Model Output Discussion

[yamkin]

http://www.hpc.ncep.noaa.gov/discussions/pmdepd.html

Some interesting discussion on the noaa update.Looks like some severe weather to come over in the states.

very interesting. I noticed they commented on the GFS 00Z remaining an outlier..........

[karyo]

I think some of the behaviour in here by certain posters has been dismal and very disappointing! This nit picking and being argumentative for the sake of it especially aimed at Tamara is very poor IMO!

I wholeheartedly agree!

Anyway, the 18z is interesting throughout and has similarities with the 12z ECM. The ECM ensembles were milder than earlier runs.

The 18z ensembles are unexciting: http://www.netweather.tv/index.cgi?action=ensviewer;sess=

It's an unclear picture so let's see where tomorrow will take us.

Karyo

Edited January 14, 2010 by karyo

[davehsug]

Blimey this is a controversial place tonight! Seems to me it's because in particular the models are showing all things are possible. As a result the "coldies" seem to be digging their heels in, of course they all seem to be reasonable & acknowledge that the other side may be right, whilst putting the boot in at the same time.

I've been around NW for a long time & it seems to me that the recent cold spell has emboldened some people, who don't actually know that much but have become quite popular by saying what coldies in particular want to hear & the fact that their predictions have finally come true. We even have promises of secret methods being revealed, interestingly only if what they predict comes true!

Personally I prefer the views of people who actually know what they're on about, either because they've been there & done it (& have recently been grossly insulted by "neo-grebists") & those who clearly have the technical knowledge. When a forecast/guidance goes TU, at least they tell us why.

I'm actually quite looking forward to May, when we can get back to discussing & reading about what the models show (not what they would show if red was pink & your Auntie was your uncle) & having a bit of sense around here.

Sorry if I'm adding to your problems mods, you have a tough job & I appreciate the time you give freely to police this madhouse!

[PB22]

No sign of any huge shift in the 18Z ensembles.

Suffolk 850hPa temperature ensemble: http://91.121.94.83/modeles/gens/graphe_ens3.php?x=358&ext=1&y=92&run=18&runpara=0

London 850hPa temperature ensemble: http://91.121.94.83/modeles/gens/graphe_ens3.php?x=306&ext=1&y=141&run=18&ville=Londres&runpara=0

No real signs of much cold at the surface either:

http://91.121.94.83/modeles/gens/graphe_ens4.php?temp=1&x=306&y=141&ext=1&run=18&ville=Londres&runpara=0

The operational was the coldest run at 2m temperatures for much of the high resolution run.

[casparjack]

Must say I don't get all this excitement about a Siberian High. It's called a "Siberian" High because that's where it lives.

It's there virtually all of most winters (and people are always pinning hopes on them).

But there is always cold to our North in the Arctic (and it gets here a lot quicker when it decides to come).

And yes the Siberian pressure is very often over 1050.

The looming situation is worrying because it is all to threatening of a very familiar , and very stable, pattern. Large Siberian High + South Greenland PV.

(It's not quite the usual yet)

Perhaps there will be an Easterly, but the ones that limp here over weeks usually land up very lame affairs and just because it's there, don't mean squat that it's headed this way.

Same goes for the split jet. Personally I believe we've had these very rare oldtime synoptics of late precisely because at last we had a Southerly unitary jet.

Bifurcated jets to our West have plagued us with dreary raw faux cold & returning TM air in recent winters and to our East they send winter into Greece and the Levant with tastes of faux cold for us

That's the first time I've heard the term 'faux cold' this term, bad sign I think, or maybe I just haven't been paying attention.

The 12z ECM just continues the tantalising High, it appears to decline from 1065mbs to around 1050mbs out in FI, T196 to T240, but does anyone else think the evolution of a 960 low W of Iceland spinning off SWs holds some potential?

[phil nw.]

No sign of any huge shift in the 18Z ensembles.

Suffolk 850hPa temperature ensemble: http://91.121.94.83/...un=18&runpara=0

London 850hPa temperature ensemble: http://91.121.94.83/...ndres&runpara=0

No real signs of much cold at the surface either:

http://91.121.94.83/...ndres&runpara=0

The operational was the coldest run at 2m temperatures for much of the high resolution run.

