Winter Model Discussion - Cold Hunting -12Z 03/01/13

[Bobby]

The GEFS/ECM ensemble upper means at day +240

GFS

ECM

No strong signal for cold yet IMO in any kind of reliable time frame. Lots of potential though as we're seeing in some of the runs but a long way to go yet. Plenty of cold air out to the N and E, that's certainly something I'm seeing but can we tap into it is the question.

Edited January 4, 2013 by Bobby

[bradymk]

Have to disagree bobbydog, fair enough ignore t384 but fairly often the general set up is seen up to t240 end even slightly beyond sometimes, it depends on the set up you are currently in, sometimes its 72hrs dont look beyond and sometimes much further

Depends on the model and situation but GFS goes low resolution after t+192 but ECM stays high resolution up to +240 so ECM is normally more reliable post 192 than GFS but post +192 should not be "binned" as it is good at showing trends just not the detail which can make all the difference for us in the UK. Im not sure about this but i am sure the GEFS ensembles have the same resolution from 0 to 384, could someone confirm this?

[bobbydog]

Have to disagree bobbydog, fair enough ignore t384 but fairly often the general set up is seen up to t240 end even slightly beyond sometimes, it depends on the set up you are currently in, sometimes its 72hrs dont look beyond and sometimes much further

but this is not a situation we're in 'fairly often'. ian said only yesterday that the Meto's own model is "unconvincing" at t144

[bradymk]

Big improvement on the short term ensembles on the 6z compared to the 00z and this is also shown when viewing each ensemble member.

[Isolated Frost]

Okay.. the point in question that

a ) is stopping the movement of a seperate PV lobe into Scandinavia

b ) stopping the amplified arctic ridge move southward into Iceland and Scandinavia

c ) is therefore giving Britain a mean chance of a more S/W flow as the high progresses into central Europe or southern Scandinavia.

is this:

A small feature generally to the NE of Norway (best spotted at D7 atm), which extends from a low pressure system in the Atlantic, it stops the PV lobe (in purple) from transferring energy into Scandinavia, instead it directs it back into Greenland. The less amplified flow due to the shortwave mean that the jet can then run on top of the high pressure successfully, and build high pressure in Europe.

The 06z GEFS isn't all that bad, but includes that crucial feature that it did not include on it's 00z suite.

Above is what happens when the low becomes part of the circulation. An amplified polar high, suitable flow for a PV lobe in Scandinavia and a strong chance of Scandinavian or Arctic winds across the UK.

Edited January 4, 2013 by Isolated Frost

[Troubleatmill]

but this is not a situation we're in 'fairly often'. ian said only yesterday that the Meto's own model is "unconvincing" at t144

Sorry Bobby i misunderstood, i though you were saying dont ever look at the models past t144, for here and now what we are in i completetly agree

Edited January 4, 2013 by Nick JB

[kumquat]

IGNORE EVERY RUN FROM EVERY MODEL AFTER 144HRS

alternatively, ignore every post from ian ferguson which contains information from a world class professional forecasting organisation....

I agree with you on the FI aspect, but with all due respect to Ian, I don't know why there are so many posts urging us to hang onto the coat tails of every thing he posts (the way you post it) almost at the detriment of everything else. All I've seen (and thank him for) is news of hints from the MO professionals that they see the potential propensity towards colder weather in the MR to LR future due to the effects of the upcoming (and current) SSW events. They (and nobody else) are guaranteeing anything at this stage. I guess that this is what you mean, but I'm not sure they're much the wiser than many here at the moment and opinions here based on the models we see unfold are what this thread is about.

[Isolated Frost]

wow!

[No Balls Like Snow Balls]

I agree with you on the FI aspect, but with all due respect to Ian, I don't know why there are so many posts urging us to hang onto the coat tails of every thing he posts (the way you post it) almost at the detriment of everything else. All I've seen (and thank him for) is news of hints from the MO professionals that they see the potential propensity towards colder weather in the MR to LR future due to the effects of the upcoming (and current) SSW events. They (and nobody else) are guaranteeing anything at this stage. I guess that this is what you mean, but I'm not sure they're much the wiser than many here at the moment and opinions here based on the models we see unfold are what this thread is about.

I would rather listen to the Met O than you and most other non professionals on here. The hint is in the word professional I think. Oh I think they are much wiser than most on here LOL and i don't think many on here (myself included) would argue with that.

