General Model Output Discussion

[Guest]

I'll no doubt be as popular as a skunk in a very small bag but it has to be said. I've just posted this in the Yorks etc thread as there seems a lack of realism in there also-no doubt in the other regional threads.

I find some of the comments on this regional thread and the model thread pretty amusing.

What we have this morning was correctly predicted about 5 days ago. The deep cold going and being replaced by +ve daytime temperatures, slight precip and that of sleet or at best wet snow, frost unlikely after late Saturday evening.

What have we got-precisely that-so why the consternation?

I've plotted outputs from Extra and NMM daily and its not done at all badly-it has failed to get the minimum values I've had but other than that its done okay.

I suggest a closer and more objective look at the models for some people and an acceptance that the various models will show slightly different end solutions. The trick is being objective and plotting a 'middle' path. That way there is less chance of thinking something is going to happen when the reality is its not going to.

As to what is likely through the latter end of the week then its not going to get mild anywhere other than the far SW. Will the cold return, whatever that means. If you mean the bitter cold with -12C 850's, then that currently looks unlikely as there is no source of such cold air. That is not to say it cannot develop as a result of the weather most of Europe and Scandinavia has experienced for the past 7-14 days-it can. In the meantime we have to live with a more traditional British winter scene-heavy snow in places, especially over high ground with a more wintry mix for southern lower lying areas and the lovely fluffy snow many of us had for several days becoming rather slushy by day and horribly icy when we get an overnight frost.

I'll go now before I get lynched!

Excellent post.

[weather eater]

I'll no doubt be as popular as a skunk in a very small bag but it has to be said. I've just posted this in the Yorks etc thread as there seems a lack of realism in there also-no doubt in the other regional threads.

I find some of the comments on this regional thread and the model thread pretty amusing.

What we have this morning was correctly predicted about 5 days ago. The deep cold going and being replaced by +ve daytime temperatures, slight precip and that of sleet or at best wet snow, frost unlikely after late Saturday evening.

What have we got-precisely that-so why the consternation?

I've plotted outputs from Extra and NMM daily and its not done at all badly-it has failed to get the minimum values I've had but other than that its done okay.

I suggest a closer and more objective look at the models for some people and an acceptance that the various models will show slightly different end solutions. The trick is being objective and plotting a 'middle' path. That way there is less chance of thinking something is going to happen when the reality is its not going to.

As to what is likely through the latter end of the week then its not going to get mild anywhere other than the far SW. Will the cold return, whatever that means. If you mean the bitter cold with -12C 850's, then that currently looks unlikely as there is no source of such cold air. That is not to say it cannot develop as a result of the weather most of Europe and Scandinavia has experienced for the past 7-14 days-it can. In the meantime we have to live with a more traditional British winter scene-heavy snow in places, especially over high ground with a more wintry mix for southern lower lying areas and the lovely fluffy snow many of us had for several days becoming rather slushy by day and horribly icy when we get an overnight frost.

I'll go now before I get lynched!

Seems sound to me John, but then I don't get into the habit of only taking notice of what I want to see, or as some do, only taking notice of what I don't want to see.

[Snowyowl9]

Can you really pick and choose which model, just to give you the answers you want? It's like cheating at exams, the only person you cheat is yourself.

3" reduction of snow cover overnight, temps of +2ºC and lots of dripping water = thaw in my book.

Thats just bad luck for you`re area cloudcover will be alot to do with it, still -1c here with light snow.

GFS still wants to bring this low in and snow tuesday.

http://www2.wetter3.de/Animation_00_UTC/72_30.gif

As long as the winds come in from the east or SE it`s still going to be cold and with drier air coming in as ECM shows very little in the way of a thaw here going to be.

http://91.121.93.17/pics/Rtavn13217.png

[Arnie22]

I'll no doubt be as popular as a skunk in a very small bag but it has to be said. I've just posted this in the Yorks etc thread as there seems a lack of realism in there also-no doubt in the other regional threads.

I find some of the comments on this regional thread and the model thread pretty amusing.

What we have this morning was correctly predicted about 5 days ago. The deep cold going and being replaced by +ve daytime temperatures, slight precip and that of sleet or at best wet snow, frost unlikely after late Saturday evening.

