Winter Model Discussion - The Hunt For Cold -12z 14/12/12

[Man With Beard]

Whats going on here then? Thats one messy fax.

Is it normal for the 564 line to get so close to Spain at this time of year?

[LomondSnowstorm]

Is it normal for the 564 line to get so close to Spain at this time of year?

It's certainly a fair bit above average, though how rare I'm not sure:

[Cecil Hogmanay Melchett]

Somtimes i wonder if im looking at the same models as others!!!maybe im to old and grumpy but all i see is essentially the zonal train full steam ahead for the forseeable.must admit im suprised that dec couldwell turn out to be a snowless month around these parts,with ENSO pretty weak/neutral i was quite optimistic in November for a decent December but something somewhere is driving this flat upstream pattern.

[Matty M]

Somtimes i wonder if im looking at the same models as others!!!maybe im to old and grumpy but all i see is essentially the zonal train full steam ahead for the forseeable.must admit im suprised that dec couldwell turn out to be a snowless month around these parts,with ENSO pretty weak/neutral i was quite optimistic in November for a decent December but something somewhere is driving this flat upstream pattern.

i think the quick re-freeze of the arctic didnt help. with such anomalously low extent i expected slp anomalies in arctic regions to be greater but the pack froze up so quickly that the exposed ocean didnt really have much time to influence the early winter pattern.

[The Eagle]

The ensembles on the 18z are very interesting as early as 96hrs. Some good outcomes in there for coldies. Seems to be a shift more towards at least a temporary easterly incursion.

[Bonjangle]

d

The only vague similarity I can see is 1962

Classic , and that's the one i am going for ... all this model watching and boring posts i see in here day in day out are to mental and prozac time for many , as like i said just over 2 weeks ago that it was going to go PETE TONG ?? and it did , well all i am going to say (as i lurk and read on here as i hate posting) it will come and it will be Brass balls very soon ... take my word for it i smell it.

[Kentish Snowman in Yorks]

I think the striking thing for me on the 18z GEFS (for my area at least) is that there is a spread of around 12c in the uppers at just T96 with anything from -6 to +6 being modelled;

Now whilst the further North you go the more likely you will be influenced by air from the North / East at that time frame and the reverse further South, as has been mentioned earlier in this thread, until we know what direction that Atlantic Low is headed after mid week, it is just impossible to make any sort of forecast for the Christmas period.

Edited December 17, 2012 by Kentish Snowman

[Robbie Garrett]

Azores high providing Summer Synoptics during Christmas, there isn't really much support for it in my eyes. Except flat pressure for Iberia, a rise in pressure yes but not a massive amount. There is way to much scatter in the ensembles even past the 20th it's struggling slightly, yet there is some agreement we could drop off with marked interest from the 20th December, with some support for this to go Milder on the 24th briefly before with quite some support there for temperatures to lower slightly come Christmas Day.

They key interest for me is the shortwave showing on the GFS, ECMWF and UK Fax at 96 hours...

GFS

ECM

FAX

It seems to advect warmer air towards Europe, and slowly disrupting the high pressure that we have towards eastern Europe/Russia allowing the low to make a movement further east as it has practically stalled in the North Atlantic in that timeframe..... This associated shortwave located over Northern Scotland, send this warmer air up towards the UK. Notice the Eastern Euro high sets movements towards south western Russia as the low then makes some progress as the Atlantic becomes blocked.

I suspect in the next few days, these options may change and vary slightly with lots to offer on the ensembles... to quickly head towards a northerly/Northeasterly by early January as the troughing moves ever east as we want it to.... Just had a look at the CFS see what it brings up, it also goes with my idea before the high heading up towards Greenland collapses.

[Paul T]

With the amount of shortwaves being created at the moment, F.I is from 72-96hrs, total gibberish after that.

Edited December 17, 2012 by Paul T

[Paul T]

GFS just rolling out now, up to around 60hrs thus far....

Key for me from the 06z is the low that develops from Newfoundland and moves into the Atlantic around 78hrs. there is a period between 90-120hrs where it could 'dither' and stay further west, with the cold block pouncing on this weakness.

120-144hrs on the 12z ECM has this Dithering shown in all its glory. I dont buy it; the cold will incur....its interesting.

Barring this interest, its zonal ll the way unfort....

[Cheshire Freeze]

Excuse me whilst I go and throw up.

The 12C 850 line approaching our shores in Mid-December? That's just...

Why can't we have that in summer!?!

God damn Azores High.

Don't worry Jordan, you can be assured the Greenland HP will be there come May....

[swfc]

Nothing to report on the oz only that its as you were in the early stages but pretty dire past the 160hr mark.hopefully into the new year things may improve cold wise but it looks a long job to be fair

[Snowmad79]

The GFS and UKMO 00z's for the 21st time frame (96 today) is an upgrade on the same frame on yesterdays 00z runs. Babushka block is backed even further West (over or to the NNE of the UK) on both models.

GFS Yesterday - 120hr

UKMO Yesterday for the 21st:

UKMO 96hr today:

Much better signs of the block backing west and the undercut looks a bit better. Now here's an improvement jet wise (I think the jet energy shown in the following chart heading north from the UK to Svalbard didn't really help with regards to allowing LP sliding south east or allowing the block to back west:

Where as today this has been removed:

Everyday, we are getting subtle changes as output edges towards the immediate reliable so I can't even bring myself to believe 120hr output now nevermind +144. The only thing that worries me is the tendency for the block to back up the longwave pattern with the trough in the Atlantic. I am seeing the trough slowing down allowing for more WWA on the eastern side of the trough, leading a ridge close the UK, guiding the Jet orientation north (temporarily). While the troughs are slowed, faster moving Shortwave troughs embedded in the pattern upstream are able to catch the Atlantic toughs, amplifying the Atlantic trough each time leading to a much more amplified ridge close the UK which keeps cutting off the chances of LP Diving SE fluidly.

