WInter Model Output Discussion 12z- 28/01/2013

[lorenzo]

If the pub run goes on with its game of I will copy what the ECM 12z does then we are in line for some fun charts later this evening.

The models simply don't project well the core vortex shifting around, this was the case Nov/Dec and appears to be a similar replay this time, looking at the blistering 100hpa analysis chart not sure why but they do drag their heels with this.

CPC charts will be very interesting this evening.. GP post also an interesting one regarding the pattern outcome for GWO, is this a 50:50 all or nothing shout coming up? Fat lady or no Fat lady, going to be a good watch this week.

Maybe another step away from a brief pattern that flattens quickly to something more substantive this evening..

[Cheshire Freeze]

Steve M I feel is quite right in what he is saying of no real cold in the next 10 days.

There seems to be an element of confusion here. No-one has said there would be 'real cold' pre 7th Feb. I really don't know where this idea has come from...it's a self started argument.

I was quoted as saying (4 or 5 days ago) that phase one of next cold spell to start between 3-7th Feb. The ECM shows this transition tonight in that allotted time frame. I'll say again, phase ONE. Post this timeframe I expect the blocking to gain more of a foothold at high latitude.

I can't think of one person who said severe cold before 7th Feb.

In fact, on second thoughts, I think there's a shifting of the goalposts here because only a few days ago any suggestion of a cold pattern AT ALL setting up in February was dismissed. Now it's within 10 days.......

Edited January 28, 2013 by CreweCold

[Buzz]

Steve M I feel is quite right in what he is saying of no real cold in the next 10 days.

Please define "real cold".

These statements really get my goat as they are so incredibly subjective and do NOT belong in the model output thread.

[chris55]

& here is your dayime temp on that day

http://91.121.16.5/m...6-580.GIF?28-12

Cold- what cold?

S

Once the colder air, that is over Scotland on that chart, comes south it's certainly is cold.

[SnowBallz]

Just for a laugh, who ordered Mr Happy Face in March?

He's not a warm Mr Happy Face either...

Some bonkers cold CFS solutions on the intra-days too

Ooooooo Matron...

In fact, check all of March out.

Fair to say, we'd be f**ked if that happened

[SMU]

Quality not quantity.

What has post length got to do with the price of fish?

I've seen some lengthy posts on this forum in my time spouting nowt but a load of half baked claptrap.

Quality not Quantity- Sure I agree-

How about relevence though..... Im sure some on here could write one sentence or a whole page about worldly & global teleconnections- doesnt make it relevent to the UK.

My comments were more pointed towards the fact that the scientific non relevent stuff posted has 'loose' connections with the UK- & are not direct correlators- infact other than the NAO which is the highest correlator to the UK the rest all bagged together are loose ( some better than others ) then what is the point of posting such measures of global tendancies when the signal for the UK is non specific.

Lets look at the NAO which has been convieniently overlooked of late-

http://www.cpc.ncep....ndex_ensm.shtml

the mean around +0.5 ( neutral )-- so nothing really exciting there-

& the AO

http://www.cpc.ncep....ex/ao.sprd2.gif

The mean around -2 which is better, however there is a considerable disconnect between the AO & NAO which is unusual-

This is important around my comments above because if we are getting excited about the 'overall' state of the jet then it should be tempered by the fact that the height anomalies across our quadrant doesnt favour UK cold- IE the NAO.

Even the PNA is flat

http://www.cpc.ncep....k/pna/pna.shtml

So the broad assumption is that if the AO ensembles are trending quite negative- supported by the Global AAM & any other measure thrown in for good measure the bottom line is its not driving the NAO.

Should we dwell on the Global measures, no- Worth a comment yes as if the AO is continually trending low then eventually we 'should' tap some of the cold, however some context needs to be presenting when plucking random measures & quoting them into the thread- especially when a large portion of people reading it arent quite sure of what that means for the UK-

In the last week ive seen plenty of assumptions banded around- 'from the regulars, & prior to that it was a quick reload from the NE when the pattern relaxes- according to some.

Very confident forecasts & presumptions being made- 'sustained cold' etc etc - reloads from the North east & east' etc etc.

Well sorry that picture thats being painted by some isnt reflective of whats being modelled, with the H5 pattern & the means not being condusive to anything other than 'flirting' with cold shots from the North West .

The pattern will of course deliver the -5c line crossing the UK from time to time, however the bottom line is in the next 8 days the height of the amplified pattern will deliver very minimal for the UK in terms of below average temps- SOME cold yes, but not sustained & certainly not supportive of low lying snow events.

