Model output discussion - 5th December 2016 - Into Winter we go

[karlos1983]

3 minutes ago, feb1991blizzard said:

No the core of heights (darker colours) are over Southern UK and France, SW winds with a Bartlett type, drier in the South, wetter for Scotland, very mild everywhere - That's a very broad brush statement and obviously it wouldn't apply to the whole 3 months but that would be the 'default' if you like over the 3 months, There would be greater instances of that type of setup set against climatology.

I think it was a tongue in cheek comment 

[Scandinavian High.]

4 minutes ago, feb1991blizzard said:

No the core (darker colours are over Southern UK and France, SW winds with a Bartlett type, drier in the South, wetter for Scotland, very mild everywhere - That's a very broad brush statement and obviously it wouldn't apply to the whole 3 months but that would be the 'default' if you like over the 3 months, There would be greater instances of that type of setup set against climatology.

I just thinking back  I'm not sure what year it was same model went for a mild winter a few years ago but then had  one the coldest winters  for like 30 years I'm not sure what year 2009 - 2010.

[Dennis]

GFS6z para ; today the 0z was also good for winter late dec

Edited December 12, 2016 by Dennis

[Mucka]

3 hours ago, Man With Beard said:

Since you did not specify a particular date "by" Christmas, I think the world is about to see you in all your glory, Mucka.

About 1000 miles of easterly from the Polish border to West Wales, just about including Manchester. 

LOL that is an insult to the term "Easterly" and the term "glory"

There has been some form of slack continental flow in the models for quite some time over the period but you you will never get the cold you want from a set up like that.

To get cold uppers we need to tighten the isobars and have high pressure further NW and the only way to do that is to have low pressure under the block.

I still see very little chance of this happening  over the next two weeks as the core heights to our East are actually in SE Europe rather than Scandinavia in most of the output.

Since the jet profile looks very unlikely to allow the necessary undercut from the West the only other way would be to have have shortwave trough drop down and run West along the base of any high but again the high would be at too lower latitude for even that scenario to be especially beneficial.

So no Easterly.

What is more plausible is to get the Atlantic trough further South to allow the high to attempt to retrogress as previously stated. In this situation you will get a temporary flow from the E of sorts but nothing we would describe as an "Easterly" with all the wintry connotations that come with that. If the retrogression went well we could get high pressure far enough NW to drag in a N/NE flow as a trough dropped into Scandinavia (opposite of high pressure dominating there giving an Easterly flow) but the more likely scenario there is for the Atlantic flow to be too strong to allow such success and so the high would likely sink back over us and give us high pressure over the UK.

We have seen lots of output showing high to the E and trough to the W through into FI with slack continental flow generally S/SE around the high but we have not seen the undercut necessary modeled to get low pressure into the continent, just enough tilt on occasion in the Atlantic trough to encourage the high NW.

For now I am still happy with my Christmas forecast of a few days ago, generally dry, average temps, possibly a little milder NW, cooler SE.

And even though it looks as unlikely as any Easterly I still think we have more chance of pulling in cold air from the N/NE with high pressure to our W/NW than to our E/NE (Which goes against the anomalies so unlikely)

Most likely is for Christmas is mid lat high pressure close to the UK, possibly centered around NW Europe off current output but of course there is scope for change but an Easterly still looks very unlikely to me.

 

Edited December 12, 2016 by Mucka

[bluearmy]

Yes Dennis - the para reading the Atlantic script in week 2 by digging the Atlantic trough (can we get it into Iberia) whilst bigging up the scandi ridge. Manages to deliver distinct cold pools travelling around the ridge but to rely on those to bring deep cold is a real tombola !! No sign of low heights developing to our south unless we can get that trough into Iberia imo

[Singularity]

28 minutes ago, Dennis said:

some nice news to hear for poss winter late dec 2016 Europe: USA hasnt the cold anymore  

 

A flatter N Pacific pattern bodes well for the N Atlantic pattern becoming more amplified.

Also, we have the MJO signal lurching in the right direction for once. Questions now are 'how real is this signal given TC involvement' and 'will it be sustained for the next 8-10 days as per most models or turn out to be a red herring after 4-5 days as per ECM ens?'

Best case scenario I believe would be a genuine signal moving at a similar pace to recent days toward phase 7. Worst case is simple - the ECM ens. version of events!

[feb1991blizzard]

13 minutes ago, abbie123 said:

I just thinking back  I'm not sure what year it was same model went for a mild winter a few years ago but then had  one the coldest winters  for like 30 years I'm not sure what year 2009 - 2010.

Yes it was 09-10 and it was the MO - their model then was the GLOSEA4 - its predecessor, I actually remember John Kettley predicted a cold start to winter on talksport but I don't think he worked for the MO then, I think that was his personal prediction.

[Captain Shortwave]

Day 6 charts

GFS/UKMO

      

Well the GFS does get the high as far north as the UK and offers a developing continental flow for the following week, if we get into this pattern which seems fixed we could try to erode the core ridge over central Europe (Squeezed by the next trough moving eastwards from the Atlantic and also from the east as further pulses of Arctic air move towards the far south east of Europe). Fair to say the UKMO is much flatter and would be very undesirable with most places remaining mild into next week.

At day 8

With the Azores ridge sheering away, there is just an ounce of hope that we could develop something interesting around Christmas day if we get a favourable interaction between the approaching Atlantic trough and that cluster of shallow low heights over Iberia. I think we are due a Christmas miracle to be honest, it wouldn't take much to pull something much colder in from east even if it was brief (an isolated cold pool for example).

Edited December 12, 2016 by Captain Shortwave

[phil nw.]

Today's 12z GFS a little better at holding back the n.arm of the jet and thus better ridging of the second attempt from the AH.

