Model Output Discussion 19th January 2014-18z onwards.

[Mark Neal.]

It looks very much on the cold side to me at 192zhttp://www.meteociel.fr/modeles/ecmwf/runs/2014012312/ECM0-192.GIF?23-0Many with any moderate elevation would see snow.However it is too far out for specifics i suppose.

Yes even the uppers quite widely you could say are sufficient enough to see snow especially with added elevation but possibly down to lower levels - problem is you don't want the models to show mild sectors as the difference between a snow fest and cold rain can change quickly. Ideally you want cold uppers and a continental windflow from the SE which will help with dew points akin to jan 18th 2013. Interesting model watching as we see the block the NE continue to shows its strength and without any pressure rise to the NW anytime soon continued low pressure systems from NW across us. Keep watching as cold builds to the NE in the models and we can perhaps finally tap in as we head into February. Edited January 23, 2014 by Mark N

[bradymk]

the ecm 12z run is cold for much of the uk. large swathes under slow moving low pressure with thicknesses sub 528, uppers -4/-7c and continental feed at times. how anyone can make a prediction of no snow or loads of snow defeats me. fwiw, i would say that if you live in the chilterns, i would be surprised if you couldnt make a snowman come the end of next week.

http://www.yr.no/place/United_Kingdom/England/Birmingham/long.html  Basic forecast for Birmingham using ECM data reinforcing this.

 

I'd love to see the dew points for the ECM T144hrs chart

ECM DP's here nick for 144/150 (Left to right), brrrrrrrrr

Edited January 23, 2014 by bradythemole

[weather eater]

Tsk Tsk.....

You missed out the following...

 

Ian Brown, for comedy value of his mild ramps

OON, for sarcastic put downs (my hero)

Frosty, you post a spanish plume and he'll show you a beast from the east perturbation as he's that dedicated to the cause

I tried

Ian brown where is he, because actually I pay attention to what he says, at least when I think he’s not on a wind up, because he offers an alternative view, and on a forum full of cold weather nuts its sometimes useful

OON, forecasting? But he just does do sarcasm really well, I'm deeply envious

And Frosty has got better and better over the years, maybe needs to rein himself in sometimes, as his enthusiasm for cold knows no bounds, but nothing wrong with that.

[Man With Beard]

the ecm 12z run is cold for much of the uk. large swathes under slow moving low pressure with thicknesses sub 528, uppers -4/-7c and continental feed at times. how anyone can make a prediction of no snow or loads of snow defeats me. fwiw, i would say that if you live in the chilterns, i would be surprised if you couldnt make a snowman come the end of next week.

This is exactly how I read it, and I also think the ECM 12Z from T144 onwards is a very reasonable picture based absolutely every model run so far today.

 

 

It's fair enough to call it zonal and perhaps rain is the general precipitation type to be expected away from Scotland, but that block to the NE & the jet stream directs the lows in a SE direction and that keeps us in touch of a blizzard at any time - and if anywhere did get snowy, there could be a huge amount of snow in those places. I would rate the chances of a good snowfall in the next 10 days as:

 

Scotland: 70%

N Ireland / N England: 55%

Midlands: 45%

South of M4: 30%

 

The main way that T168 onwards could vary is the Azores High ridging in a bit than shown, which would reduce the snow risk. I can't see Eastern blocking pushing much further back than already shown, too much coming out of Canada.

 

Final point; note how the ECM has - again - dropped its mid-Atlantic amplification towards Greenland. Quite predictable.

[Paul_1978]

Sorry to be so ignorant but what does that mean in layman's terms?  Thanks

Basically, any wintry period will be temporary and we're back into westerlies after the brief easterly event. I'm a coldie as much as the next man, but sadly this is the likely outcome :-(

[snowking]

I'd love to see the dew points for the ECM T144hrs chart, that could be some backedge snow away from windward coasts.I think a lot depends on what happens to the east/se as the low slowly sinks away.

 

I've only got access to them in Fahrenheit in increments of 5F i'm afraid, but generally at +144 it's sub 35F (so sub 1c-ish) for all but the far South-West. Most of Scotland is sub 30F, so it would be touch and go I would suggest.

Far more interesting (though merely stated for the purposes of interest as this is 9 days away) is the low sliding South-Eastwards between 192 & 216 - an almost all snow event suggested for the UK from that.

 

SK

[nick sussex]

http://www.yr.no/place/United_Kingdom/England/Birmingham/long.html  Basic forecast for Birmingham using ECM data reinforcing this.

 

ECM DP's here nick for 144/150 (Left to right), brrrrrrrrr

I think a shallower low and orientated more nw/se will be needed to give a better chance of some backedge snow for more people, the ECM overall is a positive run for cold potential and some snow but the low shape at T120hrs leaves a lot to be desired. So that's something we need to see change in future outputs.