Remember in Northerly & NE events where the air is modified over the sea you will need a parcel of cold thats lower than the 'assumed' value of -5c @ 850 to deliver convective snow, & lower still if you want any back edge frontal snow.

To many on here now hang off the words of posters that have an agenda as opposed to presenting the reality.

Have I changed, Am I negative, well no- Im being realistic in trying to manage the expectations of what may be around the corner.

In the means this winter has been poor, but luckily the recent cold spell has generated enough snow weather to satisfy most for the winter.- however that doesnt mean to say something is around the corner again.

Is the glass empty or full- well neither- Im saying what I see & commenting on the rather odd assumptions of others, my comments would be that in the 12 years of looking at the models this current evolution will never slow the jet down enough to amplify enough to build a wedge of high pressure over Svalbard which some are alluding to / expecting. its a 1:10 return when it does land ( 2005 ) so its not the form horse.

The lack of clarity shown & minor details to resolve all the way from day 6-10 is what angle the jet takes & where that sets up- over the UK or to the east- the models wont suddenly pump heights into greenland.

Worst case is east of the UK & flat with very average temps.

Best case in strong NW flow with the odd day nearer the North at the height of the Amplitude of the azores high.

I think post that we are scratching around for any trough dropping into Iberia & developing a push of colder air through western Europe.

S

Edited January 28, 2013 by Steve Murr

[SMU]

I wonder how it is that you and I and many on here today can find lots of positives regarding a cold outlook but steve murr is having none of it, as for the no cold within 10 days, well we have a cold snap this weekend which is only 5 days away and probably more cold weather during next week, even today's meto say trending colder from the north as time goes on with more of a wintry pattern developing from the north over time..what is steve m talking about?

There is a difference I am clarifying for the last time-

No cold in abundence, No sustained cold, no cold from East of NORTH.

Colder shots from the NW & north at best.

The ECM 240 is NOT cold. its average at the surface for the UK- it also has NO hallmarks of sustained cold or high level blocking.

S

[Cheshire Freeze]

Steve....I think we may have wires crossed here. I think your prognosis for the next 7-10 days is a fair assessment. I don't think I am disputing the fact that there is not a proper high latitude block currently showing in the NWP.

I think we have a case of potential here, especially post 7th Feb.

As such, there isn't really a disagreement here as I can see.

[bradymk]

There seems to be an element of confusion here. No-one has said there would be 'real cold' pre 7th Feb. I really don't know where this idea has come from...it's a self started argument.

I was quoted as saying (4 or 5 days ago) that phase one of next cold spell to start between 3-7th Feb. The ECM shows this transition tonight in that allotted time frame. I'll say again, phase ONE. Post this timeframe I expect the blocking to gain more of a foothold at high latitude.

I can't think of one person who said severe cold before 7th Feb.

In fact, on second thoughts, I think there's a shifting of the goalposts here because only a few days ago any suggestion of a cold pattern AT ALL setting up in February was dismissed. Now it's within 10 days.......

By no means is it me, i was just saying that Steve M is quite right with no sustained cold within 10 days. For a few days now, I have personally felt post day 10 we could be back into a much colder pattern once again. The ensembles are very good and have been for a few days and just a little patience may be needed.

[Cheshire Freeze]

By no means is it me, i was just saying that Steve M is quite right with no sustained cold within 10 days. For a few days now, I have personally felt post day 10 we could be back into a much colder pattern once again. The ensembles are very good and have been for a few days and just a little patience may be needed.

See my post above ^^

[SMU]

Steve....I think we may have wires crossed here. I think your prognosis for the next 7-10 days is a fair assessment. I don't think I am disputing the fact that there is not a proper high latitude block currently showing in the NWP.

I think we have a case of potential here, especially post 7th Feb.

As such, there isn't really a disagreement here as I can see.

]

What are you forecasting post day 10..-

S

[Isolated Frost]

There is a difference I am clarifying for the last time-

No cold in abundence, No sustained cold, no cold from East of NORTH.

Colder shots from the NW & north at best.

The ECM 240 is NOT cold. its average at the surface for the UK- it also has NO hallmarks of sustained cold or high level blocking.

S

Plenty of snow/wintry shrs for northern areas, and some southern hills with this.

