Model Output Discussion: 12Z (02/12/12) And On...

[Weathizard]

Just had a quick look, 00z rubbish as well! Oh no!

[Mucka]

Just had a quick look, 00z rubbish as well! Oh no!

It's a good deal better than most of its ensemble members and last nights 18z. Still, a big wobble from GFS but at least the Op and control still want to set up the block.

http://modeles.meteociel.fr/modeles/gens/graphe_ens3.php?x=292&ext=1&y=120&run=0&runpara=0

Could all look very different again by tonight.

Edited December 4, 2012 by Mucka

[Jonan92]

They keep moving everything to the east, the difference between two days ago and now is huge

[Long haul to mild]

It's a good deal better than most of its ensemble members and last nights 18z. Still, a big wobble from GFS but at least the Op and control still want to set up the block.

The block is certainly likely to be there but the orientation is key. The 0z shows yet another solution, with drier (but still cold) SE winds over the UK, much like TWS was mentioning on here last night.

A few days ago, a deep LP was forecast for this coming weekend, now high pressure looks set to be in charge! Lots of changes still to be modelled in the 7-10 day range I feel........

Edited December 4, 2012 by Chalk Serpent

[Mucka]

They keep moving everything to the east, the difference between two days ago and now is huge

Here is a comparison.

Edited December 4, 2012 by Mucka

[Rob K]

GFS 00z ensembles certainly suggest a big shift away from a cold solution for the UK with the block too far east. Still at least the block looks like forming which is a good first step.

[Jupiters Winter]

GFS 00Z run and the ensembles have taken the cold away. Big shift on ensembles that were sustaining the cold a few days ago.

[snow drift]

GFS 00Z run and the ensembles have taken the cold away. Big shift on ensembles that were sustaining the cold a few days ago.

In model terms, this is what could be descirbed as the leveller. The patern has not changed much except with everything a bit more East. Clearly this has an impact on the weather we would get.

[IDO]

Short term, the hi res models are downgrading the snow for tomorrow morning in the south. The front decays and although cold enough at sea level on the backend it looks like a light dusting at best. The NE, Scotland, Pennines and north central areas might get more substantive falls. Fridays snow event has also been downgraded for southern area but earlier days here.

As for medium to longer term it is apparent that like last weekends forecasted early start, things have got more complicated and the pattern has become less promising. The ensembles highlight this:

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

As early as D6 there is over 12c split in 850s. This increases and peaks at 17c difference. It appears that the milder (average temps) option is now showing a greater chance. Even the control/op are showing a faux-zonal temp profile suggesting the block is struggling to hold back the Atlantic. At the end of FI it loses, even on the two hi-res runs.

As some experts have been saying, the block isn't bomb proof. In fact as I understand it this is a bottom up warming which is more difficult to beat a very cold stratosphere, so the latter will reform quicker (or not disintegrate) than top down warming. Even without the synoptics an easterly is very difficult to sustain and we would need a very co-operative block to get us there.

Oe step forward, two back. We were heading for a cold outlook a couple off days ago now there is the chance it will go average/cool. The 0z is better than last night because it gives us a few days of cold and potential fo snow in the SE and south. However the easterly goes after D10 on the GEFS mean:

http://modeles.meteo...h-0-1-252.png?0

The Scandi high gets pushed east by a reinvigorated west flow with low after low spawning off the Eastern Seaboard. At T384:

http://modeles.meteo...h-0-1-384.png?0

The upper PV has shifted its axis to a very poor tilt to get cold too the UK:

http://modeles.meteo...h-0-0-384.png?0

All very fluid at the moment so expect more too-ing and throwing and hope when the dice fall its a double six.

Edited December 4, 2012 by i'm dreaming of...

[snow drift]

ECM throws this in and says "don't panic Mr Mannering!!!!"

[Long haul to mild]

Much better ECM for cold prospects next week though.......

http://www.meteociel.fr/modeles/ecmwf.php?ech=192&mode=1&map=0&archive=0

[Wilxy]

ECM 12z and ENS still show blocking to are NE but the easterly trend is slowly getting pushed further east even on this run, i still favour the GFS, it seems to be slightly ahead of the game as it stands, feel free to comment if iv missed anything.

Thanks

Tom

[Jupiters Winter]

ECM/NOGAPS vs GFS/UKMO it seems. plenty of chopping and changing to come I am sure, But the tilt must be towards the GFS solution at the moment with its shift of ensembles playing a strong part.

[warrenb]

Meto is with ECM, look at both 144 charts

Edited December 4, 2012 by warrenb

[Timmytour]

The GFS is heartbreaking.....still good in terms of what we'd ike to see in a winter, and better than the pub run,but compared to yesterdays 12z, deflating nonetheless. They call the 18z the "pub run", but it seems it was on to something.