Edited January 4, 2013 by No balls like Snow Balls

[peterf]

very harsh.

[Duane S.]

When we get the Arctic high - the situation is very much like the game Wheel of Fortune - where the high offloads itself to will be the lucky winner. Not us this spin.

Quote / analogy of the week. Fantastic way of putting it!

[SnowBallz]

I agree with you on the FI aspect, but with all due respect to Ian, I don't know why there are so many posts urging us to hang onto the coat tails of every thing he posts (the way you post it) almost at the detriment of everything else. All I've seen (and thank him for) is news of hints from the MO professionals that they see the potential propensity towards colder weather in the MR to LR future due to the effects of the upcoming (and current) SSW events. They (and nobody else) are guaranteeing anything at this stage. I guess that this is what you mean, but I'm not sure they're much the wiser than many here at the moment and opinions here based on the models we see unfold are what this thread is about.

With respect, you're an amateur meteorologist with access to a limited data suite. Bit different to a verified professional, working at a multi-million pound governmental agency with unlimited access to data, computing tools and other professional bodies.

The considered advice from Ian, was to largely ignore - or, at the very least, don't become too married to solutions at this very specific moment in time. It's because there is obviously a consensus at Exeter, that downstream SSW influence is going to over-ride what we currently see as outputs from NWP.

Ian alludes to the fact that this view is born from a professional experience from those who have seen such events previously, and therefore are able to make an informed judgement as to how plausible current outputs are, in light of the knowledge of a significant background signal.

The advice isn't about putting implicit trust in Ian, or the Met Office. It's about bearing in mind current outputs, within the context of advice given by professionals. That is what should frame the analysis; your guiding principle, if you will. You're entirely at liberty to carry on MR-LR analysis though, if you want - it's just that the professional view, is that they would rather not waste their time.

[phil nw.]

Looking further out than around 4-5 days on the operational runs as ever will continue to frustrate.

The trends in the mean outputs at day 10 are still showing a steady erosion of those low hts to our north.

The Greenland lobe of the vortex on the retreat to Canada still showing and the ridging in the flow north through the UK towards the gap created.

What we also see is the a developing trough digging into E.Europe and hopefully with time as zonal wind reversal increases with more warmings the whole pattern will start to retrogress.

Whilst we remain under the high we will retain those mild uppers-hence the reluctance for the 850hPa ens to show any real cold yet.

We are only at the first stage yet ie a slowing jet,the weakening and splitting vortex and the end of zonality.

[EML Network]

Just going through the various GFS runs, I think there will be some big smiley faces on here, at least up until 3:30 pm :-)

pick of the bunch ??

nope found a better one !!

Edited January 4, 2013 by EML Network

[TwisterGirl81]

wow!

Can I ask what this shows, i'm guessing the blues and purples mean cold and by that i mean cold enough for snow? What would you expect conditions to be likein the southwest of the uk with this graph you've posted? Is that a hugh winter storm to the southwest of the uk? Would it bring snow and blizzards widespread to the uk?

[Coast]

Do you know, I could have sworn this thread was opened with the intention of discussing current meteorological modelling and how it might pan out. But it seems some have forgotten what this thread is for. Please let me remind you:

Winter model discussion.

Not bickering, snipes or pointed comments at other members thank you.

Edited January 4, 2013 by Coast

[Bobby]

Something interesting from over the strat thread, the statistics suggest SSW's actually turn things warmer on average? : http://forum.netweat...80#entry2463540

From a total of 54 SSW events compared with 1940-2012 CET anomalies

1-20 days following SSW is 0.038°C warmer than the 20 days preceding SSW.

7-28 days following SSW is 0.116°C warmer

15-45 days following SSW is 0.089°C warmer.

So maybe a further note of caution as to whether the models will start showing a big freeze. Combined with the big scatter in the ensembles, OP runs it's quite a confusing outlook.

Edited January 4, 2013 by Bobby

[Troubleatmill]

With respect, you're an amateur meteorologist with access to a limited data suite. Bit different to a verified professional, working at a multi-million pound governmental agency with unlimited access to data, computing tools and other professional bodies.

The considered advice from Ian, was to largely ignore - or, at the very least, don't become too married to solutions at this very specific moment in time. It's because there is obviously a consensus at Exeter, that downstream SSW influence is going to over-ride what we currently see as outputs from NWP.

