Winter Model Discussion Thread 12Z onwards 5/1/13

[gaia rules]

Ensembles much more consistent and still the op and control leading the cold pack (initially!)

Edited January 6, 2013 by gaia rules

[Weathizard]

Another magnificent ecm, especially for longevity of cold! Gfs totally out on a kilter here, like a naughty schoolboy it will hopefully come back with its tail between its legs.

Saying that, the ens are pretty stunning.

Edited January 6, 2013 by Weathizard

[Fozfoster]

Cough

With these charts you could catch one!!!! ;-)

[Iceaxecrampon]

Saturday 12th:

London 600ft ASL

Really gets going for the SE on Sunday - NE streamer potential

Could be some nice totals

Midday Max Temps

Then attack from the NW?

SE looking good at present.

Ian

[IDO]

I was expecting the models to meet in the middle but ECM have kept to their guns and will deliver a cold spell if the 0z run verifies, and potential down the line:

The GFS Pressure ensembles show they split mid week so still a good chance for them to amplify the pattern:

Loads of scatter so low confidence in anything post D3/4. The op and control both pressure outliers in FI so little help the 0z main runs. The mean (850s flow) at T180 suggests an easterly element:

And at T300 a NE'ly:

Then more a northerly at the end of FI: The ensembles are therefore looking OK and tie in with a blocked pattern.

We should know in a couple of days if ECM have a better grip on this SSW than the GFS.

Edited January 6, 2013 by i'm dreaming of...

[cooling climate]

Superb ECM run for cold lovers with winter wonderland scenes likely as early as next

weekend if the run were to verify.

Prolonged cold would be the order of the day if the ECM is correct. The UKMO seems

to be taking the same route just the GFS to play catch up.

[bluearmy]

For those of you who dont like roller coasters, who prefer a fixed rate to variable, who prefer an ISA to ladbrokes, tomorrows 12z's should be your next port of call!

yes, ukmo is closer to ecm than gfs at day 6 but it isnt a carbon copy. My interest is the fact that gem goes alng a very similar route to ecm. Fascinating to see how the energy gets into western europe compared to what the runs were showing only two days ago. At the same time, heights look much lower over the pole at the same as opposed to what the models were showing even yesterday morning.

[Liam J]

Superb ECM 00z and if anything along the lines of that verified then it could well be a memorable cold spell, more of the same today please!

[TEITS]

Nothing really add as the excellent posts have covered the output this morning. I still feel the GEFS ensembles are catching up as is sometimes the case.

http://cdn.nwstatic....bridgeshire.png

Yet again the OP/Control are much colder than the mean and if you combine this with the other models then upper temps of -8C is more likely around the 12th Jan onwards.

Beyond this and the GFS does seem to be on its own with regards to what happens after the initial E,ly. However at first this morning I was concerned because to be fair to the GFS it did pick up on the initial E,ly before all the other models and I was concerned if it had picked up a new trend beyond +168. However the recent GFS runs in FI do not tie in with whats happening in the Stratosphere so for the time being im assuming its gone off on one!

So overall delighted with the model runs especially at the +120/+144 timeframe and the ECM is the pick of the bunch.

Edited January 6, 2013 by THE EYE IN THE SKY

[Gibby]

Good morning. Here is the report on the 00z output from GFS, UKMO, GEM and ECM for today Sunday January 6th 2013.

All models show an agreed outlook up until Thursday of this coming week. The UK remains under the influence of High pressure to the South although it is declining slowly. The resulting slack winds have allowed for some mist and fog patches to form overnight where skies have cleared and these may be slow to clear today. There will be a lot of cloud around, especially in the North and West where some rain is likely over Scotland and Northern Ireland. The trough over Scotland edges a little further South tonight with Southern areas staying dry and cloudy with some more rain for the North. Tomorrow shows another quiet day for many with cloud and a little rain possible almost anywhere in the rather mild air. On Tuesday a band of more organized rain moves SE over the UK followed by brighter and fresher weather with a touch of frost possible on Tuesday night along with some fog. On Wednesday another ridge moves in from the West giving a dry day before a new Low pressure edges into the SW through on Thursday bringing rain to the South and West with rather colder conditions developing everywhere.

GFS then develops High pressure between Scandinavia and Scotland with a cold ENE flow developing over the South with some rain or sleet for a time. The North could well become cold and frosty with fog through this period. High pressure then in the Atlantic with a ridge to the Scandinavian High takes control as it collapses the ridge over the UK SE with further dry, frosty weather. Through FI the the pattern is shown to include a Jet flow travelling well South of the UK with deep Low pressure areas moving into the UK and disrupting over us to give another spell of potentially very wet weather with some snowfall too on higher ground as the air remains on the cold side of normal at the surface.

The GFS Ensembles show a cold spell for Southern Britain for a while though this is less marked for the North. There is nothing very cold shown when taken as a whole with once more too many members showing rather milder outcomes including the Control run in the final third of the output. Some rainfall looks likely to develop once more as we move further into the run.

