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

[That ECM]

37 minutes ago, johnholmes said:

Why on earth would it move SE?

The upper flow is from the SW which is what will move the surface feature, or am I totally up the creek!

 

Agreed but a little harsh John. This is why some chose not to post in fear of being wrong. Not your normal style you are usually more tactful. Glass of red maybe...

Edited December 6, 2016 by That ECM

[frosty ground]

2 minutes ago, Steve Murr said:

 

What exactly are you hanging onto?

The GFS bending to your will! 

[northwestsnow]

1 minute ago, Steve Murr said:

 

What exactly are you hanging onto?

Hand on heart there is zip to hang onto, this side of christmas fog and frost is surely the best bet for coldies.Looking at the projected jet coming off the eastern seaboard is a sickening sight,, 

[doghouse]

2 minutes ago, Steve Murr said:

 

What exactly are you hanging onto?

What about the day 16 charts posted this morning. I take it that is different

[SMU]

 

11 minutes ago, doghouse said:

What about the day 16 charts posted this morning. I take it that is different

Theres a world of difference between commenting on a day 16 chart than making a forecast with specifics for day 26 through 33.

Stewart - week 4- instability? Whats that supposed to mean-? Pretty pointless by anyone's standards -

we are almost in the realms of Piers Corbyn fantasy nonsence...

[Seasonality]

1 minute ago, Steve Murr said:

 

Theres a world of difference between commenting on a day 16 chart than making a forecast with specifics for day 26 through 33.

Stewart - week 4- instability? Whats that supposed to mean-? Pretty pointless by anyone's standards -

we are almost in the realms of Piers Corbyn fantasy nonsence...

Come on Steve, GP works very hard to make his forecasts and his knowledge is incredible. If I knew a tenth of what he did about forecasting I'd be a happy man. There is no need to insult him.

[bluearmy]

3 minutes ago, Steve Murr said:

 

Theres a world of difference between commenting on a day 16 chart than making a forecast with specifics for day 26 through 33.

Stewart - week 4- instability? Whats that supposed to mean-? Pretty pointless by anyone's standards -

we are almost in the realms of Piers Corbyn fantasy nonsence...

I suppose not blocked over us given that the met seem to indicate cold = blocked under high pressure??

[markw2680]

Am I actually reading all this???  The models chop and change like the wind, a few days time they will be showing a totally different outcome which may be showing snow, frost, rain, mild or cold for next week so pretty pointless in looking for end of month let alone Jan. I study the models myself and have been for a few years just don't normally have the confidence to post in here but common this is laughable 

[Paul]

Can we get back to the model output please.

[Seasonality]

And look whats coming for Christmas. More UK HP.

Edited December 6, 2016 by Seasonality

[Frosty.]

15 minutes ago, mountain shadow said:

Because Steve, if your looking for snow, that's all we have to grab onto.

There is nothing in the model output showing any kind of snowy wintriness up to the end of the month.

I'm sure there is some ensembles showing a snowy set-up, there were even some during the last few days which were otherwise dire. Anyway the best chance of getting a potent cold spell is for high pressure to build in and then either retrogress towards Greenland or migrate to Scandinavia.

[northwestsnow]

Anyway, gfs still promoting a fairly settled picture as we move forward but my goodness retrogression is going to be nion impossible with the sort of crazy jet streaks across the pond.I wonder if fergie is on to something regarding gfs and its insane Atlantic bombs...

[SMU]

6 minutes ago, bluearmy said:

I suppose not blocked over us given that the met seem to indicate cold = blocked under high pressure??

Its meaningless - or vice versa so many meanings that one has be right.

Edited December 6, 2016 by Paul
Removed reply to an already removed post

[Downburst]

1 minute ago, Seasonality said:

And look whats coming for Christmas.

1040 Center on that High, that's some pressure. Too far out for sure to be taken very seriously, but one can't but notice the strength the model has configured here, and assume some sort of High will be about around that time.

[Seasonality]

2 minutes ago, Downburst said:

1040 Center on that High, that's some pressure. Too far out for sure to be taken very seriously, but one can't but notice the strength the model has configured here, and assume some sort of High will be about around that time.

I believe it is an Omega block in fact, just not positioned in the way most here would hope it would be. But just look at the cold air flooding around either side, certainly good for me considering where I will be Xmas week!  But it is 384h after all 

[Singularity]

 

How much of an issue might this broad tropical circulation in the Bay of Bengal become?

It's far enough east that it may be linked to the models indicating phase 3 MJO in the near future. In which case, not an issue for mid-lat blocking provided the usual analogues are at least a loose guide to how the mid-lats will respond.

 

Now - briefly examining a relatively small but significant variation between the 12z GFS and UKMO, for the heck of it;

 

Notice how GFS has a weaker western end to the low over Scandinavia than UKMO. That means you've not got much of an easterly to import some cold air into the developing ridge which may then circulate around to the UK (assuming enough northward ridge building thereafter). UKMO is much better in this regard.

The trough disruption shown by GFS two days later is an important step for that circulation round. While UKMO looks slightly pointy at the base of the trough at +144, I'm not sure it would quite manage it on that run. It's just a bit too mobile still - go figure.

