Model Output Discussion

[weather eater]

I dont think think a cold pattern is likely to develop based on the premise of one run. The 06z was showing something completely different. In all honesty if these Atlantic patterns in the near time disappoint people then well, I find that truly shocking - the fact is weve just come out of one of the most intense winter cold spells for 30 years and people are disappointed about the Atlantic, seriously I have to wonder about people sometimes.

In the 'realistic' timeframe there's no real signal either way so we'll have to wait for a few days before knowing where this one is going.

The 06z was different but it still developed a HP ridge in the mid-Atlantic, as have other recent GFS runs, this to me is a clear trend, at least on the GFS. We often talk of trend spotting, but it always strikes me as odd when some people can't seem to see them. Maybe they are just looking in the wrong direction, west not east will be where the crucial block forms, if we are to have a chance at activating the cold to the east over us. I'm not for one minute suggesting that this will absolutely happen or that it will automatically lead to a cold spell in the manner of the 12z. I don't get into this cold hunting malarkey, I just comment on what the models show, I'll leave it for others to decide whether it’s plausible.

[cooling climate]

I dont think think a cold pattern is likely to develop based on the premise of one run. The 06z was showing something completely different.

Um no it wasn't, remember we are talking about trends not details and on the 06z GFS the trend for

t192 and beyond was for northern blocking. This has just been repeated on the 12z GFS run and if this

is so then a pound to pinch of salt says we are just days away from another very cold spell of weather.

[Ben_Cambs]

Um no it wasn't, remember we are talking about trends not details and on the 06z GFS the trend for

t192 and beyond was for northern blocking. This has just been repeated on the 12z GFS run and if this

is so then a pound to pinch of salt says we are just days away from another very cold spell of weather.

Agree with you there, this has appeared on the past few runs of GFS. IMO its still not a trend yet though, but great signs

[Weather-history]

In the shorter term the UKMO brings some colder upper air further west than the GFS at 72hrs, the shortwave looks well placed to deliver some snow for those on the northern flank.

http://www.meteociel.fr/modeles/ukmo2.php?nh=&ech=72&carte=1021

http://www.meteociel.fr/modeles/ukmo2.php?nh=&ech=72&carte=1007

Even at this timeframe still likely to be further changes but overall a good chance of some snow, some doubt though about the next front coming in on Thursday as to what that would produce but a chance of two snow events but the second probably needs much higher ground.

I think the highest risk areas for the first event are the Midlands towards EA but away from coastal fringes down towards the SE north of the Thames, the second more northern areas with elevation.

2m temps are chilly

Plenty of preciptation

Uppers

Pennines and Peak District look favourable.

Not to far off from what happened in mid January 1922

[mcweather]

I have to say the most noticeable thing about the ecm 00Z and the gfs 12Z operational runs is their convergence at 216 onwards. They both now want to send the low southeastwards into Europe and help pull out the block in the longer term.

A long way off I know but this time it is the ECM which is moving towards the gfs rather than the other way round.

I personally think that the Atlantic is flattering to deceive at the moment. The core fact is that the Atlantic is moving in

because the block is retreating slightly not because it has suddenly found some new powerful lease of life.

[john mac]

there seems to be a bit more interest on here this afternoon, i get the feeling that a lot of people on here are suffering from a cold spell hangover,

[karyo]

Plenty of preciptation

Uppers

Pennines and Peak District look favourable.

Hopefully another snow event for Manchester too! The band of precipitation seems to stall and not even make it to the east of England, while yesterday, the models were showing a slow west to east progression.

Karyo

[SP1986]

Um no it wasn't, remember we are talking about trends not details and on the 06z GFS the trend for

t192 and beyond was for northern blocking. This has just been repeated on the 12z GFS run and if this

is so then a pound to pinch of salt says we are just days away from another very cold spell of weather.

Well to be fair having just viewed the NAO and AO, it seems it is set to become deeply negative again so if anything that suggests a return to colder weather, if not colder than we've already had, but this is not necessarily written in.