The Jet Stream shows a weakening of the flow though still ridging around the UK and down into Europe in the coming days. In time the flow weakens further eventually becoming more organized again with it's flow pushing over the Atlantic and well South of the UK in 7-10 days.

UKMO for midnight on Saturday shows Low pressure over much of NW Europe with a developing cold pool over the UK. There would be rain at times and this may begin to fall as sleet or snow over the hills with time, especially in the North.

GEM shows a Low pressure centre moving slowly East just to the South of the UK. An Easterly flow in the South would bring rain and strong winds to these parts where it would feel raw cold out and about. Late in the run the Low recedes South as a ridge topple SE over the UK with cold and frosty weather already in the North extending to other areas in the later days of the run.

ECM shows another cold outlook this morning. It too shows Low pressure just to the South of the UK next weekend with a colder Easterly flow with rain, sleet or even snow possible as the air becomes steadily colder. Later as the Atlantic High retrogresses towards Greenland winds back Northerly but it stays cold with the likelihood of even colder air arriving after Day 10 with snow showers moving South to the UK with time.

In Summary today the models continue to show various scenarios on an overall trend to rather colder conditions. Low pressure is set to move near to Southern areas next weekend and this could be a catalyst to an Easterly flow and rising pressure to the North, pulling in much colder air from the East with some chance of wintry precipitation, innitially but not exclusively over the hills. Later on it seems that a Northerly is possible as High pressure develops in the Greenland region and pressure is Low over Scandinavia. GFS though does continue to show something rather different though it is an improvement for 'coldies' from last night's offering bringing rather cold and unsettled weather into the UK with rain or snow in places in generally cyclonic conditions. There will be plenty more options towards cold weather in the coming days but the overall trend for cold is a strengthening one.

[IDO]

MattHugo81

00Z EC ENS supports the EC model in terms of a cold E'ly for next wkend, but it isn't quite as cold or as unsettled.

06/01/2013 08:33

MattHugo81

00Z EC ENS mean is again in close agreement with the EC Det model with the main area of high pressure moving to the NW of the UK by 240hrs

06/01/2013 08:34

MattHugo81

Bulk of the EC ENS members agree on the E'ly for next wkend, just variations on the strength of it or whether it's more settled/unsettled.

06/01/2013 08:40

Promising...

Edited January 6, 2013 by i'm dreaming of...

[Timmytour]

So a cold spell coming which the GFS has breaking down quite quickly and ECM does not.

Hope the ECM is right but I remember which way it went this time last month

[Long haul to mild]

Promising outlook again from the models this morning.

The GFS ultimately doesn't deliver in terms of cold because it takes a piece of energy west of Greenland, blows it up and runs it through Iceland, right between the attempt from the Azores high to ridge into Greenland. This then topples the ridge over the UK.

http://cdn.nwstatic....192/h500slp.png

The subsequent powering up of the vortex in low res is entirely predictable but goes against the background signals, so will be surprised if it turns out as shown.

Edited January 6, 2013 by Chalk Serpent

[Shunter]

Joe B's latest 30-45 day update here. Alludes to forthcoming US and European cold spells with the UK seeing two peripheral "hits".

http://t.co/btVgWw51

[ChartViewer]

Not forgetting the BOM

T144

T168

T240

[UV-RAY]

Some cracking charts on offer this morning with the SE looking the best bet for some wintry precipitation towards Friday and next weekend. Thereafter a cold and unsettled period of weather with heights building over Greenland possibly leading to a NE airflow with snow showers for many areas into week 3.

Edited January 6, 2013 by Sceptical Inquirer

[Timmytour]

News flash the sunday express has no headline about the impeding cold so it is still safe from the curse

Any caution the GFS run gave me in its low resolution part, not forgetting it did the same thing when we were all getting excited last month, has just been hit for six!

[snowking]

Some stunning output this morning both stratospherically and tropospherically speaking, and its always nice to have the ECMWF at the top of the pile (although as we know even this cannot guarantee us anything!)

My very slight, niggling concern this morning ties in to what TEITS says above, and its whether the GFS has picked a new trend once again (its done this a couple of times so far this winter) and whether the other solutions are edging towards it.

Heres the ECM and GFS at +192 this morning:

Different at our locale, however, if we look over the pole, theres my slight concern - we are not getting a clean split of energy.

Now without any shadow of a doubt the ECMWF yesterday was always going to be pure eye candy and we would expect changes, but if we take a look at whats happened over the pole over the last couple of runs before this:

As you can see there the slightly cleaner break of those low heights, and we see the western PV lobe backing away from Greenland. But over the last few runs this has become less and less visible.

The same happened to the GFS:

Now it must be said that stratospherically this has NO support, with the western PV lobe being sent packing by secondary and possible tertiary warnings, and a resultant ridge replaces this.

However, I guess that depends on whether we do see a downwelling of the pattern (still not guaranteed by any means!), and when you look at some of the wave activity forecasts from the ECMWF:

Things do seem to be hitting a bit of a wall at around 100mb.

