Model Output Discussion

[Altostratus]

This is looking like a bad run. Maybe too early to say, but there is surely far too much energy going up into GL. I can see a sinker coming.

[Duane S.]

This morning is the morning when a 'cold spell; has been nailed on. TBH as I said in my last post last night, I couldn't see how the ECM was NOT going to backtrack from what it had showed the past 2 days. It went against all the signals and the other models. Someting was wrong and that seemed a bit of a no-brainer.

What concerned me was that the GFS was going to start to falter, it hasn't and in fact has produced a Stella run which if offered I think anybody on here would take in an instant.

The METO isn't quite as good but is still excellent (to put it into perpective to an average mid December UK weather chart!)

For my neck of the woods it doesn't matter what the charts forecast 3,4,5 days ahead, even taking into account a good level of accuracy, it is always going to be marginal for me out that far. But it is looking better initially for the South and East before the whole country joins in the fun later on next week.

A major backtrack is now VERY unlikey IMO (but not totally impossible). That block is going to take some shifting and yes there will no doubt be milder interludes but I struggle to see the Atlantic steamrollering back in any time soon for sure.

Regards the ECMWF. No loss of face, I think it's still a very good model. It has been outperformed by most other models in the lead up to this cold spell (assuming of course it does take place), it may be as simple as it doesn't seem to know how to handle the incredible -AO (with a decent -NAO) forecasts that are out there, although the sharp falloffs in values down towards -4, , -5 :o :o and possibly even -6!! :o :o :o are still to actually occur (however all the signs are it is a high probablity that a very negative AO value will be reached).

I will rest easier on this time tomorrow but it hasn't been a bad week so far!

Edited December 11, 2009 by s4lancia

[Geordiesnow]

Demonstrates the fact that the synoptics are constantly evolving, and nothing should be taken for granted.

Nope you shouldn't, and this run demonstrates that nicely as it looks like to me 06Z will be an easterly toppler with the high sinking. We shall see.

[Lewis]

This is looking like a bad run. Maybe too early to say, but there is surely far too much energy going up into GL. I can see a sinker coming.

It's not that bad, brings the colder air in much quicker. I don't think they'll be a sinker.

Spot the difference btw

You could say the gfs has been very very consistent.

Lewis

Edited December 11, 2009 by Storm Force Lewis

[Neilsouth]

Easterly looks initially less potent on this run so far

http://www.wetterzentrale.de/pics/Rtavn1261.png

[nick sussex]

This is looking like a bad run. Maybe too early to say, but there is surely far too much energy going up into GL. I can see a sinker coming.

As long as pressure remains low in the med then thats good news for the pattern to remain cold, IMO this is a safer run than the 00Hrs, theres a more elongated area of negative anomalies stretching into southern europe.The upper air profiles are likely to change with each run, these can't be called correctly till within 48 hours.

Edited December 11, 2009 by nick sussex

[Eugene]

Better blocking over greenland on this run, liking it so far

http://www.wetterzentrale.de/pics/Rtavn1321.png

[mountain shadow]

Nope you shouldn't, and this run demonstrates that nicely as it looks like to me 06Z will be an easterly toppler with the high sinking. We shall see.

Not sure your looking at then same run as me then.

That Greenland/iceland block ain't sinking anywhere.

[Lewis]

Come on guys, no wall bashing, this morning we have seen a fantastic 00z with the ECM backtracking, and the second theres the slightest wobble, or looks like there is to be a slight wobble the post's/comments go down hill again.

Keep faith, these charts are fantastic

[Duane S.]

What are people talking about above, what is soooo bad about this run so far?? Maybe I am looking at a different run to some. Most bizarre.

[Southender]

Cold delayed a tad?

[TEITS]

That's what I was thinking...

The HP won't sink with LP underneath, if anything beyond the E,ly the HP is likely to move NW!

The general theme we are seeing with the models is the block is likely to be slightly further S than intially progged locating around Iceland/ S Greenland.

Now I said a few days ago the further N you are the better. However now the block is likely to be slightly further S the opposite could be true. Basically the further away from the HP means greater convection.

Precisely what happens.

http://www.wetterzentrale.de/pics/Rtavn1501.png

Lets not panic because these charts are going to change right into +72.

Edited December 11, 2009 by THE EYE IN THE SKY

[John Snow]

Chart looks fine to me, don't understand why it is panic stations on here, if I was offered that chart as final outcome it would be "Deal Mr Banker"

[Geordiesnow]

As long as pressure remains low in the med then thats good news for the pattern to remain cold, IMO this is a safer run than the 00Hrs, theres a more elongated area of negative anomalies stretching into southern europe.

