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

[No Balls Like Snow Balls]

Some rain for the South tomorrow. First bit of decent rain since December begun.

[jvenge]

28 minutes ago, swfc said:

Wasnt matts tweet yesterday calling a blocked dec/jan?????.Seems this has more flexibilty than a carp pole  atm,ah well

That was from the seasonal output and the ones he is quoting today will be the 10 day operational and the 15 day ensembles, I'd guess. 

 

[swfc]

20 minutes ago, MattHugo said:

That's a good way to sum things up really from Nick this morning...

The frustrating aspect, especially from a forecasting point of view, continues. It is quite unusual now to have such a prolonged disconnect and difference between the ensemble output of the GEFS and the EC ENS. The EC ENS, to me, is the form horse and I now believe, bar some sort of Christmas miracle, that the more progressive solution will come about. You can't discredit the persistence of the GEFS in terms of the blocking signal, especially given the 'flip flopping' that has been produced by the EC ENS. The overnight EC monthly was useless as it highlights -ve pressure anoms to the W of the UK, as per the EC ENS output, whilst blocking is in evidence to the east and north-east, but the UK then ends up within a no-mans-land of no anomalies at all, so a run where some meteorological insight comes in handy to gauge what it is showing and to me, the outcome is a predominantly S or SW'ly type, before a potential blocked regime by week 4. Whether the monthly can be trusted at the moment though is another question as it's only 2 weeks or so back that it was clearly going all out, guns blazing for a blocked regime, that to me now doesn't look likely.

In what is turning into a particularly strange month then the last week of the month may well be up for grabs, but speaking 'off the record', as such, then personally I would sooner see a more zonal pattern break through, at least within that you can potentially get colder W or NW'ly flows, especially given the deep cold that is loitering over E Canada for example. This steadfast scenario of blocking to the east, in some shape or form, just means the UK lies on the edge of a situation where it's either mild, wet and windy, or potentially more blocked drier and chilly, there's nothing really in-between and that, for now at least, really does mean that the chances of getting some 'true' cold air into the UK is very unlikely within the next week to two weeks. The other aspect to mention as well is that November was a below average CET month and more regionally temperatures were over 1C below average, what are the chances in the UK these days of getting 2 consecutive months where the CET ends up at or below average?...little chance!

As Tony and I titled the Winter Forecast, "A Winter of Wildcards", I will also copy and paste the below from the start of it as it really seems to heading this way...

"From the outset this has been an incredibly difficult forecast to work through, with multiple variables this season that are outside expected parameters. In essence, it is a winter where wildcards are in abundance."

Have a good weekend,

Matt.

Good post matt.So in your opinion are all bets off with anything over 7-10 days regarding the nhp and outcomes???.Thanks in advance

[Sperrin]

I'm no expert but I'm assuming that these last 5/6 weeks will be very interesting for retrospective study. Considering all the strong signals for positive (i.e. cold) winter weather, that havn't *as yet* come to fruition, there must be some greater forcing mechanism that has caused the weather pattern we are experiencing (and look to be experiencing in the near future) to unfold.

Edited December 9, 2016 by Sperrin

[Nick F]

36 minutes ago, MattHugo said:

That's a good way to sum things up really from Nick this morning...

The frustrating aspect, especially from a forecasting point of view, continues. It is quite unusual now to have such a prolonged disconnect and difference between the ensemble output of the GEFS and the EC ENS. The EC ENS, to me, is the form horse and I now believe, bar some sort of Christmas miracle, that the more progressive solution will come about. You can't discredit the persistence of the GEFS in terms of the blocking signal, especially given the 'flip flopping' that has been produced by the EC ENS. The overnight EC monthly was useless as it highlights -ve pressure anoms to the W of the UK, as per the EC ENS output, whilst blocking is in evidence to the east and north-east, but the UK then ends up within a no-mans-land of no anomalies at all, so a run where some meteorological insight comes in handy to gauge what it is showing and to me, the outcome is a predominantly S or SW'ly type, before a potential blocked regime by week 4. Whether the monthly can be trusted at the moment though is another question as it's only 2 weeks or so back that it was clearly going all out, guns blazing for a blocked regime, that to me now doesn't look likely.

In what is turning into a particularly strange month then the last week of the month may well be up for grabs, but speaking 'off the record', as such, then personally I would sooner see a more zonal pattern break through, at least within that you can potentially get colder W or NW'ly flows, especially given the deep cold that is loitering over E Canada for example. This steadfast scenario of blocking to the east, in some shape or form, just means the UK lies on the edge of a situation where it's either mild, wet and windy, or potentially more blocked drier and chilly, there's nothing really in-between and that, for now at least, really does mean that the chances of getting some 'true' cold air into the UK is very unlikely within the next week to two weeks. The other aspect to mention as well is that November was a below average CET month and more regionally temperatures were over 1C below average, what are the chances in the UK these days of getting 2 consecutive months where the CET ends up at or below average?...little chance!

