Model Output Discussion - 28th November

[Mark Bayley]

Have to say the 18z is far from inspiring this evening.

Next week is looking like an endurance test imo

All the background factors are in our favour but it has to be said not much is showing in the models yet

Still if I was a betting man I would think we are due a belter of a run very soon!!

I would agree, especially when one views the mean ensemble 500hpa and 850hpa anomalies.

Edited November 29, 2012 by Mark Bayley

[Tim Bland]

Spot the difference with the 12z... I can't see many, not good for collides Hope the overnight runs smell the coffee and we can get some good Synoptics showing soon

[Allseasons-Si]

Still too much energy in the northern arm of the jet which stops the ridge from extending towards Scandi.

The GFS 18hrs run though could bring some very cold temps under that slack flow later, freezing fog and harsh frosts possible.

On the other hand theres always the UKMO fax chart for 120hrs:

Looks quite wintry for northern areas.

Wow,that looks quiet good nick,if only it went out to 144hrs,one of the best faxes i have seen for a while,BANK .

[Bristawl Si]

Just checked on wunderground and there is no tropical storm development forecast for the North Atlantic for next 48 hrs - so maybe it's a 'rogue' in the computer!

And yet it's on the fax Nick just put up!

[bradymk]

Also, looking at the hemishperic view of the p vortex, it is wonderful to see with it nearly gone to the ENE , but unfortunately and a bit of bad luck, too much energy in the canada/greenland segment.

[Weathizard]

Run looks better within 96-120, really don't see the point in looking past this, whatever dirge or eyecandy they produce, we need to be patient, we are on a run of bad luck but the charts shown would not take much at all to turn into a very cold outlook. Keeping an eye on the Ens though.

[Snowman.]

That tropical low is more amplified and wants to slam into the High over Europe and is really trying hard I'm watching this as it could help us much further down the line.

[Snowy Liverpool]

Spot the difference with the 12z... I can't see many, not good for collides Hope the overnight runs smell the coffee and we can get some good Synoptics showing soon

I doubt there will be much change for next week. At least a more southerly tracking low is looking the most likely, with Northern areas remaining quite cold. After that the models are trending towards high pressure building near the UK which slows everything down and this could open up some doors for a block to develop. Still too soon to talk about that I think, need to get next monday's low pressure out of the way first.

[TEITS]

This is what I love to see agreement from the models.

GFS 18Z has the UK under HP at +192.

http://www.wetterzentrale.de/pics/Rtavn1921.png

ECM 12Z has the UK being influenced by LP and a cold N,ly.

http://www.wetterzentrale.de/pics/Recm1921.gif

My conclusion is its a waste of time watching the runs beyond +144 at the moment.

[Snowman.]

Retrogression to Greenland?

[davehsug]

So what if it's all wrong & we should be looking South & not North? Everyone is talking about vortex this & High level block that & yet we see a strange depression in the Southern North Atlantic, & it's not alone if some of the output of the last couple of days is to be believed. This could have a much bigger impact on our weather than a ridge over Kamchatka or the PV over Svalbard.

Edited November 29, 2012 by phil n.warks.
removed aggressive tone

[Allseasons-Si]

Retrogression to Greenland?

Yes,and i feel that that trop low will force it at some point,i just have that felling.

[Cheshire Freeze]

This is what I love to see agreement from the models.

GFS 18Z has the UK under HP at +192.

http://www.wetterzen...s/Rtavn1921.png

ECM 12Z has the UK being influenced by LP and a cold N,ly.

http://www.wetterzen...cs/Recm1921.gif

My conclusion is its a waste of time watching the runs beyond +144 at the moment.

That may be so but the 18z shows great consistency following on from the 12z. The ECM has shown a few outcomes from run to run but GFS has shown good intra model agreement today. I stand by what I said earlier and that is I really don't see any prospect of a widespread cold/snowy spell in the next 14 days. After that,who knows?

This thread today has, at times, added a whole new dimension to the phrase 'clutching at straws'. If anyone can point me towards more than the odd ensemble or lone operational run that suggests otherwise to the above, feel free.

[Grimsby Snow Lover]

The past 3 runs from todays GFS have been pretty much outliers in terms of the 850 temps, so whats to say the current run will not follow suite? I do believe anything past 4/5 days is open to quite significant change. Sometimes I wish the GFS only went out as far as the UKMO.

[damianslaw]

FAX chart shows quite an unusual set up 128 hours with a cold plunge from the north thanks to trough being forced southeast, however, it is hard to say whay might happen next - with the unusual intense low pressure near the azores, I suspect we would see a classic 'col situation' and when this occurs it is a guessing game where things might go next.

The reliable timeframe is Sunday, I think the models will continue to show various scenarios for next week in the coming runs... but the overall trend will be a cold one with heights staying very strong over the arctic which will be the dominant factor, the building blocks for a substantial cold period are certainly setting up shop....

[TEITS]

That may be so but the 18z shows great consistency following on from the 12z. The ECM has shown a few outcomes from run to run but GFS has shown good intra model agreement today. I stand by what I said earlier and that is I really don't see any prospect of a widespread cold/snowy spell in the next 14 days. After that,who knows?

