Model Output Discussion - 1st - 7th January

[SP1986]

Pressure rises over Greenland mean absolutely nothing unless you can either get a link with the Azores high (which seems to be the issue on these latest runs), or that the High pressure is so intense that it forms a true Greenland High.

What is occurring at the moment is any modelled high is a product of the topography of Greenland, and because of that the jet keeps running normal service.

[Frosty.]

No sign of Armageddon cold in either the GFS or the ECM this morning although a hint of a return to mobile Atlantic and storms once again with returning pm air. The quieter spell of weather starting now but the weather here hasn't read the script so far.

That's old news, the gfs 06z is now similar to the gem 00z with a better chance of colder prospects after next week's settled spell.

[cold snap]

oh dear not great viewing.just maybe there is a small hint that gfs could follow the gem,just a tiny hint.the ecm is very poor and could go on and on being zonal

One country that want like a pattern change is bulgaria ,non stop snow there.there on the right side of that high nice block for them

we await the 12z .hopefully we can see something close to the gem

Edited January 7, 2012 by cold snap

[SMU]

At the moment im following the control run it looks like the GEM-

S

[nick sussex]

Yet another scenario popping up now in FI with some support for the GEM.

I wonder what tonights output might bring? Putting aside the volatility in the output the chances of a nw/se tilt to the jet with initially some cooler zonality then pressure increases to the ne seems a good starting point.

From there given the background strat warming this could easily see the jet pushed much further south with high pressure transferring from the ne or east to Greenland, remember many Greenland blocks start off as an easterly and then the pattern retrogresses with trough developing over Scandi, you do though have to have that background signal for northern blocking.

[k19]

Sorry folks to butt in but I follow this thread daily like a big kid. I have a couple of questions that I need answering.

What is the GFS 6z run

What is the GFS 12z run and why it is different to the 6z.

What FI means.

I also use the meteociel site daily but the above questions annoy me following this thread because I am not sure what you guys mean when quoting them.

Thanks,

A keen 38yo weather fan.

1) The gfs 6z is the GFS model that is run starting at 6am everyday (although it is released starting at 9-45)

2) The 12z is the same as above but released starting at 12pm daily. The data inout will be slightly different as raw data will have changed, giving new charts.

3)FI is fantasy island, as in, it is so far away that it is unlikely to come off, and therefore is just fantasy

[TEITS]

Only just got chance to view the ensembles but now the GEFS control is moving towards the GEM. Are we about to see a massive turnaround in the model output with a E,ly developing around the 15/16th? Answer who knows but I wouldn't bet against it!

[bluearmy]

http://www.weathercast.co.uk/services/ensemble-forecast.html

that small uptick in mean temps around the 17/18th is still there. mean ridge passing through before the next depression moves in ??? looking at the general scatter, i'm not surprised that there really aren't any clusters showing at day 10 on the ecm mean charts. very uncertain as we approach the 20th.

[shedhead]

Yet another scenario popping up now in FI with some support for the GEM.

I wonder what tonights output might bring? Putting aside the volatility in the output the chances of a nw/se tilt to the jet with initially some cooler zonality then pressure increases to the ne seems a good starting point.

From there given the background strat warming this could easily see the jet pushed much further south with high pressure transferring from the ne or east to Greenland, remember many Greenland blocks start off as an easterly and then the pattern retrogresses with trough developing over Scandi, you do though have to have that background signal for northern blocking.

Agreed Nick, that's why I think the pattern shown by the 06 GFS in FI is looking increasingly plausible around mid month, though I'm yet to be convinced that an Easterly, let alone a Beasterly will ultimately transpire. For my money late Jan and Feb look set to be dominated by a flow from a N'erly quarter though.

Edited January 7, 2012 by shedhead

[bluearmy]

Ongoing poor outlook for cold fans. The 06z shows the Arctic High and that is as close as it is likely to come to influencing matters and if those synoptics happen and it duly fails it does us no good in the long run.

Essentially the models are continuing with the theme of a northerly jet and Azores High, The US guys are not hopeful of amplification upstream going forward.

you keep talking about the US guys. why are they any more relevant than the more knowledgeable guys on here ?? the pattern is changing, as you expected it would. i wouldn't be over confident that we stay on the mild side of it once it has. a little less certainty in your posts will do your reputation a power of good ian.