As Tony and I titled the Winter Forecast, "A Winter of Wildcards", I will also copy and paste the below from the start of it as it really seems to heading this way...

"From the outset this has been an incredibly difficult forecast to work through, with multiple variables this season that are outside expected parameters. In essence, it is a winter where wildcards are in abundance."

Have a good weekend,

Matt.

Don't envy you and Tony trying to fathom out how the winter may pan out, as there seems to be a lot of conflicting signals. A weaker than average PV to start winter but is increasing in strength, but even so,  there is the question of whether there is a disconnect between the strat and trop atm. The lobe of the PV shifting into Canada and cranking up the jet may not have been easily foreseen back in late November either. The persistence of deep cold over N America over the coming days really has the writing on the wall for our fortunes, so not surprised you have the hunch that the EC/EPS maybe calling correct on a mobile run up to Xmas. And if so, this does really question the credibility of those EC monthly runs with the +ve anomalies to the NE it has shown recently.

I'm torn between whether I like the  idea of the zonal train taking over, as from a cold and snow potential it favours the north. But the Atlantic storms with their wind, rain and cold and potentially wintry Pm flows would provide more interest for us forecasters to write about compared to the quiet and unexciting anticyclonic conditions close to the east proffered by 00z GFS/GEFS. Though, with the high close to the east or over the UK, there is potential, if the flow buckles and splits with more energy going to southern Europe, that the high may build N and NE across Scandi in a more sustained fashion. But the current upper pattern doesn't favour this outcome in the coming 10 days at least. Would need some increased tropical forcing, i.e. MJO through 7-8-1. to change the upper pattern, but any favourable movement would not impact the upper pattern for us until later in the month anyway. For now the deep cold over N America and the strong jet it drives NE over the Atlantic  is dictating our destiny for now.

Edited December 9, 2016 by Nick F

[Ben Lewis]

14 minutes ago, No Balls Like Snow Balls said:

Some rain for the South tomorrow. First bit of decent rain since December begun.

Yes, charts and models have had this pretty much since Tuesday. Although this is just another added unseasonable blow. A rainy mild Saturday. Riveting

Although it may be the first bit of appreciable rain it doesn't feel it out there. Everything damp and wet constantly and fields bogged and muddy as if it had been raining for weeks

[karlos1983]

17 minutes ago, Sperrin said:

I'm no expert but I'm assuming that these last 5/6 weeks will be very interesting for retrospective study. Considering all the strong signals for positive (i.e. cold) winter weather, that havn't *as yet* come to fruition, there must be some greater forcing mechanism that has caused the weather pattern we are experiencing (and look to be experiencing in the near future) to unfold.

Well one thing I've learned this year is not to take the longer range signals as a forecast and more as a guidance. I got pretty convinced this year that December was going to be a stonking month, blocked all the way! But it takes a Tropical storm that emerges, which can ultimately change all of that. Which we have to accept is more and more likely these days with SST's on the rise globally. Usually you would expect it to become easier to predict longer range, but I think it's quite the opposite now with so many unknowns. Anyway I'm probably waffling on a  bit now.

Bottom Line is, a long range prediction is not a forecast, it's more of an idea on what pattern is more favored IMO, but it doesn't take much to change that, so we shouldn't shoot anyone down if it's wrong, the weather is complex! (not saying you've shot anyone down Sperrin) , plus a lot of effort goes into them and I certainly enjoy reading them. 

Edited December 9, 2016 by karlos1983

[mountain shadow]

The next two weeks definitely look relatively flat. The latest AAM plot shows low angular momentum forecast so its difficult to see how we'll get any amplification in our sector.

http://www.atmos.albany.edu/student/nschiral/gwo.html

I think GP's forecast of height rises to the North West are not going to happen unless there is a major turn around in the models.

[Man With Beard]

GEFS mean starting to move towards ECM mean at T192

This will put you off your Christmas dinner

It does feel that the pattern is set?

[booferking]

A marked swing in the GEFS 06z towards the more zonal pattern thank god for that least we can move on now till Jan in hoping for HLB to show up.

My only fear now is we missed are chance early on,  now the vortex is firing up we could well go through to Feb like this who knows.

