Model Output Discussion 12z 30/11/2012

[phil nw.]

A brand new thread in time for the 12z outputs and on the eve of the Meteorological Winter too.

Usual requests-please keep to the subject matter and show respect for differing opinions.

If you disagree with another post then please refer to the model output to support your view.

Any moaning or ranting posts in this thread are liable to disappear.

Just a reminder there are other threads for general chat or opinions- including the moaning thread for the glass half empty approach and, at the other end of the spectrum, a ramping thread.

http://forum.netweat...ng-winter-chat/

http://forum.netweat...moaning-thread/

http://forum.netweat...ramping-thread/

Away we go then.

[phil nw.]

Just to underline the continuing generally cold outlook here are the Dutch and London Ens Graphs from the 00z outputs showing the expected 2mtr.temperatures.

a brief milder spell around Monday and then cold again.I dare say some UK locations will see some lower readings than London,especially further north.

[Timmytour]

Dammit! I hate it when you finish your post only to see one that's crept in before it to say the thread will be soon locked! so here goes again...

^{Looking through the latest} GFS ^{run, there are some amazing looking charts, of the type I suspect are rarely seen.}

^{While there's a lot to be encouraged about, I really don't see the signs of prolonged cold spells, but rather intermittent bursts.....still a vast improvement on some years ago.}

^{I can't help thinking that the models now are bearing out what some were saying a month ago. Both those who were saying that everything looks set for a classic winter, and those who were exercising caution because the UK might just be in the wrong position to benefit from all the positive stuff going on in the background.}

^{Just a shift of a few hundred yards east or west makes a hell of a lot of difference to us. To me its no wonder the models fluctuate so much, especially when I imagine the kind of set up we have now is one for which precious little experience would have been factored into the programming}

I'm fascinated to see what difference at T120 there will be between the 06z and the upcoming 12z and if the fluctuation continues.....i suspect it will be fairly considerable....

[Frosty.]

The latest GEFS 06z mean and ECM 00z ens mean show a trend to more settled weather from T+240 hours onwards, the ecm is more progressive towards this outcome whereas the gefs hangs on to the cold troughing over the uk for a few days longer, both agree on a cold snap during the second half of next week with sleet and snow showers pushing south on a strong NEly arctic flow with frosts returning after a less cold/milder interlude early next week. So, next week becomes cold/v.cold again but from the end of next week onwards, it looks like pressure will be rising from the southwest and the east, the two anticyclones will probably then join forces and the uk would then become settled, cold and frosty with freezing fog. The pressure rise on the ens mean output is very much the forward thinking of the latest metoffice 16-30 day update with cold and frosty weather and with any ppn more likely to be of snow in that period, so that could mean a northerly with mid atlantic high or snow showers to the east with a blast from russia, just how I see things.

Edited November 30, 2012 by Frosty039

[Buriedundersnow]

on the models some of them have that warmer segment with the front on sunday night monday morning in different places some have it slightly more north than others if that warm segment misses scotland with that front is there a chance that front will fall as snow in scotland and not turn back to rain or are the conditions just not there for that

[West Sussex Kate]

Met Office:

UK Outlook for Saturday 15 Dec 2012 to Saturday 29 Dec 2012:

Temperatures by both day and night are most likely to be below average during this period, with a greater incidence of overnight frost and, at times, fog or freezing fog. The signal for rain and snowfall amounts during this period shows a high degree of uncertainty, however, on balance, slightly drier conditions compared to average are favoured for most of the UK. Even though there is a drier-than-average signal for much of the UK, where precipitation does occur, there is a greater chance that it will fall as snow compared to normal.

Updated: 1218 on Fri 30 Nov 2012

[Iceaxecrampon]

One last look at the 06z before the 12z fun begins....

Considering what has gone on - encouraged by this for the 3rd if you are lucky to have the altitude in Scotland the Pennines East Cumbria and N Yorks.

Did somone mention an event for next Thursday - as I am struggling to see one.

Ian IAC

Edited November 30, 2012 by Iceaxecrampon

[Summer Sun]

Has some thing gone wrong with the precipitation type charts?

This morning they were fine

http://forum.netweat...ttach_id=146506

But now theirs lots of pixels

[SMU]

http://modeles.meteociel.fr/modeles/gfs/runs/2012113012/gfsnh-0-114.png?12

Better ridge thrown to Eastern Iceland- could be perfect positioning on this run.. CMON ON!