[nick sussex]

I would . I will lay you 100/1 on an easterly within the next 9 days.

25/1 against one before the 26th.

The emergence of a possible Arctic High is a foe not a friend.

Could you explain Ian why an Arctic high would be a bad thing, surely the way to cold is through a negative AO eventually transferring to the NAO sending this negative.

[Cloud 10]

The gfs operational heads into mild outlier territory around the 15th.

It pushes the "limpet high" to far east compared to ensemble guidance,so maybe

one for the shredder.

edit.

Latest meto update looking a bit better.

UK weather forecast - Met Office

Edited January 7, 2012 by Cloud 10

[Catacol]

The emergence of a possible Arctic High is a foe not a friend.

eh? I know we cant disagree with your face value interpretations of the models at present - it is the model thread after all - but this I dont understand. How can an arctic high, which is characteristic of the vortex on the move, be a foe? Always the chance of ending up on the warm side of the amplified pattern as a result, but also a chance of being on the cold side? And are the models not hinting at such a shift to an amplified pattern? I note that you do not want to acknowledge that at all.

Edited January 7, 2012 by Catacol_Highlander

[Stuie]

1) The gfs 6z is the GFS model that is run starting at 6am everyday (although it is released starting at 9-45)

2) The 12z is the same as above but released starting at 12pm daily. The data inout will be slightly different as raw data will have changed, giving new charts.

3)FI is fantasy island, as in, it is so far away that it is unlikely to come off, and therefore is just fantasy

Thank you very much!

[nick sussex]

There are countless synoptic set-ups I could run through where the Arctic High emergences but fails to influence matters at mid-latitude, the one massive exception being Jan 87.

I deal in probabilities from the proposed synoptic set-ups going forward. And where we are at the end of the reliable timeframe is historically poor for cold fans going forward. Anything else is straw clutching when you look at the NAO set-up.

The US guys are often quick to spot amplification and how they see things in the Pacific. They see a flattish jet going forward and an SE ridge.

Thanks for at least explaining how you to get to that conclusion. I'm happy to see how things develop over the next few days, I think you'd agree that strat warmings in terms of effects on modelling aren't an exact science.

For this reason I think several options remain on the table.

[SP1986]

I can understand where Ian is coming from, as the Arctic High is forming with still an intense PV alongside, if the Arctic High forms, as it stands it will most likely go into Europe (the true cold air), and could create a bottled up situation whereby the Atlantic explodes into life due to the pressure differential (hard to explain but you may understand), however on the other hand, the GEM creates a scenario whereaby the high sets up in such a position that it brings in a more continental run with easterlies.

At the moment though, we'll really have to wait until the 12z run to ensure that the GEM (and GFS) have started a trend - there are not even guarantees from that of notable cold, initially though.

[nick sussex]

I can understand where Ian is coming from, as the Arctic High is forming with still an intense PV alongside, if the Arctic High forms, as it stands it will most likely go into Europe (the true cold air), and could create a bottled up situation whereby the Atlantic explodes into life due to the pressure differential (hard to explain but you may understand), however on the other hand, the GEM creates a scenario whereaby the high sets up in such a position that it brings in a more continental run with easterlies.

At the moment though, we'll really have to wait until the 12z run to ensure that the GEM (and GFS) have started a trend - there are not even guarantees from that of notable cold, initially though.

Yes thats a good point re the Atlantic and why I don't think theres going to be a sudden change in pattern, more a transition spell with that cooler/colder zonality before anything else can happen.

As the Arctic high starts to push the cold air out of the polar regions its like throwing a grenade into a warehouse of fireworks, this is likely to ignite the jet, this is why the axis of the jet as this happens is important.

So the orientation of the Arctic high will be a key component, I think Ian expects the jet to remain flat in tandem with that high and hence thats why he's called it a foe, now the difficult part comes in relation to the PV, nobody really knows yet what exactly is going to happen to this and what effect and how quick any changes will be felt if we do indeed see a SSW.

In these types of situations its difficult to decide where the balance of power will be regarding the Arctic high versus the PV, if that weakens then a change to colder conditions looks much more likely, if it remains powerful then we need to hope that the jet remains far enough south and tilted favourably, there is of course the flatter scenario.

