Model output discussion - is the beast awakening?

[winterof79]

19 minutes ago, snowblizzard said:

Yes, for Scotland.

But for South UK air originates from Med? 

I would still take it

[Griff]

2 minutes ago, Doctor96 said:

Watching the gfs this morning , surely this is great for most of the east of the uk , but many on here seem down this morning , don’t get it , unless you live in the west . Also the south east gets hit hard with snow from the front coming up from south east .

Error increases at range. High res models struggle with specifics at short range even. Day 10 charts are synoptics, which by definition means general picture. Consider op against a mean etc, the charts aren't saying to 100 miles exactly where cold or mild air will be, imagine that error increasing with time, so there will be a spread in possible temperature, location and precipitation. Consider any chart as representative of a range, at that point in time, rather than a precise pinpoint bullseye. As the clock counts down you would expect accuracy and precision to increase. Last Sunday showed how difficult it can be.

What does the pattern show? Yes some places may be favoured but you wouldn't put money on it and expect to win a bet. 

 

[IDO]

Not my favourite evolution but after the last few runs it would be acceptable, an Iceland high slowly sinking:

The arctic high has favourable orientation an extra 36h on this run so we get a better cold pooling which is topped up with scraps now and then keeping a relatively cold pool, essential to get anything out of this hiatus from the collapse of the pattern.

I have also noticed on the gfs in the last few runs the Pacific ridge being downplayed and I wonder if the interference on the modelled MJO signal is now being spotted in the data? Also, another run that suggests the signal for the trough to our east does look like it is not going to be anything but transient, so no sustained easterly or NE'ly winter wonderland likely?

 

 

Edited January 30, 2021 by IDO

[Smoggieontour]

Looking at the short ENS rolling out, the OP is one of the slowest to bring the cold in and almost a mild outlier for my location (Middlesbrough) at day 6. There is a 12c spread by 4th Feb, with 850s ranging from 1 to -11, so going to be a while before this sorts itself out.

[TEITS]

If this low is going to take ages to move S then locations to the N of this within the cold zone could recieve a right dumping. For example the end of the week could be very tasty for the far N of N England/S Scotland.

These Arctic highs are a bloody nightmare. The link with the high in the Atlantic and the Arctic high is causing mayhem. If the Arctic high edges further S then the low will be forced to move S much faster. The influence the Arctic high has on the UK can clearly be seen on the models when viewed from the N Hemisphere. Remember me mentioning the cross polar flow?. If you look at the ECM this doesn't really become established (nearly at +144) but then look what happens at +168!

Lack of forcing prevents low from moving S much faster. End result is opportunity for spoilers to occur and ruin our chances. My motto has always been get it in as fast as possible to enjoy the rewards!

[Griff]

Parallel 132

[TSNWK]

2 minutes ago, Smoggieontour said:

Looking at the short ENS rolling out, the OP is one of the slowest to bring the cold in and almost a mild outlier for my location (Middlesbrough) at day 6. There is a 12c spread by 4th Feb, with 850s ranging from 1 to -11, so going to be a while before this sorts itself out.

This is potentially good news.. we want to see a few lines dropping before the op does at day 9 onwards for the southern 3rd..

Can someone please share where we can view spaghetti plots ?

[Tim Bland]

Like the GFS the GFSp gives snow for eastern areas to end the week..

Edited January 30, 2021 by Tim Bland

[bluearmy]

It’s not rocket science to appreciate that the manner and speed that the lows clear to our south dictates the 6/9 day period - hopefully tomorrow’s 12z runs will give us some cross model agreement on that 

the period beyond day 9 is a wide envelope indeed .....

[Griff]

For a better block, // 168

[sheikhy]

12zs we need to see that low slide south east more quickly between 120 and 144 hours!!if we can get that then BINGO!!!!!!

[Griff]

Might link up with Arctic high 

[Griff]

I'm talking to myself

[sheikhy]

Thats one beautiful gfs p!!!!please ecm and ukmo stop being party poopers and join the cold crew!!!

[Tim Bland]

17 minutes ago, Smoggieontour said:

Looking at the short ENS rolling out, the OP is one of the slowest to bring the cold in and almost a mild outlier for my location (Middlesbrough) at day 6. There is a 12c spread by 4th Feb, with 850s ranging from 1 to -11, so going to be a while before this sorts itself out.

Same for the south. Expect ECM to come on board later, at least for a short easterly starting Friday..

[Griff]

I know not what happens next (in terms of persistence etc) but even if fleeting this would be lovely 

[KTtom]

18 minutes ago, TSNWK said:

This is potentially good news.. we want to see a few lines dropping before the op does at day 9 onwards for the southern 3rd..

Can someone please share where we can view spaghetti plots ?

Hopefully the link works....as mentioned, op is almost a mild outlier for the period 04th to 06th...

Wetterzentrale.de - Diagrams

 

Edit: Link doesnt work...google 'gfs wetterzentrale ensembles'

Edited January 30, 2021 by KTtom

[TSNWK]

1 minute ago, Tim Bland said:

Same for the south. Expect ECM to come on board later, at least for a short easterly starting Friday..

That plot is precisely what I was hoping to see.. plenty of lines dipping before the op suggesting that that the trough will clear through quicker..

right.. off until the 12z what one is meant to do on a wet lockdown Saturday is the next challenge this morning.. :) nice thread this morning I thought with sound contributions and input. NW at is best :)

[Matt H]

The GEFS 06z ensembles are still looking good for a decent cold spell starting on the 6th February. Once again we can only hope that the ECM trends towards this later!

[mushymanrob]

4 hours ago, CreweCold said:

People will disagree but the EC is pretty awful this morning. Glancing blow of sufficiently cold uppers for most. 

GFS not great with its mid lat HP scenario into FI. 

UKMO is meh.

We're basically hanging on the GEFS and GEM. That isn't a great situation to be in.

Oh come on, you know better then that!

Its normal for the ops to go off on one after previously agreeing in the 7-10 day timeframe.

To get a clearer picture of whats most likely out of this synoptic mess recent runs have thrown up... use the anomalies!  They are not so prone to these wild swings and are more often then not much nearer the mark for the timeframe they cover. This would save so much wasted time and energy, silly posts like "its all over" and such like.

The anomalies are consistent, have a 5/5 confidence rating for the 6-10 day mean

this chart shows
- Ridging from the mid Atlantic through to the Arctic North of Siberia
- Troughing over Portugal
- Most Atlantic energy tracking well South of the UK
- Slack mean Northwesterly over the UK
- A slack mean upper flow IMHO allows the positive and negative surface pressure anomalies to determine more of the surface flow.

This chart is a cold one. So im not buying the wild swings of the ops... as far as these charts are concerned, the cold spell is still very much on.

[Don]

40 minutes ago, IDO said:

I have also noticed on the gfs in the last few runs the Pacific ridge being downplayed and I wonder if the interference on the modelled MJO signal is now being spotted in the data? Also, another run that suggests the signal for the trough to our east does look like it is not going to be anything but transient, so no sustained easterly or NE'ly winter wonderland likely?

That's been the warning recently so wouldn't surprise me sadly.  What can go wrong tends to go wrong these days, but this isn't over just yet I'm sure!

[Notty]

Prefer these ensembles to yesterday's:

 

[Griff]

I think I'm going to be surprised... 

[northwestsnow]

Gfs para is a beauty...

[Notty]

1 minute ago, Griff said:

I think I'm going to be surprised... 

Pleasantly I hope