Model Output Discussion - 12th December Onward

[WhiteFox]

The Thursday/Friday storm looks like the strongest winds will be to the south of the low however as the storm whips out to the north sea, it looks like an intense severe gale could develop across east anglia and the south east on the western flank - severe north westerlies anyone? Any movement to the north could bring back memories of 1987?

At the risk of sounding like Michael Fish, doubtful. The 1987 storm was extreme and one of the most powerful to hit the Southern part of the UK for many, many years. Conditions turned out to be perfect as it formed to the south/south west, bombed and headed towards the UK. Certainly we could still see a strong storm, but like comparing very snowfall with 1947/63, I think we have to have some perspective and not go down the Daily Mail hyperbole route.

[Coast]

Morning all! long time lurker etc.........

Just posted these up which if as GFS suggests turns out correct, will be phenomenal in France:

Still along way to go of course and only one run, one model I know.

[lorenzo]

Looking at the panel of solutions presented by GEFS this looks like the most severe outcome at present.

http://176.31.229.228/modeles/gens/run/gens-15-1-84.png?0

Headaches all round for forecasters, easy for us to speculate on here. Would be good if the UKMO model was in 12 hr intervals vs 24.

[johnholmes]

Looking at the panel of solutions presented by GEFS this looks like the most severe outcome at present.

http://176.31.229.22...s-15-1-84.png?0

Headaches all round for forecasters, easy for us to speculate on here. Would be good if the UKMO model was in 12 hr intervals vs 24.

yes to see it, the global in 12 hour steps yes, Wx Online and the NAO I think has that?

just switching between here and Wx Online and you can see both Met global and NAE at T+42 hours, there is quite a large difference in how much further east the NAE has it than the Global and considerably lower.

It would seem that Met have no alternative with both their own model and GFS, less so ECMWF at T+72 (more an open wave but similar position) to accept the main low is going to run somewhere through southern England perhaps the Channel and amend their forecasts and warnings along those lines.

I honestly cannot ever remember their own model switching by such an amount in such relatively short time scales. GFS better this time for sure. I wonder on a hemisphere level this blip will show up on the NOAA 5 and 6 day checks?

Edited December 13, 2011 by johnholmes

[SMU]

http://www.knmi.nl/exp/pluim/vijftiendaagse/index.html

A BIG swing on the ECM control & Operational this morning-

Both would seem to peak on cold around the 24th / 25th period-

Lets hope to see the slightly lower resolution ensembles start to drop away today & some sort of consistency from the OP on the 12z..

S

[Weather Boy]

It seems that plenty of the models have the storm along the channel or even in France, but last night the BBC forecast put it firmly way up north giving the strongest winds for northern England and the Midlands. I'm wondering why they don't seem to have adjusted it because it's not just a one-off run that has put it so far south. However, the uncertainty was emphasised, although not with specific reference to the path of the storm.

[UV-RAY]

Exciting model watching for all I'd say. I've never seen such a turnaround from the UKMO in such a short time. Too me it looks like Fridays low will zip along the channel, maybe even into France. One thing that is noticeable over the last few winters, is how these LP systems end up further South than originally forecasted. Could be a few more surprises in store in the run up to Christmas.

Edited December 13, 2011 by Seven of Nine

[Craigers]

Looks like the cold theme is being hinted on the model runs today up to christmas! big turn around from last week for sure. Reminds me of late November last year how things panned out and the unexpected. Model watching has been so different these past 3 years compared to how they used to be.

Edited December 13, 2011 by Craigers

[Eskimo]

Looks like the cold theme is being hinted on the model runs today up to christmas! big turn around from last week for sure. Reminds me of late November last year how things panned out and the unexpected. Model watching has been so different these past 3 years compared to how they used to be.

For the better I might add!

[chionomaniac]

I wonder how the models would have handled 1987's storm in the days prior, if todays output was available then?

The GFS track spares us the wind and could give a white bonus.

Looking further afield I see signs that the Atlantic high will try to link with the Siberian high at some point. I think it is the natural pattern evolution and would bring mild southwesterlies before it becomes established. Would the jet then undercut any Scandi high?

Edited December 13, 2011 by chionomaniac

[TEITS]

This mornings output is a good example to any newcomers following this thread how fickle the model output can be. We had posts yesterday referring to "hairdryer" weather and how that pattern can remain for weeks, yet todays ECM has trended towards colder weather towards xmas. We also have a storm that has virtually disappeared and now instead of storm force winds we are looking at possible snowfall on the N flank.