Yup looking at all the output you have to say rather mild in the Far West and nearer average to rather cold elsewhere for the next 5days.

This stalemate could run for several days,

Some encroachment from the East is always possible subject to the behaviour of the vortex.

However this is currently modelled too close to Greenland to allow more than some temporary modified continental influences.

http://www.wetterzentrale.de/pics/Recm1441.gif

http://www.wetterzentrale.de/pics/Rukm1441.gif

http://www.wetterzentrale.de/pics/Rtavn1381.png

Certainly no real cold temps are showing here in 2m ens.

http://charts.netweather.tv/ensimages/ens.20100114/18/t2mWarwickshire.png

Pretty close to average throughout except for a short dip by the operational run,which was a cold outlier for days 5 and 6.

[J10]

The GFS 2m temps from the op run, are usually very different to the ensembles so, this doesn't really mean anything.

As for any possible easterly, the lack of a Greeny High really doesn't help here at all.

[musician]

Blimey this is a controversial place tonight! Seems to me it's because in particular the models are showing all things are possible. As a result the "coldies" seem to be digging their heels in, of course they all seem to be reasonable & acknowledge that the other side may be right, whilst putting the boot in at the same time.

I've been around NW for a long time & it seems to me that the recent cold spell has emboldened some people, who don't actually know that much but have become quite popular by saying what coldies in particular want to hear & the fact that their predictions have finally come true. We even have promises of secret methods being revealed, interestingly only if what they predict comes true!

Personally I prefer the views of people who actually know what they're on about, either because they've been there & done it (& have recently been grossly insulted by "neo-grebists") & those who clearly have the technical knowledge. When a forecast/guidance goes TU, at least they tell us why.

I'm actually quite looking forward to May, when we can get back to discussing & reading about what the models show (not what they would show if red was pink & your Auntie was your uncle) & having a bit of sense around here.

Sorry if I'm adding to your problems mods, you have a tough job & I appreciate the time you give freely to police this madhouse!

Thank goodness - some common sense at last! I'm a newcomer and trying to learn something from the experts but I'm not getting a very good impression so far!

[TEITS]

I think some of the behaviour in here by certain posters has been dismal and very disappointing! This nit picking and being argumentative for the sake of it especially aimed at Tamara is very poor IMO!

Yes I agree Nick. As much of the discussion is about who wins the synoptic war i.e Siberian HP or the PV then its pretty obvious that when someone comments on the Atlantic they are referring to next week. Anyone who says otherwise is deliberately ignoring this and using it as an excuse to have a pop at Tamara.

Back to the models and despite the uncertainity it makes fasinating viewing. Whatever the outcome is, im enjoying the current model output. Anyone who is confused about next week and doesn't know how to read the models then let me say the outlook couldn't be more uncertain. We could have mild SW,lys, Cold with possible snow events, very cold with snow showers.

Earlier on today I said if the models trend towards an E,ly then this won't occur until its within the +96 timeframe. Until then all we can do is look and see which way this battle is going because this will shift E & W over many runs. The reason why I say +96 is with good reason and this is due to many years of following such battles. For starters the models will always underestimate the extent of blocking and it isn't until +96 that this becomes evident. Also at the current timeframe the models will be reluctant to show SW tracking underneath the HP. However once you get within +96 the models tend to agree to the idea of SW tracking SE. Once this happens then the chances of the HP moving further W become apparent. Each time a SW tracks underneath the HP the cold air tends to back further W with each SW. So it does remain possible that more than one snow event could occur.

As Tamara correctly states this isn't over yet. I still think the chances of -15C upper temps with frequent snow showers is a long shot for the time being. However the chances of snow events occuring due to SW tracking S remains very possible. What could of course happen is we pull in enough colder air to allow these snow events to occur. After this the HP might be further W to allow these bitterly cold upper temps to spread W.

I do find the latest +120 fax chart very encouraging.

http://www.wetterzentrale.de/pics/brack4.gif

Just seen your post dave. Lets get the facts right before you comment. I said I didn't want to say what this sign was until the E,ly appeared at +72. The only reason I said this is because I didn't want to put a jinx on it. If the E,ly doesn't occur I will still reveal what this sign is.