What have we got-precisely that-so why the consternation?

I've plotted outputs from Extra and NMM daily and its not done at all badly-it has failed to get the minimum values I've had but other than that its done okay.

I suggest a closer and more objective look at the models for some people and an acceptance that the various models will show slightly different end solutions. The trick is being objective and plotting a 'middle' path. That way there is less chance of thinking something is going to happen when the reality is its not going to.

As to what is likely through the latter end of the week then its not going to get mild anywhere other than the far SW. Will the cold return, whatever that means. If you mean the bitter cold with -12C 850's, then that currently looks unlikely as there is no source of such cold air. That is not to say it cannot develop as a result of the weather most of Europe and Scandinavia has experienced for the past 7-14 days-it can. In the meantime we have to live with a more traditional British winter scene-heavy snow in places, especially over high ground with a more wintry mix for southern lower lying areas and the lovely fluffy snow many of us had for several days becoming rather slushy by day and horribly icy when we get an overnight frost.

I'll go now before I get lynched!

Well said John - an honest appraisal and a touch of realism

[Candice]

I'll no doubt be as popular as a skunk in a very small bag but it has to be said. I've just posted this in the Yorks etc thread as there seems a lack of realism in there also-no doubt in the other regional threads.

I find some of the comments on this regional thread and the model thread pretty amusing.

What we have this morning was correctly predicted about 5 days ago. The deep cold going and being replaced by +ve daytime temperatures, slight precip and that of sleet or at best wet snow, frost unlikely after late Saturday evening.

What have we got-precisely that-so why the consternation?

I've plotted outputs from Extra and NMM daily and its not done at all badly-it has failed to get the minimum values I've had but other than that its done okay.

I suggest a closer and more objective look at the models for some people and an acceptance that the various models will show slightly different end solutions. The trick is being objective and plotting a 'middle' path. That way there is less chance of thinking something is going to happen when the reality is its not going to.

As to what is likely through the latter end of the week then its not going to get mild anywhere other than the far SW. Will the cold return, whatever that means. If you mean the bitter cold with -12C 850's, then that currently looks unlikely as there is no source of such cold air. That is not to say it cannot develop as a result of the weather most of Europe and Scandinavia has experienced for the past 7-14 days-it can. In the meantime we have to live with a more traditional British winter scene-heavy snow in places, especially over high ground with a more wintry mix for southern lower lying areas and the lovely fluffy snow many of us had for several days becoming rather slushy by day and horribly icy when we get an overnight frost.

I'll go now before I get lynched!

Excellent - nice to see some have their feet firmly planted on the ground. Too many only see the bits they want to see - all down to perception. Thanks for that JH

[Frosty.]

Nothing mild about the GFS 06z, the week ahead looks very cold with max temps never higher than +2 or +3c and lower than that in many areas so the snow cover should survive, just become slushy during daylight hours before freezing over at night. There seems to be a real battle raging in FI with the scandi high fighting hard to gain control against the atlantic which is desperately trying to swamp the uk in mild air but is being held back by the eastern blocking. So, if the 6z verifies, we will have more snow, especially on hills and in the north generally but mild air is shown to encroach into the southwestern extremities of the uk and southern ireland but still no sign of a full scale mild invasion during the next few weeks.

[robnor1]

Excellent - nice to see some have their feet firmly planted on the ground. Too many only see the bits they want to see - all down to perception. Thanks for that JH

Yes i saw the BBC forecast last night for wiltshire area today

light snow 2 -5 cm , strong winds drifting snow and -3 to -4 quite widely

WRONG WRONG WRONG

[Cecil Hogmanay Melchett]

Nothing mild about the GFS 06z, the week ahead looks very cold with max temps never higher than +2 or +3c and lower than that in many areas so the snow cover should survive, just become slushy during daylight hours before freezing over at night. There seems to be a real battle raging in FI with the scandi high fighting hard to gain control against the atlantic which is desperately trying to swamp the uk in mild air but is being held back by the eastern blocking. So, if the 6z verifies, we will have more snow, especially on hills and in the north generally but mild air is shown to encroach into the southwestern extremities of the uk and southern ireland but still no sign of a full scale mild invasion during the next few weeks.

