEATHER, so any talk of the Atlantic coming back in should not automatically be viewed in this way.

 Not wanting to prolong this but he does have a point Shedhead, your original post shows the same 1st Feb chart for the GFS and ECM as the Meto and GEM chart that he is using as an alternative to your own view. They are not T+ 192 charts that you posted.

Edited January 26, 2014 by Gmax

[chionomaniac]

It's pretty rare for a definative forecast to be given 4-5 days hence in any set up, but the overriding signal this morning is for the Atlantic to start pushing through again later this week, as the Scandi block becomes the Kazak block.

 

This has been the consistent evolution for several days now; whether it actually happens or not remains to be seen, but that is what the charts suggest and charts are what we're supposed to be discussing.

 

 

In trying to offer balance to this thread, Shed, I feel that you go too far the other way and present a bias of the opposite to the predominant cold bias that most members here show. What it would be nice for you to present is a truly balanced post, more along the lines of there is great uncertainty regarding how far the Atlantic will push through against the Scandi block following mid week. There are a number of solutions on offer from all the different models which have chopped and changed against themselves from run to run.

 

Perhaps even put up the ensemble anomalies, rather than one or two cherry picked operationals (even these show stalling lows) - here is one from the ECM for T+240 - this suggests that any Atlantic inroads stall or slide SE as they come up against the block:

 

 

The NAEFS suite for the same time stretches the Atlantic trough over the UK but again suggests that any Atlantic attack will not travel further east than the UK and there are suggestions again that this will slide SW.

 

 

Balance in thread is great, but when those offering it justify it by offering a bias in the opposite direction it can be very frustrating. At least those searching for cold are quite overt with the bias!

 

Oh and just to differentiate, here is a chart from 2 years ago showing the Atlantic 'pushing through'

 

[shedhead]

The switching of modeling emphasis between the block and the Atlantic continues for the period after the low moves to our south around T96hrs..

ECM and GFS want to move it away but the UKMO holding firm as the next system comes in for Friday hitting the cold air.

I think this could still result in a snow event for quite a few if the UKMO is correct,especially for areas away from the sw.

T144hrs on that model shows every sign of rebuild of heights to our north as the approaching trough hits the brick wall.

 

http://www.meteociel.fr/ukmo/runs/2014012600/UN144-21.GIF?26-06

 

of course until we get nearer and agreement beyond T96hrs amongst the other models this is only one option.

What raises my expectations on a more UKMO type of setup though is looking at the GFS?ECM means for T144hrs

http://www.wetterzentrale.de/pics/Rz500m6.gif

http://www.wetterzentrale.de/pics/Reem1441.gif

 

We can see the trough inclining se and held back further west compared to the op runs.This would draw the surface flow off the continent with consequently lower dew points.

Thurs/Friday looks like the days to watch to see if the block has more life in it.If it holds then i can see the pattern really changing for a colder spell.

In the short term Phil we may well get some clues from the fronts expected to cross Germany in the next 24-36hrs.  On the face of it their progress eastwards seems fairly easy, despite temps of -10 to -15c now being in place, so whilst not exactly in our neck of the woods we may well learn some interesting lessons regarding the models/block durability.

[shedhead]

In trying to offer balance to this thread, Shed, I feel that you go too far the other way and present a bias of the opposite to the predominant cold bias that most members here show. What it would be nice for you to present is a truly balanced post, more along the lines of there is great uncertainty regarding how far the Atlantic will push through against the Scandi block following mid week. There are a number of solutions on offer from all the different models which have chopped and changed against themselves from run to run.

 

Perhaps even put up the ensemble anomalies, rather than one or two cherry picked operationals (even these show stalling lows) - here is one from the ECM for T+240 - this suggests that any Atlantic inroads stall or slide SE as they come up against the block:

 

get_orig_img-2.gif

 

The NAEFS suite for the same time stretches the Atlantic trough over the UK but again suggests that any Atlantic attack will not travel further east than the UK and there are suggestions again that this will slide SW.

 

get_orig_img-3.gif

 

Balance in thread is great, but when those offering it justify it by offering a bias in the opposite direction it can be very frustrating. At least those searching for cold are quite overt with the bias!

 

Oh and just to differentiate, here is a chart from 2 years ago showing the Atlantic 'pushing through'

 

Rrea00120111208.gif

That how I see things this morning Chiono..sorry about that.  If you looks back across the past 24-48hrs of posts from me I was seeing it rather differently, so if 'balance' is what you truely seek, look back and understand the balance is there.

[SLEETY]

The GEM is EPIC!!

 

 

disagreement at +6 if you look at the 3 models and the center of the low

the whole run is immense.please just once can a model run verify as shown.

 

the siberian express approaching at the end as well