Model output discussion - mid January

[Catacol]

Well - there's no getting away from the fact that the outlook over the next 10 days is disappointing and not what was hoped for. For those watching snow fall in Scotland and the north - ignore this of course. The embedded Nina pattern is bringing cold enough air a-plenty for numerous wonderland pictures on social media, and watching the machinery at Scotstoun on Saturday sucking snow off the pitch prior to the game with Exeter Chiefs illustrated the point exactly. But for snow starved southerners such cold zonal patterns rarely deliver.

What's happened? Remember the elastic band analogy with reference to the angular momentum budget? In simple terms it scarcely had the spring to pull the momentum gradient back to neutral, let alone spike pacific forcing enough to help support scandinavian heights. Hindcast data shows it very well:

Frictionals never got going properly - notice the near 20 day negative slide

and as a result little in the way of spiking mountain torque. Note east asian conditions in negative territory

Overall then the relative budget held firm in negative to neutral territory

and as one twitter guru posted a few days ago "the earth is spinning faster than the atmosphere right now." End product is dominant easterlies overall at the equator serving to enhance the strength of sub tropical high pressure and, in turn, add further weight to westerlies at higher latititudes. The signal for a scandy block was blown away.

Key to this has been the strength of trade winds in the pacific, clearly highlighted here:

Our current MJO cycle has a lot of these to combat as it tries to push in the western hemisphere - but the hopeful picture of around 10 days ago has certainly been turned on its head.

So - the atmospheric elastic band barely made an impact, and our Nina pattern has entrenched solidly as the atmosphere remains coupled to ocean forcing. MetO forecasts now at last see Nina fading - but one has to conclude that this will be too late for this winter to recover from Nina dominance

It is interesting how strongly coupled the atmosphere has been to what looks like only a weak Nina - but coupled it most certainly has been.

Where does this leave us? Wave 2 forcing on the stratosphere will start to fade soon as the favourable tropospheric pattern begins to dissolve. We can expect a renewed cycle of torque impacts as nature tries, once again, to balance the GLAAM budget in the face of Nina forcing, and there is the hope that the MJO can force its way to a 7/8 orbit - but after two failed opportunities (Xmas week and the week ahead) the sense that high lat blocking is going to elude us strengthens. EPS date sees the departure of the West Russian high receding taking pressure off the vortex, and the azores high strongly in place.

Can we break out this pattern? Mother nature can always spring a surprise... and MJO phase 7/8 might give us something to work with in February, but right now we will need to see the next cycle of pacific forcing do much better than the last 2 against dominant Nina trade winds in the pacific if we are to see anything change substantially. I suspect the passage of the MJO will aid in development of high pressure in or around the UK, and the MetO text forecast suggests as much at the moment, but a high lat block to pull in cold continental easterlies? Not in sight at present.

Those in northern England and Scotland - enjoy your polar westerlies!

 

 

Edited January 21, 2018 by Catacol

[Jason M]

Control and four or five GEFS finish very cold tonight. That suggests several things.

1. A big easterly is possible 

2. It remains no more than a 15-20% long shot at best

3. At least we have a ticket to the lottery

So IMHO its odds against but if we were to get lucky it could pack a punch. My own gut feel FWIW (probably not much!) is that we will end up with a 'bowling ball' high stuck in the mid-Atlantic with alternating rTM and PM air from the north / north west being the dominant pattern (not an uncommon pattern for Feb). In essence a just below average start to the month but nothing noteworthy. That's a cold pattern for most of Europe though so if there was to be an easterly........  

 

 

 

 

[fat chad]

@Catacol..... A very sobering read. Thank you for your informative time and effort. I would personally be happy with a break from all the wind and rain. But the weather is, what the weather is. If we cannot get something wintery, then I would rather a dry high. Usable weather for those working outdoors. But such is life..

[bobbydog]

BOOM!!

 

 

well, i say "boom"... i mean... like the sound of someone farting at the far end of a quiet train carriage....

[feb1991blizzard]

Just now, bobbydog said:

BOOM!!

 

 

well, i say "boom"... i mean... like the sound of someone farting at the far end of a quiet train carriage....

GEFS a bit of a downgrade from the 12z but we were coming off a very high base for such a timeframe - still good just not as many perfect setups and a bit more atlantic dominance although still a lot of amplified solutions and still very cold Easterlies (although less and less perfect).

[bobbydog]

Just now, feb1991blizzard said:

GEFS a bit of a downgrade from the 12z but we were coming off a very high base for such a timeframe - still good just not as many perfect setups and a bit more atlantic dominance although still a lot of amplified solutions and still very cold Easterlies (although less and less perfect).

right now, less than perfect is fine.  still a long way to go and with low confidence in any outcome, there is still hope!

[feb1991blizzard]

Just now, bobbydog said:

right now, less than perfect is fine.  still a long way to go and with low confidence in any outcome, there is still hope!

Not confident after reading the teleconnective posts, I wonder why these stonking Easterlies pop up, it would be interesting to know if those GEFS members are artificially rebounding AAM / GWO  and why or whether it really does represent a 20% chance or 0%.

[bobbydog]

Just now, feb1991blizzard said:

Not confident after reading the teleconnective posts, I wonder why these stonking Easterlies pop up, it would be interesting to know if those GEFS members are artificially rebounding AAM / GWO  and why or whether it really does represent a 20% chance or 0%.

the atmosphere does appear to be in a weak state at the moment and with apparently little atmospheric forcing in the offing (e.g. MT events) then i suppose its just a case of 'wait and see'.

[Scandinavian High.]

Do have trend here with high pressure building to north east ..

