Model Output Discussion 29th December - Into mid-Winter.

[mulzy]

1 minute ago, booferking said:

Near mess once again and that will probably 100% happen the block is to far west.

Close but no cigar - need the higher heights to be much closer to Greenland to allow a meaningful retrogression. 

[chris55]

Take note of what BA (Blue Army) has been saying, if we can manage a ridge before the west based NAO kicks in we are looking ok, and potentially very cold, if not then a milder south westerly may well ensue. 

Its a fascinating period as the ens and anomalies can only predict the broad-scale pattern and the ops should lead the details. ECM 12z is getting there, and showing what could be, but so much to be decided yet. And so much that can go wrong ha.  

[Ali1977]

3 minutes ago, Summer Sun said:

ECM eventually starts bringing the colder air in at D10

 

Not discounting it so clearly a possibility 

[booferking]

Just now, mulzy said:

Close but no cigar - need the higher heights to be much closer to Greenland to allow a meaningful retrogression. 

Yep very close im basically trying to pull that high east with my fingers as it came out.

[blizzard81]

28 minutes ago, booferking said:

And the misery model will no doubt be right again.

This is the problem, the misery model has been king this winter.

[feb1991blizzard]

7 minutes ago, chionomaniac said:

It's far better viewing than looking at a strong jet barrelling towards the UK. There won't be many times that we will look at a chart such as the ECM T+216 in history. An intriguing run - how many times have we seen Mid latitude blocking winters turn into something better - a lot more often than those with any Vortex intensification. Strat looking primed to give a nudge in the right direction as well. May have to go back and look at the set up prior to Feb 91 as I can't remember off the top of my head.

 

Edit just looked and there are similarities in the blocking pattern over the UK

It was so lucky though, we had a rampant PV to the North West, we were lucky to eject a shortwave SE just at the right time so that the frigid air could march West.

[Dean E]

6 minutes ago, Summer Sun said:

ECM eventually starts bringing the colder air in at D10

 

 

3 minutes ago, chris55 said:

Take note of what BA (Blue Army) has been saying, if we can manage a ridge before the west based NAO kicks in we are looking ok, and potentially very cold, if not then a milder south westerly may well ensue. 

Its a fascinating period as the ens and anomalies can only predict the broad-scale pattern and the ops should lead the details. ECM 12z is getting there, and showing what could be, but so much to be decided yet. And so much that can go wrong ha.  

 

Totally agree with these, along with Chino... Anything past mid next week is open to all sorts of uncertainties, as with any long range modelling, especially recently given the 'unusual' behavior of the Atlantic and the broader Northern Hemispheric profile.

We've had a very quiet second third of winter from the Atlantic, When have you seen charts like this, during the depths of winter?

GFS                                                        ECMWF                                                  GEM

 

Incredibly interesting period coming up, and overall has been a very interesting part of 2017. Something I've not experienced in my lifetime, anyway.

 

 

[mcweather]

14 minutes ago, chionomaniac said:

It's far better viewing than looking at a strong jet barrelling towards the UK. There won't be many times that we will look at a chart such as the ECM T+216 in history. An intriguing run - how many times have we seen Mid latitude blocking winters turn into something better - a lot more often than those with any Vortex intensification. Strat looking primed to give a nudge in the right direction as well. May have to go back and look at the set up prior to Feb 91 as I can't remember off the top of my head.

I have to concur with Chiono here. There is as IF has also mentioned in a tweet above a good deal of uncertainty in the medium range and beyond, without a super strong jet  and a raging vortex in the mix  the cold solutions are just as realistic as any other. could it be that the strat will come riding over the horizon to save the day cement those' building blocks of potential' into something special.

Edited January 13, 2017 by mcweather

[Johnp]

7 minutes ago, blizzard81 said:

This is the problem, the misery model has been king this winter.

Let's not forget it's only predicting the weather, not causing it!

[blizzard81]

3 minutes ago, Johnp said:

Let's not forget it's only predicting the weather, not causing it!

I didn't say that did I ? I will try to make it a little clearer for you - the ukmo has had the edge on the other models in the 6 day range in terms of verification.

[joggs]

25 minutes ago, chris55 said:

SOOOOO SLOOOOOWWWWW, but.....full of potential (i love that word ha) But I reckon 240 will finally get there!

A fail we'll end up with westerly later.

[karyo]

I have to say I find it hard to feel pleased with the outlook. The easterly has now vanished with just high pressure for later next week.

The potential for a Greenland high is mouth watering but looking at the afternoon output and the Met Office update a northerly is likely to miss us.

[nick sussex]

I wonder whether the ECM is over reacting here. There are some big differences between the 00hrs and this output. The problem with it rushing to retrogress then not going through with it is the very low margin for error outcome it delivers which just about scrapes over the line and even then it looks like it will go pearshaped after that point.

We're left in the unenviable position of really not knowing what to cheer on because if the ECM went full on retrogression you could end up with a very cold northerly as long as the block was further east which is a big if.

The GFS trend is a less fraught evolution with some potential but again that might not deliver the goods at the end of the day.

The problem at the moment is that theres going to be a change of pattern over the USA with troughing developing over the western USA which will downstream try and build a ridge further east, you can see that with the high building over Canada in the ECM however this is too far west and unless we get a progression east and high pressure to build over Greenland then the Atlantic will try and nose ne, now this is all fine if that nose occurs further to the east because you're on the cold side of the jet but if its to the west then you're on the mild side of that.