But n24 bbc are saying all over by wed! :crazy:

I guess they are getting their headline from the metoffice but ukmo doesnt say all over by wed and neither does ecm???

[Eugene]

Nothing mild about the GFS 06z, the week ahead looks very cold with max temps never higher than +2 or +3c and lower than that in many areas so the snow cover should survive, just become slushy during daylight hours before freezing over at night. There seems to be a real battle raging in FI with the scandi high fighting hard to gain control against the atlantic which is desperately trying to swamp the uk in mild air but is being held back by the eastern blocking. So, if the 6z verifies, we will have more snow, especially on hills and in the north generally but mild air is shown to encroach into the southwestern extremities of the uk and southern ireland but still no sign of a full scale mild invasion during the next few weeks.

Nice to see someone actually discuss the models for once frosty, spot on post there, remember countryside areas will be colder than urban areas so hardly any thaw likely for countryside areas.

Excellent trends on the models this morning esp ECM for our blocking high to our east to remain in place and stop a mild invasion, its amazing to watch all the mild atlantic air filtered out on GFS 06Z so we have a mass of cool to cold air to our west, watch out for later in the week for the High to our east to edge further west on each subsequent GFS run.

http://www.wetterzentrale.de/pics/Rtavn2162.png

[snowingtequila]

I haven't seen the BBC forecast but it would seem to me that what is all over is the deep cold for a while. The models all show this and have done for a while. However the models do not all show mild conditions and snow is still probible in places this week particularly in the north and the ECM is still showing possibilites of the bloack coming back over us as soon as next monday. I knew the coldest spell was going to end when the met office and BBC started announcing there was no end in sight and grit has been ordered from abroad which will arrive when all the ice has gone!

[Snowmoon]

I find some of the comments on this regional thread and the model thread pretty amusing.

What we have this morning was correctly predicted about 5 days ago. The deep cold going and being replaced by +ve daytime temperatures, slight precip and that of sleet or at best wet snow, frost unlikely after late Saturday evening.

What have we got-precisely that-so why the consternation?

It's constantly reinforced in this forum that anything beyond the next 3 days or so is to be regarded as FI, so any predictions made a week ago would fall into that category. It's also been said that snow amounts and locations can change within hours of "now", so I think many people have been basing their expectations on forecasts made during past 24 hours. Yesterday, the BBC forecasts were suggesting widespread light snow throughout the day right across the southern half of England and Wales, with significant amounts in a number of places. Today, they've downgraded that to being little more than snow flurries here and there with the possibility of something more significant overnight on some hills. I believe that's the reason for the consternation.

As others have commented, I feel there's a gap in these forums, when there's uncertainty in what might happen, where what models are saying regarding the weather in the near/immediate future is either ignored or lost in a sea of FI posts. It would also be interesting to see more posts within a day or two of the event comparing what actually happened to what the models predicted would happen, thus reviewing which models called it best. There's an understandable concentration on what's to come rather than what's been but, as far as models are concerned, analysing their performance is arguably more important than their future predictions. Perhaps the forum structure might be reviewed to compartmentalise things more, although I appreciate more forums would mean more work for the mods.

Just my two penneth! <_<

[weather eater]

But n24 bbc are saying all over by wed! :crazy: <_<

I guess they are getting their headline from the metoffice but ukmo doesnt say all over by wed and neither does ecm???

I suspect that what they mean by that, is that by mid week we will have seen the last of the country wide snow falls, we will also have seen the last of the truly cold temperatures. This also entails a slow thaw for many, especially in the south. Looking at the recent model runs this seems to be fair assessment. Of course things may change but I think we have a fair agreement across the board model wise at the moment.

Edited January 10, 2010 by weather eater

[chionomaniac]

I'll no doubt be as popular as a skunk in a very small bag but it has to be said. I've just posted this in the Yorks etc thread as there seems a lack of realism in there also-no doubt in the other regional threads.

I find some of the comments on this regional thread and the model thread pretty amusing.

What we have this morning was correctly predicted about 5 days ago. The deep cold going and being replaced by +ve daytime temperatures, slight precip and that of sleet or at best wet snow, frost unlikely after late Saturday evening.

What have we got-precisely that-so why the consternation?

