Model Output Discussion - Tuesday 20:25 -->

[WhiteXmas]

With the sheer mass of freezing cold air that the models are showing to our North and East if that does establish itself around us it will result in, dare I say Siberian Snow conditions! Although that is still a big big if of course!

[Nick F]

I understand what you are saying Lewis however it is amazing the differences in one run to another at times. It can be a total contrast to what it had been suggesting previously. This was particularly the case last year however there has been more general agreement at the start of this winter between the models which is a really good sign. I wonder what the cause of this is?

I think it maybe the shortwave modeled dropping down from Svalbard area on the eastern flank of the ridge, down over Scandi towards Denmark area early next week which is causing quite a few differences, certainly the 12z ECM delays the southward movement of the low - which in turn delays the backing west of the *real* cold cP air over NE Europe/NW Russia.

[Lewis]

Looks like a much slower version of the 12z GFS thus far, the shortwave is diving southwards, colder air should tuck in around 192hrs hopefully!

Certainly not as cold between 72-144hrs as the GFS though it has to be said, but maybe a longer lasting set-up in a trade off.

Yes, totally agree Kold.

It's weird but lovely is it not? GFS and ECM/UKMO and parallel all showing a cold Easterly/NE blast. Middle next week into FI. And in reliable time frame its chop and change.

Generally the ECM is normally better at short range, and i favour the GFS for longer range, and for short range shortwave developments.

So folks, don't worry a bit.

Because we have a little disagreement for Sunday/Monday regarding the shift of the HP, which tbh does not really make too much difference as long it don't shift ESE.

Game on people!

[kold weather]

Yep, I'd asume the cold would fly down once that LP clears away, could get some pretty decent cold from that chart...however I still much perfer the 12z GFS to that chart, simply because it has cold pretty much locked over the UK once the intial easterly comes in, where as the 12z ECM doesn't seem to want to have any of it, indeed the 120hrs chart probably isn't that much below average.

[Mark Bayley]

ECM looking very good at T168, not as cold as the GFS in the earlier time frame but still not bad. Perhaps people should wait for whole run to come out before jumping the gun? Little changes here and there are bound to happen but overall some fantastic models so far tonight

[bluearmy]

would say that the 12z ecm looks a much less messy way to get to the cold flow than has been shown by some of the other runs. initially less cold due to no tightening of the pressure gradient around T96. will be cold at the surface though!!

[loophole]

ECM 192 is beautiful

[Nick F]

The door opens from the NE eventually though by t+192 ... that chart would certainly cause meltdown on here if it verified - shame it's FI and unlikely to verify like that!

[Neilsouth]

http://www.wetterzentrale.de/pics/Recm1921.html

Yay for snow showers just scurting along the coasts , south east england would be dry... I still say it looks poor!

[cyclonic happiness]

Bang! this is a really good chart!!!!!

[Frosty.]

ECM 168h is simply stunning.

I think the run is fine.The high is going North the jet is going south.

I don't care how long it takes as long as it gets here, Yes, by T+168 the ECM 12z couldn't be better...there are some on here who are too impatient, mega wintry spell ahead but delayed by a day or two maybe.

[Cecil Hogmanay Melchett]

The door open from the NE eventually though by t+192 ... that chart would certainly cause meltdown if it verified

Nick look where the flow comes from on that ecm 192 h chart.

How far NE?

ECM is an absolute snow fest towards the end of next week.

With that flow and a warm North sea we could be seeing literally staggeing ammounts

of snow .

Im gobsmacked.

Edited December 9, 2009 by happy days

[I remember Atlantic 252]

Bang! this is a really good chart!!!!!

cold enough at low levels though, looks like a hills event to me, but still FI

[Dartmoor_Matt]

Didn't the GFS pick up on this originally for the 17th? So it does all seem to be on track, not bad considering it picked up on it last Thursday.

[Harsh Climate]

As i said the ecmwf is fine! great infact!

What happens here: http://www.wetterzentrale.de/pics/Recm1921.gif

Is with the high further south, there is greater pressure aggainst the low to the south east giving a stronger feed of easterly winds.

[kold weather]

In that flow NS you'd see trough a plenty, I think there would be a heck of a lot of snow to be had from that set-up, plus any cold front would probably have snow tucked in very tightly given the strength of the cold...that really is a very good chart, even here in the SE!

[cooling climate]

ECM at t216 there must be -16 850's over the country surely.

What an incredible chart, and the snow potential would be huge.

I think S.Murr's fainted.

Edited December 9, 2009 by cooling climate

[Neilsouth]

Funny how the people saying it looks stunning living UP norf , what happened to the strong north east winds?. I've seen low pressure systems in this general area like that in winter and snow showers come down across east anglia and die as they hit the south east. Unless the ECM shows north east winds at all next week i'll not be pleased with this run!

EDIT - Kold i'm still not so sure! , but i'd love to be proved wrong

Edited December 9, 2009 by neilsouth

[bluearmy]

cold enough at low levels though, looks like a hills event to me, but still FI

thicknesses low enough mark.

flow fast enough over the sea to avoid modification

i think snow

[Neilsouth]

http://www.wetterzentrale.de/pics/Recm2161.html

MUCH BETTER , see that north east wind in the east/south east?.... THATS WHAT I WANT!

[on the coast]

Excellent charts tonight by all models. Agreement by all. Here it comes

[cyclonic happiness]

cold enough at low levels though, looks like a hills event to me, but still FI

If you follow the source of the low back, then yes, i think it will be cold enough at low levels.

There aren't many sources that you can get a colder looking low

[Nick F]

Nick look where the flow comes from on that ecm 192 h chart.

How far NE?

ECM is an absolute snow fest towards the end of next week.

With that flow and a warm North sea we could be seeing literally staggeing ammounts

of snow .

Im gobsmacked.

Certainly would be brutal the cold airmass crossing the N Sea!! Hopefully the freebie banner charts on the ECM website will show the 12z T850s like the 00z output did - which will give an idea.

And with N sea temps around 9-10C still ... it would cause rather steep lapse rates and some rather heavy snow showers.

Hard not to get excited ... even though the arrival of the coldest air is still in FI.

[kold weather]

Also those charts are *beastly* cold, the thickness is really very impressive indeed, the east coast getting down to around 510 on the 216hrs chart, NE Scotland is not all that far from 500!

Thats exceptional cold, would expect 850hpa temps between -10 and -14C on the 216hrs chart and probably the coldest period of weather for a long time!

[Guest North Sea Snow Convection]

There really isn't any point in taking in the detail too much, but FWIW the ECM isn't a good output for the SE in terms of getting into the colder air and snow as the low doesn't away south but gets stuck nearby meaning that this part of the country would stay in the milder sector associated with the low. Elsewhere though it would be a case of digging yourself out of the snow!!

However, this is all still a way off and there isn't agreement completely in the shorter term yet - so not much point in trying to firm up what may or may not happen later

Edited December 9, 2009 by North Sea Snow Convection