As for 06z yes it was different, although the realistic evolution was similar, the extended evolution was completely different which suggests it could go either way.

Still of course I enjoy watching the reactions to anyone who doesn't automatically subscribe to the next cold spell!

[shiver]

You won't be missing out on anything other than rain unless you fancy a trip to a high hill in Derbyshire or somewhere further North !

you have not seen the meto run yet then ian?

[john mac]

Well to be fair having just viewed the NAO and AO, it seems it is set to become deeply negative again so if anything that suggests a return to colder weather, if not colder than we've already had, but this is not necessarily written in.

As for 06z yes it was different, although the realistic evolution was similar, the extended evolution was completely different which suggests it could go either way.

Still of course I enjoy watching the reactions to anyone who doesn't automatically subscribe to the next cold spell!

Well thats good news stephen about the AO & NAO going deeply negative, this all bodes well and goes in our favour for a renewed cold spell.

Why do you think that it may be colder than the last one? Thats got to be pretty special

[karyo]

I said yesterday that if there was to be a snow event (which I don't think there will be away from the Highest ground of the Southern Pennines Northward) then it will be because the front stalls over the spine of the country. However it will be weakening in the face of the High to the East.

Yes, I suppose there will be further small changes from now till Wednesday. Worth watching!

Karyo

[john mac]

Well it will be very interesting to see what the ECM shows tonight with some very encouraging charts this afternoon.

[SP1986]

Well thats good news stephen about the AO & NAO going deeply negative, this all bodes well and goes in our favour for a renewed cold spell.

Why do you think that it may be colder than the last one? Thats got to be pretty special

It is hard to tell really, I suppose I'm assuming the blocking will be as stubborn as the last lot. I know it doesn't work like this but with the solar minimum in force and the NAO/AO going negative in the forecasts once more I can't help but think it could be colder - of course it depends on whether the NAO/AO is able to be sustained in the forecasts, plus also things like snowfall/snow cover.

Even if it did happen it would probably a few weeks away.

I personally don't think this realistic timeframe at the moment is alluding to anything, and as Ian says I think it will change - eventually there will be another cold spell but it's all tenter hook stuff at the moment.

[BLAST FROM THE PAST]

Moring Fred.

Have to say mate im not convinced of this stormy period. The SLP ensembles for Dublin suggest a mean around 1010mb for this period with the Aberdeen SLP mean at 1005mb.

http://charts.netweather.tv/ensimages/ens.20100117/06/prmslDublin.png

Whilst there is plenty of scatter the mean doesn't suggest a deep LP system bringing a stormy period.

Hi Dave

Yes I am on your side re renewed cold spell developing because it will form off the back of LPs that crash through the UK. I say stormy as in that the LPs will gatecrash the UK rather than be hundreds of miles to north of Scotland so well feel the brunt. I will stick with very end of Jan into beginning of Feb for any real cold shot.....BUT we must look north and NE. Ridge in Atlantic and sinking trough in Scandi...very similar to what we had.

BFTP

He may feel that, because the Lunar Module is in full pedigree chum, or maybe that a couple of recent runs have hinted at a deep depression for around that time, certainly the ECM does.

Nice one W E ....but nowt to do with the models...they didn't go that far out in November...did they?

BFTP

[john mac]

The trend from T144 onwards shows a subtle change from the output of yesterday with High pressure building towards the UK from the South rather than a pattern driven by Lows to the W/NW. If the AO and NAO are to turn negative again then it's very difficult for the models to handle with such low height already in place to the NW; there could be some wild swings in the output past T120 over the coming days.

Yes I have but I back the GFS at this range.

Hi Ian what makes you think that there will be such wild swings in the charts, is it because you think there's a new trend being picked up by the models?

[492]

Latest T+72 UKMO fax appears to be an upgrade and puts a bit more of the UK at risk for snow.

