Model Output Discussion

[Thundery wintry showers]

Not sure about the UKMO- it's a smidgeon away from having the -NAO too far west and bringing mild cloudy southerlies into the UK, though the T+120-144 charts may be just about cold enough to support a marginal snow event.

GFS illustrates how a slight shift east of the whole setup would give the whole country the cold air. With the sun being stronger and higher in the sky, homegrown convection can't be ruled out in such an unstable northerly/north-westerly regime and indeed the GFS Precipitation has showers developing almost nationwide on the 17th February instead of the usual wishbone effect. However for those after a frontal snow event the more east based -NAO would disappoint as the emphasis in that case would strongly be on sunshine and snow showers- though as the 5th January showed, in a sunshine and snow showers regime you can still get the odd frontal event, and in that case frontal snow and lack of marginality combine.

Sunshine and wintry showers looks set to be the theme for most central and eastern parts through to Saturday, though staying dry in the west. However tomorrow the showers should turn back to a wintry mix as less cold air moves down from the north and I think significant snowfalls on Friday and Saturday will be largely confined to Kent and Sussex and high ground further north.

[Iceberg]

Two distinct camps in the ensembles 1 camp keeps the cold going al la GEFS control and possibly the METO.

The other camp brings in milder SW winds.

On the 12Z the coldies win IMO the camp is getting bigger and the London 850's never really mean much above -5.

[Harsh Climate]

I wonder what the odds are on the next ECM showing a stonking easterly around 216h

[Frosty.]

Scotland, being further North certainly has the advantage, however Ireland is very favoured indeed on the latest UKMO T+144 Chart. Winds are actually from the South across the UK on that T+144 chart, so areas across the south in particular would not be heavily favoured for snowfall, especially to low levels.

Ireland is never mentioned on the UKMO Update Frosty.

SA

Thanks SA

The GFS 12z is certainly a more wintry run than the 6z and cold for northern britain for the whole run but a little milder in the south later.

[Frosty.]

Did he not say Scotland and Ireland in his post??

Anyway, I agree that the north looks win/win regardless of which model output (if any I suppose!) verifies.

I hope for the sake of most of the UK including Scotland that the low is further east, as the chances of it being pushed too far east look to be pretty much zero. The 12Z is an improvement from the 6Z, though clearly there is a marked warm sector http://charts.netweather.tv/gfsimages/gfs.20100210/12/150/h850t850eu.png

http://charts.netweather.tv/gfsimages/gfs.20100210/06/156/h850t850eu.png

Yes sorry I didn't read his post properly, still up for grabs next week with the will the pattern trend east or west, west based still seems more likely but win win for the north as you rightly say.

[Eugene]

Well it's snowing today and temps are below 0C already so we did get something from it.

http://www.wzkarten3.de/pics/MT8_Manchester_ens.png - Impressive ensembles below average temps just go on and on

[Barometric]

The 12z GME is looking rather good too

http://www.wetterzentrale.de/pics/Rgme1081.gif

http://www.wetterzentrale.de/pics/Rgme1321.gif

All a step in the right direction

[Thundery wintry showers]

The ECM, as ever, will be important, but the GME clearly siding with the GFS there with placing the low pressure to the east and giving us a distinctly unstable looking northerly airflow. Troughs and widespread snow showers would be near-guaranteed.

[Tom D]

Comparing UKMO t+144 with the GEFS, only one vaguely matches - P5 as I said above. There's a small ridge of increasing pressure over Scandinavia.

http://91.121.94.83/modeles/gens/run/gens-5-1-144.png?12 GFS 12z +144

UKMO 12z t+144

Edited February 10, 2010 by Tommyd1258

[MR EXTREMES]

ecm looks like everything west flicking though two charts you can clearly see where its heading:wallbash:

edit its similar to ukmo.

but nice ridging around greenland.