 

The T120hrs has a knock on effect in terms of the cold pooling over Germany and central Europe and this impacts the snow potential at T144hrs, the ECM postage stamps I'm sure will have some better options.

Edited January 23, 2014 by nick sussex

[Bristawl Si]

Only just caught up on today's posts.

would i be right in interpreting that the Meto are less bullish than some of the 'Top Guns' on here, for cold and snow next week?

[Cecil Hogmanay Melchett]

ecm = cold zonality

[Frosty.]

 

I tried

 

Ian brown where is he, because actually I pay attention to what he says, at least when I think he’s not on a wind up, because he offers an alternative view, and on a forum full of cold weather nuts its sometimes useful

 

OON, forecasting? But he just does do sarcasm really well, I'm deeply envious

 

And Frosty has got better and better over the years, maybe needs to rein himself in sometimes, as his enthusiasm for cold knows no bounds, but nothing wrong with that.

 

cheers weather eater, there are so many high quality posters on here. I miss mushymanrob's early morning updates, what the hell happened to mushy.

 

We have taken another big step forward today, cold weather and a risk of snow early / mid next week could be close to verifying, I will try and post some charts soon.

[Pembroke Dangler]

As IF alluded to yesterday the swing of the models over and after the weekend could either make or end our winter and it's really down to that chunk of vortex over Canada and Greenland which needs to take a hike allowing heights to build into Greenland settling the Atlantic and giving our little island a chance to dry out in peace and cold quiet with ice days oh what a dream that would be, not even snow just crisp sunny and dry would do for the vast majority of people i think!!!

[bradymk]

I think a shallower low and orientated more nw/se will be needed to give a better chance of some backedge snow for more people, the ECM overall is a positive run for cold potential and some snow but the low shape at T120hrs leaves a lot to be desired. So that's something we need to see change in future outputs. The T120hrs has a knock on effect in terms of the cold pooling over Germany and central Europe and this impacts the snow potential at T144hrs, the ECM postage stamps I'm sure will have some better options.

if you zoom in more to the dp maps I sent, 1c for most of south! And the dew points decrease quite quickly 156/162 timeframe once the low moves through. As you say, probably need a better shape to the low for snow for lowland southern Britain at that point. Although any temp, dp, precip prediction for that timeframe at this range is just a toy as we know.

[Snowfan50]

Does anyone have have a link to view northern hemisphere T850 temps? Thanks.

[Mark Neal.]

Does anyone have have a link to view northern hemisphere T850 temps? Thanks.

You can view them here- http://www.meteociel.fr/modeles/ecmwf.php?ech=72&mode=0&map=1&type=0&archive=0

[Essan]

True and especially all those poor children who had their Xmas ruined by the ridiculous amounts of rain and floods, the least we can do is find some snow for them so that they can go and make some snowmen and have some fun. That's my cure for all lifes ills, snow=happy people,  as long of course you don't have to suffer public transport!

When we have floods here, the usual comment is "at least it's not snowing, so we can still get around".I don't think many people over the age of 10 actually like snow under any circumstances ....

[SMU]

Evening All

An I phone post so appologies for spelling errors and no links.

So ive missed all the shennanigans of the ECM, however Ive just sat here on the platform reading the posts-

In terms of the ECM output and THIS only there seem to be a lot of underplaying of any snow - well I think thats a big mistake -

The ECM is all snow events from 168 to 240 for scotland and the NE, mostly snow for midlands East and a mix to rain the further SW you go-

Obviously theres no point in defining a line at this stage but the areas above would be the general zones-

I would imagine quite a substantial cover building up by day 10 for the usual hilly areas -

However comments of hill snow only are wrong and max temps of 5/6c would only be found in the sw-

As I posted earlier ( which has been quoted above ) the evolution at day 9/10 is neither zonal or blocked - i would call it quasi-stationary with high level blocking in equilibrium to the NE & SW and troughing flowing SE from greenland across to France.

Its a tightrope margin we are talking between atlantic mild and bitter continental air & at the dividing line across a piste of about 100 miles you can develop heavy snow.

The ECM paints such a picture, ignore the uppers- the dewpoints will be sucked out of benelux and sit below freezing across the uk

With the atlantic snow machine in full effect.

Post thst 240 sees more or the same with low heights and a low drifting south we should remain in a continental feed-

In terms of the broader picture remember the drop we saw in debilt means this morning ( from the 12z yesterday to the overnight ) I expect another incremental drop tonight and the extension of the cold for debilt to 4-5 days with hopefully the mean dipping to -1/-2.