[Iceberg]

GFS 06Z is quite bizarre as it doesn't develop a closed low at all on for Friday and passed a curved open waves further south.

Instead it takes in a big swallow of cold air and drag it further south, giving potential snow now for south of the M4.

It's difficult to see what will happen out to T70 atm.

[UV-RAY]

Well uncertainly in the short-term with the possibility of snow on Thursday night for elevated parts of the Central and Southern Midlands and then later further East. It is highly marginal as the air that it is bumping into is not cold enough and snow would be dependent on how much cold air wrap around there is on the northern flank. A slim chance.

Beyond the brief NWerley that follows the models this morning want to dig the trough into Europe a little which delays the natural toppling, but a delay is all it will be as we have a raging +ve NAO going forward, and if heights do stay relatively low over Europe, that means a Biscay High ridging towards Southern UK and an extended mild period

Is that your delayed extended mild period Ian. :winky:

[stewfox]

Hi Steve,

Nice to see you back. If only eh! Models looking a bit more interesting this morning, hoping to see the jet run out of steam soon! All that talk of 84/85, remember this.

http://www.wetterzen...00119841227.gif

http://www.wetterzen...00119841231.gif

and finally this

http://www.wetterzen...00119850105.gif

Took a few bites of the cherry to get there but come the end of this month hoping to see this kind of pattern developing in the models.

Regards,

Tom

What was the stratosphere doing back then ?

Would any linked high be unsustainable at present

[SMU]

http://176.31.229.22...gfs-0-114.png?6

another slider on the GFS

Edited December 13, 2011 by Osbourne One-Nil
Unnecessary comments removed.

[nick sussex]

Interesting the GFS continues to want to eject some energy east/se with that shortwave running towards the UK, possible snow on its northern flank.

The attention of course has been on the possibilities of some severe winds but are we seeing a different way forward regarding the more medium term?

[bobbydog]

is it a temporary blip, or are the models showing a trend to a more southerly tracking jet?

[SP1986]

After the mis-modelling of the storm earlier on in the week, from most models, I wouldn't take anything as gospel, especially where the GFS is involved. That includes cold scenarios!

[Iceberg]

Yep totally agree Nick , only 1 way this run is going after the open wave and then closed low zip down with a more S/N tilt to the WAA i the Atlantic.

[Cecil Hogmanay Melchett]

Well uncertainly in the short-term with the possibility of snow on Thursday night for elevated parts of the Central and Southern Midlands and then later further East. It is highly marginal as the air that it is bumping into is not cold enough and snow would be dependent on how much cold air wrap around there is on the northern flank. A slim chance.

Beyond the brief NWerley that follows the models this morning want to dig the trough into Europe a little which delays the natural toppling, but a delay is all it will be as we have a raging +ve NAO going forward, and if heights do stay relatively low over Europe, that means a Biscay High ridging towards Southern UK and an extended mild period

That may be Ian but for someone who has got it very wrong on so many occasions you do come across as awfully confident,bordering arrogant at times.

Sorry i had to say it.

[nick sussex]

If we can keep low heights over northern Italy then this will stop the Azores high from trying to move in. Also even if the ridge wants to move in it will be forced to go ne not east, anyone for an easterly?

I don't think we'll manage it on this run but I would be surprised if some of the ensembles don't have an easterly, we do need though that shortwave to verify, the ECM doesn't have this so we'll have to wait and see whether its a false dawn or something better.

Edited December 13, 2011 by nick sussex

[Nick F]

GFS seems to be on a constant game of catch-up at the moment, now the 06z has followed the 00z ECM by pulling an open wave across Nern France rather than a deeper closed low across southern England, threat of snow on northern flank not quite so clear cut either, will not be able to quantify this risk until much nearer the time - especailly as the low's track is yet to be resolved.

Then GFS goes on to bring a shortwave across the south on Saturday, just as the cold northwesterly kicks in, could prove interesting northern edge snow wise, though a new development that may disappear on subsquent runs. Continuing headache for forecasters, where's that paracetamol?!

[Cecil Hogmanay Melchett]

GFS 6z takes us into the freezer with maxima of -3 here next monday after a pretty freezing weekend,lol#

Has to be an outlier,surely?

[Paul White.]

Well Sunday looks quite a cold day minus 5s to 10s on the 850s

http://hw.nwstatic.co.uk/gfsimages/gfs.20111213/06/144/h850t850eu.png

[Bobby]

Darn, if only everything was moved a few hundred miles North we'd be in business. Not far from a snowy easterly there.