Winter Model Discussion 12Z 15/02/13 onwards.

[bluearmy]

The ecm 12z op is a colder run for se uk than previous runs with an ice day next friday. Uppers are not relevant with a continental flow.

[seabreeze86]

I feel some perspective is needed by some we have this at 96hrs from the ECM UKMO AND GFS the three leading models.I will take that anyday.

http://www.meteociel...512/ECM1-96.GIF

http://www.meteociel...gfs-0-96.png?12

An easterly is now nailed on, the smaller details will change from run to run so are not worth worrying about in my opinion. We are on the edge of a cold spell how cold and how much snow who no's.

Edited February 15, 2013 by seabreeze86

[Ian Brown]

Broadly speaking yes, but I think we're still quite far off being able to call whether it will be mostly dry or not. Many times over the years people have written off a spell as being cold and dry - the pre Christmas period of 2009 for Scotland, numerous slack easterlies round my neck of the woods (even on the day of them the BBC forecast was for it to be dry) which delivered snow and even December 2010 which delivered so much for the south at points was thought to be dry because of the slack trough. If the cold is well established features can and often do pop up at short range, so that's what I'd focus on at this stage, and synoptically things still look promising for all in that regard.

Yes, it's impossible to say 'mainly dry' once you are in a cold flow with fairly low heights because you don't know what will pop up.

[That ECM]

Things will only be any good for the north if there is an arctic outbreak sometime down the line, early march say.. it currently only looks like south of the M4 corridor will feel the bite from the Easterly and with wintry showers spreading into kent/essex etc, and then maybe some snow for the south/sw as atlantic lows push northeast and hit the block before retreating sw again, the gfs 12z has the high further north so the wintry showers would also feed in across ne and e coastal counties by the second half of next week but for the northern half of the uk at least, there is nothing to get excited about as things stand.

Hi Frosty, it will change tho and if it is cold then snow can appear from seemingly no where.

Not directed at you at all, we are talking about a possible cold out break in five plus days time. In weather terms, that's miles out. Being here on the south coast, snow normaly gets moved away from this area as the time gets nearer. If that happens then good luck to those who get it. IMBY posts at this time range is very frustrating. People have short memories, it was only jan when snow was forecast and the detail changed right upto t0.

[Frosty.]

Just look how much the ECM has downgraded the snow potential for the north today, synoptically it's now inferior unless you are in the snow threat zone in the southwest, the really bitter arctic air is much further away to the north compared to the very wintry NEly blast it was showing a few days ago. Things will change and I hope it's a change for the better up north.

Edited February 15, 2013 by Frosty039

[nick sussex]

Still quite a variation on the ECM postage stamps at 168hrs in terms of high placement and depth of cold:

http://www.ecmwf.int/samples/d/inspect/catalog/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!168!pop!od!enfo!enplot!2009112700!!/

[phil nw.]

I am happy that all 3 main runs go with the pattern at T120hrs showing the easterly setup and the cold reaching the UK.

Surface details will continue to change further on but the main pattern of a block to the NE and advancing Atlantic trough to the SW is the same.

So we get the cold and chances of snow flurries into the east and later maybe something more from the southwest at the end of the week.

[bradymk]

Just look how much the ECM has downgraded the snow potential for the north in recent days, synoptically it's now inferior unless you are in the snow threat zone in the southwest, the really bitter arctic air is much further away to the north compared to the very wintry NEly blast it was showing a few days ago. Things will change and I hope it's a change for the better up north.

some people have still not even seen a snow flake in the south west and Ireland so maybe they deserve it. Anyway, way too far out too discuss snow threat zone at the moment when there is so much variation occuring between ops and ens as expected at this timeframe.

[Tristrame]

http://www.meteociel...M1-240.GIF?15-0

ECM ends mouthwatering for the SW & Southern Ireland- If anyone thinks it wont be snow then look at how the 850 drop in decending air in 24 hours - down to -8c.

If you want further clarification look up Jan 1982.- 50cms of snow over Ians corner-

^^ thats a SW blizzard waiting to happen

S

lol I remember jan 1982.

10ft drifts at sea level at my location,very similar to last weeks Boston storm only lasting 2 days,with the snow not thawing for 10 days.

Helicopters had to air lift supplies to rural areas even as low as 400ft asl.Up at a 1000ft asl and higher in the wicklow mountains the drifts were up to the tree tops.Now that was epic.

At sea level my road was completely blocked for a week.

I think the worries over the poor uppers are just that there would be little or nothing in the way of convective snow showers,lapse rates wouldn't support them.

[Dexter29]

Just look how much the ECM has downgraded the snow potential for the north today, synoptically it's now inferior unless you are in the snow threat zone in the southwest, the really bitter arctic air is much further away to the north compared to the very wintry NEly blast it was showing a few days ago. Things will change and I hope it's a change for the better up north.

Frosty I really wouldn't keep beating yourself up about the North being dry!

It's 5 days away, so absolutely pointless looking at specifics. Remember snow can crop out of nowhere at T6.

The trend for an easterly is there and we now have all big models in agreement - let's get there first.

[swfc]

Frosty I really wouldn't keep beating yourself up about the North being dry!

It's 5 days away, so absolutely pointless looking at specifics. Remember snow can crop out of nowhere at T6.

The trend for an easterly is there and we now have all big models in agreement - let's get there first.

good call that.The positioning of the high will probably change numerous times over the next 3 days ete .Imo the movement will finish slighty further north and west but thats a gut instinct looking at the nhp ete.