Edited February 10, 2010 by badboy657

[Ben_Cambs]

ecm looks like everything west flicking though two charts you can clearly see where its heading:wallbash:

I wouldnt be so premature yet, its only out to T+96 at the moment! I agree with other posters re how curious the UKMO T+144 is, interesting stuff

[chionomaniac]

ecm looks like everything west flicking though two charts you can clearly see where its heading:wallbash:

I would say things have shifted East upto T+120 bb so I don't know what charts you are looking at!

[Cloud 10]

I would say things have shifted East upto T+120 bb so I don't know what charts you are looking at!

Quite a big shift from the ecm 00z and looks very much in line with the gfs.

Edited February 10, 2010 by Cloud 10

[I remember Atlantic 252]

ecm maybe better, low seems further East, hopefully its time to start thinking cheshire gap again, but miles off yet

think the gfs 12Z is very good after the initial rain on monday to introduce the northerly, then cold air arrives

[MR EXTREMES]

I would say things have shifted East upto T+120 bb so I don't know what charts you are looking at!

yes they have here they are:

[swfc]

yes they have here they are:

game up at 160+.

[The Eagle]

144hrs

168hrs

[MR EXTREMES]

yep not a good ecm low travels down the spine of the uk but moving sw not good for anyone except the highest ground.

one thing i notice though although here in the south we dont get anything exciting atleast we dont get cold rain lol.

infact it looks dry here.

it must be noted though the ecm may not be the model to be watching it also possible another shift east happens in the next couple of days.

Edited February 10, 2010 by badboy657

[The PIT]

yep not a good ecm low travels down the spine of the uk but moving sw not good for anyone except the highest ground.

Yup evening forecast mentioned becoming less cold with milder air moving south. If the low keeps sinking it wouldn't be too bad.

[The Eagle]

yep not a good ecm low travels down the spine of the uk but moving sw not good for anyone except the highest ground.

I disagree - for Scotland, Ireland, Northern England and Wales, higher ground elsewhere a potential snow event there...850 temps -5C or lower pretty much everywhere. Thicknesses are not too bad either.

Of course things will change but it's an interesting setup coming IMO.

Edited February 10, 2010 by The Eagle

[bluearmy]

a couple of days ago, next weeks trough seemed to be from the north scandi shortwave sending energy sw. over the past few runs, it appears to me to be solely from a shortwave developing around iceland which doesnt interact with the scandi shortwave at all before it arrives over us. uppers we will see next week under this trough are marginal to say the least. without advecting the colder air from scandi sw into the circulation, i cant see where lowland snow is going to come from. the further north and west, the better the chance but even then, its 50/50. thicknesses also marginal away from the nw and the colder air.

thats how it currently looks and the change of emphasis with this shortwave origin seems to be responsible.

[mountain shadow]

I disagree - for Scotland, Ireland, Northern England and Wales, higher ground elsewhere a potential snow event there...850 temps -5C or lower pretty much everywhere.

Exactly and it is better than the 0z for sure.

[cooling climate]

ECM up to t144 (which was this mornings t156 ) is definitely further east along with the

Arctic high.

The ECM was the most aggressive model with regards to the retrogression and westerly

-NAO so very good signs.

The potential in the t168 is awesome.

Edited February 10, 2010 by cooling climate

[Eugene]

TBH exact details at this range don't matter what is important is the overall trend and that is for a greenland high and cold LP moving southwards, exact positioning won't be known until much nearer the time, usually models have things too far west and push it further east nearer the time so having it too far west at this range is good

It's so refreshing to have HP to our northwest and LP forming in cold regions instead of the reverse and HP to our southwest with LP forming in the tropical atlantic

[MR EXTREMES]

I disagree - for Scotland, Ireland, Northern England and Wales, higher ground elsewhere a potential snow event there...850 temps -5C or lower pretty much everywhere. Thicknesses are not too bad either.

Of course things will change but it's an interesting setup coming IMO.

ofcoarse always a possiblity maybe futher north and on higher ground but id say marginal looks more likely, remember there not much deep cold sticking around if this weeks cold had been deeper with snow lying with colder land temps then id say better odds but right now the ecm is not a good run.

although the gfs is much better.

Edited February 10, 2010 by badboy657