WAA up W Greenland- favourable stalled amplified trough off NE Canada w/ associated jet energy-

retrogressive ridge SSE-NNW, not quite SE-NW yet, but it's a very positive set-up+ 552dm moving into Greenland

It may not be the mystical easterly some set out for, but it would be some cold NW/N'lies with the chance of a NE downstream as the upper trough builds energy in C Europe and advects the cold pool W/SW..

Some very pleasing synoptics from the north in the output.. that may not favour some certain areas but us up north will be very pleased..

[Frosty.]

There is a difference I am clarifying for the last time-

No cold in abundence, No sustained cold, no cold from East of NORTH.

Colder shots from the NW & north at best.

The ECM 240 is NOT cold. its average at the surface for the UK- it also has NO hallmarks of sustained cold or high level blocking.

S

Cold shots from the NW can be pretty potent with winds blasting down from eastern greenland, there have been plenty of charts today showing nwly blasts and arctic blasts, although not prolonged, they are far better than the current pattern and could evolve into something more severe as long as we get the nw/se jet tilt in place.

[Cheshire Freeze]

]

What are you forecasting post day 10..-

S

I'm firmly leaning towards the prognosis of GP et al in as such as I don't think there is a signal of any real note for mobile, Atlantic driven weather throughout the middle portion of February at least. I've not waivered in this stance.

The one clear trend I have noted is the erosion of low heights to our north, a weakening PV (on a general scale) and a much more amplified pattern setting up.

Just out of interest, what would your punt be? I respect and appreciate your views as you've been at this game a lot longer than I have!

Edited January 28, 2013 by CreweCold

[Catacol]

mean or anomoly CH ??

Well - I'm not a great mathematician as A level was a long time ago... but my understanding of the ECM "moyenne" chart is that it is an anomaly chart created from the mean of the entire suite of runs (ensemble) - so both in answer to your question. Am I wrong?

[Polar Maritime]

Yes after this week which leads us to a cold Northerly, surly anything after that is FI ? As Frosty say's above lot's of potential after that !

Edited January 28, 2013 by Polar Maritime

[weather eater]

Some fascinating model runs of late, and some really interesting weather lined up for the UK in the next few days, however, two things of note, weather and model analysis is not just about the prospects for cold and snow and why is it that the thread appears to consist mainly of posts about whether Mr S Murr is in an optimistic or pessimistic frame of mind with regards the prospects for cold in the next ten days. With all due respect to Steve, I personally don’t care about his mood or any other aspects of his state of mind, at least not when it comes to weather prospects, and in regards his analysis of model output, he is entitled to his opinion and only time will tell if he is right or wrong.

[Gibby]

Good evening. Here is the evening look at the 12z output from GFS, UKMO and ECM for tonight Monday January 28th 2013.

All models show the rest of this working week as being unsettled and often windy with rain or showers at times for all. Tomorrow looks particularly wet as a warm front scoots NE over the UK followed by a cold front late in the day, all bringing spells of rain in a gale force SW wind. At least it will be mild in the South for a time through the day. Through Wednesday and Thursday more showery weather is likely but some of these will be heavy and prolonged especially on Thursday. By Friday a new wave depression or deeper Low ensures the end of the working week stays unsettled and wet, especially in the South before a drier and colder interlude feeds down from the NW over the weekend with a welcome 24-48 hours of dry and rather chilly weather over the weekend with a slight overnight frost likely for many.

GFS then brings milder maritime air down over the UK through Sunday with rather cloudy and benign conditions early next week with some light rain possible in the North for a time as a front passes by bringing slightly colder air back to the NE by midweek. FI tonight repeats the process of weak troughs toppling SE over the UK at times followed by a toppling ridge too for most if not all of its latter stage output as High pressure lies close to the SW for most of this time. At least the SW would have a chance to dry up somewhat as only small amounts of rain would occur here.

The GFS Ensembles show a gentle cooling to levels just below the long term mean as a more NW influence to the winds over the UK take hold next week. There is little evidence of any significant cold shown on tonight's output from GFS members for the UK though no really mild weather is likely either. Amounts of rain will reduce beyond this week as the displaced Azores High to the SW of the UK diverts the majority of frontal rains towards Europe.

The Jet Stream shows the flow blowing strongly over the UK ridging North over the Atlantic later this week over the top of the Azores High before returning South over the UK.

UKMO for midday on Sunday shows a strong Anticyclone to the SW of the UK, Northeast of the Azores. A warm front is shown crossing the UK from the West through the day. The likely weather would be an early frost in the East and South giving way to milder and drizzly weather as the weak warm front crosses East through the UK later in the day.