[CHOCOBLUE]

Things will only be any good for the north if there is an arctic outbreak sometime down the line, early march say.. it currently only looks like south of the M4 corridor will feel the bite from the Easterly and with wintry showers spreading into kent/essex etc, and then maybe some snow for the south/sw as atlantic lows push northeast and hit the block before retreating sw again, the gfs 12z has the high further north so the wintry showers would also feed in across ne and e coastal counties by the second half of next week but for the northern half of the uk at least, there is nothing to get excited about as things stand.

so what about midlands,we aren't in north?

[Summer Sun]

Full ECM ensemble

Short term looks like cooling down longer term (towards the end of the month) looks like warming up

Edited February 15, 2013 by Gavin.

[peterf]

so what about midlands,we aren't in north?

You would be if i lived in Cornwall.

[Freezing-Point]

so what about midlands,we aren't in north?

No. That's why its called the Midlands. Another good prediction by a few members that the UK would get a cold spell at this period. Easterly regions look favoured for any snowfall at this point, but as many have said.... once the cold is here then anywhere in in UK is at risk. Personally I would like to see a GH high and -10 uppers, but there is more chance of that than MU losing the premiership.

[Carlrg]

No. That's why its called the Midlands. Another good prediction by a few members that the UK would get a cold spell at this period. Easterly regions look favoured for any snowfall at this point, but as many have said.... once the cold is here then anywhere in in UK is at risk. Personally I would like to see a GH high and -10 uppers, but there is more chance of that than MU losing the premiership.

Snow for more than the East if the Bom is to be believed.

http://www.meteociel.fr/modeles/bome_cartes.php?&ech=6&mode=2&carte=0

[SE Blizzards]

CMA at 168h... majority of UK -8 to -12 uppers

If the ECM would have showed this earlier this place would be in meltdown!

Edited February 15, 2013 by SE Blizzards

[shotski]

No. That's why its called the Midlands. Another good prediction by a few members that the UK would get a cold spell at this period. Easterly regions look favoured for any snowfall at this point, but as many have said.... once the cold is here then anywhere in in UK is at risk. Personally I would like to see a GH high and -10 uppers, but there is more chance of that than MU losing the premiership.

As a liverpool fan I look forward to Man U losing the Premier league.

[legritter]

Stand by your beds gang ,stand easy .GFS IS READY TO ROLL .a brilliant day data and modell wise with plenty of icy charts on offer ,lets get the cold in and then we stand a very good chance of some fun and games .the most important chart in my opinion will be tonights 120fax .what ever the outcome i hope it gets shared out a bit .catch up with you all tomorrow

[Tim Bland]

Does anyone have a link or know where to find the ECM precip charts please?

[bradymk]

As a liverpool fan I look forward to Man U losing the Premier league.

Those are height anomalies not pressure. Even a signal for increased Greenland heights does not mean a greenland high as normal heights for Greenland can be 995mb pressure with above heights being just 1000mb. Above heights for Greenland are not unusual during Feb. We need a much stronger Greenland anomaly for a GH

[snowking]

Nothing much to report in terms of change from the 500mb anomalies tonight from where we were this morning. Heights focused north of the UK, retrogressing with time, with heights to the south of the UK lowering.

The key detail we're all now looking at, the 850's (albeit until we get the synoptic pattern set, this is fairly fruitless. Nevertheless...). Well:

ECMWF painting largely the same picture (here it is at day 7)

At 3c below average, we are looking at roughly -5 to -7c uppers from the ensemble means.

The NAO continues to tell the story really rather well:

GFS remains an outlier solution beyond day 10 (and before that point it remains rather in line with ensemble mean suggestions)

SK

[stodge]

Evening all

Well, having viewed the myriad 12Z output, I expected this place to be in meltdown but it seems the doubters and the cynics are out in full force this evening. I agree it doesn't look like a snow fest initially and I recognise for many on here, snow is all that matters but for fans of cold it's a very strong scenario going forward.

For those who are already worrying about the breakdown (yes, I know), the favourite looks to be a shift toward a west-based negative NAO which opens the door for an attack from the SW.

http://www.wetterzentrale.de/pics/archive/ra/2011/Rrea00120110103.gif

http://www.wetterzentrale.de/pics/archive/ra/2011/Rrea00120110104.gif

This is what killed off the late 2010 cold spell and ushered in a benign start to 2011. The much-talked about Greenland High isn't a holy grail or even a help if it is oriented wrongly as these show.

http://www.wetterzentrale.de/pics/archive/ra/2011/Rrea00120110106.gif

There you are - lovely Greenland High but no help at all. Having the HP to the North (as BOM shows tonight for example) may not bring a lot of snow to the north but it keeps the cold in place for most if not all. The irony of all this is that the south wins from the scenario that keeps the cold while the north is left cold and dry.

[steelermark]

Yes, it's impossible to say 'mainly dry' once you are in a cold flow with fairly low heights because you don't know what will pop up.

Exactly, the same 2 or 3 posters banging the "it's going to be dry" drum all evening when I've lost count of the number of times I've read the same thing on here over the years and then I've sat watching 6 inches of snow fall outside my window just a few days later. It seems that some just never learn, or aren't willing to learn.

Things pop up out of anywhere in cold easterly flows.

[Grimsby Snow Lover]

Does anyone have a link or know where to find the ECM precip charts please?

Will this do mate?

http://en.vedur.is/weather/forecasts/atlantic/#type=prec