I've plotted outputs from Extra and NMM daily and its not done at all badly-it has failed to get the minimum values I've had but other than that its done okay.

I suggest a closer and more objective look at the models for some people and an acceptance that the various models will show slightly different end solutions. The trick is being objective and plotting a 'middle' path. That way there is less chance of thinking something is going to happen when the reality is its not going to.

As to what is likely through the latter end of the week then its not going to get mild anywhere other than the far SW. Will the cold return, whatever that means. If you mean the bitter cold with -12C 850's, then that currently looks unlikely as there is no source of such cold air. That is not to say it cannot develop as a result of the weather most of Europe and Scandinavia has experienced for the past 7-14 days-it can. In the meantime we have to live with a more traditional British winter scene-heavy snow in places, especially over high ground with a more wintry mix for southern lower lying areas and the lovely fluffy snow many of us had for several days becoming rather slushy by day and horribly icy when we get an overnight frost.

I'll go now before I get lynched!

John, after reading that I feel I have just put my head in a small bag containing a skunk and sniffed hard!

Another realistic analysis, thank you.

[chapmanslade]

Yes i saw the BBC forecast last night for wiltshire area today

light snow 2 -5 cm , strong winds drifting snow and -3 to -4 quite widely

WRONG WRONG WRONG

It was -3C last night, it was never predicted to be -3C during the day, light snow falling here as predicted

But n24 bbc are saying all over by wed! :crazy: <_<

What is all over - the world or the cold weather ?

We have to remember that what we have had over the last few days is very rare and extreme and so unlikely to continue for long. The models are showing nothing mild at all, maybe a return to somewhere near average in the far SW. It just isn't possible to have a continental style freeze in the UK as we stick out into a relatively warm bit of water

[anvilhead]

I'm not so sure though a reload is on the cards for a considerable amount of time- the NH lowest heights seem to go into a stage of retracting and consolidating towards the pole and rosby waves get a shift on in the normal direction. The High seems to hold on for a while and there are signs of continued low heights in the med and trough disruption/absorbtion out over the atlantic, but I dont see the pv playing ball to the NE of the high for quite some time & this I believe will eventualy shunt the high east if things stay out of phase..

gfs:

http://91.121.94.83/modeles/gfs/run/gfsnh-0-24.png?12

http://91.121.94.83/modeles/gfs/run/gfsnh-0-60.png?12

http://91.121.94.83/modeles/gfs/run/gfsnh-0-84.png?12

http://91.121.94.83/modeles/gfs/run/gfsnh-0-120.png?12

http://91.121.94.83/modeles/gfs/run/gfsnh-0-168.png?12

ukmo:

http://www.meteociel.fr/ukmo/run/UN24-21.GIF

http://www.meteociel.fr/ukmo/run/UN60-21.GIF

http://www.meteociel.fr/ukmo/run/UN96-21.GIF

http://www.meteociel.fr/ukmo/run/UN144-21.GIF

[swfc]

It was -3C last night, it was never predicted to be -3C during the day, light snow falling here as predicted

What is all over - the world or the cold weather ?

We have to remember that what we have had over the last few days is very rare and extreme and so unlikely to continue for long. The models are showing nothing mild at all, maybe a return to somewhere near average in the far SW. It just isn't possible to have a continental style freeze in the UK as we stick out into a relatively warm bit of water

Very knife edge situation regarding a cold outlook and any break down.granted the extreme temps of the last few days are gone but the outlook model wise is far from clear.regarding the bbc forecast,its not been mentioned about any end to cold weather and there uncertainty is shown in the forecast.

[Uncle_Barty]

I like what TWO have done and had a separate thread for mesoscale / short term model analysis, maybe something we could adopt here.

I am not surprised that things have turned out slightly different to that forecast WRT snow - history is littered with such events and I always temper any snow forecasts with a remark that these things can turn out differently - it's simply the nature of the beast. Exactly as happened here last Tuesday.

Anyway - back to the models. Plenty of uncertainty beyond 72-96h and I am taking on board GP's comments that the models may well struggle for a few days with upstream developements suggesting that the building blocks may be there for a renewed attack of cold from the E/NE in a week-10 days.

WE shall see!