[Snowy Hibbo]

7 hours ago, Gael_Force said:

That seems a bit harsh considering he is just commenting on what the latest ECM monthly shows. Surely the model will have 'considered' Nina base state parameters when the algorithms churned out the forecast?

 

Not really, I would be expecting more from a 'professional', than to just look at one model, that doesn't exactly have a massive reputation. It shows a bit of the Niña base state enacting upon the MJO, but not really. It might be a pitfall of EC, or an exxageration by RMM, etc. 

7 hours ago, Thunderywintrysnow said:

Not nice calling a professional paid  meteorologist a joke just because your teleconnections says otherwise they have been wrong before and will be wrong again that's the same man who predicted the eastern USA big freeze over a month before it happened nobody is right or wrong until Feb is over play nice.

I know people who actually predicted that freeze, unlike Bastardi. A couple of guys from NY area, plus Anthony Masiello. They know their stuff, and used the strat + GWO + MJO + other factors, to predict the big freeze. I know Bastardi knows what the GLAMM is, but he fell into the GEFS trap like so many before him. 

There are varying standards of professional, just because someone holds a degree, doesn't mean they are better than an amateur. I have met amateurs that are so good at predicting long term patterns, they beat all, but the most elite professionals. And Bastardi is certainly not elite whatsoever.

 

[Ali1977]

Well, looking at the FI GEFS winter could really get going early Feb. Plenty of interest there, the PV is in tatters on plenty of the ENS . If anyone want to look at an extremely cold Feb possibility look at P4 - that would bring in -14c uppers to the SE

Edited January 22, 2018 by Ali1977

[KTtom]

Not sure why you didn' post it...but here' P4

 

 

Edited January 22, 2018 by KTtom

[Penrith Snow]

Cold zonality has been the theme this winter but its not all snow up north and nothing down south.

The cold spell of ear!y December delivered for the Midlands while the recent cold north westerly was disappointing in north west England with limited snow.

So the situation under co!d tonality is more complex than some people imagine, I do however agree its pants if you live in the south east.

Andy

Edited January 22, 2018 by Penrith Snow

[lassie23]

The bbc mentioned the models in their forecast and are going for very mild start to the week, then cooling off midweek, before becoming very mild again next weekend, in other words, a filthy week ahead.

[bluearmy]

2 hours ago, Snowy Hibbo said:

I am free to say what I want, and you are free to ignore. Yet narrowing your focus to a coldie point of view is still not good model analysis. I didn't realise Bastardi being a poor forecaster was a weird concept to some here. Each to their own anyway.

An interesting view which should be elsewhere I guess - having a coldie perspective doesn’t seem to hinder him predicting warmth but he does. But the coldie in him does mean he publicises looking for cold in his bloggs etc. it doesn’t mean he predicts it against what the modelling is showing though. and he does have a nack of looking at the extended modelling and correctly pointing out where it is likely wrong. 

Note the gefs and gfs drifting towards the eps perspective on the ridging days 7/9

[beng]

7 hours ago, Snowy Hibbo said:

I know people who actually predicted that freeze, unlike Bastardi.

 

He did predict it.

[Polar Maritime]

Can we please continue with only Model Discussion as per thread title, Thanks.

 

 

[nick sussex]

Not quite as good this morning from the ECM although it does displace the Azores high into the mid Atlantic towards days 9 and 10.

The GFS has improved not greatly but it does split the energy upstream.

Getting the high further west is probable but it’s really now how much amplitude upstream we’ll see as to whether the jet can cut back sufficiently to pull colder air into the UK.

The ECM ensembles wind directions split from the turn of the month , allied with some colder solutions.

In terms of the MJO , I see that’s been discussed earlier. The issue with the GEFS and something NOAA have commented on, two issues , it often overdoes interference from Rossby waves etc and this can mean it overweakens the signal and its verification falls below that of the ECM.

La Niña is always an issue with the forecasts, it’s really a fight between that and the MJO.

The road gets steeper as you get towards the more favourable colder phases for Western Europe.

I think first things first though , to see the high to the south pulled west. We have been somewhat marooned with that popping up but not making a lot of headway into the earlier timeframes.

Because of La Niña we have to be a bit more wary of any amplification shown until it has cross model agreement and gets into the more reliable timeframe.

 

[Summer Sun]

UKMO extended pretty much the same as the past few days with high pressure extending up from the south leaving the UK in a milder set-up

 

[SLEETY]

30 minutes ago, Summer Sun said:

UKMO extended pretty much the same as the past few days with high pressure extending up from the south leaving the UK in a milder set-up

 

Back to the usual setup in the winter months then.A dreadful looking chart if your looking for cold weather.

[CK1981]

4 minutes ago, SLEETY said:

Back to the usual setup in the winter months then.A dreadful looking chart if your looking for cold weather.

And we all know what usually happens when this pattern becomes established!

[SLEETY]

26 minutes ago, CK1981 said:

And we all know what usually happens when this pattern becomes established!

True,but still some very cold gfs ensemble members ,so maybe a big change to cold in feb,like this

[CK1981]

Just now, SLEETY said:

True,but still some very cold gfs ensemble members ,so maybe a big change to cold in feb,like this

I do hope so! How much support does it currently have?

[SLEETY]

here is the graph,so a few very cold runs

Edited January 22, 2018 by SLEETY

[stainesbloke]

30 minutes ago, CK1981 said:

And we all know what usually happens when this pattern becomes established!

Often, but certainly not always. We still have a good third of winter proper to go. Many of the best snow events here in the SE occurred in the month of February, so I’m not overly pessimistic about a properly cold and snowy episode happening.