[Methuselah]

6 minutes ago, Frosty. said:

I'm sure there is some ensembles showing a snowy set-up, there were even some during the last few days which were otherwise dire. Anyway the best chance of getting a potent cold spell is for high pressure to build in and then either retrogress towards Greenland or migrate to Scandinavia.

So long as the 'owsyerfather plays ball, a blast from the NNW could still happen...I'm stuck at T+336!

[karlos1983]

29 minutes ago, johnholmes said:

Why on earth would it move SE?

The upper flow is from the SW which is what will move the surface feature, or am I totally up the creek!

 

Well if I was reading it wrong then fair enough, not sure it was a "why on earth would it do x,y,z" warranted comment. Blimey, shoot me down 

[Catacol]

14 minutes ago, Steve Murr said:

week 4- instability? Whats that supposed to mean-? Pretty pointless by anyone's standards -

Instability was a reply to a question on wet and mild. So actually it is a pretty pointed comment Steve that can only point to a north or easterly component around a high latitude block. It's all very well you being annoyed at the lack of snow charts inside 10days at present, but perhaps you would be less annoyed if you tried to grasp the drivers that create those charts in the first place?

[AWD]

3 minutes ago, Steve Murr said:

Its meaningless - or vice versa so many meanings that one has be right.

Im not being funny

but if joe bloggs popped up with a winter forecast on the 6th of Dec with a week by week forecast for Jan then they everyone would ignore it knowing its just made up -

The same rule applies for anyone painting any detail onto a forecast for 26 days away.

Jackanory.

I'm sure we can all make up our own minds with regards to who we want to take serious & who we want to ignore.  After all, we are all here to enjoy a hobby rather than provide serious, public dependant forecast.  If the model output isn't to your liking, take a break, enjoy something else & come back when things improve.  Anyway, that's all a little unrelated for this thread, apologies for that, I won't comment no further on other peoples emotions now.

The latest GFS Op & GEM Op aren't a million miles away at T240 with regards to the broad NH pattern;

 I

Perhaps another step towards a possible settled & eventually cooler Christmas period?  

The main issue for proper cold rather than surface cold, is the lack of output supporting lowering heights over southern Europe IMO.

[Cheshire Freeze]

1 minute ago, Singularity said:

 

How much of an issue might this broad tropical circulation in the Bay of Bengal become?

It's far enough east that it may be linked to the models indicating phase 3 MJO in the near future. In which case, not an issue for mid-lat blocking provided the usual analogues are at least a loose guide to how the mid-lats will respond.

 

Now - briefly examining a relatively small but significant variation between the 12z GFS and UKMO, for the heck of it;

 

Notice how GFS has a weaker western end to the low over Scandinavia than UKMO. That means you've not got much of an easterly to import some cold air into the developing ridge which may then circulate around to the UK (assuming enough northward ridge building thereafter). UKMO is much better in this regard.

The trough disruption shown by GFS two days later is an important step for that circulation round. While UKMO looks slightly pointy at the base of the trough at +144, I'm not sure it would quite manage it on that run. It's just a bit too mobile still - go figure.

Look at heights to the S of the UK...sorry but you've not got a cat in hells chance of any meaningful disruption with a set up like that. Height are anchored all the way down to Africa! Couple that with a strong jet streak....Don't understand why the possibility is even being discussed. 

As I said last night, we're on hold now until the latter stages of December.

[Singularity]

  . . . 

I'll give this run half marks for at least trying to split the lower-to-mid vortex pre-Xmas. 

In the late stages of the run, the dual wave action suggests that the vortex won't be having it easy any time soon.

[Paul]

And once again can we get back to the models please, I get that it's reasonable to have an opinion, and to voice disagreement with someone else's opinion, but it's less reasonable to turn that into some sort of willy waving contest and allow it to escalate into insults. 

[Frosty.]

Well that glancing blow cold shot really helps to turn the anticyclone into a cold high at the end of the Gfs 12z. I think a chilly blocked 2nd half of dec is the form horse with crisp settled weather with sunny spells and widespread frosts / fog.

Edited December 6, 2016 by Frosty.

[SMU]

I will a final comment like this-

If the forecast for Jan is that easy to predict with so much confidence to paint any detail around then it would indicate its pretty straight forward with minimal variability -

However just yesterday at 315 we see a post claiming that 12z data had significantly different initialised data around   Indian ocean convection than the 00z & 06z - & the ramifications of this could effect the UK down the line at say day 8-12 ...

So in one breath there is a confident post about specifics at the period 26 - 33 ( T624 - 792 ) yet just 24 hours before we have a massive potential swing in outputs as a result of different starting data covering 12hours - 

So if that disparity can occur in just 12 hours having a exponential effect at just day 8 how does one arrive with such bold statements at day 26....

The seasonal models - like the CFS swing around daily from run to run all because the starting data is slightly different from the run before leading to huge hemispheric change at week 4..

I will leave people to make up their own minds...

So far - The glosea long range has been not very good, the assumption of a front loaded winter looks to bomb ( which includes me as well ) & were just 6 days in ...

Anyway enjoy the eve 

Edited December 6, 2016 by Paul
Tidied quote