Model Discussion - January 17th

[Weathizard]

Why is it as soon as you get towards low res the gfs just reverts to muck time and time again? Its a better run(to my eyes) in a reliable timeframe but then as normal reverts straight back to its factory settings

[MP-R]

Eastern based ones vary but this is a good example:

As Dave just mentioned western based negative NAO,they make me want to throw the laptop out of the window as all the cold heads into the Atlantic!

I'm trawling through the archives to find a good example of a west based one.

I think the second half of February 2010 featured a lot of this with plenty of snowfall but a lot of it marginal.

A big change yet again in the models this morning. It can be clearly seen on the GFS when flicking through them and end up finding 00Z charts that haven't changed to 06Z yet, next to the new 06Z charts. Not much to comment on as it's so different to previous runs; consistency is yet to be had.

[tinybill]

http://www.meteociel...2&carte=&mode=0

looking on here F1 looks like we in the uk could get a very cold time coming something the cold lovers on here will love at long last

Edited January 18, 2012 by tinybill

[Severe Siberian icy blast]

Snow fest anyone?

I no i no i shouldnt do that as it prob wont come off but quite clearly there is obvious signs of a pattern change aloft which is a breath of fresh of air.

Absolute horror show fi , totaly goin against teleconnections and upper strat developments and a typical gfs wild card it actually makes me laugh because the gfs actually tries its best to give western europe mild weather all of the time and even when its goin against every sign it still puts in the ovan even when we have southeasterly winds!

[SP1986]

the GFS is struggling with a pattern change right now, that much is obvious in the outputs, but can't say I'm blame the GFS for this, as it seems were heading for split possibility, in fact the GFS 0z went for the easterly, and the 6z has gone for the southwesterly, much as the Met-office have suggested in their 30 day outlook. So really no close to finding the answer, and this equally applies to the ECM too, which look messy, consistent with a model that hasn't quite got it worked out yet.

Can you blame the models for struggling? definitely not in my opinion.

[nick sussex]

I think the outlook is complicated by by the ridge to the east, if its going to remain there then you want it to ridge over the top of troughing near the UK and Scandi and not underneath it.

This way you get a little more forcing on that trough to sink, I'm pretty sure whichever way this goes will determine what happens for the tail end of January and into February as its likely to be a slow moving pattern.

[No Balls Like Snow Balls]

IMO the GFS 06Z looks good up until T120. Heights are increasing with each run over Greenland, and generally each run is becoming colder. The low over Scandi at T120 seems to be heading more East, It would not take much from T120 onwards to give us a N/Easterly. As GP said yesterday expect the unexpected, and IMO don't look beyond T120.

[weathe20]

I know I shouldn't compare run to run, but the 06z looks much more promising at 120 than the 00z. Im not looking further.

[nick sussex]

IMO the GFS 06Z looks good up until T120. Heights are increasing with each run over Greenland, and generally each run is becoming colder. The low over Scandi at T120 seems to be heading more East, It would not take much from T120 onwards to give us a N/Easterly. As GP said yesterday expect the unexpected, and IMO don't look beyond T120.

Unfortunately the ECM ensemble maps are solidly behind the trough over the UK at 168hrs:

http://www.ecmwf.int...t!2009112700!!/

It's a shame the ECM 00hrs didn't kick on from its 144hrs chart of yesterday evening which hinted at the possibility that we could see some trough disruption to the west, with high pressure to the ne.

This would IMO been a much less stressful way to some colder conditions!

Here is that chart from last night:

Edited January 18, 2012 by nick sussex

[Biggin]

And anybody that still wants to cling onto the notion that somehow we are going back to a November pattern, this of course will not necessarily send cold to the UK but it will go a long way to seeing through the pattern change I suspect...

At 10hpa level (where it should be in June)

Lower down at 30hpa (where it should be in May)

Im sorry I cant let this go, without saying is this extraordinarily unusual for Jan Feb up there and has it happened before??

Also where can I find that chart / info

Cheers

Edited January 18, 2012 by Biggin

[Radiating Dendrite]

Im sorry I cant let this go, without saying is this extraordinarily unusual for Jan Feb up there and has it happened before??

Also where can I find that chart / info

Cheers

Just venture into the stratosphere thread, you will find all the info in there.

It has happened before, and whilst unusual, it is not a freak event that has not occured before. I believe Feb 2009 saw a similar warming event.

[TEITS]

Just want to follow up my earlier comment about the differences at +96/+120.

When I mention this I don't mean we're going to see NE,lys at +120. However there does seem to be some uncertainity around Iceland/S Greenland with regards to LP. The differences at this timeframe are having an impact on what happens between +168/+192. So although the actual weather is pretty certain at +120 I don't think this is the case at +168/+192.

Shall have a look at the 06Z GEFS ensembles shortly.

[BLAST FROM THE PAST]

Anomaly wise we are progged to see trough over UK, what isn't certain by no means is where it will centre itself. Yesterday I spoke of very good signal for 25-27 Jan to be a stormy period with deep LP near to UK, just where it will be is undecided. Models are firming up on this and showing strengthening ridge. All important IMO is that the massive Arctic Russian HP exists. I wouldn't be surprised to see more support for the jet to kick south

BFTP

Edited January 18, 2012 by BLAST FROM THE PAST

[ITSY]

GEFS ENS show massive potential this morning, with that NEly potential shown in FI (not F1!)