[weather eater]

Hi Dave

Yes I am on your side re renewed cold spell developing because it will form off the back of LPs that crash through the UK. I say stormy as in that the LPs will gatecrash the UK rather than be hundreds of miles to north of Scotland so well feel the brunt. I will stick with very end of Jan into beginning of Feb for any real cold shot.....BUT we must look north and NE. Ridge in Atlantic and sinking trough in Scandi...very similar to what we had.

BFTP

Nice one W E ....but nowt to do with the models...they didn't go that far out in November...did they?

BFTP

Everybody gets some luck sometimes Fred. As for the future, What you say seems possible, certainly the 12z hints at something like that, as have other recent GFS runs and I know you're a good reader of the models.

[karyo]

It is hard to tell really, I suppose I'm assuming the blocking will be as stubborn as the last lot. I know it doesn't work like this but with the solar minimum in force and the NAO/AO going negative in the forecasts once more I can't help but think it could be colder - of course it depends on whether the NAO/AO is able to be sustained in the forecasts, plus also things like snowfall/snow cover.

Careful Stephen, you're going to rise people's expectations and there could be some wrist slushing in the near future!

Karyo

[nick sussex]

An interesting ECM 120hrs which disrupts the trough further west, very close to keeping the cold air hanging on in the east. At that timeframe the margin for error could mean it goes one of two ways.The ECM 144hrs gets even more interesting with the block holding firm and pressure rising to the ne, looking at the trend from the ECM those boarding the mild train over the last few days are about to be delayed as this looks like derailing.

Edited January 17, 2010 by nick sussex

[cooling climate]

Like the GFS 12z it looks like it will take a second bite of the cherry before the cold is

ushered in on the 12z ECM run.

Very, very encouraging signs though.

[igloo]

good consistency between the GFS and ECM up to +168 a positive sign

[Severe Siberian icy blast]

To think just a few days ago ones were saying the next 10-15 days were mild and wet with a near bartlett situation, infact that was this morning also . In reality it says how hard this block is to shift as its looking more and more likely that its nothing more than a milder blip , intersting times ahead.

[BLAST FROM THE PAST]

Everybody gets some luck sometimes Fred. As for the future, What you say seems possible, certainly the 12z hints at something like that, as have other recent GFS runs and I know you're a good reader of the models.

We all need a little luck and it seems I've had a lot of luck this Nov and winter.....for folk that like strong winds and heavy cold rain[as I do] lets hope for more!! The set up and proposed set up for me screams of the jet angling southwards again and the models are certainly hinting that way. It is of course still FI BUT what we have seen this winter and how things quickly develop then T120+ has to be viewed with suspicion and one needs to add instinct, experience, differing methods, teles etc. Even next Wed is not set in stone...very interesting times. I tell you what it was pretty chily today and it is cold right now...I'm supposed to be under fog and +2c tonight...I reckon sub 0c is on.

Another angle coming from 12z ECM, looks chilly 144 to 168. Many twists and turns to come.

BFTP

Edited January 17, 2010 by BLAST FROM THE PAST

[Eugene]

To think just a few days ago ones were saying the next 10-15 days were mild and wet with a near bartlett situation, infact that was this morning also . In reality it says how hard this block is to shift as its looking more and more likely that its nothing more than a milder blip , intersting times ahead.

Yes some did but others like myself didn't.

ECM 12Z is a run full of potential, the kind of run in winters past we would all get excited over but due to how good this winter has been so far we are less interested.

Not much mild, wet and windy weather on that run that's for sure.

Feels chilly right now, some mild spell

[MR EXTREMES]

im skeptical tomorrow is likely to be total oposite.

models are not handling things very well im not saying this for any other reason than to be carefull of the hype,

its nothing like the setup just gone so id expect anything cold to be a fleeting visit.

im still in the opion that tonights outputs are rather to much of a backtrack perhapes and i hope im wrong.

im now 70/30 mild will dissapoint us.