Winter Model Discussion - Cold Hunting -12Z 30/12/12

[Geordiesnow]

Nice too see signs of a drier spell of weather, with the flow being a cloudy one, this high pressure influence won't be exciting at all apart from how mild it may get in any sunshine but it is certainly a welcome relief from all the rainfall.

Don't see any signs of significant cold coming, although I love peoples predictions of cold is heading further back, at this rate, people will be saying I think the end of February could be interesting :lol: Basically, no one has got a clue and nor do I, so we just have to sit back and wait and see what develops.

On a side note, loving this windy spell although today has been a little disapointing, looked like GFS overdone the tightness of the isobars of this low somewhat.

[TEITS]

Reading some of the posts aren't some expecting too much from the ECM as +240 only takes us to 9th Jan. If we look at some of the recent GFS runs then its around the 13/14th Jan when we could finally see the PV weaken and blocking develop. So really we need to wait until the middle/end of this week before the ECM becomes in range.

[johnholmes]

I think what we all have to accept is that there is no sure fire way to predicting a cold spell, be that in the Troposphere or in the Stratosphere. To repeat my self everything is connected and nothing can be disconnected and treated on its own or with a few other links that seem to support whatever outcome we want, cold or mild.

Until such time as we have all the bits of the jigsaw in the right place at the right time we will continue to see some successes and some failures as individuals and met centres continue to strive to look for the solution to both accurate short range forecasting and seasonal forecasting.

Slowly, very slowly, accuracy in all the time scales is improving-slowly I know but take a look at the statistics of model prediction and the forecasting from 10 years ago compared to now.

40 years ago the Met Office used jet stream analysis over PART of the northern hemisphere when it first started doing monthly forecasts. It had one or two spectacular successes but too many failures before it finally decided there was nothing to be gained by following that particular avenue. It and other centres have tried various other ways, amateur individuals have also tried since the advent of the web, we still wait for a major advance but it will come from one source or another-but not this year and probably well into this centurty before it does happen.

end of jh mutterings for now!

good night

Edited December 31, 2012 by johnholmes

[bryan629]

mmm. big difference by +159 that high is making quite an appearance... absolutely no idea what this could lead to..??

[Summer Sun]

A nice dry set of ensembles from the 2nd to the 8th

Slightly wetter on the Aberdeen run but nothing major

Edited December 30, 2012 by Gavin.

[Great Plum]

Top temps for the next few days, again for the London area according to the 18z GFS...

10, 6, 6, 9, 9, 7, 7...

Not a great deal above average!

[Cheshire Freeze]

Again at 216 hrs the most interesting solution we've seen for a while being touted. ECM not buying it for the minute though

Hello there.....

Further on into FI the eye candy keeps on coming...

Edited December 30, 2012 by CreweCold

[bryan629]

great run ..from the GFS 18z shame its still way out though.. still hanging on to that straw though.!!

No doubt this place will be buzzing again soon

Edited December 30, 2012 by bryan629

[Weathizard]

What an odd chart,

The sheer size of that cold pool, looking forward to the ENS here, you know when you start to see very odd charts something is afoot

Greenie high coming with PV coming to visit? Haha if only!

Edited December 30, 2012 by Weathizard

[Grimsby Snow Lover]

Just for fun at this stage but did anyone order a cold pool? Plenty of cold air to tap into if charts similar to this verified. I'm beginning to have more optimism now, be it fairly small at this stage lol

http://cdn.nwstatic.co.uk/gfsimages/gfs.20121230/18/348/h850t850eu.png

[on the coast]

Interesting FI from the 18z. Looking forward to where we are at the end of the week come these runs.

[snowking]

Well a near perfect evolution tropospherically, and in the Stratosphere the best warming yet up at 10mb from a UK perspective (or should I say, a Greenland blocking perspective)

Our central date of the 13th:

SK

[bryan629]

Just for fun at this stage but did anyone order a cold pool? Plenty of cold air to tap into if charts similar to this verified. I'm beginning to have more optimism now, be it fairly small at this stage lol

http://cdn.nwstatic..../h850t850eu.png

i did , i did and could you serve it with a stonking GH please

[Snowman.]

