Model Output Discussion 5/12/2012 18Z onwards - the one after THAT ECM

[Paul Sherman]

Jan 87 was certainly cold.... but i remember it as only having an inch of snow, albeit it stuck around for a long time. in fact it was weird going into the City (London) and seeing more snow there! It was great for those to the east and south of the river who couldn't get to work for being snowed in, but not so good for us green-with-envy types :-)

Wow!

52cm of level snow, Sea Froze over at Leigh On Sea and 20ft drifts! Still to this day the best with Feb 1991 a close 2nd and December 2010 3rd!.......In my lifetime i should add!

Anyhow enough of all that or the Blues and Reds will cut me balls off for straying off Topic!

Edited December 6, 2012 by Paul Sherman

[kumquat]

Being cautious is the way to go when model watching.Give it while the weekend and see how things lie.One thing for sure is the latest ecm run coudnt be bettered.The winters of 78-79-81 were very severe and to be honest anyone north of watford got on with it!!!!

Indeed - living up in Northamptonshire (not a million miles north of Watford lol) back in the day it was pretty run-of-the mill childhood and great fun for me at age 8, 9, 11.

I grew up thinking winter would always be like that.

After the intervening years - not too surprising that we're astonished to see charts like this. However, life goes on generally, and we get up, dust the snow off and get on with it. I'd enjoy it while you can to be honest. It seems to me that these "batches of cold winters" come in for a few years and then disappear for a decade or so. All mini-cycles in the big scheme of ice ages and global warming. Looks PDO driven to me but what do I know?

[Cheshire Freeze]

I would urge caution for tonight, a signifficant number of the GFS ensembles erode high pressure from the south around day 10 which usher in milder uppers. About 3 or 4 members show a clean evolution from an easterly to a Greenland high and NE'ly winds.....this is the scenario you want to see gain support if you're a cold lover.

[West Sussex Kate]

All the best to you Hagler.

[Weather-history]

I would urge caution for tonight, a signifficant number of the GFS ensembles erode high pressure from the south around day 10 which usher in milder uppers. About 3 or 4 members show a clean evolution from an easterly to a Greenland high and NE'ly winds.....this is the scenario you want to see gain support if you're a cold lover.

I don't quite understand why people are looking for a breakdown already of something that's not happened yet? Not sure what is going to happen before, so why speculate over a breakdown when we don't know what exactly is going to breakdown, should it breakdown.

Edited December 6, 2012 by Weather-history

[Bonjangle]

I would urge caution for tonight, a signifficant number of the GFS ensembles erode high pressure from the south around day 10 which usher in milder uppers. About 3 or 4 members show a clean evolution from an easterly to a Greenland high and NE'ly winds.....this is the scenario you want to see gain support if you're a cold lover.

What do you mean by this , sorry for asking but i am still learning and also others who just read but embarrased to , i was one but i love to learn now .

I could be the next Ian Mcaskell ...lol no storm tommorow

[Cheshire Freeze]

I don't quite understand why people are looking for a breakdown already of something that's not happened yet? Not sure what is going to happen before, so why speculate over a breakdown when we don't know what exactly is going to breakdown, should it breakdown.

Nowt wrong with a bit of speculation and forward thinking Kev

Also it could make a big difference to whether we see a 3-4 day spell or something much more severe and sustained. This is why there will probably be focus in the next couple of days in this area. Assuming the initial easterly comes off of course.

Edited December 6, 2012 by CreweCold

[robb]

I would urge caution for tonight, a signifficant number of the GFS ensembles erode high pressure from the south around day 10 which usher in milder uppers. About 3 or 4 members show a clean evolution from an easterly to a Greenland high and NE'ly winds.....this is the scenario you want to see gain support if you're a cold lover.

Very cold air is building to the north at the end of that run and advancing south and as you say this could end up with a classic battle ground scenario across the UK

[LomondSnowstorm]

I don't quite understand why people are looking for a breakdown already of something that's not happened yet? Not sure what is going to happen before, so why speculate over a breakdown when we don't know what exactly is going to breakdown, should it breakdown.

Not to mention how badly potential breakdowns are modelled. Even once in a cold spell, a potential breakdown at even a 4/5 day range can often be delayed, or occasionally a breakdown can appear with relatively little notice. For what comes after, at this stage the best guidance comes from bigger ensemble suites like the NAEFS and ECM ensembles along with the teleconnections and background signals, most of which seem to indicate retrogression as the more likely option, but we're still way off that stage.

[Cheshire Freeze]

What do you mean by this , sorry for asking but i am still learning and also others who just read but embarrased to , i was one but i love to learn now .

I could be the next Ian Mcaskell ...lol no storm tommorow

Something a bit like this....

Looks OK to begin with

but then as we progress further, the low tracks north and we end up back on the mild side

The other scenario I talked about is the clean 'cold to cold' scenario....

Goes from biting easterlys

to the trough dropping into Scandi and heights remaining around Greenland

[Duane S.]

It's safe to say if it all goes wrong it it will be remembered as another notorious failed easterly.

Pros

Backgrounds signals are firmly behind this occuring (to what degree yet to be determined though)

Good consistency of late from the models

Tonight's fax

Good margin for error at the moment

Against

Still way too far out to be 'set in stone'

The 'proper' Easterly as we have seen modelled tonight is extremely rare, the hurdles needed to jump along the way are plentiful and any one can often derail the continental express in one foul swoop.

IF we can get to Saturday 00z's (a lifetime in model watching terms!) and we have something like we have seen from Wednesday still on display then we are there. If I had an ounze of sanity in me I would not return back here until then but somehow I don't think that isn't going to happen!