Edited January 15, 2010 by THE EYE IN THE SKY

[Eugene]

That is some beast of a siberian high upto 1060 MB

http://www.wetterzentrale.de/pics/Recm1441.gif

Maybe just maybe the models are really under playing it, i'm sure modelling isnt that great up there.

[KTtom]

Looks like the second half of January will be dominated by wet, windy and mild weather. We have a bit of a stand off between Atlantic lows and Scandi/Siberian high before the high finally gets beaten into submission. There on it looks to be back to a traditional winter pattern with strong PV to the north and high pressure to the south.

Hopefully we'll be looking to the north in Feb for our next cold shot when the jet dies down a little.

[Troubleatmill]

Looks like the second half of January will be dominated by wet, windy and mild weather. We have a bit of a stand off between Atlantic lows and Scandi/Siberian high before the high finally gets beaten into submission. There on it looks to be back to a traditional winter pattern with strong PV to the north and high pressure to the south.

Hopefully we'll be looking to the north in Feb for our next cold shot when the jet dies down a little.

Yep its looking that way. Unless the Siberian high is going to nudge its influence over us i think we are better off seeing it out of the way rapidly, otherwise we we only see these atlantic lows stalling out to our west leaving us with mild Westerlies/ South westerlies and daily bands of rain. If the high sucks back eastwards then at least we will have a chance of some Returning PM air as the lows push through.

But lets see if that high can nudge further west first, even though most if not all models are backing away from the idea

Edited January 15, 2010 by arron123

[snowingman]

3 words to sum up the next 2 weeks from our friend GFS

Mild, Wet, Windy

oh - how good is nature at balancing out things - could end up with a just below average CET for January based on these charts

Also - any thought of big chaps from the East is pure Fantasy!!

HISTORY says - that these patterns once entrenched can last anything up to 3 months!! so roll on spring

[PB22]

Looks like the second half of January will be dominated by wet, windy and mild weather. We have a bit of a stand off between Atlantic lows and Scandi/Siberian high before the high finally gets beaten into submission. There on it looks to be back to a traditional winter pattern with strong PV to the north and high pressure to the south.

Hopefully we'll be looking to the north in Feb for our next cold shot when the jet dies down a little.

The GFS 00z ensembles sum it up for me to be honest:

http://www.wzkarten.de/pics/MT8_London_ens.png

http://www.wzkarten.de/pics/MT2_London_ens.png

http://www.wzkarten.de/pics/MT8_Manchester_ens.png

http://www.wzkarten.de/pics/MT2_Manchester_ens.png

http://www.wzkarten.de/pics/MT8_Aberdeen_ens.png

http://www.wzkarten.de/pics/MT2_Aberdeen_ens.png

No sign of anything notably cold, and look at all those precipitation spikes, starting from tomorrow.

[The Weather Yoda]

Yes, a real kick in the teeth from all the models this morning for those hoping for the Siberian high to win the east v west battle and exert its influence westwards. As Ian says, this could become a static pattern for a while. I'm off to pile up all the snow in my back garden in the hope of keeping some until the next cold shot arrives...I don't rate my chances

[casparjack]

The ECM this morning initially showed some promise I thought, at T120...

Then at T144 it seems to be trying to put in place the building blocks for the renewed Easterly...

Then it all flounders beyond that and looks disturbingly wet and westerly (if like me you want renewed cold/snow), but hey let's be positive, that's FI isn't it, so it'll never verify!!

Edited January 15, 2010 by casparjack

[cooling climate]

Considering the way the models have been back and forward with regard to a

continental feed next week and we are still talking about the t144 range then nothing

is settled yet and I think it is a bit premature to say it is.

Next week certainly does not look mild, not in the east anyway.

[SussexmarkyMark]

Well I might just as well post exactly what I posted this time yesterday morning as the trend to less cold weather continues:

'The Siberian HP seems very unlikley to exert any significant influence on the UK weather for next week, with LP in the North Atlantic looking to be the more dominant feature for NW Europe. The SE will probably have fairly benign weather and, although chilly at times, it will probably be fairly dry and overcast from a cold continent, but never really getting a true easterly to pull in any significant cold. The west of the UK more prone to attack from the Atlantic, so fairly average temperatures and some rain at times. Towards the end of next week the Atlantic looks more likely to exert it's influence over the whole of the UK.'

