Model Output Discussion - 16th Jan 12z onwards - Smile While You Post!

[Penrith Snow]

Yes, the ECM 240 is a Stella chart and with the -5c 850 covering the whole UK it would be snow for most.

Normally I would regard this as a ECM tease but with so many signals for a deep Euro through this could easily verify.

In some ways this has been an interesting winter but not as snowy as it should have been IMBY so I still feel a bit cheated.

Andy

[Ali1977]

The problem with Northerlys and their set up in this pattern is they don't last long enough to entrench the UK with the cold air required for UK wide snow.  Hights pushing towards the southern tip of Greenland don't reallly block off the Atlantic for long enough, what we need is heights pushing in from the other side of the Arctic to connect with an Atlantic ridge...The GEM 10 day kind of hints at that, and also strenghtens high pressure over greenland.

[TEITS]

The ECM N Hemishere chart at +240 is very similiar to some of the GEFS control runs I posted yesterday morning and Monday night.

 

If we look at the ensembles its pretty clear we see a drop in temps around the same time as the ECM +240 (29th Jan). Now the real question is will the synoptic pattern be a N/NW,ly blast replaced by W,lys or something more sustained from the N/NE,ly as HLB develops. Personally i haven't a clue as I have lost all confidence in my forecasting!

 

http://max.nwstatic.co.uk/ensimages/ens.20150121/00/t850Cambridgeshire.png

[fergieweather]

Yes, the ECM 240 is a Stella chart and with the -5c 850 covering the whole UK it would be snow for most.

Normally I would regard this as a ECM tease but with so many signals for a deep Euro trough this could easily verify.

EC began offering potential for a larger-scale veering of flow later (10+D period) in EPS suite of 24hrs ago. Yesterday's 12z, as I mentioned last evening, also offered more veered solutions (including a few going to NE'ly, accompanying trough disruption) with generally more meridional upper pattern. The 00z EPS are trickling-out at the moment, so not yet checked. The broad potential for a switch to colder NW-N-NE outcome, although at present not considered to result in anything too extreme (cold-wise), is something we are watching closely for signs of better continuity in EC and MOGREPS.

[nick sussex]

Good agreement this morning for the Euro troughing but as to how that could develop afterwards a difference of opinion between the ECM and GFS, the former splits the PV and separates the Euro trough from low heights over Greenland, the latter doesn't.

 

Unless you can get troughing to the sw then for any decent cold you need that separation and ridge building in from the ne.

 

I think many who have missed out any snow aren't too keen on yet more marginal set ups and chasing a few hours of slush around, for that reason say a prayer for the ECM!

Edited January 21, 2015 by nick sussex

[Timmytour]

Promises Promises and we hope they start to verify.......but

I seem to recall the ECM coming out with what was described as a "very snowy run" about this same time last year so I'm not counting chickens by any means.  I wonder if it's got a time of the year bias?   

[TEITS]

Promises Promises and we hope they start to verify.......but

I seem to recall the ECM coming out with what was described as a "very snowy run" about this same time last year so I'm not counting chickens by any means.  I wonder if it's got a time of the year bias? 

I agree and this is why I want to see some consistency from the ECM before I even begin to get excited. Im not sure if others agree but I have been disappointed with the performance of the ECM this winter especially +192/+240 charts. I don't have any proof of this but more of an observation.

[Gibby]

HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY WEDNESDAY JANUARY 21ST 2015.

NEXT UPDATE THURSDAY JANUARY 22ND 2015 08:00

THE CURRENT GENERAL SITUATION A weakening Low pressure area across Southern England will move away South today leaving a weak ridge of High pressure across the UK tomorrow.

MODELS-2 WEEK HEADLINE Changeable with rain at times but some drier spells too. Less cold. Turning more unsettled and colder again later with some snow in places, especially over the North.

THE JET STREAM ENSEMBLE FORECAST The Jet Stream Forecast shows the flow moving North over the UK through the coming days as the trough weakens over Southern Europe. However after some days the flow is predicted to move back to a position South of the British Isles in a week or so.

GFS OPERATIONAL The GFS operational today shows a series of coldfronts crossing East over the UK later in the week and again later in the weekend bringing rain at times in from off the Atlantic in temperatures nearer to average at times but still cold enough for night frosts behind the fronts and wintry showers to the NW. Then later next week all areas become under the influence of cold zonality with plenty of rain and strong winds mixed with spells of wintry showers including the South with temperatures falling back to rather cold levels again.

THE GFS CONTROL  The GFS control run is very similar in the first week with several cold fronts bringing less cold air in from the West with rain at times and bright weather in between when frosts at night could occur. It shows a marked cold snap under a Northerly in 10 days tme with no dount some snow in showery form almost anywhere before the flow is cut off once more with less chilly Westerly winds and rain at times later in the run.