[Rob K]

Yes some of next weeks projected charts bear a canny resemblance to that amazing 6 day event.

Which just got worse and worse - Nice 7 days of School though

Jan 87 was very extreme though because not only did the synoptics fall into place but they also did so at exactly the right time when there was a deep cold pool over the continent: http://www.wetterzen...00219870112.gif

Even if next week's easterly is the most perfectly aligned, the cold pool is likely to be a good 10C warmer than that, even if you go by the more "extreme" ECM charts: http://www.wetterzentrale.de/pics/Recm2162.gif , so I hope nobody is expecting anything to compare with that one. No subzero maxes likely on this one, more like +2C with a nagging breeze.

GFS shows the 850s even less cold, more like -8C.

Edited December 6, 2012 by Rob K

[Cheshire Freeze]

Jan 87 was very extreme though because not only did the synoptics fall into place but they also did so at exactly the right time when there was a deep cold pool over the continent: http://www.wetterzen...00219870112.gif

Even if next week's easterly is the most perfectly aligned, the cold pool is likely to be a good 10C warmer than that, so I hope nobody is expecting anything to compare with that one. No subzero maxes likely on this one, more like +2C with a nagging breeze.

The longer the easterly digs in for the colder it will get. The ECM post 192 hrs, you're looking at sub zero maxes......except for right on the east coast.

Even with -8 uppers you'd be looking at barely getting above freezing inland after a few days. A combination of little solar input (near shortest day), CAA from continent and general cooling of the landmass would see us struggle above freezing after a few days. All conjecture though at this range.

Edited December 6, 2012 by CreweCold

[Rob K]

The longer the easterly digs in for the colder it will get. The ECM post 192 hrs, you're looking at sub zero maxes......except for right on the east coast.

Even with -8 uppers you'd be looking at barely getting above freezing inland after a few days. A combination of little solar input (near shortest day), CAA from continent and general cooling of the landmass would see us struggle above freezing after a few days. All conjecture though at this range.

Yes it would get colder. But to see people asking whether it could be as cold as 1987 or 1991 is just asking for disappointment. No there is nothing on any model that suggests anything remotely as severe as those legendary spells. Something more akin to early Feb 2009 is a better match: http://www.wetterzentrale.de/pics/archive/ra/2009/Rrea00120090202.gif

which led to http://en.wikipedia.org/wiki/February_2009_Great_Britain_and_Ireland_snowfall

And even there the 850s were generally colder than I expect next week.

I think a few people are getting unrealistic - yes we've got an easterly on the horizon but not a mega cold one.

[john pike]

i am not sure saying this chart is not cold

[Cheshire Freeze]

Yes it would get colder. But to see people asking whether it could be as cold as 1987 or 1991 is just asking for disappointment. No there is nothing on any model that suggests anything remotely as severe as those legendary spells. Something more akin to early Feb 2009 is a better match: http://www.wetterzen...00120090202.gif

which led to http://en.wikipedia....reland_snowfall

And even there the 850s were generally colder than I expect next week.

I think a few people are getting unrealistic - yes we've got an easterly on the horizon but not a mega cold one.

I would say the ECM is comparable......it would certainly be notable; especially as it's still only December and cold pooling tends to stand a better chance in Jan anyway historically. Saying this the ECM is at the very extreme end of the ensembles so I'm inclined to agree with what you're saying.

Edited December 6, 2012 by CreweCold

[swfc]

i am not sure saying this chart is not cold

It is a cold chart and very good for mid december

[john pike]

It is a cold chart and very good for mid december

i know swfc

this is an amazing chart and only the start of the cold air digging in

fingers crossed for tomorrow

[alan776600]

If that is a 1991 forecast (I'm on my mobile so can't watch it now) then no chance. That was a once in a lifetime easterly. Next week I'd expect highs of +2c by the end of the week and a few snow showers with modest accumulations in favoured spots. I certainly wouldn't expect snowy Armageddon!

Put it this way - I can't see anything as severe and snowy as Dec 2010 (or Jan 2010 when I got 25cm+ of snow here in Hampshire).

Yateley had amazing snow 2010

[Rob K]

i am not sure saying this chart is not cold

It is very much the coldest of any output though (e.g. GFS here http://www.wetterzentrale.de/pics/Rtavn2162.png ) and even then it's not a patch on the sheer size and depth of the 1987, or the intensity of the 1991 cold pool: http://www.wetterzentrale.de/pics/archive/ra/1991/Rrea00219910207.gif

But 2009 would be plenty good enough for me - we got a good 15cm of snow round here with twice that on the Downs.

[swfc]

I would say the ECM is comparable......it would certainly be notable; especially as it's still only December and cold pooling tends to stand a better chance in Jan anyway historically. Saying this the ECM is at the very extreme end of the ensembles so I'm inclined to agree with what you're saying.

During the build up to the 87 cold eastern europe had been having record cold for weeks hence the severity of the easterly.It was the severest outbreak ive ever seen even it wasnt sustained that long.If we do get an easterly next week theres know doubt it will be cold and prog wintry Edited December 6, 2012 by swfc

[SnowObsessor90]

Just banked that ECM run in all of it's Netweather, Metiociel and Wetterzentrale glory, let's don't hope that things don't end up going 'too' downhill from here. That's all that can really said at stage

[Tubs]

Seems that we are all right as Express is also forecasting some cold weather. They are always right so there cannot possibly be a problem.

[Jezzer]

Seems that we are all right as Express is also forecasting some cold weather. They are always right so there cannot possibly be a problem.

Oh dear, that'll bring back the mild south westerlies before we know it!

[Snowy Easterlies]

good news so far, 00z is an upgrade compared to the 18z at T120