General Model Output Discussion

[Duane S.]

ECM isnt good this morning, still looks good up to t120 but then the SW over norway gets pulled back round and links up with the low to our southwest! ends up with most of us having milder southerlies or southeasterly's! were not there yet

Yes it gets a bit disappointing after +144 but the main thing is that up till then it looks very good. I'd rather it was that way around!

[West is Best]

ECM isnt good this morning, still looks good up to t120 but then the SW over norway gets pulled back round and links up with the low to our southwest! ends up with most of us having milder southerlies or southeasterly's! were not there yet

To be fair it's a stonking run up to T144 and not until T192 that it goes awry. Certainly need to keep an eye on that though: it's the breakdown of the block that's worrying. Total contrast to the GEM. ECM has not been on good form, but the GFS shows something similar in far FI. But ECM out to T144 is fab.

Edited December 26, 2009 by West is Best

[Mondy]

At this rate, it will be a frozen tundra over much of Scotland! We haven't had it mild for weeks on end. Ground is frozen solid, with an abundance of snow on top. Reached -12c at my rural(ish)location on Xmas Eve, with two -7's also occuring at end of Nov and mid-Dec. Currently, it's -6c. Sometimes I wonder what all the fuss is about with regards talk of losing cold air and mild air returning, lol

[Frosty.]

At this rate, it will be a frozen tundra over much of Scotland! We haven't had it mild for weeks on end. Ground is frozen solid, with an abundance of snow on top. Reached -12c at my rural(ish)location on Xmas Eve, with two -7's also occuring at end of Nov and mid-Dec. Currently, it's -6c. Sometimes I wonder what all the fuss is about with regards talk of losing cold air and mild air returning, lol

You make a very good point there, it looks like scotland will see the best of the very wintry spell during next week and even beyond, maybe the south would become less cold later.

[yamkin]

ECM isnt good this morning, still looks good up to t120 but then the SW over norway gets pulled back round and links up with the low to our southwest! ends up with most of us having milder southerlies or southeasterly's! were not there yet

Don't worry about the milder set up being shown on the models as this is in FI and when the colder period sets in, the cold will be difficult to budge.

Susan Powell on BBC24 News just said that it will turn very cold on Tuesday with rain which will turn to snow on Wednesday

[Polar Continental]

Thanks Steve, a brilliant read this morning. It would indeed be great if we are on the cusp of classic.

Was out all day yesterday, so only saw the early runs, so pleased to see very cold runs continuing again from the models. The GFS is again very good, it seems to evolve in to something similar to what just happened before Christmas, cold stagnating low pressure over the UK, followed by an easterly.

But the GEM has my vote this morning, bitterly cold, especially later on with a Greenland block from heaven.

[Stu_London]

We are still on track for a potent cold snap, but this mornings models and ensembles are quite a big downgrade in respect of the longevity of any severe weather.

Some may see more snow from this event than in the last week, but doubtful at this stage if it will stick around as long.

That said, breakdowns are in FI, so things could change dramatically still.

[Rommy]

is the snow still on for next week for the midlands or will it be rain?

[nick sussex]

Morning all

Still some differences with the track of the low this morning, the ukmo again has this the furthest north but seems to be slowly coming into line with the ecm. In terms of the ensembles on the face of it less support for the cold to last, however we need to bear in mind the majority of the ensemble members keep the Greenland block well into FI, looking back to the cold spell over Xmas we saw the ensembles want to end this much earlier than has actually occured, in situations where a block remains and shortwaves and lows are likely to either head ne or go under the block then the ensembles can be very misleading.

For the timebeing we need to see exactly what this first low is going to do before worrying too much about post 144hrs.

[yamkin]

We are still on track for a potent cold snap, but this mornings models and ensembles are quite a big downgrade in respect of the longevity of any severe weather.

Some may see more snow from this event than in the last week, but doubtful at this stage if it will stick around as long.

That said, breakdowns are in FI, so things could change dramatically still.