The broad trend of the day has been subtle but meaningful upgrades that have washed over some and perhaps ignored by others-

I expect the official line from Exeter to be the same as the morning with a caveat that there is growing support for an extension to the cold & along with it the increase in snow potential.......

Best regards

S

[karlos1983]

Evening All

An I phone post so appologies for spelling errors and no links.

So ive missed all the shennanigans of the ECM, however Ive just sat here on the platform reading the posts-

In terms of the ECM output and THIS only there seem to be a lot of underplaying of any snow - well I think thats a big mistake -

The ECM is all snow events from 168 to 240 for scotland and the NE, mostly snow for midlands East and a mix to rain the further SW you go-

Obviously theres no point in defining a line at this stage but the areas above would be the general zones-

I would imagine quite a substantial cover building up by day 10 for the usual hilly areas -

However comments of hill snow only are wrong and max temps of 5/6c would only be found in the sw-

As I posted earlier ( which has been quoted above ) the evolution at day 9/10 is neither zonal or blocked - i would call it quasi-stationary with high level blocking in equilibrium to the NE & SW and troughing flowing SE from greenland across to France.

Its a tightrope margin we are talking between atlantic mild and bitter continental air & at the dividing line across a piste of about 100 miles you can develop heavy snow.

The ECM paints such a picture, ignore the uppers- the dewpoints will be sucked out of benelux and sit below freezing across the uk

With the atlantic snow machine in full effect.

Post thst 240 sees more or the same with low heights and a low drifting south we should remain in a continental feed-

In terms of the broader picture remember the drop we saw in debilt means this morning ( from the 12z yesterday to the overnight ) I expect another incremental drop tonight and the extension of the cold for debilt to 4-5 days with hopefully the mean dipping to -1/-2.

The broad trend of the day has been subtle but meaningful upgrades that have washed over some and perhaps ignored by others-

I expect the official line from Exeter to be the same as the morning with a caveat that there is growing support for an extension to the cold & along with it the increase in snow potential.......

Best regards

S

 

good old SW force field 

 

ah well, I'll enjoy watching it all unfold on here *if it happens. tbh i could prob do without snow as the wife is 38 weeks pregas, but i wouldn't complain  .

[Frosty.]

Well I was beginning to wonder if we would ever see wintry charts like these from the Ecm 12z op run tonight within the semi-reliable timeframe but here they are in all their glory, usually we would see charts like this at T+240 hours and take a leap of faith but not this time, the charts from T+96 hours, for me represent the start of winter proper and I think we will get something along the lines of this, perhaps even better as the models continue to firm up and fine tune. This would do very nicely for me considering what most of us have endured so far. If anything like this verifies, there will be snow events next week, occasional deep cold with sub 522 dam and generally 528 dam covering the uk next week so a risk of snow just about anywhere but especially further north and east, there could be significant falls and drifting for parts of the uk and increasingly icy with sharp frosts at times...let's hope this happens, uk coldies have suffered enough!  BOOM

[Downpour]

Very cold westerly tonight! Having ventured out I'm surprised to feel how cold it is - even here in the UHI of Walthamstow. Good ECM. All to play for now... With Westerlies this chilly anything is possible - not surprised to hear of the shock rush hour blizzard up in Yorkshire.

[NorthYorksWeather]

Although there is plenty of interest within 180 hours time, not sure if this has been noted as of yet but the PV is in bits out in F.I, its very strange  not seeing a large purple blob over NW Canada and Greenland. if this trend is to be continued chances of cold as we enter February will most likely increase

 

[Captain Shortwave]

ECM ens, err.... the massive raging mean canadian vortex over Greenland/Canada of yesterdays runs has vanished. A much more meridinal pattern is favoured going into week 2 now. Low heights look like continuing to drop south east through the UK much like the operational.

Not bad really.

850s are solid too

 

Earlier on, we have the -8 isotherm touching the east coast at day 7

Plenty of interest I think in the next few weeks.

Edited January 23, 2014 by Captain shortwave

[fergieweather]

good old SW force field 

 

ah well, I'll enjoy watching it all unfold on here *if it happens. tbh i could prob do without snow as the wife is 38 weeks pregas, but i wouldn't complain  .

The signal for SW snow showers in the markedly lower WBFL by Sunday night over uplands remains consistent however... some hope yet for those wanting a few flakes!

[IDO]

Evening AllPost that, 240 sees more or the same with low heights and a low drifting south we should remain in a continental feed-I expect the official line from Exeter to be the same as the morning with a caveat that there is growing support for an extension to the cold & along with it the increase in snow potential.......Best regardsS

 

Hi Steve, I know its a D10 chart but when I looked at the pattern, it looked like the cold uppers were being pushed back east. Would a Continental feed be cold enough for the next low for snow? Especially as it appears to be dragging in a warm sector?