THE GFS CLUSTERS The GFS Clusters today show overwhelming support of 70% or more that in two weeks time the UK will lie under West or NW winds with rain or showers at times with snow at times on higher ground of the North as Low pressure is likely to lie to the North and NE of the UK with High pressure well to the SW.

UKMO UKMO this morning shows milder conditions at the weekend and start to next week as weakening cold fronts cross the Uk from the west with some rain for many followed by brighter conditions. High pressure then ridges strongly towards the UK from the SW with dry and bright if frosty weather possible by night but bright days with sunny spells early next week.

THE FAX CHARTS The Fax Charts show a 'col' area slipping South over the UK tomorrow clearing away todays messy pattern from the decaying disrupting trough. then over the end of the week and weekenda series of fronts bring cloud and rain followed by brighter weather over the weekend before a warm front approaches from the West late in the weekend.

GEM GEM today shows a continuation of a basic NW flow with troughs of Low pressure crossing East and SE across the UK at times bringing less cold air with rain at times followed by clearer, largely dry and bright weather with night frost. Later next week the weather becomes more deeply unsettled and cold again with Low pressure to the East bringing cold North winds and snow in places.

NAVGEM NAVGEM shows a similar evolution taking us up to the point in a weeks time when the westerly flow across the UK at that time becomes more disturbed with more prolonged and heavier spells of rain as pressure falls away with stronger winds as a result.

ECM ECM this morning shows a series of cold fronts crossing steadily East and SE across the UK over the coming week with occasional rain and temperatures generally closer to the seasonal average though not discounting frost at night in clearer interludes and wintry showers across the NW. Later in the run a plunge of cold Low pressure to the NE and East of us sets up a much colder period again with snow or snow showers in many places under a cold North flow to end the run.

ECM 10 DAY MEAN The ECM 10 Day Mean Chart today is much more supportive of the risk of cold NW winds returning by later next week with strong support for Low pressure to be centred over Europe with a cold and strong NW flow over the UK giving rise to wintry showers for many especially in the North.

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trend today is for the models to be indicating a strong chance that a return to colder weather is in the pipeline in a week or so with the return of some snowfall in places

MY THOUGHTS We are approaching the beginning of a less cold period across the UK as the cold pool of air currently across the UK gets shunted away East over the coming days. In the process there will be some rain bearing fronts pushing through before brighter skies and dry condiftions follow for the weekend. Frost could still occur at night and temperatures don't look like exceeding average levels for late January. It may then become a little milder early next week as some mild air wafts over the UK for a time again accompanied by some rain, especially in the North. All models then indicate thet we look likely to dip into cold zonality again as pressure deepens to the North and spreads down across the UK next week bringing wet and windy weather. Later still there is strong support that Low pressure migrates to scandinavia or Europe in general and with High pressure ridging North somewhat through the Atlantic cold NW or even North winds look very possible with cold air sweeping South to all areas giving rise to sleet and snow showers to all and if pressure stays low enough some longer spells of snow too especially over the North and East. The question then is how long this lasts before the Atlantic wins back ground again. Well of course it is impossible to say at such a range and coldies should be encouraged that the pattern looks like setting itself into a cold scenario again so soon after we lose the current one. As I hinted at yesterday it comes as no surprise to me that charts are showing this evolution and as I have been indicating most of the Winter so far we have to look to the NW or North for our cold this Winter rather than East or NE and I see this changing little in what's left of the season. So all in all after a brief less cold period there again looks something to look forward to as the models firm up how this new pattern develops over the coming days. It is encouraging though to see such cross model support though at this early stage. Let's hope it is maintained.

[BLAST FROM THE PAST]

 

ECM wanting some of the action?  Turn of month into Feb maintains a 'severe' weather warning from me of very wintry impactual weather from NW to N and at times NE quadrant due to trough over UK/Scandi and NW Europe locale, .  As you know I've been targetting this period for some time and it for me is going to be a repeating pattern [as in not a real cold blast and HP to calm down and keep it cold, crisp and even] more real cold blasts with the trough being very much in charge with repeated volatile conditions.  Interesting pdate from I F isn't it?

 

BFTP     

Edited January 21, 2015 by BLAST FROM THE PAST

[fergieweather]

Strong broadscale support for the markedly veered, colder solution in 00z EC DET amongst EPS circa 29-31 Jan (pronounced trough just E of UK), but likely a short-lived phase based on direction of clusters thereafter into early Feb.