Maybe I've got it wrong but that's what I think I'm seeing anyway.

Edited December 17, 2012 by Snowmad79

[Matty M]

well well well. the ECM furthers the trend. The 120hr chart the pick of the bunch this morning.. even chance of that cold sticking about for a bit.

Cold incursion probably now the favoured outcome for northeast Scotland

Edited December 17, 2012 by Matty M

[Matty M]

Then ECM gives us the final blowtorch take out at T168hrs... but does anybody get the feeling it could be falling for the same mistake twice and going overkill on the Atlantic at that time period?

[MattH]

Personally this signal for perhaps a weak E'ly flow to become established has been a possibility for quite some time, but I do believe that it is nothing more than delaying the inevitable. It's unlikely to happen as the energy in association with the flow from the SW as a major ridge builds over Iberia is far too strong and will, eventually, make an appearance.

From a Christmas perspective having this weak E'ly signal a few days before now is the worst thing that can happen as it is now sort of delaying the arrival of this main low from the SW until Christmas Eve and as a result would signal a very mild (yet again!) Christmas Day. Previous runs didn't really do much with the blocking to the NE and any low pressure systems approaching from the SW were able to move up into the UK and also clear away to the E or NE and allow a colder W or NW'ly flow in time for Xmas Day and Boxing Day. This scenario now is looking less likely thanks to this annoying, half-arsed attempt at another E'ly flow.

I've said this on twitter, but Scandinavian blocks are more hassle than they are worth for the UK unless near-perfect ingredients and a synoptic setup can develop, clearly that isn't the case this time and unfortunately I have a feeling Xmas now may well be nearly as mild as last year.

As the phrase goes; "Que Sera, Sera"...

Cheers, Matt.

[IDO]

Another run with slightly different parameters by GFS and the end result again is zonal after the Atlantic wins. Looking for patterns and it is clear there is little hope for anything approaching a cold outlook, apart from the far north, within the next 15 days. The mean at T180:

http://modeles.meteo...-21-1-180.png?0

At T240: http://modeles.meteo...-21-1-240.png?0

Track each of the members on the ensembles:

http://cdn.nwstatic..../t850London.png

They are mostly showing the ups and down of a transitional ridge and trough, phasing is just out of kilt, hence the apparent scatter. Doesn't mean FI starts early, to me it looks like the speed of the westerly flow varies depending on how the interaction stalls at the block.

ECM looks the same synoptically but the placement of the low (more south and west) drags transitional colder air in (T144), so the north may see some wintry weather this week, before the ridge brings a brief milder air flow:

http://www.meteociel...1-168.GIF?17-12

whilst the next low moves in.

A poor pattern showing at the moment and a reset is needed to prevent more days/weeks wasted with these synoptics.

Edited December 17, 2012 by i'm dreaming of...

[Jason M]

Odd really, we keep getting upgrades in the 96 hour timeframe but looking at the charts this morning the signal for a full on blowtorch SWester keeps getting stronger from 120 to 140 hours out. Perhaps we will reach a tipping point but ultimatly I think the smart money has to be on the Iberian high winning out.

Some of the ensembles in deep FI are starting to look a bit Bartlett to me, and I'm not convinced that this pressure rise will be transient. Heights over Iberia can be very persistent once in place.

Jason

Edited December 17, 2012 by Jason M

[mountain shadow]

No Matty, i fear that were in for a Christmas blowtorch all be it temporary.

The North east may see something but for the rest of us miserable.

The block to the north east has done for December.

[cooling climate]

Looking at the ECM t192 northern hemispher chart and its striking how virtually all of

the PV is located on the eastern side, This ties in with what the strat charts have been

sugesting to.

[keithlucky]

The met forecast this morning seems to say a colder end to the week which ties in with the fax chart, but turning slightly milder on Christmas Day with only Scottish mountains seeing a white Xmas.

[Dan the Man]

Those lows are just relentless.

[Isolated Frost]

Heavy snow across ne scotland, moving into other parts of Scotland at times on Friday and Saturday according to the EC op solution this morning- parts of high ground in north england may also see some snow come Saturday-

breakdown on Sunday, strong signal for a snow to rain event- with a south/south-east flow in most eastern areas.

[Liam J]

A few tweets from Matt Hugo, lets hope the seasonal models are woefully wrong! Some dreadful outputs this morning and the less said about them the better. The EC32 updates today so lets hope for some good news later.

Matthew Hugo

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@

MattHugo81

To finalise the seasonal models for this year, the EUROSIP model has updated and shows a zonal picture for the rest of the winter.

Matthew Hugo

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@

MattHugo81

Despite the other 'signs and signals' the seasonal models have been steadfast in their agreement/consistency for an unsettled/zonal winter.

Edited December 17, 2012 by Liam J

[PMPhotography]

A few tweets from Matt Hugo, lets hope the seasonal models are woefully wrong! Some dreadful outputs this morning and the less said about them the better. The EC32 updates today so lets hope for some good news later.

Matthew Hugo

â€

@

MattHugo81

To finalise the seasonal models for this year, the EUROSIP model has updated and shows a zonal picture for the rest of the winter.

Matthew Hugo

â€

@

MattHugo81

Despite the other 'signs and signals' the seasonal models have been steadfast in their agreement/consistency for an unsettled/zonal winter.

Are these not the same models that were showing blocked pattern and an Easterly last week. Pinch of salt.