So IMO nothing is ruled in or out at the moment.

[January Snowstorm]

I would . I will lay you 100/1 on an easterly within the next 9 days.

25/1 against one before the 26th.

The emergence of a possible Arctic High is a foe not a friend.

I'm inclined to agree with Ian.

The azores high remains (has done now for weeks) the key player and its as strong as ever in 10 days time.

I'm beginning to Nick S has handed out prozac in extra doses and folk are seeing all sorts of things in the charts when in all honesty things look brutal for cold

[SP1986]

Nick, yes, the PV really needs to be destroyed (can't think of a better word), in order for full potential to be realise, otherwise the pressure/temperature gradient over east Canada will mean we keep spawning those lows. A PV broken into little pieces might work, but it's case then of dodge the piece of the PV! If we manage that, then we can manage some persistent cold.

[nick sussex]

I'm inclined to agree with Ian.

The azores high remains (has done now for weeks) the key player and its as strong as ever in 10 days time.

I'm beginning to Nick S has handed out prozac in extra doses and folk are seeing all sorts of things in the charts when in all honesty things look brutal for cold

JS remember the high to the south is just a response to the upstream pattern and not some awful entity thats moved in got a job, married and waiting for the grandchildren to arrive! with no intention of ever moving from there.

I think an open mind until we see the exact orientation of Arctic high and jet is the best way to go. I do have the prozac supplies though on standby in case of net weather emergencies!

[Backtrack]

GFS 06z FI is nice today.

It's illustrating clearly how GP's expectations of a rinse and repeat attack of Northerlies can come off.

We have plenty of reload NW'erlys and Polar Westerlies bringing colder air over the UK. I expect to see further upgrades during the coming days.

[Matty M]

the entire ECM suite at 168hrs there isnt one good chart for anyone looking for cold weather.

Edited January 7, 2012 by Matty M

[bluearmy]

JS remember the high to the south is just a response to the upstream pattern and not some awful entity thats moved in got a job, married and waiting for the grandchildren to arrive! with no intention of ever moving from there.

I think an open mind until we see the exact orientation of Arctic high and jet is the best way to go. I do have the prozac supplies though on standby in case of net weather emergencies!

if the 06z had been the same as the 00z op run wrt the azores ridge, i would be more concerned. its so different in high res that i really wouldn't be reading too much into any of its current output. until it gets a handle on what it expects to happen pre T192, what hope can we have on the reliability of its trending in low res.

the entire ECM suite at 168hrs there isnt one good chart for anyone looking for cold weather.

and how much of the NH can you see matty at T168? no one is predicting anything cold in the next week. the postage stamps are not able to show upstream or the polar profile so why worry about them wrt to what is likely beyond day 10 ?

[Yorkshiresnows]

Ongoing poor outlook for cold fans. The 06z shows the Arctic High and that is as close as it is likely to come to influencing matters and if those synoptics happen and it duly fails it does us no good in the long run.

Essentially the models are continuing with the theme of a northerly jet and Azores High, The US guys are not hopeful of amplification upstream going forward.

Which US guys are you talking about?

Joe B and Joe D are gunning for a major pattern change mid month ......... have you even looked in on the Stratos thread. What do you think the chances of a SSW event. Looks mighty probable to me.

Jet to head South and pressure to rise over Greenland with time as whats left of the PV gets shunted towards Scandi. That's if there's anything left of the Polar Vortex by months end.

Anyway, we will see how it all pans out.

Y.S

Edited January 7, 2012 by Osbourne One-Nil

[Cecil Hogmanay Melchett]

Whilst it would be idiotic to rule out the whole of Jan at this early stage it does appear that the first 20days or so are almost certainly not going to produce anything wintry for the vast majority in the UK.

As alluded to by IB the +NAO signal is there for all to see yet again this morning and i see little or nothing to suggest a change is coming anytime soon.,

On the other hand we do have a fairly decent warming of the strat going on so the hope of something more seasonal into Feb is a fair shout right now.

The clock is ticking now though,if we wipe off half of jan (which is almost certain),then in my book we have around 4 weeks of potential for proper decent cold (not snow thawing by dinner time).

If we are still seeing the same dross in 2 weeks i'll be worried,or fed up,or come to think of it,both.