[Nouska]

 

ECM wanting some of the action?  Turn of month into Feb maintains a 'severe' weather warning from me of very wintry impactual weather from NW to N and at times NE quadrant due to trough over UK/Scandi and NW Europe locale, .  As you know I've been targetting this period for some time and it for me is going to be a repeating pattern [as in not a real cold blast and HP to calm down and keep it cold, crisp and even] more real cold blasts with the trough being very much in charge with repeated volatile conditions.  Interesting pdate from I F isn't it?

 

BFTP     

 

We've been footering around with a winter that, in reality, has been an extended autumn - real winter in Europe is about to begin and probably extend its grip beyond February. The seasonal models were right in the blanket of warm anomalies for Europe, these are now turning to blues for the early spring period - the background signals are changing.

 

If these charts in todays models come to fruition, there will be plenty to please all flavours of weather enthusiast.

[mushymanrob]

another chance at a cold spell developing?...

 

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well done the gfs IF this pattern verifies, it picked up a scandi/western european low a couple of days ago in odd runs. some runs have suggested a major cold spell (with the expected mean trough over scandinavia) or like this morning a more marginal event (for snow).

so on the horizon theres another cold/snowy shot, big question is will this one deliver a widespread snow event or just be yet another let down for most?.

 

[Severe Siberian icy blast]

A massive part of me wants to say do we never learn ?

This cold spell firstly has by in large been a let down , I live on high ground and iv woken up on 4 different occasions to a light covering of snow only for it to be gone 3 hours later , and last nights snow was an absolute let down for most , apart from northern England , when only yesterday the likes Birmingham were in for it , so if that's how bad our cold spells have got in the uk then I think il move abroad .

With regards to the next chase of cold , take the ECM for example T240 , how many times have we saw a complete ensemble suite go for cold only for it to be removed 2 days later . Only last wk we were looking possibly at a freeze from the beast . The difference there I suppose was the met weren't really gunning for it.

But from experience when it looks like the Azores high is gonna head north , even toward Greenland , as we approach t72 the models pick up that the high can't penetrate higher enough mainly because of the vortex segment left over Greenland/Canada which ejects short waves our way , in turn this topples the high after 48 hours . Is that enough this winter that had so much promise ?

I haven't had a catch up on the strat yet this morning but we need to see the strat play its part on the vortex . If we'r to have a sustained HLB to our northwest we need a tanking AO , if we haven't then it's very unlikely to deliver more than a 2 day affair .

I'm just been realistic and chasing a cold spell 10 days away is fraut with danger unless we see stong correlation within the stratosphere .

Edited January 21, 2015 by Severe Siberian icy blast

[BLAST FROM THE PAST]

I don't think we are going to have a sustained NW or NE block that wil dominate, Feb imo will be dominated by the troughing with AZH playing its part backing west and at times ridging towards Greenland, thus no sustained HLB [that no doubt will be the talk of Spring knowing our luck] but waves or cold from the N quadrant.

 

BFTP

[bluearmy]

The extended ens ecm promote the sceuro trough as per other postings but thereafter, the pattern looks to be a tad too far East for the uk to be under its influence. This allows for the Azores ridge to be closer which would allow for it to ridge far enough North and west to bring a nor'easter around the trouging to our East. Given the mobility Ian speaks about above and the naefs 'flatter' pattern to follow, I would be thinking that the chances of a sustained cold perod are not high at the moment.

However, in the post 10 day period, colder cannot be ruled out within the broad pattern.

[nick sussex]

The extended ens ecm promote the sceuro trough as per other postings but thereafter, the pattern looks to be a tad too far East for the uk to be under its influence. This allows for the Azores ridge to be closer which would allow for it to ridge far enough North and west to bring a nor'easter around the trouging to our East. Given the mobility Ian speaks about above and the naefs 'flatter' pattern to follow, I would be thinking that the chances of a sustained cold perod are not high at the moment.

However, in the post 10 day period, colder cannot be ruled out within the broad pattern.

BA what do you make of the PV split? The GFS 06hrs run almost gets there and looks like its edged towards the ECM. I think most would be happy to just get a couple of days of non-marginal snow, which has been difficult so far this winter away from more elevated areas of the north.

[Captain Shortwave]

another chance at a cold spell developing?...

 

Rtavn2402.gif Recm2402.gif

and supported by

 

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well done the gfs IF this pattern verifies, it picked up a scandi/western european low a couple of days ago in odd runs. some runs have suggested a major cold spell (with the expected mean trough over scandinavia) or like this morning a more marginal event (for snow).

so on the horizon theres another cold/snowy shot, big question is will this one deliver a widespread snow event or just be yet another let down for most?.

 

Yeah certainly a trend over the last 24 hours to offer something decent at the end of next week. The Euro/Scandi trough looks a good bet based on the output from all fields. The reality of how cold/duration will be dependent on what happens over the pole as this will ultimately decide how much ridging northwards the Azores high is allowed. Anything from a simple PM north-westerly to a fairly prolonged toppler evolution is up for grabs. If the Pacific ridge can nudge towards northern Greenland you may get a deep north/north easterly developing as the Canadian lobe of the polar vortex separates from the Siberian lobe and this sinks further south into the US.