Just for fun at this stage but did anyone order a cold pool? Plenty of cold air to tap into if charts similar to this verified. I'm beginning to have more optimism now, be it fairly small at this stage lol

http://cdn.nwstatic..../h850t850eu.png

Wasn't me but I think I know someone who did

[nick sussex]

I think if we get more amplification upstream and more retrogression then theres a way out of the current set up.

So given the background strat warming the GFS is perfectly plausible if those things occur. The question is will they?

We can only hope.....

[Nick F]

Top temps for the next few days, again for the London area according to the 18z GFS...

10, 6, 6, 9, 9, 7, 7...

Not a great deal above average!

Met Office have 11, 7, 7, 12 next 4 days for London - mild tomorrow, cooler for a few days under Pm air then mild again Thurs onwards as mild southwesterlies return.

18z FI ties in nicely with what the CPC H500 outlook suggested this evening.

[Grimsby Snow Lover]

Wasn't me but I think I know someone who did

Yep it was me and a thousand others on here

[cooling climate]

Yes I think I would settle for the evolution that the 18z is showing us in FI. Of course there

could very well be even more stunning runs to come over the coming days or in the 18z

ens themselves.

Definitely a trend from the GFS now for a build of pressure to our north in the longer range

with a possible east to northeasterly airflow to follow.

[Snowman.]

This is the reason why the 18z got smashed today.

See that little shortwave?

[Froze were the Days]

To me the 180-216z period looks strange on the GFS (and on other recent runs) - I'd place money that a secondary LP would break the ridge of HP down and a NE/SW jet stream becomes evident, this is what the ECM is showing at present but a day or so later. For some reason the GFS is showing the Atlantic weaker - certainly a difference between the 2 models at present.

Edited December 30, 2012 by Froze were the Days

[Nick F]

Well you can often rely on the 18z to lift the spirits! Does seem the most logical route to get cold and wintry weather our way.

Always wary of such a sudden switch to a southerly tracking undercutting jet though.

Edited December 30, 2012 by Nick F

[Great Plum]

Met Office have 11, 7, 7, 12 next 4 days for London - mild tomorrow, cooler for a few days under Pm air then mild again Thurs onwards as mild southwesterlies return.a

18z FI ties in nicely with what the CPC H500 outlook suggested this evening.

I expect the met to be far more correct than the GFS! I guess they may compensate for the heat that the city would generate, hence the higher temps...

http://www.wetterzentrale.de/pics/Rtavn3842.png

I think this is my favourite FI chart of the winter... Look at the cold to the east of us and look at that area of positive values right up to the west of Greenland!

[Weathizard]

I expect the met to be far more correct than the GFS! I guess they may compensate for the heat that the city would generate, hence the higher temps...

http://www.wetterzen...s/Rtavn3842.png

I think this is my favourite FI chart of the winter... Look at the cold to the east of us and look at that area of positive values right up to the west of Greenland!

Agreed definitely mine, only one way that 384 chart is going and it screams GH. But anyway its all silly talk because we know it wont happen like that, lets hope the ens continue the downwards trend, I think there will be a few corkers in there

[TEITS]

Probably a good time to start looking at the Iceland SLP mean which was very useful during the Dec 2009, 2010 cold spells.

So after the 12Z the mean stands at 1009mb during the anticipated period of interest.

http://cdn.nwstatic.co.uk/ensimages/ens.20121230/12/prmslReyjavic.png

Lets see if this increases over the next few days. The 18Z isn't that surprising although the blocking did develop around 3 days earlier than some other GFS runs. The main date remains around 14th Jan but any blocking that develops sooner is a bonus.

[phil nw.]

The trend in the later frames is no surprise.A weakening vortex with those low heights to our north west on the retreat allowing heights to build further north.

This is the picture painted by mean Ht.Anomaly outputs over recent days.