The recent cold period had mild breakdowns in FI only for the cold to progress further over the UK. The models are indicating a colder period next week and the MetO are making this very clear in their TV forecasts.

[Weather-history]

ECM at 0z 240hr

[Duane S.]

Thanks Steve, a brilliant read this morning. It would indeed be great if we are on the cusp of classic.

Was out all day yesterday, so only saw the early runs, so pleased to see very cold runs continuing again from the models. The GFS is again very good, it seems to evolve in to something similar to what just happened before Christmas, cold stagnating low pressure over the UK, followed by an easterly.

But the GEM has my vote this morning, bitterly cold, especially later on with a Greenland block from heaven.

Yep the GEM is a beauty, in fact there are no stinkers at all. Some are not as good as others but by definition that is always going to be the case.

I'd say this is pretty much going according to plan laid out a month or so ago by knowledgable contributors GP & BFTP. We are in a mild(er) spell (those in the North of the UK may argue this point though ), but from early-mid next week that is all going to change once more, with much colder air over most of the UK by then. The real fun is likely, and always was, during the month of January. All sorts of potential from here on in. An early mild breakdown to a zonal feed is one particular outcome out of several but certainly not one I can see occuring any time soon, it would go against current teleconnections which is why when I see a quick breakdown of Northerly heights in a model run I treat it with sceptisism.

Edited December 26, 2009 by s4lancia

[yamkin]

WMC Moscow 00Z 84t 500 & 850 are not bad

Edited December 26, 2009 by yamkin

[phil nw.]

Don't worry about the milder set up being shown on the models as this is in FI and when the colder period sets in, the cold will be difficult to budge.

Susan Powell on BBC24 News just said that it will turn very cold on Tuesday with rain which will turn to snow on Wednesday

This mornings fax for Tues.

Shows the colder air north of the border at this stage which would mean rain from that approaching front at first,as described by this mornings tv forecast.

As the colder air comes south later,something like GFS here then this would turn to sleet and then snow as the temps. drop.

http://www.wetterzen...s/Rtavn1202.png

Detail on snowfall depth and the areas most at risk are still to be defined at this stage but the favoured region would be midlands and wales based on the current positioning of the fronts and low.

The doubt in my mind regarding snow is whether there would enough percipitation still around for long after the cold air tucks in.

Certainly a cold looking overall pattern going forward,

http://www.meteociel...=144&carte=1021

http://www.meteociel...44&mode=1&map=1

http://www.meteociel...44&mode=1&map=1

Southerly jet and good heights near Greenland and a good shape to the troughing over Scandi. particularly on GFS.

Edited December 26, 2009 by phil n.warks.

[TEITS]

Interesting models this morning because they are trending towards something I suggested yesterday evening. A few days ago the models were suggesting N,lys via the GH in F.I. However I said last night they are swinging away from that towards an E,ly via a link between the GH & SH. That is exactly what has happened this morning.

http://www.wetterzentrale.de/pics/Rtavn1921.png

http://www.wetterzentrale.de/pics/Recm1681.gif

http://www.wetterzentrale.de/pics/Rukm1441.gif

The only downside is the block is just too far N to affect the whole of the UK. However having said this the LP systems coming up against the pool of cold air across the UK would bring a snow event.

Overall I would say the models are still fantastic but they seem to back away from a prolonged cold spell. Having said this I shouldn't be worrying about F.I!

[Frosty.]

ECM at 0z 240hr

Indeed Mr_Data,

Some don't like the latest ecm run but I think it's a brilliant run for a prolonged wintry outbreak.

[snowmadchrisuk]

This mornings fax for Tues.

Shows the colder air north of the border at this stage which would mean rain from that approaching front at first,as described by this mornings tv forecast.

As the colder air comes south later,something like GFS here then this would turn to sleet and then snow as the temps. drop.

http://www.wetterzen...s/Rtavn1202.png

Detail on snowfall depth and the areas most at risk are still to be defined at this stage but the favoured region would be midlands and wales based on the current positioning of the fronts and low.