There seems to be a tropospheric/stratospheric tandem pattern going on so this may offer confidence in this evolution too.

Edited January 21, 2015 by Captain shortwave

[TEITS]

I don't think we are going to have a sustained NW or NE block that wil dominate, Feb imo will be dominated by the troughing with AZH playing its part backing west and at times ridging towards Greenland, thus no sustained HLB [that no doubt will be the talk of Spring knowing our luck] but waves or cold from the N quadrant.

 

BFTP

Forgive me for saying but doesn't that contradict your previous post. Synoptically you are describing what we have seen already this winter i.e brief colder spells. The problem with this is that without HLB the N/NW,lys are not sustained enough to bring the very cold air S. What generally happens is upper temps of -5C arrive which generally only give snow showers to Scotland especially over higher ground. What this winter has taught us is we need to see HLB to bring severe wintry weather across the UK.

Edited January 21, 2015 by TEITS

[492]

http://meteocentre.com/analyse/map.php?map=Europe&date=2015012110&size=large〈=en&area=eur

As the low slips to the south of the UK the flow backs drawing in drier air from the near continent where modest cold pooling is occurring within the cold high. The south easterly fetch from the English channel is keeping temperatures relatively high along the south coast at the moment but as the wind continues to back even here temperatures look set to fall away. So a couple more quite cold days and nights ahead for much of the UK.

[West is Best]

I think we might just have to accept that, for the foreseeable future, the jet stream is roaring out of America like dragon's breath:

 

 

With the AZH in place to our south-west that's going to encourage a lot of cyclogenesis and mobile zonality for the UK. I wish it weren't so.  Still time for changes before winter's end.

[Man With Beard]

Not really much to add to discussions; T240 has snow opportunities to be sure and what would make these charts different is that winds would be more northerly than north-westerly, which will help a bit in a marginal set-up. However, there's nothing yet to suggest more than a colder one-two days before the Atlantic returns. Being T240 charts, there's much scope for change anyway, somewhere between the ECM op (probably on the extreme side for a colder set-up) and a flatter version of the GFS, which would be another northerly high-ground affair. 

 

Absolutely no sign of a nationwide freeze right at this moment. Some rather trashed January forecasts, then, and some rather smug faces at the MET Office who this month have beaten allcomers like a Premiership side crushes a Conference one in the FA Cup 3rd round.

 

On to February, then!!

 

[Banbury]

I think we might just have to accept that, for the foreseeable future, the jet stream is roaring out of America like dragon's breath:

 

 

 

 

 

 

 

With the AZH in place to our south-west that's going to encourage a lot of cyclogenesis and mobile zonality for the UK. I wish it weren't so.  Still time for changes before winter's end.

Of course assuming GFS Operational is correct

[Hotspur62]

Well as this cold spell draws to a close(disappointing for many as most have said already)the models are looking at end of the month for another potential cold  spell/snap. But it seems the same old chesnut to me. Unless we have HLB to N or NE the likelihood is it will be watered down(even if it occurs!) as we get closer to T0.It is frustrating as we have lower pressure over Northern Italy but still the AH is just sitting too close to Iberia. If this moves North Westwards and links up to Greenland that would be a start.

 

I think what is happening in Strat could be vital to a cold Spell developing and sending large chunk of PV to a favoured Siberian side for us.With my basic knowledge it looks encouraging but I will leave that to experts like Recreatos,Matt Hugo etc to hopefully give us positive updates. 

 

I think until the above factors change we wont see any significant changes to the Met Office stance which although looks coolish is unlikely to bring what most on here dream of(a Full blown cold spell with no Margainilty!!).

 

Just a quick question to Met Office and I apologise if it has been asked before but how much do the factor in Strat Movements in their forecasts.

 

At least there is Potential this winter and already is a darn sight better than last winters rain,wind and mild temps.

[TEITS]

Going to post the ECM mean at +240 to show you what we need to see in future outputs. Forgive the rather crude drawings but you will get the gist.

 

Right so note the PV (B) & © we need to see this split with this highlighted by the arrows. This is turn will allow heights across the pole (A) to extend S. Now note (D) & (F) we need to see the trough extend as far S as possible whilst low pressure (D) tracks N towards the W side of Greenland. At the same time this will allow the Azores HP ridge N. All of this combined will allow a sustained flow from the N.

 

[Interitus]

Fortunately don't think tides are predicted to be particularly high because there would be North Sea storm surge risk from the charts at the end of the month that have been appearing for a while -