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

[knocker]

Today

A band of rain moving south east during the day. So cloudy with rain at first in western Scotland and N. Ireland coming brighter and breezier as the cloud and rain reaches N. England and N. Wales Elsewhere mainly dry with sunny intervals. Everywhere continuing mild particularly in the south west.

The GFS this morning sticking to the next ten days. The overall long wave pattern is very much the same with the trough in the NW Atlantic orientated south east and the HP around the southern North Sea area. Ergo we are looking once more at the variation of the day to day weather caused by the interaction of the war/cold air in the form of the Atlantic troughs and the ridging of the Azores HP

So with this in mind the beginning of next week sees renewed ridging from the Azores and the movement east of the large, complex upper trough so that by Wednesday 00z we reach this position with surface fronts lying just to the west.

.

And once more (this is really getting very familiar) the Azores has a little burst and the trough deconstructs sending a little wave around the north of Scotland and a cut off upper  low SE to the western Mediterranean. And by Friday midnight we are back with a new upper low in the Iceland area with associated trough running south and the HP ridging NE over the North Sea. Thus this surface analysis

From here the trough once again deconstructs but the high pressure is much stronger this time around and even has an enclosed circulation over the North Sea which is about where we came in with the anomaly.

Quick summation

Thanks largely due to the durability of the high pressure the UK will remain largely dry during the period. There will be some incursions of sporadic rain from the west as troughs struggle east but this will mainly be confined the west and north west. Temps will be above average to start but will return to the cool side later in the period as the high pressure becomes more influential

 

Edited December 9, 2016 by knocker

[cookie27]

Well this would certainly make an interesting Christmas Eve for the North West....100mph winds

 

 

[Ali1977]

GP mentioned that models won't start picking up on certain drivers till later today, I hope he's right as the nights GFS and GEFS look very poor. If we can establish a blocked pattern now before Xmas I'd be very surprised. I know not to trust FI but when FI is warm it's generally more trustworthy than when showing cold! Anyway, hopefully today is when we start seeing a change. 

[blizzard81]

6 hours ago, joggs said:

Still a hell of a lot colder than blighty.Point is,super charges the jet and most of the time we know where the jet goes,over the top.Hope you watched the 91 video of Ian on YouTube. 

I remember watching that forecast at the time

[mb018538]

Still very frustrating that the GFS and ECM refuse to sing from the same hymn sheet - GFS again bullish in bringing high pressure, ECM keeps things mobile. So another day is upon us, and we're still none the wiser as to how this will pan out. I think as a few have pointed out, if it's more along the ECM route, you can wave goodbye to a good 2-3 weeks of winter....GFS gives us a shot at least.

[winterof79]

A colder than average November and early December with hard frosts for many parts.

A milder period at present and then who knows? And people still not happy as they search the depths of Fantasy Land which will always revert to zonal when the model is struggling with the drivers.

I am hoping for a rapid cool down toward year end when days are shortest.Very interesting posts from GP and Tamara and I look forward to seeing how their thoughts pan out.Top up the glass and enjoy what mother nature brings

[bluearmy]

6 hours ago, CreweCold said:

Yeah....it basically shows what we have been/are about to experience with HP to the S and LP to the NW (if you ignore the shading and look at the MSLP). Those height anomalies are rather weak to be basing a forecast of blocking on.

we all know that you can't use slp beyond 7/10 days because the ens will  nearly always return the mslp flow towards climatology. In the  46  it's more essential to use the anomolys, especially without access to clusters. 

Those md dec onwards charts from November fail mainly in two areas for us - euro heights are more persistent and the south greeny low is much more marked which drives the Azores. no chance of low heights developing to our south. we had a pretty good ticket to the raffle for second half December but when it came to it, we missed out again. I recall posting on TWO that some of the mid latitudes were certain to be very cold in December and that will verify. Not much of a call given the vortex but a twek here and there and we could have been in the game, so to speak.

anyway, the envelope is just about wide enough approaching new year and gets better thereafter but until we see evidence that the Euro heights are going to relax their grip, forget it for upper cold. the wintry possibilities exist for sliders but that's far away in terms of mean charts. 

[knocker]

The ecm goes along with the GFS until around T132 when the upper trough deconstructs just to the west. Crucially it doesn't then initiate further amplification of the Azores HP NE and once this brief window is closed the trough can continue to track east before deconstructing over the UK.  Thus the surface fronts and Atlantic are more progressive although the Azores does make a bit of a come back towards the end but too little too late. For all that one has a feeling in one's water that it wouldn't take a huge correction to put them back on the same page.

[Man With Beard]

Now I've found the link to the ECM46, I really want to know for sure how good/useful it is by looking at archives - not to "bash" it, but simply to evaluate how much we should read into it. 

I intend to go through far more examples than this, as it is not fair to evaluate a model on the basis on a small sample - but this is what I've looked at in the small time I've had this morning. First, up to the current time, starting at W1 and going back weekly for 4 weeks:

      

And I thought I'd choose another timeframe at random - the end of November

      

 

[jvenge]

4 minutes ago, Man With Beard said:

Now I've found the link to the ECM46, I really want to know for sure how good/useful it is by looking at archives - not to "bash" it, but simply to evaluate how much we should read into it. 