The only difference from yesterday is that an easterly next week looks even less likely than it did 24 hours ago

[snowingtequila]

Well I might just as well post exactly what I posted this time yesterday morning as the trend to less cold weather continues:

'The Siberian HP seems very unlikley to exert any significant influence on the UK weather for next week, with LP in the North Atlantic looking to be the more dominant feature for NW Europe. The SE will probably have fairly benign weather and, although chilly at times, it will probably be fairly dry and overcast from a cold continent, but never really getting a true easterly to pull in any significant cold. The west of the UK more prone to attack from the Atlantic, so fairly average temperatures and some rain at times. Towards the end of next week the Atlantic looks more likely to exert it's influence over the whole of the UK.'

The only difference from yesterday is that an easterly next week looks even less likely than it did 24 hours ago

can you please post the charts that make it less likely than yesterday morning because I think it still hangs in the balanace, it seems dependant upon the track of the two low pressures that either head north or south, until this is decided which is in FI then I am not too sure

[Timmytour]

i don't wish to make direct comparisons between this year and 1962/3 but I know from reading up about it that a high pressure with an centre of above 1050mb collapsed just before Christmas which then led to the developments that led to such an outstanding winter.

Of course no guarantee would come with the collapse of the current high pressure system in terms of what cold weather it might bring, but since it dominates a lot of the thinking on here, could I ask a few questions...

1) how common is it for such systems to collapse within a day or two as I believe happened in 1962?

2) are the models in place complex enough to forecast such collapses and, if so, do any of them forecast the collapse of the current Siberian one?

Many thanks

Edited January 15, 2010 by Timmytour

[Cecil Hogmanay Melchett]

I would guess most posters realise when the games up and to me the games up.I think Ian and Paul B have summed it up perfectly,you can have the mother of Siberian highs but if that jet doesnt play ball forget it.

Pretty good model consensus that the high is going to lose,potential for copious ammounts of rain in the next week or two as those lows slam into the uk.

[Nick F]

can you please post the charts that make it less likely than yesterday morning because I think it still hangs in the balanace, it seems dependant upon the track of the two low pressures that either head north or south, until this is decided which is in FI then I am not too sure

If you are looking at prospects into the medium range, we really need the upper flow pattern needs to change from what has been shown over the last few days. The direction a few surafce lows takes will not make much difference in the great scheme of things with regards to the broadscale upper pattern - which suggests N. Atlantic/greenland trough remaining intact and not moving far - keeping the Siberian High back from retrograding.

We need to see a change in the upper pattern - i.e. wave lengths, position and alignement of upper troughs to improve prospects into the medium term for cold to return.

[Frosty.]

The Atlantic is powering up and will push the scandi block further away with time, if this was december when the atlantic was slumbering we would be looking at a bitter spell probably even more severe than we have had this last 4 weeks but we won't get lucky this time, mild will win and this next few days of wet & windy, milder weather will bring a rapid thaw to all low ground britain but it will linger on the hills into next week.

[nick sussex]

The Atlantic is powering up and will push the scandi block further away with time, if this was december when the atlantic was slumbering we would be looking at a bitter spell probably even more severe than we have had this last 4 weeks but we won't get lucky this time, mild will win and this next few days of wet & windy, milder weather will bring a rapid thaw to all low ground britain but it will linger on the hills into next week.

Well at the moment it might look like that but theres still enough scatter in the ECM ensembles to keep the outlook especially for eastern areas more uncertain. Also a major stratospheric warming is imminent which could put some reverse zonal winds into the atmosphere. Perhaps GP might be around later to tell us what the implications could be regarding that.

[Frosty.]

Well at the moment it might look like that but theres still enough scatter in the ECM ensembles to keep the outlook especially for eastern areas more uncertain. Also a major stratospheric warming is imminent which could put some reverse zonal winds into the atmosphere. Perhaps GP might be around later to tell us what the implications could be regarding that.

I thought I had read somewhere that GP thought feb was going to be very mild with high pressure to the south and lows tracking between iceland and scotland, hope I misread it.

Edited January 15, 2010 by Frosty039