Ian alludes to the fact that this view is born from a professional experience from those who have seen such events previously, and therefore are able to make an informed judgement as to how plausible current outputs are, in light of the knowledge of a significant background signal.

The advice isn't about putting implicit trust in Ian, or the Met Office. It's about bearing in mind current outputs, within the context of advice given by professionals. That is what should frame the analysis; your guiding principle, if you will. You're entirely at liberty to carry on MR-LR analysis though, if you want - it's just that the professional view, is that they would rather not waste their time.

Dont the met office have a MR-LR view Snowballz? surely they look out further than seven days for potential pattern changes?

Edited January 4, 2013 by Nick JB

[Rocheydub]

Can I ask what this shows, i'm guessing the blues and purples mean cold and by that i mean cold enough for snow? What would you expect conditions to be likein the southwest of the uk with this graph you've posted? Is that a hugh winter storm to the southwest of the uk? Would it bring snow and blizzards widespread to the uk?

on the phone, and can't post the link. Can somebody direct this lady to the URL of the beginners thread please?

[peterf]

Can I ask what this shows, i'm guessing the blues and purples mean cold and by that i mean cold enough for snow? What would you expect conditions to be likein the southwest of the uk with this graph you've posted? Is that a hugh winter storm to the southwest of the uk? Would it bring snow and blizzards widespread to the uk?

http://forum.netweather.tv/forum/24-learning-about-weather-and-meteorology/

[Frosty.]

Can I ask what this shows, i'm guessing the blues and purples mean cold and by that i mean cold enough for snow? What would you expect conditions to be likein the southwest of the uk with this graph you've posted? Is that a hugh winter storm to the southwest of the uk? Would it bring snow and blizzards widespread to the uk?

Yes the blues and especially the purples are what all coldies want, the yellows, greens and oranges are what we have now but hopefully not for much longer. I will just be happy to get the cold air first and then focus on snow and blizzards later.

[Glacier Point]

A cracking 06z GEFS ensemble mean which sits well continuity wise with the 00z GFS and ECM runs. Not overly cold at face value but get the synoptics into position first....

The split tropospheric vortex looks like following the strat lead at this range. The fundamentals being residual vortices over North America and Siberia with a ridge over the Arctic. The balance of energy post split in these two vortices being the key modelling issue at present. Todays runs have placed a bit more emphasis on the North American vortex whereas yesterdays were favouring the Siberian / Scandinavian one.

What doesn't seem to be an issue here is long term. Strat lead pulls the North American vortex further and further west and south. We should continue to see the tropospheric vortex pull away from Greenland allowing for height rises (06z op an outlier here!).

The upper and middle stratospheric modelling is unbelievable at this stage and is as clear a signal as you could get for a Greenland ridge.

[johnholmes]

my views on the developing weather pattern in the upper air and a stab at the surface in pdf format as usual

7-weekly update on anomaly charts-fri 4 jan 12.pdf

[Frosty.]

We have taken a very important step in the right direction today in terms of a colder outlook becoming more and more likely from mid month onwards, perhaps earlier than that because the risk of frost and fog should begin to increase for at least the eastern side of the uk or at least for southeastern britain, the north and west continue to look windier, milder and more unsettled for the early part of the period but even the north and west trending colder later. The latest metoffice update has upgraded the chance of cold and is now within the 6-15 day period, also the 16-30 day is looking even more wintry, especially for the north and east, this is great news for coldies and we could see a very wintry pattern emerging soon, along the lines of the Gfs 00z op run.

[Timmytour]

I agree with you on the FI aspect, but with all due respect to Ian, I don't know why there are so many posts urging us to hang onto the coat tails of every thing he posts (the way you post it) almost at the detriment of everything else. All I've seen (and thank him for) is news of hints from the MO professionals that they see the potential propensity towards colder weather in the MR to LR future due to the effects of the upcoming (and current) SSW events. They (and nobody else) are guaranteeing anything at this stage. I guess that this is what you mean, but I'm not sure they're much the wiser than many here at the moment and opinions here based on the models we see unfold are what this thread is about.

Nobody knows for sure, you either choose to be optimistic or you choose to be pessimistic.

And you either plot your own path or you hang onto the coat-tails of others. I quite like the look of Ian's coat-tail!