What we don't want is another half hearted solution like the easterly which thought about it and then was derailed by the models picking up a signal to move the PV east before we had the Scandi high sufficiently north.

So at this point and because of changes taking place upstream the models are likely to throw out a basket of solutions and what will land is to be honest anyones guess. I just hope whatever lands comes with snow and cold and not what might have been.

[chris55]

After what could have been a more pronounced easterly flow we now seem to be trending into a quieter, dryer period, with some frost and fog if the high stays clear, more especially towards the southern half of the UK. 

The interest now lies in where we go from there, and with such a quite Atlantic and some blocking meandering about something is bound to give one way or the other. At that point we will get the gears moving again, in which direction is uncertain though. 

Have faith people, the background synoptics are actually pretty favourable.

[chris55]

3 minutes ago, nick sussex said:

So at this point and because of changes taking place upstream the models are likely to throw out a basket of solutions and what will land is to be honest anyones guess. I just hope whatever lands comes with snow and cold and not what might have been.

Nail on the head there Nick! Though IMO our patch is for once not to badly placed synopticly for the odds to be slightly more in our favour than the norm.

[nick sussex]

1 minute ago, chris55 said:

Nail on the head there Nick! Though IMO our patch is for once not to badly placed synopticly for the odds to be slightly more in our favour than the norm.

The problem is we seem to have had all 7 runners in a steeplechase where you'd think we couldn't fail to win however one by one they either slipped up on the turn, unseated the rider or fell at the last fence. So yes there are some good factors but its been an uphill struggle to get everything to come together at the right time. Hopefully that will change and hopefully soon.

[Jason M]

The issue as always (or at least in recent years) is that we simply can't sustain any high pressure at northern latitudes. Other than the ECM which keeps throwing out false signals there is still pretty much zilch signal for this that I can see in the charts. Even the GEFS can't be bothered to throw in the usual imaginary Greenland high pressure signals at the moment. Rather than being unlucky I think we could argue that this rather cold spell has seen our luck dialed up to 10. To get the snowfall yesterday given the poor overall synoptic was IMHO about as lucky as we can get in the SE especially.

A transitory ridge maybe, but a stable HLB this winter? time will tell but I'll not be putting any money on it! GEFS are singing euro heights again in the longer term and that's one trend that does often move smoothly through the timescales.

 

[chionomaniac]

Look at these strat zonal wind profiles. No strong Vortex Intensification here,

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/ts.php?plot=all&alert=1&lng=eng#fig1

We have been used to far stronger zonal winds in previous winters and have had to rely on a SSW to break the cycle. This year not so, and this means that the strat does not override the trop influences as in years gone by.

And the forecasts suggest that the strat vortex will stay subdued allowing the trop patterns more 'freedom' to express themselves.

I think that we would all like to see some more icicles this winter as seen in my twitter profile pic, and I certainly wouldn't rule it out at this stage.

[tight isobar]

Cannot get this out of my head!!!.

Its weirdly like reverse zonality just a bit colder..yet PACKED With potential. .

There's certainly some major interest  coming. .

[Jonan92]

The blow for northen Spain by the ECM is huge, what a difference between the prediction this morning and now.... it's a kick on the balls

[snowbob]

Prob a stupid question

but could the models be confused with the fact there is no raging jet,no barrelling Atlantic and low strat zonal winds. As they seem to not know what to do from one run to the next. Now I know they are billion pound super computers but this winter just feels weird .

like I said prob a stupid question still learning.

thanks to any one that seems it a reasonable question to ans.

Edited January 13, 2017 by snowbob

[Cheshire Freeze]

To look at the medium-further range modelling at this moment and take it at 'face value' is quite frankly naive IMO. Yes we can only comment on what is in front of us BUT the mid to longer term is going to evolve further over the coming days and what we see at the moment as a WB -NAO and the Atlantic sector not playing ball will also change. We're in the process of rolling the dice at the minute and we have to hope we at least hit a couple of higher values or a double- even a double 6 isn't out of the question at this range.

[chionomaniac]

4 minutes ago, snowbob said:

Prob a stupid question

but could the models be confused with the fact there is no raging jet,no barrelling Atlantic and low strat zonal winds. As they seem to not know what to do from one run to the next. Now I know they are billion pound super computers but this winter just feels weird .

like I said prob a stupid question

thanks to any one that seems it a reasonable question to ans.

They won't be 'confused' as such. They will enter the current strat data and come out with their computations in the usual way. No different to any other year really except that blocking patterns are probably more difficult to evaluate.

[marksiwnc]

56 minutes ago, Day 10 said:

Too far west, too far east, too far north, too far south, our little island always puts up these magic cold buffers!!!

Is this a low or high pressure???  It seems wrong 

[Duane S.]

That's weird. I ran through the Jan to Feb 91 cold spell evolution yesterday evening as I suspected it may contain similarities. It did indeed . Almost 26 years to the we day embarked on 3 odd weeks of a meandering UK / mid Lat high, until finally as we went into Feb we finally got one of the best cold spells in the past 30 years. These are not standard winter charts,  I maintain we will be unlucky if we do not cop a sustained cold spell before winter end.

Edited January 13, 2017 by s4lancia