See today's day 5 and yesterday's  day 6

see how this goes on to give a better continental flow by T192 on this run.Little steps.

Edit. What CS said lol

Edited December 12, 2016 by phil nw.

[Man With Beard]

14 minutes ago, Mucka said:

LOL that is an insult to the term "Easterly" and the term "glory"

There has been some form of slack continental flow in the models for quite some time over the period but you you will never get the cold you want from a set up like that.

To get cold uppers we need to tighten the isobars and have high pressure further NW and the only way to do that is to have low pressure under the block.

I still see very little chance of this happening  over the next two weeks as the core heights to our East are actually in SE Europe rather than Scandinavia in most of the output.

Since the jet profile looks very unlikely to allow the necessary undercut from the West the only other way would be to have have shortwave trough drop down and run West along the base of any high but again the high would be at too lower latitude for even that scenario to be especially beneficial.

So no Easterly.

 

Ahhh - the terms and conditions So what you really meant was "beast from the east" - I think that's our official terminology isn't it?

I've still got a hunch on this easterly Mucka - the vortex is throwing everything at the block and hasn't got through - but I'm not confident enough to bet my nudity on it just yet!

[bradymk]

Could be quite chilly next week and the run up to Xmas if we can get that high north enough. Cold, dry and frosty in any cloud breaks. Better than the 13/14c mush the last few days but still not what we all crave unfortunately.

Parallel even chillier. UKMO just rubbish

Much more seasonal!

 

Edited December 12, 2016 by bradythemole

[Singularity]

Disappointing to see UKMO merging the multitude of smaller systems on day 4 into a single intense low on day 5. This sort of solution is what GFS has moved markedly away from and ECM to a lesser degree; the systems don't merge and this allows the jet to maintain more of a SW-NE angle from the western N. Atlantic.

We're seeing pretty good continuity from GFS today - the jet pattern as a whole right out at day 9 has remained similar but the strength of the N. Atlantic jet was slackened off quite a bit between the 00z and 06z.

  

Let's hope it counts for something... strange thing is this is a bit soon in time for the MJO conundrum to be having that much of an impact. Just what is it that's made recent ECM runs tend to be flatter in the 8-10 day range?

[Singularity]

One more jet chart to exercise your eyes 

On the fact of it a good pattern here; a cut-off high to our east and the Atlantic jet orientated with Europe in its sights.

The S tracking low is rather a long way west, though! 

[Mucka]

3 minutes ago, Man With Beard said:

Ahhh - the terms and conditions So what you really meant was "beast from the east" - I think that's our official terminology isn't it?

I've still got a hunch on this easterly Mucka - the vortex is throwing everything at the block and hasn't got through - but I'm not confident enough to bet my nudity on it just yet!

Unfair. I think it is pretty clear what was meant.

We likely would not even get a frost out of the chart you posted with daytime temps around 6C to 8C

It is actually more disingenuous for you to call me out and say we will get an Easterly that I didn't predict based on a single chart that shows a slack continental flow that was actually in charts when I posted!

I even mentioned temporary slack S/SE flow. 

If we get a genuine Easterly I will be the first to hold my hands up.

 

[Summer Sun]

A settled and chilly Christmas day on the 12z

Thankfully no issues of flooding this year

[frosty ground]

A Classic Easterly to end the GFS run......

[-uksnow-]

What was that? The two biggest winters didnt start until after Xmas? Nothing to see here!

Enjoying the continuity of the GFS, makes up for the poor ECM outputs we've had to endure lately. Let's hope the more festive theme can be picked up more uniformly over the next couple of days..

[Ali1977]

Now that is a better FI, awesome chart but can't post the picture.  This would turn into a freeze of quite some strength as the high migrates towards the Pole with an undercut and a gale force Easterly...WHY do these turn up in FI!!!

Edited December 12, 2016 by Ali1977

[feb1991blizzard]

Some support from the parallel for this evolution too.

[Seasonality]

8 minutes ago, Mucka said:

Unfair. I think it is pretty clear what was meant.

We likely would not even get a frost out of the chart you posted with daytime temps around 6C to 8C

It is actually more disingenuous for you to call me out and say we will get an Easterly that I didn't predict based on a single chart that shows a slack continental flow that was actually in charts when I posted!

I even mentioned temporary slack S/SE flow. 

If we get a genuine Easterly I will be the first to hold my hands up.

 

Time to hold your hands up?

 

[Singularity]

That was cheeky from GFS; the broadness of the low to our south, followed by the gentlest of disrupting troughs somehow making eastward progress into NW Europe, led to the colder continental air being heavy modified on its way to our shores, so we were no lower than average for 2m temps days 10-14... but at least the run finished with a flourish!

[Seasonality]

3 minutes ago, feb1991blizzard said:

Some support from the parallel for this evolution too.

Are you feeling ok? You just suggested a cold outcome had support...  Must be the festive season!

[feb1991blizzard]

Strat vortex stretched as well, and with the trop PV sliced completely, we would be looking at a protracted spell from the Eastern quadrant as well - problem is actually getting to that point!

 

 

[mountain shadow]

6 minutes ago, frosty ground said:

A Classic Easterly to end the GFS run......

It would be a prolonged spell too as the High is retrogressing to Greenland.

[Mucka]

6 minutes ago, Ali1977 said:

Now that is a better FI, awesome chart but can't post the picture.  This would turn into a freeze of quite some strength 

It's a cracker

Neg tilted trough, retrogressing high, with best case temporary but (true) Easterly.

The issue is it is always the last couple of charts in any given run.

It is interesting GFS has repeatedly suggested such a pattern over several weeks in FI but as yet it has not made it into day 10 territory yet alone more reliable time-frames.

Rather it show that than raging Atlantic though.

Edited December 12, 2016 by Mucka