ECM tonight shows a much more potent Low on Friday than the other models with rain and gales in the South giving way to colder and brighter conditions to start the weekend. The overall pattern is back on track by Sunday with ECM following UKMO in bringing a warm front East over the UK on Sunday with rain and drizzle on recovering temperatures due to a large and strong Azores Anticyclone parked to the SW of Britain. Later in the run a few days of milder Atlantic Westerlies bring rain at times for many before a deep Low moves across the Atlantic to Scotland and on Day 10 across to NE England. Cold NW winds are then shown to sweep South over all areas with wintry showers for all the hills and low ground too in the North.

In Summary tonight the pattern look like changing a little as we move into next week. After this weeks relatively mild, windy and wet conditions a change to rather colder conditions looks likely next week . Of more importance to lower lying locations some of the output suggests rather drier conditions, especially to the SW where winds blowing from the NW around a displaced Azores High keep meaningful troughs away, but further North and East those same troughs bring some rain and wintry showers at times with a more full blooded attempt at something more universally cold for the UK from ECM in 10 days time. We really do need that Azores High to weaken or become displaced further NW or West as well as ridging North to allow the Jet flow to buckle, weaken and to relocate further South, something that ECM is showing on that day 10 chart.

[Frosty.]

Yes after this week which leads us to a cold Northerly, surly anything after that is FI ? As Frosty say's above lot's of potential after that !

Yes Pm, my view of the models today is reload after reload potential from the NW or N or both as long as we get the jet angled nw/se, that is the crucial thing and then we will have cold incursions throughout the next few weeks, maybe with lows sliding southeast over the uk and then drawing even colder air down across the uk in the mid range.

Edited January 28, 2013 by Frosty039

[Catacol]

Just seen the ECM. This 10 day chart is an almost carbon copy of the GFS yesterday:

It certainly seems to be one of the solutions on the table - matches closely the AM spiking and MJO composite for the current time. However I still have a nagging feeling about incorrect modelling of vortex energy, have not forgotten what happened in December (despite GP's little comment about the sun being quiet...!) and really want to see the ECM mean come into line. As soon as we get some kind of agreement between the big 2, and an even stronger indication from CPC charts, I am going to be as cautious as Steve M is being. He is right - the current NAO prediction is really very modest and not indicative of a big swing to GHP and a blocked atlantic.

At least - not yet.

[chris55]

Quality not Quantity- Sure I agree-

How about relevence though..... Im sure some on here could write one sentence or a whole page about worldly & global teleconnections- doesnt make it relevent to the UK.

My comments were more pointed towards the fact that the scientific non relevent stuff posted has 'loose' connections with the UK- & are not direct correlators- infact other than the NAO which is the highest correlator to the UK the rest all bagged together are loose ( some better than others ) then what is the point of posting such measures of global tendancies when the signal for the UK is non specific.

Lets look at the NAO which has been convieniently overlooked of late-

http://www.cpc.ncep....ndex_ensm.shtml

the mean around +0.5 ( neutral )-- so nothing really exciting there-

& the AO

http://www.cpc.ncep....ex/ao.sprd2.gif

The mean around -2 which is better, however there is a considerable disconnect between the AO & NAO which is unusual-

This is important around my comments above because if we are getting excited about the 'overall' state of the jet then it should be tempered by the fact that the height anomalies across our quadrant doesnt favour UK cold- IE the NAO.

Even the PNA is flat

http://www.cpc.ncep....k/pna/pna.shtml

So the broad assumption is that if the AO ensembles are trending quite negative- supported by the Global AAM & any other measure thrown in for good measure the bottom line is its not driving the NAO.

Should we dwell on the Global measures, no- Worth a comment yes as if the AO is continually trending low then eventually we 'should' tap some of the cold, however some context needs to be presenting when plucking random measures & quoting them into the thread- especially when a large portion of people reading it arent quite sure of what that means for the UK-

In the last week ive seen plenty of assumptions banded around- 'from the regulars, & prior to that it was a quick reload from the NE when the pattern relaxes- according to some.

Very confident forecasts & presumptions being made- 'sustained cold' etc etc - reloads from the North east & east' etc etc.

Well sorry that picture thats being painted by some isnt reflective of whats being modelled, with the H5 pattern & the means not being condusive to anything other than 'flirting' with cold shots from the North West .

The pattern will of course deliver the -5c line crossing the UK from time to time, however the bottom line is in the next 8 days the height of the amplified pattern will deliver very minimal for the UK in terms of below average temps- SOME cold yes, but not sustained & certainly not supportive of low lying snow events.