S

[Neilsouth]

After looking at all the models lately we are certainly in a great position for a proper cold spell and it really does look as if it will come from the north, north east. There are also no signs in the models that I can see of mild air pumping into europe or any azores high's. Checking the snow cover across europe it's very much on an increase over last year so that will take some shifting, I'm glad we didn't have that cold spell in earler nov as it's a far better chance of giving us a real bite in december.

You can also factor in for those that believe in that sort of thing, increased berries on the bushes, nearly the same amount of waxwings as in 2010.

We also didn't have any french imports and throughout this year the jet stream has been alot further south, I can't even remember us having a hot summer?

[IDO]

In six hours the difference with the tropical low by T114:

12z: http://cdn.nwstatic....114/h500slp.png

06z: http://cdn.nwstatic....120/h500slp.png

This has disrupted the jet, 12z: http://cdn.nwstatic..../114/hgt300.png

06z: http://cdn.nwstatic..../120/hgt300.png

Which may have knock on effects for the ridging and trough. Off course it looks like Bullseye UK for that storm, so short term a lot of rain and milder air edging our way? But better in the medium term.

Cold attacked by mild: http://cdn.nwstatic..../h850t850eu.png

Differences by T147, 12z: http://cdn.nwstatic....147/h500slp.png

06z: http://cdn.nwstatic....153/h500slp.png

When is FI with these types of changes?

Edited November 30, 2012 by i'm dreaming of...

[bobbydog]

http://modeles.meteo...nh-0-114.png?12

Better ridge thrown to Eastern Iceland- could be perfect positioning on this run.. CMON ON!

S

look at that low though, it doesn't stall and die, mid-atlantic, like the 06z - could be interesting!

[karlos1983]

look at that low though, it doesn't stall and die, mid-atlantic, like the 06z - could be interesting!

Is this a good thing?

[Tom Jarvis]

Can I just ask what if the tropical low that the models are showing never actually formed. What would it mean model wise??

[Cheshire Freeze]

Is this a good thing?

Yes! it'll keep heights low over Europe....Much better scenario being shown than last night when the ridge was shunted into Europe ahead of the low.

[bobbydog]

Is this a good thing?

don't know yet but it just shows how things can change dramatically in a fairly short timeframe... we'll see

(dare i say it) its looking good so far....

Edited November 30, 2012 by bobbydog

[chionomaniac]

That low is a bloomin' good thing as it draws the cold air from the continent on its northern flank!

It stalled in the modelling yesterday rather bizarrely but this is almost the ideal path to take.

Edited November 30, 2012 by chionomaniac

[SMU]

http://www.meteociel.fr/ukmo/runs/2012113012/UN144-21.GIF?30-17

a little disapointing from the UKMO tonight at 144- the Huge ridge over siberia looks great but the pattern in our corner a little flat-

Lets see what the ECM brings

S

[karlos1983]

That low is a bloomin' good thing as it draws the cold air from the continent on its northern flank!

It stalled in the modelling yesterday rather bizarrely but this is almost the ideal path to take.

Would I be right in saying, all would benefit if the centre of the low passed through the channel rather than skirting the south coast?

[Methuselah]

That low is a bloomin' good thing as it draws the cold air from the continent on its northern flank!

It stalled in the modelling yesterday rather bizarrely but this is almost the ideal path to take.

With -8 850s into the SE, and a long sea-track, things might be interesting?

[EML Network]

We seem destined for High Pressure to find it's way to the UK, no matter what path this Low Pressure over the Mid North Atlantic takes, the end result seems to be the placement of High pressure directly over the UK.

So my punt for this time next week is a continuation of the cold but with little in the way of Precipitation

Edited November 30, 2012 by EML Network

[Cheshire Freeze]

Where do we go from here? That high is trapped in no-mans land

[karlos1983]

is that another Tropical development heading up??

[chionomaniac]

Would I be right in saying, all would benefit if the centre of the low passed through the channel rather than skirting the south coast?

It depends where you live. The further south you are, the less you want the northerly extent. The channel low situation will give occluded precip over southern counties and will create a strong cold easterly over east coasts with possible snow showers - Hypothetical of course - but that is what we would like to occur on the south coast. Further north less so.

[scottishandy]

The second ex-tropical feature is hot on it's heels, but where will that one go? Or will it just stall and pump up the block?

Just speculation as I don't think these features are being anywhere near consistently modelled yet, lots of swings in output to come.