So theres my only niggles this morning (they are very small niggles in the grand scheme of things). My initial thoughts are that the GFS has done one of its famous wobblers which we have seen quite a few times over the past few years, and from which it takes a few runs to recover. The problem seems to arise from its modelling of the PV around Greenland. But as TEITS points out (although of course then allays those fears somewhat) the GFS was the first one to start picking out this current modelling trend, and it was also the first to drop it in the previous ordeal.

To be fair the 0z has corrected this a little, however, for the sake of my nerves, I would like to see further backtracking towards the rest of the output.

We should bear in mind that this is all about the medium term potential, the shorter term continues to look better and better, but this particular post concerns the longer term height transfer to Greenland.

That said, enjoy the output, because to have so many models on board with an idea is very pleasing indeed.

I'll leave you my pick of the Ensemble means (with the usual caveats).

ECMWF:

NAEFS:

GFS:

SK

[UV-RAY]

Some stunning output this morning both stratospherically and tropospherically speaking, and its always nice to have the ECMWF at the top of the pile (although as we know even this cannot guarantee us anything!)

My very slight, niggling concern this morning ties in to what TEITS says above, and its whether the GFS has picked a new trend once again (its done this a couple of times so far this winter) and whether the other solutions are edging towards it.

Heres the ECM and GFS at +192 this morning:

Different at our locale, however, if we look over the pole, theres my slight concern - we are not getting a clean split of energy.

Now without any shadow of a doubt the ECMWF yesterday was always going to be pure eye candy and we would expect changes, but if we take a look at whats happened over the pole over the last couple of runs before this:

As you can see there the slightly cleaner break of those low heights, and we see the western PV lobe backing away from Greenland. But over the last few runs this has become less and less visible.

The same happened to the GFS:

Now it must be said that stratospherically this has NO support, with the western PV lobe being sent packing by secondary and possible tertiary warnings, and a resultant ridge replaces this.

However, I guess that depends on whether we do see a downwelling of the pattern (still not guaranteed by any means!), and when you look at some of the wave activity forecasts from the ECMWF:

Things do seem to be hitting a bit of a wall at around 100mb.

So theres my only niggles this morning (they are very small niggles in the grand scheme of things). My initial thoughts are that the GFS has done one of its famous wobblers which we have seen quite a few times over the past few years, and from which it takes a few runs to recover. The problem seems to arise from its modelling of the PV around Greenland. But as TEITS points out (although of course then allays those fears somewhat) the GFS was the first one to start picking out this current modelling trend, and it was also the first to drop it in the previous ordeal.

To be fair the 0z has corrected this a little, however, for the sake of my nerves, I would like to see further backtracking towards the rest of the output.

We should bear in mind that this is all about the medium term potential, the shorter term continues to look better and better, but this particular post concerns the longer term height transfer to Greenland.

That said, enjoy the output, because to have so many models on board with an idea is very pleasing indeed.

I'll leave you my pick of the Ensemble means (with the usual caveats).

ECMWF:

NAEFS:

GFS:

SK

Great post SK and a reminder too all not to get too carried away with what the charts are showing ( yet ).

[weather eater]

A familiar story unfolding with the GFS leading a reluctant ECM towards a cold solution, having done so the GFS then goes rather more lukewarm on the idea and the ECM buys into it big time, Fascinating stuff, it wasn’t many days ago when dire predictions of Bartlett’s and locked in zonality were dominating discussion, just goes to show that predicting more than a few days ahead weather wise can be a major mistake, let’s hope this is one of those rare occasions when that’s not the case.

[Severe Siberian icy blast]

Joe B's latest 30-45 day update here. Alludes to forthcoming US and European cold spells with the UK seeing two peripheral "hits".

http://t.co/btVgWw51

Very interesting video there if your a joe b fan I suggest you watch it. I personly like him , I think he has called some cold winters bang on the mark, granted his over the top sometimes and not always right , but from a personal pov I respect him.

[lorenzo]

ECM this morning is a cracker. Back to hunting down that Easterly !!

Here we go again folks !!

ECM Ens at Day 10 continuing to grab the Greenland High solution, less pronounced than last nights 12z.

GEFS getting there, with control run keeping ridging further east.

I think Nick should order in some Valium for this next model watching period, we won't need Prozac anymore, shredded nerves are the order of the day.. Going to be good fun.. !

[snowblizzard]

Joe B's latest 30-45 day update here. Alludes to forthcoming US and European cold spells with the UK seeing two peripheral "hits".

http://t.co/btVgWw51

Fantastic analysis from Weather Bell

Looks like much of USA and Northern Europe are in for a really severe spell of winter weather!

UK only on the peripheral of the real cold as usual, lets hope it all pushes a little further West!

[ITSY]

Peripheral in this sense could mean lots of snow, so be careful what you wish for!

Very happy with this morning output. Trend seems to be towards an Easterly for a starter and then a Greenland block for our main. Now that is a pattern I like. Lets hope to see it develop further in the next few days. Fingers crossed once more.

[Mike Storm]

Wow 34 pages since yesterday lunchtime! The output does look very encouraging for some cold hopefully snowy stuff fingers crossed!