[The Northern Ramper]

IMO the GFS 06Z looks good up until T120. Heights are increasing with each run over Greenland, and generally each run is becoming colder. The low over Scandi at T120 seems to be heading more East, It would not take much from T120 onwards to give us a N/Easterly. As GP said yesterday expect the unexpected, and IMO don't look beyond T120.

I am going to call that we are going to see heights developinitially to our north-west and then see the troughing go further south pulling the cold uppers over us from a nnw direction. From there i can see heights strengthen to the north east pulling the russian high further west.

[snow drift]

Update from Met is as was yesterday and viewing the output it was to be expected. Fi is what T120?

[Backtrack]

Update from Met is as was yesterday and viewing the output it was to be expected. Fi is what T120?

I would say even less at times at the moment. The ensembles say it all!

Edited January 18, 2012 by Backtrack

[karyo]

I would say even less at times at the moment. The ensembles say it all!

Operational and control are in agreement and close to the mean until the end of January. It doesn't look that uncertain to me.

Karyo

[James M]

I find it quite encouraging that most of the ensembles develop heights to the NW or NE at some point during the run, perhaps it's a case of being patient and see if the atmosphere organises itself in a more favourable position. We can still get decent cold spells in February after all.

[Pixel]

I would say even less at the moment.

5 days ago FI was +144 ish...

based on the observations illustrated above - 24th Jan could look something like these:

but I like surprises

[nick sussex]

I'm not sure we can avoid the trough over the UK, even though some of the GEFS ensembles hint at a different route and last nights ECM 144hrs was hinting at perhaps the chance of a different way forward.

I find it hard to believe that the ECM ensembles at 168hrs could be basically all wrong, I think its the shaping and tilt of the trough thats a little more uncertain and this does make a difference in how it will react to any upstream changes.

If you look at the ECM ensemble maps:

http://www.ecmwf.int...t!2009112700!!/

What we're trying to avoid is for the Azores high to try and ridge in again under the trough, a positively tilted trough is ok if you're sure that this will get far enough to the east and south but I'm not liking this route as it could go badly wrong .especially as this may see ridging from the Azores high sucked towards the Russian high, for this reason I'd much prefer to see a negatively tilted trough digging into Europe.

So for example negatively tilted ensemble member 22, or we can get by on neutrally tilted 14, what we don't want to see is something like member 34.

Edited January 18, 2012 by nick sussex

[Backtrack]

Operational and control are in agreement and close to the mean until the end of January. It doesn't look that uncertain to me.

Karyo

Just because the operational and control run are in agreement does not mean they are going to be right.

I do not expect them to be accurate for some time.

5 days ago FI was +144 ish...

based on the observations illustrated above - 24th Jan could look something like these:

but I like surprises

Ah man, so blurry, wish I could read them, they hurt my eyes!

[Alex]

Interesting in the "stratosphere warming thread" and definitely worth a read, running well with the models that have discounted a powerful ridge to develop over Greenland in the short to medium term.

I noticed the Met are being cautious though and this seems a good call with so much uncertainty in the 10 day+ timescale.

[AWD]

I dont know how reliable the CFS model is, but seeing as it is one of very few models that go into Feb at the moment, I thought I would take a look, see if I can find anything that would support a colder Feb winning out!

CFS Seems to want to plunge most of Central and Eastern Europe into the freezer, with another cold plunge into the Mid Atlantic. The UK is in somewhat milder air inbetween, with milder air shooting over the Uk and into South Western Scandinavia.

http://www.meteociel.fr/modeles/cfse_cartes.php?ech=354&mode=2&carte=0&run=10

http://www.meteociel.fr/modeles/cfse_cartes.php?ech=474&mode=2&carte=0&run=10

http://www.meteociel.fr/modeles/cfse_cartes.php?ech=558&mode=2&carte=0&run=10

http://www.meteociel.fr/modeles/cfse_cartes.php?ech=558&mode=2&carte=0&run=10

http://www.meteociel.fr/modeles/cfse_cartes.php?ech=690&mode=2&carte=0&run=10

http://www.meteociel.fr/modeles/cfse_cartes.php?ech=714&mode=2&carte=0&run=10

But then, just for laughs, it does produce this at the end of the run!

http://www.meteociel.fr/modeles/cfse_cartes.php?ech=960&mode=2&carte=0&run=10

http://www.meteociel.fr/modeles/cfse_cartes.php?ech=1074&mode=2&carte=0&run=10

[karyo]

At least the CFS is looking a bit more positive for the final month of winter. It was going for average temperatures over the UK and parts of Scandinavia but the latest update is showing below average temperatures over Scandinavia.

http://www.cpc.ncep....s3/euT2mMon.gif

Karyo

Edit: re the above post from Active Weather Dude . I wouldn't bother looking at every individual CFS run as it is like the gfs (4 a day). The temperature probability chart that I posted above updates once a day and I find it more reliable for spotting trends up to 2 months ahead. It has performed excellently again so far this winter with the way above average temperatures for December and January although some people here were criticising it as they were expecting a cold January! lol

Edited January 18, 2012 by karyo