This thread today has, at times, added a whole new dimension to the phrase 'clutching at straws'. If anyone can point me towards more than the odd ensemble or lone operational run that suggests otherwise to the above, feel free.

Based on my experience, when you have such disagreement amongst the models it usually means none of them are right.

[chionomaniac]

So what if it's all wrong & we should be looking South & not North? Everyone is talking about vortex this & High level block that & yet we see a strange depression in the Southern North Atlantic, & it's not alone if some of the output of the last couple of days is to be believed. This could have a much bigger impact on our weather than a ridge over Kamchatka or the PV over Svalbard. I feel quite annoyed that there is something genuinely interesting going on that may well directly effect us & yet we have the usual obsessive claptrap about a snowflake over the Southern uplands. The synoptics & modelling of the flooding of last week were largely ignored whilst posters chased another phantom snowfest. Perhaps we could have 2 model threads, one for those interested in what the models are showing, WHATEVER THE WEATHER & one for those who want to obsess with the next Arctic fantasy!

Dave, instead of ranting you could be spending the time putting forward a productive post on your take on the models -the type of post that you would like to see in the thread?

Also last week there was a thread dedicated to the severe rainfall and flooding.

[kold weather]

Hmmm more than a few hints that another ridge is going to build northwards, however there are obvious uncertainties about where this happens and at exactly what angle this happens at.

Its going to depend alot on exactly how much pressure any building block gets from the PV lobe that is over Canada/W.Greenland. I suspect at the very worst w'll get a stout upper high over our shores like the GFS suggests, which will bee quite cold given the semi decent surface cold pool formed due to us being on the right side of the jet.

[etched Chaos]

It should still be cold though for you down South if we were to receive something wintery up here.

True, only for us Coastal fools it's going to be warmer than everywhere else. It's why I'm really hoping for a beast from the East and some good old-fashioned North Sea convection.

[bradymk]

If you love cold frosty weather and fog then this is your run with some very cold nights under that high. So a good run for surface cold but not if you want snow. However huge differences between GFS and the other models. Hints at heights rising to somewhere to our N towards the end of this run aswell but where is favoured for this at the moment? Unsettled or anticyclonic? unsettled for me at the moment, even though the GFS has shown this for the last few runs, i still favour the ECM/UKMO solution. Could be some interesting weather next few weeks, a few surprises i feel. Matthew

Edited November 29, 2012 by bradythemole

[bluearmy]

Yes, which is great for you Northerners, but for us Southerners, it's depressing to see half the board enjoy snow whilst the rest go without.

on the contrary, its great cos it mean half the country is very close to being snow covered. note the 30hpa strat forecast takes the strat vortex towards eastern siberia late on again.

[NorthernRab]

Yes, which is great for you Northerners, but for us Southerners, it's depressing to see half the board enjoy snow whilst the rest go without.

You'll have a very depressing time of it unless you just accept that it snows more in Scotland, it's just the world we live in.

Anyway, considerable snow still there for Monday, excellent for the ski ranges

[Zakos]

This is what I love to see agreement from the models.

GFS 18Z has the UK under HP at +192.

http://www.wetterzen...s/Rtavn1921.png

ECM 12Z has the UK being influenced by LP and a cold N,ly.

http://www.wetterzen...cs/Recm1921.gif

My conclusion is its a waste of time watching the runs beyond +144 at the moment.

A very logical conclusion. The only consensus is low pressure over Europe, and a fairly timid Atlantic.as for for the fine details it is a complete waste of time to speculate.

As stated in the Netweather winter forecast, there is a very strong signal for low pressure over Europe, and hence the majority of models are sticking to this.

The GFS is clueless and does what it does best - revert to default.

No teleconnective support for this outcome whatsoever.

Things still looking great with lots of potential ahead. The setup beyond 96 hours looks very complicated indeed, and we are far from certain as to what will happen.

[Cheshire Freeze]

But that 'clutching at straws' has been partially fuelled by quite a bullish Winter forecast in recent days and other respected posters continuing to 'big up' the potential for next couple of weeks.

Which IMO is fuelling false hope at the minute. From where I am sitting I can't see anything of note for the next 10 days at least. There is NOTHING in any of the NWP which suggests that piece of vortex around Greenland is going to move anywhere fast. It's all well & good having the background signals conducive to a cold and snowy outbreak but it's what happens in real time at the surface which will ultimately dictate what the UK is to experience. Those expecting big swings in the moel output to a -15 easterly blast may be waiting a while & it may be better for some members to reduce their expectations accordingly.

I'll be completely honest, I can't see anything other than a mid latitude high at best for the 14 day period.

Excellent consistency following on from the 12z run of low heights deepening to the northwest throughout FI...

[etched Chaos]

on the contrary, its great cos it mean half the country is very close to being snow covered. note the 30hpa strat forecast takes the strat vortex towards eastern siberia late on again.

Ah, but that's if you exclude emotion from the process. Alas, I've never been very good at staying unemotional when it comes to cold weather.

It's why I'm glad GP hasn't erred from positive comments.