Model Output Discussion 18th Nov.2013-12z onwards.

[mulzy]

we've gone from this

to this

 

In the space of 6 hours. Fantastic!

 

 

But both charts are way out in FI so why is it a surprise?

[ARNOTT ad]

You obviously wern't here in 2009 2010 when we saw amazing synoptics..

Yep I was so we wait another 50 years now-at our latitude hmm. Not fair.

[Cecil Hogmanay Melchett]

GFS 12Z is a real horror show for coldies with a rampant jet firing away to the north.

Lets see what ukmo/ecm offer.

[MR EXTREMES]

although saving grace might be low diving down in Europe but near miss and the heights building in the later gfs run is not likely to push far enough north to benefit us in the uk and there also a sw flow here in the south although this will alternate between sw west nw in time still cold enough in the north for something wintry and pretty stormy to.

[Polar Maritime]

A warm wellcome back to the forum OMM.

[Snowman.]

taking cover.

[PolarWarsaw]

To be honest I alsways rate the 12Z over the 06z as it is more often correct.  Not good news im afraid. Lets hope there's no backtrack from the ECM later or this could be the first major dissapointment of the winter... Just glad it not actualy even winter yet!

 

I'm not sure it is. 

 

This is why you shouldn't take 1 days worth of runs at t200 as gospel. We haven't been lead up the path, it was just a small trend that had started to be picked up well into FI. I honestly can't for the life of me see why people get excited over things 10 days or so down the line and then wonder why they dissapear a run later. I for one, am not going to be dissapointed if the ECM is a bust later, because frankly we could be in raging zonality or under a supersonic Easterly by this time next week and the chances of the models getting it bang on at this stage (or even remotely synoptically close at all) is small. 

 

Models are ran by computers, they don't run the weather.

[Joe Levy]

I feel like people are jumping to conclusions based on one run! In the same way that we must not assume that one cold run is correct, we must not assume that one wet and windy run is correct. There is plenty of time left for things to change in either direction. It's a dangerous game to play if you allow yourself to be swayed by one piece of evidence and not the full picture. This particular run is very bad for cold and snow, but that doesn't guarantee the same for the next. Look for trends and key triggers that will affect the outcome of this spell of weather.

[Ian Brown]

A very different GFS reflective of some of the ensemble members, still a long way to go yet as this is still 8 days away.

[Cecil Hogmanay Melchett]

WOW gfs 12z is brining in the hairdryer in FI thos evening.

Temps of 12 and 13 degrees across the south in mid December????yuk!!

[MR EXTREMES]

ukmo looks like a near miss to out to t144 sorry I cant post charts for some reason which is annoying me.

but that's two models which have shifted the pattern to far east.

[karlos1983]

But both charts are way out in FI so why is it a surprise?

 

Fully aware of that, but we jump on it if it is Fl and it shows cold. Just showing what a huge difference the 06z and 12z are showing in the same time frame, not saying it will verify like either of them.

[radiohead]

It will be interesting to see where the 12Z GFS op fits in with the ENS later. It could be that this was as much of an outlier as some of the colder runs have been.

[Summer Sun]

UKMO and GFS look pretty similar at t144 if this proves correct the coldest air would be short lived

 

 

GFS shows the northerly hardly affecting the UK

 

 

 

 

 

 

 

[Frosty.]

WOW gfs 12z is brining in the hairdryer in FI thos evening.Temps of 12 and 13 degrees across the south in mid December????yuk!!

Probably a warm outlier but what bothers me is not this run, it's that today's met office update never mentioned the words wintry or snow, not even sure frost was mentioned either. :-(

[karlos1983]

quite big differences between the GFS and UKMO come Wednesday 13:00, which convinces me this is a mild outlier from the GFS

 

GFS

UKMO

Just my opinion of course 

[Methuselah]

Oh right, now I twig it: it's an outlier!

[Mucka]

That GFS 12z run underlines what I was saying this morning about being so reliant on the development and track of that shortwave/low making anything after tenuous.

Timing is everything. Someone mentioned about the 12 not splitting it and that is a good observation, all previous output has spit this energy and the UKMO 12z still does so another reason to treat this run with caution.