The doubt in my mind regarding snow is whether there would enough percipitation still around for long after the cold air tucks in.

Certainly a cold looking overall pattern going forward,

http://www.meteociel...=144&carte=1021

http://www.meteociel...44&mode=1&map=1

http://www.meteociel...44&mode=1&map=1

Southerly jet and good heights near Greenland and a good shape to the troughing over Scandi. particularly on GFS.

Yes Precipitation is a big problem on the GFS this morning with next to nothing all the way out to +180. Still I think things will be more showery than that. The ensembles have been hinting at rising 850's from the 3rd for quite a few runs now by the way. The Control usually being the mildest. I know it has been said before but Christmas data issues are likely to be a problem , If there is hardly any flight data going into the models then there going to be using old data or non at all and it is bound to effect the outcome in FI . I would expect things to get back to normal 27th-31st.

[yamkin]

ECM at 0z 240hr

Great 1947 chart Mr_Data Hope you do not mind me supplying info during the very cold period in 1947......

From late January to mid March 1947 many parts of the British Isles experienced record low temperatures and persistent snow cover http://www.winter1947.co.uk/

[snowmadchrisuk]

Hi Mr Data , Is there any data on model verification for last Christmas , I was wondering which model was the best to follow with less flight data. I seem to remember the GFS went a bit crazy last Christmas only to be resolved around the 27th.

[Tom D]

I've just read Steve Murr's post - I think you could easily post that up on the website as I'm sure even the less technical visitors could understand what you're saying there. Fantastic post!

Once again eyes go to the models, like a couple of weeks ago before our last cold snap!

[sebastiaan1973]

Excellent EPS

http://www.knmi.nl/exp/pluim/vijftiendaagse/Data/15DAAGSE_06260_NWT.png

[yamkin]

I've just read Steve Murr's post - I think you could easily post that up on the website as I'm sure even the less technical visitors could understand what you're saying there. Fantastic post!

Once again eyes go to the models, like a couple of weeks ago before our last cold snap!

If only we could see the MetO's private model as they are strongly indicating Heavy Snow from Wednesday onwards (BBC24 News Forecast by Susan Powell)

[Guest North Sea Snow Convection]

If the whole pattern was shifted a couple of hundred miles south along with those nuisance troughs which are cutting off the coldest air from arriving across the greater part of the BI then the models this morning would get the perfect '10'. Taken at face value they are very much spoiled by these lows which stop an amazing easterly right across the UK and on a transatlantic trip to the states and Canada. Very frustrating.

The exception is the GEM which has the less cluttered straightforward evolution to the main low staying and passing to the south with no subsequent messy spoiling link ups with the trough over the Baltic and the lows to the south west which appear to cut off the properly cold air.

Faultless blocking to the north - hopefully the models are just over complicating things and that cold air gets far enough south, before it is whisked away again.

The ECM looks rather suspect to me from t144 onwards - and over progressive. However, hoping for better this evening. Very good outlook further north, but less so in southern and south eastern most parts, where the cold air looks to be struggling to arrive and the sledges are not ready to come out yet.

Edited December 26, 2009 by North Sea Snow Convection

[nick sussex]

Given all the output so far this morning we should hopefully see the low track taken further south on the gfs 06hrs run, the ecm ensembles also show some room for taking the low a touch further south. The ukmo for some reason overdid the Xmas celebrations and is suffering from a hangover!

Edited December 26, 2009 by nick sussex

[markg]

Hi Mr Data , Is there any data on model verification for last Christmas , I was wondering which model was the best to follow with less flight data. I seem to remember the GFS went a bit crazy last Christmas only to be resolved around the 27th.

yeah chris i remember this also, the data coming in was less as not all stations reported data , its only one run and the 12 previous were all good for cold coming back, mind due it hasnt ever left us up here and we are on the coast, we had snow again last night on top of the snow we had on the ground since last friday