Thing is, people want snow and not just the cold, i expect many peeps to be disappointed with this run. To me there is signs of yesterday's ecm coming into play with the Northern arm of the jet being to strong consequently heights are lowering a touch.

We might get a Northerly reload for people to ramp over.

[Lewis]

06z shows the second wave of colder air shunt to our east, not the best run, but still good enough upto now. Blocking is fine.

You could say it's an outlier? I'll wait for the ensembles to come out.

Lewis

[Guest North Sea Snow Convection]

It does seem as though the coldest air keeps staying out of reach and the early part of the week is not looking quite as cold as it seemed yesterday. However, the situation is quite volatile, subtle changes coming and going, and the overall pattern continues to look pretty good although the models (ECM apart) don't have the block in quite as favourable position as yesterday to get that colder air towards us. In that respect I think the GFS has come more towards the ECM - although obviously the ECM has backtracked from last nights position quite clearly.

Hopefully the high will remain at a high enough latitude to get that colder air down from Scandinavia as the GFS has kept promising time after time. Would be good to see that coming within the 120 timescale where it seems to be staying beyond

[WhiteXmas]

There's no cause for concern. The high pressure set up is going to be well established by the end of the weekend. This cold set up has enough energy to last several days meaning any low pressure systems which do happen to move their way in will result in many different areas seeing snow falling. It's not surprising the GFS has changed in its last few runs but that still doesn't mean we have to ! It could easily show a different situation once again in the remaining runs of today. So don't give yourself brain damage yet! :o

[SMU]

Nope you shouldn't, and this run demonstrates that nicely as it looks like to me 06Z will be an easterly toppler with the high sinking. We shall see.

Er- high Sink- How often do you see a 1060MB greenland high Sink-

http://91.121.94.83/modeles/gfs/run/gfsnh-0-150.png?6

YEs the Easterly may get pushed away south if thats what you mean- but the upper high remains over greenland-

The pattern will reoload through Western Scandi & Scotland- hopefully the CAA will get all the way South....

Not quite the perfect run for the UK- good for the SE-

S

[Geordiesnow]

Not sure your looking at then same run as me then.

That Greenland/iceland block ain't sinking anywhere.

Nope but the easterly is sinking into europe though so it is an easterly toppler in my eyes. However still time for things to change as we know that set up like these are fickle and we could easily see an upgrade.

[MR EXTREMES]

Er- high Sink- How often do you see a 1060MB greenland high Sink-

http://91.121.94.83/...snh-0-150.png?6

YEs the Easterly may get pushed away south if thats what you mean- but the upper high remains over greenland-

The pattern will reoload through Western Scandi & Scotland- hopefully the CAA will get all the way South....

Not quite the perfect run for the UK- good for the SE-

S

indeed i agree with you steve.

and gp what do you mean:

So we are likely to keep a depressed jet and for the UK to remain in a mean position on the poleward side up to and beyond the Christmas period.?

[Altostratus]

Not quite as bad as I first thought but nothing is guranteed beyond T+96. There are even big changes at T+72 atm. I am becoming concerned that we end up with minimal pressure rise over GL.

[snowmadchrisuk]

Easterly looks initially less potent on this run so far

http://www.wetterzentrale.de/pics/Rtavn1261.png

Slight worry that on Wednesday it moves the 528 dam line away from us, but as this is at +120 then the Fax charts might have been not that far off last night. Brings it flooding back Thursday though with some really cold uppers. It is nice to see ECM has back tracked a little , but it still has the high to far south IMO , although at +72 GFS has the high slightly further south than it was yesterday. So cold is nailed , but if we get a wide spread Snow event is still up in the air .

Chris

[Eugene]

Er- high Sink- How often do you see a 1060MB greenland high Sink-

http://91.121.94.83/...snh-0-150.png?6

LOL, exactly steve pressure upto 1060 mb over greenland on this run and the high is looking much more stable to our northwest, getting ready for a northerly plunge me thinks

http://www.wetterzen...s/Rtavn1561.png

Edited December 11, 2009 by Eugene

[Neilsouth]

-12 850s clipping the far south east on this chart

http://91.121.94.83/modeles/gfs/run/gfs-1-156.png?6

[Lewis]

Is anyone like me on this run waiting for a true floodgate northerly to open! Out to t~159.

Not the worst run at all, although there is still some confusion within the next 72 hours.

lewis