 

GFS 00z(split), UKMO12z,(split) GFS 12z (no split)

 

 

I'm not sure if this lack of split ties in with others observations about the jet being less amplified upstream as the jet is similarly modelled where and when the shortwave forms.

It could just be a matter of timing, if it is delayed or develops further West it will deepen more and track more E rather than SE which is what we want and won't phase well with our trough as far as displacing high pressure West.

 

Maybe not worth over analysing this run except there are reasons to treat it with scepticism.

Edited November 28, 2013 by Mucka

[Cheshire Freeze]

UKMO and GFS look pretty similar at t144 if this proves correct the coldest air would be short lived

 

 

GFS shows the northerly hardly affecting the UK

 

 

 

Gavin, where it matters i.e upstream, the two runs are completely different.

[fergieweather]

 

WOW gfs 12z is brining in the hairdryer in FI thos evening.Temps of 12 and 13 degrees across the south in mid December????yuk!!

....or alternatively "yum" depending on individual tastes / business needs / lifestyle / etc. I know many folk who'd positively welcome a milder phase and some savings on heating expense! Anyway, much uncertainty on this outcome.

[MR EXTREMES]

but has the gfs over done the low pressure system even so its a near miss possibly there could be a second wwa behind the system could this little gap perhaps build something a little futher north although I must admit ive given up on Greenland heights.

the cfs model really does like these Greenland heights really is rather odd.

 

I think the uk met are really on the ball every year there model gets better and better I must say its the reason why the ukmo model is the one I back all the time and the ukmo also where never 100% on this cold spell even before tonights 12z so it goes to show that its not good in this pattern set up to over ramp.

 

lets get the vortex on the move and see something like a scandi block or the infamous greeny block and then we can be more confident atm I see nothing exciting at all but as ian said atleast my heating bills will come down extra presents for my kids.

Edited November 28, 2013 by emotional rollercoaster

[SomeLikeItHot]

UKMO and GFS look pretty similar at t144 if this proves correct the coldest air would be short lived

 

 

GFS shows the northerly hardly affecting the UK

 

 

I disagree they are similar. In the UKMO the low on the US east coast is split into a small fragment going north and a larger bit further south, this is what was happenning in the earlier GFS and ECM runs, which produced the amazing synotipcs later. GEM and others this morning went the one big low route and did something similar to the GFS 12Z

[fergieweather]

 

Probably a warm outlier but what bothers me is not this run, it's that today's met office update never mentioned the words wintry or snow, not even sure frost was mentioned either. :-(

However their MR folk point-out some unusually mild members in the MOGREPS and indeed EC clusters lately, albeit they are/were very much the minority. Nothing currently out of the question.

[Summer Sun]

Quick comparison of the 850's from UKMO and GFS s

 

UKMO

 

 

GFS

 

 

Out of the 2 GFS is less cold

Edited November 28, 2013 by Summer Sun

[Captain Shortwave]

That GFS 12z run underlines what I was saying this morning about being so reliant on the development and track of that shortwave/low making anything after tenuous.

Timing is everything. Someone mentioned about the 12 not splitting it and that is a good observation, all previous output has spit this energy and the UKMO 12z still does so another reason to treat this run with caution.

 

GFS 00z(split), UKMO12z,(split) GFS 12z (no split)

 

 

I'm not sure if this lack of split ties in with others observations about the jet being less amplified upstream as the jet is similarly modelled where and when the shortwave forms.

It could just be a matter of timing, if it is delayed or develops further West it will deepen more and track more E rather than SE which is what we want and won't phase well with our trough as far as displacing high pressure West.

 

Maybe not worth over analysing this run except there are reasons to treat it with scepticism.

Worth noting the ECM did not split the lows this morning, but pulled the low straight north up the west coast of Greenland and effectively out of harms way.

Whilst the ECM and GFS agreed on the northerly, the route involving the upstream pattern was different.

Just another spanner to add to the vast mountain of them appearing at the moment 

Edited November 28, 2013 by Captain shortwave