Remember in Northerly & NE events where the air is modified over the sea you will need a parcel of cold thats lower than the 'assumed' value of -5c @ 850 to deliver convective snow, & lower still if you want any back edge frontal snow.

To many on here now hang off the words of posters that have an agenda as opposed to presenting the reality.

Have I changed, Am I negative, well no- Im being realistic in trying to manage the expectations of what may be around the corner.

In the means this winter has been poor, but luckily the recent cold spell has generated enough snow weather to satisfy most for the winter.- however that doesnt mean to say something is around the corner again.

Is the glass empty or full- well neither- Im saying what I see & commenting on the rather odd assumptions of others, my comments would be that in the 12 years of looking at the models this current evolution will never slow the jet down enough to amplify enough to build a wedge of high pressure over Svalbard which some are alluding to / expecting. its a 1:10 return when it does land ( 2005 ) so its not the form horse.

The lack of clarity shown & minor details to resolve all the way from day 6-10 is what angle the jet takes & where that sets up- over the UK or to the east- the models wont suddenly pump heights into greenland.

Worst case is east of the UK & flat with very average temps.

Best case in strong NW flow with the odd day nearer the North at the height of the Amplitude of the azores high.

I think post that we are scratching around for any trough dropping into Iberia & developing a push of colder air through western Europe.

S

Steve this post could well have been written on the 5th Jan and look what transpired!!!! Look what popped up at short notice. Nothings set in stone, we have a cooling trend across the ensembles and we are entering what is often the most blocked month of the winter.

Unless you have a crystal ball, I'd recommend wasting less energy pointing out all that's against a cold spell, and rather chill out and see what unfolds.

[SMU]

Just for I.Frost- the 552 Line approaching Greenland isnt the tell tale sign of ridging into greenland, infact what I said in the ling post - the ECM would be the height of the amplitude of the azores high- thats the best you get before subsiding south.

The mean flow being from the NW oscillating cool to colder than ave at times is good for Scotland, good for the ski resorts & on occasion good for the NW & through the cheshire gap-

S

[john w]

Im inclined to agree more with Steve Murr in the position reached about sustained and persistent cold developing and the significant correlators. I find this thread interesting and scientific enough to understand, but I never really feel the urge to contribute. But in the years I have followed this there seem to be certain types of posters...those who say what shows and those who like to predict what may show once the realms of 'reliable' step outside the model time frame.

I.e. a good number will look at T120...T196 and suggest a way forward from that which is contrary to what the models may show whereas others will do a decent model summary and not really delve too much in to alternative evolutions.

Its an interesting read, but when the two collide you often get the conundrum of...half saying the models are zonal, flat and mild for the next few days and others saying, ah but if the jet off canada had a slightly steeper angle and the AH ridged jut slightly further north its game on.

I think whats important as well is context. I saw some posts getting on for a fortnight ago that suggested a prolonged and sever cold spell that contingencies should be put in place. Thats fine, but prolonged to many means more than a few days. Prolonged mild to me means 2-3 weeks, maybe more, so I can see why people would sway when its said the other way. Then you have others who post monumentally technical post that are on the periphery of my level of understanding that are related back to basic synoptics in no manner at all. I would suspect half of readers would say, 'so what if the GWO is in Phase 8. What effect does the MJO have on the UK when a Bartlett can ruin winter.

As for the models, they are decidedly not showing a huge amount of potential for sustained cold and thats what they show. I can see the potential for ridging to Greenland, its been hinted at a fair few times in the last few model runs...but none to fruition in the reliable timeframe and I agree. Many who i regard as experts on here said a 2-5 day mild blip before a quick reload from the NE...apologies, but the models dont show that so come out, say why you believed what you did and what went wrong in modelling terms or otherwise (internal thought) so that we can all believe we dont just sing our praises when we are correct.

[SMU]

Steve this post could well have been written on the 5th Jan and look what transpired!!!! Look what popped up at short notice. Nothings set in stone, we have a cooling trend across the ensembles and we are entering what is often the most blocked month of the winter.

Unless you have a crystal ball, I'd recommend wasting less energy pointing out all that's against a cold spell, and rather chill out and see what unfolds.

I think that with respect to looking at the model data that post has no relevance---

Do I need to chill out?--I didnt realise the high level people on here could remotley assess my behaviour from a distance now

I am chilled, supping on a drink thanks....

S

[Methuselah]

Please can we get back to discussing the models?