 

T168 cold continent:    T240: 

 

Hold that thought, the mean is much better:   

 

Much much better. As you said.

[karlos1983]

ECM ens, err.... the massive raging mean canadian vortex over Greenland/Canada of yesterdays runs has vanished. A much more meridinal pattern is favoured going into week 2 now. Low heights look like continuing to drop south east through the UK much like the operational.

 

Not bad really.

850s are solid too

 

 

Earlier on, we have the -8 isotherm touching the east coast at day 7

 

Plenty of interest I think in the next few weeks.

 

Yes, 850's arguably look better to me?

Edited January 23, 2014 by karlos1983

[Gibby]

Good evening folks. Here is tonight's report on the midday outputs from the NWP for today Thursday January 23rd 2014 and lifted from my website on http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm

 

All models agree on the progress of events over the UK for the next 5-6 days before some differences between the models begins to crop up by the middle of next week. A complex trough structure bringing milder air will move erratically East over the UK tonight and tomorrow with rainfall for many giving rise to further flooding possibilities in the already sodden areas of the SW. By Saturday a window of drier air will of arrived with a showery NW flow and it will feel colder than tomorrow will. On Sunday a major depression is shown to approach NW Britain and this trundles SE towards SE England by midweek. After a wet period for all on Sunday strong Westerly winds and heavy showers, wintry on hills will give way to quite cloudy conditions towards midweek with further outbreaks of rain and as colder air is drawn into the UK by midweek on the Northern periphery of the Low some of the rain will turn to sleet and snow in places, mostly across the North and East.

 

GFS then shows the remains of the cold flow across the South give way to a return to westerly winds and changeable weather at the end of the week and weekend with further rain and showers crossing the UK from a very active Atlantic with very little overall change out to the end of the run.

 

The GFS Ensembles show a continuing unsettled period with Low pressure well in control. The air will turn colder for a time next week with the chance of some snow over the North and East but the likelihood of milder air returning soon afterwards remains quite high as the Atlantic depressions maintain control to the North.

 

UKMO tonight shows a slow moving filling Low pressure close to SE England with a cloudy and raw day for many with rain or sleet in places and some sleet and snow over the higher ground of the north and East for a time.

 

GEM shows the remains of any cold easterly flow over the South along with any remaining rain or sleet moving away South to be replaced by Westerly winds and further Low pressure areas crossing the UK keeping the wet and windy theme going with temperatures likely to return to near or somewhat below average.

 

NAVGEM also removes the remnants of the Low pressure area from the SE later next week with milder Atlantic Westerly winds taking control over all areas again with rain and showers moving back in from the West by next weekend.

 

ECM tonight shows Low pressure to the SE filling quickly shortly after midweek with the resultant cold Easterly flow dissolving away along with any rain and hill snow. Then the weather returns to wet and windy conditions as further Low pressure and fronts ride in on the back of a strong Atlantic Jet stream later next week and weekend.

 

The ECM 9 and 10 Day Mean Charts show the bias being towards the UK lying in the path of Low pressure stretching between Southern Greenland and South Iceland to the UK and on down into Italy. The trough has sharpened tonight with lower pressure indicating more trough disruption over the UK and Low pressure areas in their own merit diving SE over the UK. The pattern has shifted a couple of hundred miles West in the last 24 hours or so and this could be sufficient to continue some wintry interest for the NE of the UK still in 10 days while the rest see cold rain and showers on a chilly NW'ly flow as the most common weather type likely.

 

http://www.wetterzentrale.de/pics/Reem2161.gif

http://www.wetterzentrale.de/pics/Reem2401.gif

 

The Jet Stream is undergoing a strengthening over the next few days with a very strong flow persisting from the weekend and throughout next week and possibly beyond maintaining it's trajectory of crossing the Atlantic and into the UK before turning South then East over Southern Europe.

 

In Summary tonight things remain very volatile and very interesting from a synoptic point of view. We have the classic battle of East vs West with the battleground just too far East due to a stronger than usual Jet Stream adding extra oomph and push against the block meaning we don't tap into any real exciting wintry weather over the British Isles with regard to widespread snowfall. However, being positioned as we are geographically puts us in the firing line for frequent decelerating troughs moving into the UK on the back of a powerful Jet Stream and delivering spells of copious rainfall mixed with colder and more showery spells when some snowfall could occur on higher ground. The longer term prospects do not look good for drier weather anytime soon and concern is continuing to be very high for worsening flooding issues for some over the coming period.