Slightly lifted to see Matt's tweet regarding the ECMWF this morning....let's hope it really is "the rescue" we are looking for

[Great Plum]

Once again, I would advise that Ian F's wise words that the gfs is never used post day 8 by them...

The ECM is looking good for an easterly towards the end off its range (days 7-10) this morning - http://www.wetterzentrale.de/pics/Recm2402.gif

[Duane S.]

Typical ensembles potential easterly setup scatter, for all the good ones we also get equally bad ones. It happens almost every time and highlights the fine line often between a roaring easterly and southerlies.

Models have been hinting at towawards a ridge building through us which may get us there but I've seen less stressful routes to cold shown recently.

[IDO]

ECM 12z and ENS still show blocking to are NE but the easterly trend is slowly getting pushed further east even on this run, i still favour the GFS, it seems to be slightly ahead of the game as it stands, feel free to comment if iv missed anything.

Thanks

Tom

I agree, shift east, but from T240 (0z) that looks like the easterly will lose its flow over the UK and the Atlantic will push in. Lack of heights at that point:

http://cdn.nwstatic....npsh500.216.png

Compared to yesterday's 12z at the same time:

http://cdn.nwstatic....npsh500.240.png

looks like a very reluctant easterly, when yesterday's looked more sustainable synoptically. However well into FI so that may change.

So ECMWF looks like it is also struggling against the westerly flow.

NB Love those T240 cold charts from ECMWF. It seems like the last two weeks they have been churning them out!

Edited December 4, 2012 by i'm dreaming of...

[TAFKAP]

Nogaps throws an interesting scenario into the mix. http://www.wetterzentrale.de/wz/pics/Rngp1441.gif

But seriously folks, the gfs is about as useful as reading animal entrails at the range people are on about. So put away the prozac as we're not at t48 with a Bartlett high yet. Still a long way to go with as many ups and downs as Katie Price's sports bra during the London marathon.

[snow drift]

I agree, shift east, but from T240 (0z) that looks like the easterly will lose its flow over the UK and the Atlantic will push in. Lack of heights at that point:

http://cdn.nwstatic....npsh500.216.png

Compared to yesterday's 12z at the same time:

http://cdn.nwstatic....npsh500.240.png

looks like a very reluctant easterly, when yesterday's looked more sustainable synoptically. However well into FI so that may change.

So ECMWF looks like it is also struggling against the westerly flow.

I would agree. You would like to see pressure rise to NW and the PV to not be so organised over Canada.

Edited December 4, 2012 by snow drift

[Ian Brown]

A messy GFS this morning rather like pulling teeth, one of the potential problems is that a UK High sets up on it's own detached from the Height rises to the NE and shortwaves prevent or delay a link up.

The ECM (and I think the UKMO if it went further) present a risky route to an easterly but clearly this is not going to be simple. It never is.

[Wilxy]

I would agree. You would like to see pressure rise to NW and the PV to not be so organised over Canada.

And its for this reason the block will come under pressure by the strong PV and was it only 2 days ago it was showing a greenland high and thats already disapeared so wouldn't suprise me if the alantic does win here, but this is what makes model watching so fun weather is weather and it will do what it wants.

[IDO]

Just to show the strat experts got it right. Great NH blocking bringing startling low temps:

http://wxmaps.org/pix/temp2.html

In Alaska and Canada!

Even there you can see that NE Canada has +8 temp anomalies (bottom pic) when across the Hudson Bay they have -4c anomalies. Thats the UK's predicament, we can be so close but so far.

[Iceberg]

All the models are struggling in the extreme with some very powerful drivers, lots to talk about but only 3 things from me.

Firstly None of the models have a good grasp imho, i was just looking through the ecm n.hemi view and at one point to takes a high pressure near newfoundland from 1030 and by the next frame destroys it and replaces it with a 995mb low. This is just one example but shows that the models just dont have a good grasp on the changes occuring.

Again looking at the n.hemi flow but for the UK MET GM, you get a very nice Scandy High at 1055mb at T144, higher than any model and almost off the chart high, always when these mega highs are in the charts at T144 they spell trouble for the models as they create so much of their own influence.

Finally i think people might see the low on the METO at T144 near iceland and think this is bad......it most certaintly isnt imho. Its the low that moves SE though the ridge weakness and then comes west over the S.UK as a cold pool. The strong the low and the longer it persists on its SE journey the better the eventually easterly will be. Its the high above this low from the ridging 1050mb mega high that forms the easterly everything else gets shunted.

UKMET is the best chart for cold.

Just a quicky GFS still has the building blocks for deep prolonged cold just before Christmas and i dont see this pattern really changing until post christmas now.

[Timmytour]

Matthew Hugo â€@MattHugo81

EC32 update is a cracker. It maintains N blocking throughout Dec with temps across the UK generally 1C to 3C below avg until late month.