[BLAST FROM THE PAST]

When we get temps widely above 6c then talk of rapid thaw and end of cold spell. And to show how cold spells can whimper out...the following chart ended the great freeze of Feb 86...no battle royale.

It will be less cold until Wed when it will turn a chillier again, but the change is underway BUT it will be cold for sometime yet barr the far SW. Seeing a warm front hit the south rather than troughs was always a danger signal.

BFTP

Edited January 10, 2010 by BLAST FROM THE PAST

[Osbourne One-Nil]

but im dissapointed its gone but happy with the memory of winter 2010 it was brillant.

It's January 10th.

[MR EXTREMES]

When we get temps widely above 6c then talk of rapid thaw and end of cold spell. And to show how cold spells can whimper out...the following chart ended the great freeze of Feb 86...no battle royale.

It will be less cold until Wed when it will turn a chillier again, but the change is underway BUT it will be cold for sometime yet barr the far SW

BFTP

absolutely ofcoarse it will end at some point i think that the models are a little unsure of the final outcome.

id certainly say that most of the southern half of england will continue with this thaw,

id expect by tuesday it will be all gone it melting pretty quick right now but then this mostly due to sleet and drzzle and higher air temps.

as for wed thursday frontal attack i cant see the south getting anymore maybe on the highest ground even here marginal.

as i said though always a chance of a reload later its only 2 weeks into jan and there are some indications of maybe a sww event hopefull gh and neg ao would really push things along.

is el nino about to run the show in the next 7 to 10 days or will the cold fight back classic stuff though for a nino year,

exciting stuff if you ask me.

[weather eater]

When we get temps widely above 6c then talk of rapid thaw and end of cold spell. And to show how cold spells can whimper out...the following chart ended the great freeze of Feb 86...no battle royale.

It will be less cold until Wed when it will turn a chillier again, but the change is underway BUT it will be cold for sometime yet barr the far SW. Seeing a warm front hit the south rather than troughs was always a danger signal.

BFTP

A slow thaw would be my guess, however some places on the NE coast are already reporting 5.6c, I think OON is reporting 2.6c or so in the SW, so maybe a thaw quicker than expected, we shall see.

Edited January 10, 2010 by weather eater

[Osbourne One-Nil]

I must admit to being at a loss to understand the poor precipitation forcasts so far this weekend.

May I suggest that precipitation forecasts are always wrong to some degree, but it's simply that when it's rain predicted, it's very rare for people to care and to take any notice whatsoever? I've rarely heard of anyone berate the Met Office for predicting 5mm of rain overnight, when it fails to turn up, yet when it comes to snow, there are many on here (and I'm not suggesting you're one of them) for whom it's the end of the world.

[grab my graupel]

Folks, This isn't the thread to discuss the Media forecasts etc. Can we stick to the Models please?

Thank you

Brian

[tinybill]

well could there be a reload at the end of the week!!!

[johnholmes]

I must admit to being at a loss to understand the poor precipitation forcasts so far this weekend.

The forcasts and warnings were still calling for moderate to perhaps significant snowfall for east Anglia,

the 3 counties, London and the south east during the 24 period from midday yesterday through the night

and into today.

Looking at the radar yesterday afternoon I could not see where this snow was coming from and when

family members rang to ask when was the bad weather to set in I replied "I haven't a clue" as there was

no evidence of any adverse weather on the radar for these areas in the near or longer term(overnight).

The radar images showed no precipitation over northeast France or the low countries during this time

period either and with the higher resolution radar imagery that they have at there disposal this must

have been obvious to them as well.

John I wonder if you could shed some light on this as I was just wondering in situations like this do they

tend to generalize more rather than be specific.

I think if we are all honest CC we over estimated the model prediction of intensity. As you and several others have pointed out the radar last evening showed nothing more than slight intensity. There was nothing, if one went back to first principles, of forecasting for 12-24 hours ahead, looking at pressure tendencies, skew- t diagrams, surface chart information, etc that suggested it would change much. Pockets of moderate intensity so snow at times even on low ground but not the amounts that were being predicted.

The forecasts issued were overdone-as simple as that-and most of us 'fell' into that trap and need to hold our hands up for it- I do.

Not the first time and not the last I'm sure-but it will remind me to look at first principles for 12-24 hour forecasting rather more than I did last evening.