I intend to go through far more examples than this, as it is not fair to evaluate a model on the basis on a small sample - but this is what I've looked at in the small time I've had this morning. First, up to the current time, starting at W1 and going back weekly for 4 weeks:

      

And I thought I'd choose another timeframe at random - the end of November

      

 

Are they the means? If so, I'm not sure how useful it is to look at them after more than 15 days. The problem is you can't see the clusters of the 51 members to figure out how they arrived to the mean. 

Similarly, if you then look at the control, you see something totally different to the mean, which highlights the issue quite well.

[blizzard81]

Gfs adamant with it's raising of heights over scandi in the relatively short term. Very interesting that the ukmo has moved towards this too this morning. Ecm having none of it. This is in the 5 day range now.

Edited December 9, 2016 by blizzard81

[Banbury]

A couple of days ago my opinion was there was nothing of hope for us cold brigade and if it doesn't happen soon that will be the month over and 33% of the Winter gone....................nothing has changed , can talk all you want about background signals etc , BUT as it stands there is absolutely nothing and a blocked start to the winter is HIGHLY / VERY unlikely.

 

 

Sadly

[titchjuicy]

Hi Banbury,

For a newbie like me that reads as a very bold statement- would you mind showing some charts to back it up?

 

thanks

Edited December 9, 2016 by titchjuicy

[blizzard81]

2 minutes ago, Banbury said:

A couple of days ago my opinion was there was nothing of hope for us cold brigade and if it doesn't happen soon that will be the month over and 33% of the Winter gone....................nothing has changed , can talk all you want about background signals etc , BUT as it stands there is absolutely nothing and a blocked start to the winter is HIGHLY / VERY unlikely.

 

 

Sadly

Pressure rising over scandi in the 5 day range on gfs and ukmo. If it was just gfs, I wouldn't be taking it too seriously but now it is joined by ukmo I think there is reason to be optimistic in this outcome.

[Banbury]

 

Majority are going for a milder run in to Xmas , December could well be completely different to the one we were hoping for

[jvenge]

5 minutes ago, Banbury said:

A couple of days ago my opinion was there was nothing of hope for us cold brigade and if it doesn't happen soon that will be the month over and 33% of the Winter gone....................nothing has changed , can talk all you want about background signals etc , BUT as it stands there is absolutely nothing and a blocked start to the winter is HIGHLY / VERY unlikely.

 

 

Sadly

Hi,

GEFS gives you colder options from T144 or so. I admit, there is no deep freeze showing though, but you have the possibility of frosts, along with below seasonal norms for temperatures.

 

[Banbury]

2 minutes ago, titchjuicy said:

Hi Banbury,

For a newbie like me that reads as a very bold statement- would you mind showing some charts to back it up?

 

thanks

Well current there is nothing showing on the charts and I have posted the GFS ENS, which so the majority showing a lack of Winter

[Banbury]

3 minutes ago, blizzard81 said:

Pressure rising over scandi in the 5 day range on gfs and ukmo. If it was just gfs, I wouldn't be taking it too seriously but now it is joined by ukmo I think there is reason to be optimistic in this outcome.

I really hope you are right and admit I am totally wrong but its just my opinion but I don't see a thing at the minute . Lack of cold runs on the GEFS also

[Banbury]

This is what we obviously want but these are few and far between in ENS

[mountain shadow]

1 hour ago, Ali1977 said:

GP mentioned that models won't start picking up on certain drivers till later today, I hope he's right as the nights GFS and GEFS look very poor. 

Few sign of any height rises to the North West in this mornings 0z. I think i will give it until tomorrows 0z before throwing in the towel for December.

Edited December 9, 2016 by mountain shadow

[Rocheydub]

3 minutes ago, Banbury said:

I really hope you are right and admit I am totally wrong but its just my opinion but I don't see a thing at the minute . Lack of cold runs on the GEFS also

Yes, I agree. The NWP in 2009/2010 were quite bullish in the lead up to the events and strong signals remained right up to the T-0, I'm seeing nothing to back up GP's optimism, although I do also hope to be proven very wrong indeed. 

[Banbury]

4 minutes ago, mountain shadow said:

Few sign of any height rises to the North West in this mornings 0z. I think i will give it until tomorrows 0z before throwing in the towel for December.

I'm prepared to give it another 7 days after that I will be looking or hoping for something in the NY

Edited December 9, 2016 by Banbury

[Banbury]

26 minutes ago, blizzard81 said:

Gfs adamant with it's raising of heights over scandi in the relatively short term. Very interesting that the ukmo has moved towards this too this morning. Ecm having none of it. This is in the 5 day range now.

 

Hell of a bomb for the HP to deflect , be interesting to see what the 12z shows

[Troubleatmill]

Only GEFS p1 ensemble has a handle on the way forward this morning, shocking how the rest don't have a clue!

[karlos1983]

22 minutes ago, Banbury said:

This is what we obviously want but these are few and far between in ENS

Another phantom Greeny high! Lost count of how many times these have flattered to deceive recently, oh except summer of course, they were there in abundance in summer. I think...

Edited December 9, 2016 by karlos1983