Edited December 9, 2016 by booferking

[Summer Sun]

After a slow start we are starting to see the PV waking up now

Could this go down as the winter which promised so much yet failed to deliver?

[Faronstream]

This mornings GFS 06Z is very mild, must be a outliner beacuse i thought the colder period after mid month was already almost 80% accurate now  and last days i have seen almost only cold runs and only a few runs has been very mild. It can still change back to colder conditions since 06Z is always the mildes of the day

[cheeky_monkey]

1 minute ago, Summer Sun said:

After a slow start we are starting to see the PV waking up now

Could this go down as the winter which promised so much yet failed to deliver?

yes a marked turn round in the NH atmosphere set up in the last 36 hrs...PV now looking to set up in the usual position..the pacific ridge is leaking away back south which will just reinforce the set up...bad news if your looking for a cold blocked outlook this side of the Atlantic..and will take some shifting if it shifts at all..if so better luck next winter!

[Summer Sun]

1 minute ago, Faronstream said:

This mornings GFS 06Z is very mild, must be a outliner beacuse i thought the colder period after mid month was already almost 80% accurate now  and last days i have seen almost only cold runs and only a few runs has been very mild. It can still change back to colder conditions since 06Z is always the mildes of the day

9

Going by the 00z ens for the UK I wouldn't be so sure it's an outliner we seem to be getting further and further away from cold at present

[Sky Full]

Other than a general trend towards a NW / SE split between low and high pressure areas, these GFS ensembles at only 10 days out show a staggering range of possible solutions.  

The irony for me is that they are almost certainly ALL wrong and the actual result is highly unlikely to resemble any of them.  I will keep this panel for 10 days and just for fun will compare the actual picture on the 19th December to see just how close the GFS managed to get in 24 attempts.   If none of them are close then frankly we are on a hiding to nothing putting any faith at all in FI even when it's eye candy.....

[karlos1983]

The GFS Control isn't interested in falling in line with ECM or its operational friend

 

And wants to play the Trough disruption game 

Edited December 9, 2016 by karlos1983

[karlos1983]

Ens show a large spread where heights are concerned. doesn't appear to be over....just yet

[feb1991blizzard]

Just now, karlos1983 said:

Ens show a large spread where heights are concerned. doesn't appear to be over....just yet

Hardly any showing lp though which means the LP is tracking MUCH further North, it is over and has been for quite a while IMO>

[weirpig]

1 minute ago, karlos1983 said:

Ens show a large spread where heights are concerned. doesn't appear to be over....just yet

not at all.  Quite a few of the ensembles still having blocking in place a few days up to the christmas period .  Way to early i think yet to call anything

[karlos1983]

4 minutes ago, feb1991blizzard said:

Hardly any showing lp though which means the LP is tracking MUCH further North, it is over and has been for quite a while IMO>

I'm talking in terms of HP being in or around the UK, not a snow fest! If we have High Pressure over us or near us, then chances exist!

 

Edited December 9, 2016 by karlos1983

[Scandinavian High.]

Game on this is not over yet a cold dry Christmas could still come off.

[feb1991blizzard]

Just now, karlos1983 said:

I'm talking in terms of HP being in or around the UK, not a snow fest!

 

OK, right, yes higher THAN AVERAGE pressure is very likely for your location, don't forget though, a Bartlett can do that so its not hard.

[Troubleatmill]

5 minutes ago, karlos1983 said:

I'm talking in terms of HP being in or around the UK, not a snow fest!

 

Caught between a rock and a hard place at the moment aren't we! On one hand we want rid of this block so we can reset and hope fore something to manifest, because there is pretty much no chance of snow and true cold with the block in place as it is. On the other hand the only chance at the moment of having frosty more seasonal type weather is with this block in place! go figure :/   

Edited December 9, 2016 by Nicholas B

[karlos1983]

4 minutes ago, feb1991blizzard said:

OK, right, yes higher THAN AVERAGE pressure is very likely for your location, don't forget though, a Bartlett can do that so its not hard.

That's a valid point. What do the ensembles look like further north?

Although the Mean Height Anomaly doesn't hint at it being Bartlett Feb!

 

Edited December 9, 2016 by karlos1983

[karlos1983]

5 minutes ago, Nicholas B said:

Caught between a rock and a hard place at the moment aren't we! On one hand we want rid of this block so we can reset and hope fore something to manifest, because there is pretty much no chance of snow and true cold with the block in place as it is. On the other hand the only chance at the moment of having frosty more seasonal type weather is with this block in place! go figure :/   

But with a block in place, there is always the chance of retrogression, whereas with no block, there is No Chance!