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

[kold weather]

Strat Warming only to -8c on this run.

Still very significant but not the +10c of yesterday!

On the up side, far faster at embedding into the Arctic circle, which is what really counts from what I know.

Very poor run though overall, can't be denied.

[Tim Bland]

Not that poor really.chance of snow ESP high ground if the PV slips over us and brings in a northerly

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=360&code=code&mode=2&mode3h=0&runpara=0&carte=0&

[phil nw.]

Just look at how the PV is modelled in FI, it is completely different to the 6z. Junked beyond 144 I think.

I think any model will have problems with the Northern Hemisphereic pattern if the vortex is on the verge of collapse.

See the warming at 10hPa gradually getting into the core.

Days 10 and 15

I am sure we will see plenty more of these wild swings in later outputs.

[The Eagle]

Yep UKM is good enough, possibly a sign of what ECM will show us?

12z looks far too progressive and definitely a bin job for me.

It's moved more toward the ECM which is good. I'd be more optimistic for the ECM this evening following that that it might continue it's trend at least on the operational.

[Paul T]

Fantastically strong south west jet driven charts for the 4th time in a row.

In gutted, but the Zonal lows being progged at the moment are far to powerful.

Hoping for cold in the next 8 days from these charts is like suggesting that Willie Carson can knock out Wladimir Klitschko.

[snowmadchrisuk]

likely why?looks like its heading to full blown zonality at 192 hrs.selective fi timescales apply but it's about opinions on what people see in the model output.i hope your correct "I'm a novice" but the strat warming'pv splitting ,tanking nao and the trending are platitudes I'm sick of hearing.like I said I'm know "pro"and if I see a bad set of charts then ill call it I'm afraid!!

Yeah but FI is being way to progressive , I mean I don't think I have ever seen the P/V so large and powerful as is shown in FI. I am just looking to +144 max as this will effect what happens next ... If the 12z did come off (which it won't) the P/V is so powerfull it would drag Colder air into the UK anyway ...

[snow drift]

Yes, that's one for the late 80s, late 90s period especially. The jet really fires up and pressure begins to rise over Europe.

We have to hope that the GFS is wrong with how it is handling the energy exiting the US, if we can't get some amplification or a delay then the GFS is where we weill head post day 7.

Well done on your prediction for the last at Cheltenham, hope GP took note. As your on a role, whats your thoughts, to progressive?

[Harsh Climate]

Would be nice if we could tap into a cold pool like that one day

[Paul White.]

http://cdn.nwstatic.co.uk/gfsimages/gfs.20121214/12/180/npsh500.png

I hope that that the chart above does not come to fruition I aint the best at chart reading but I imagine if that chart on gfs 12z 180 hrs happens it could be a while before it gets to a colder output. On the upside it is FI and it does seem that the forcasted Strat warming MAY be causing a few issues with the NWP models lets hope!

Paul

[The PIT]

Deep FI swings again as expected and cold is once away chucked back into the coffin and the GFS laughs all way back to it's silicone chips and programmers. GFS seemingly expecting the jet to power up. Actually ECM 00oz T168 matches the GFS 12oz T156 quite well it just what happens to block afterwards which is the major difference. So the hunt for cold continues I'm afraid. UKMO seems to heading for a mobile solution as well although at T144 is not very accurate.

[Anti-Mild]

I believe that because of the strat profile and the overall "smashed-apartness" of the PV that FI is going to be very close for much of the winter, possibly as close as +96. If nothing else the fact that the PV is situated over Siberia will cause the models problems simply because there is very little precedent in the computer model age for this situation.

Consider the failed easterly - it looked rock solid, then in the space of 6-8 GFS runs it was gone. Also, 2 or 3 days ago the models had us in zonal conditions for the foreseeable, now there are signs of something cold in little over a week. It also occurs to me that in the current atmospheric state that even watching the ensembles for trends may not be that accurate.

My advice, enjoy watching the models, enjoy the rollercoaster, but take everything beyond +120 with a large pinch of salt. Better to keep watch on the atmospheric drivers, possible SSW's, and hope for that bit of luck that allows us to take advantage.

[Methuselah]

Yeah but FI is being way to progressive , I mean I don't think I have ever seen the P/V so large and powerful as is shown in FI. I am just looking to +144 max as this will effect what happens next ... If the 12z did come off (which it won't) the P/V is so powerfull it would drag Colder air into the UK anyway ...

How do we know that, Chris? Only last week, it was dragging in -10C uppers?

[Ian Brown]

Well done on your prediction for the last at Cheltenham, hope GP took note. As your on a role, whats your thoughts, to progressive?

The GFS 12z is often very progressive in the same way that the 06z is often more blocked, but we need to see considerable Westward correction of the pattern, I don't fancy the ECM to be very good tonight.

[chionomaniac]

Strat Warming only to -8c on this run.

Still very significant but not the +10c of yesterday!

If you look properly Matty, you will realise that the max 10 hPa temp is actually -0.3ºC on this run at T+360 - before the warming starts to get intergrated into the vortex. At that point it will be case of goodnight polar jet!

[swfc]

Yeah but FI is being way to progressive , I mean I don't think I have ever seen the P/V so large and powerful as is shown in FI. I am just looking to +144 max as this will effect what happens next ... If the 12z did come off (which it won't) the P/V is so powerfull it would drag Colder air into the UK anyway ...

well I admire your confidence in what will or won't happen in fi.given that any cold weather crossing or moving in is know more likely than the weather staying unsettled and average to mild at the moment

[Anti-Mild]

Further to my post, I believe that because the current conditions are unprecedented in the christmas pudding, and the models are unable to "pattern match", they are reverting to what they know is normal for this time of year - a rampaging PFJ. I'm not saying that it wont happen, just that there doesn't seem to be (to my untrained eye) any meteorological basis for this.

In my opinion the weather charts look more like charts from the mid-80's, where a huge HP would mooch around N.W. Europe and occasionally edge West, giving us a blast of true cold, and I wouldn't be surprised if this happens in 12/13.

[TEITS]

12Z GEM takes a step W compared to the 0Z.

Absolutely no idea what the ECM may show. Lets be honest it could be either mild SW,lys or E,lys. At the moment im actually more focussed on CH posts in the Stratosphere thread to see what may happen into the New year.

[snowmadchrisuk]

How do we know that, Chris? Only last week, it was dragging in -10C uppers?

Because if you look over the last 14 days , the P/V is moving East not West and this hasn't changed. Strat forecasts have been pretty much spot on , The fact that the UK has been unlucky with snowfall doesn't change that ... There is no raging P/V over greenland currently , and the pattern is just a little far East currently for our part of the world, But with time them SW's should start to move South and that gives the Russian High a chance to back West , Main point is the P/V is not going to setup over greenland as powerful as the 12z shows and all the other signals simply over ridden .. But thats my opinion and as I think it is you that often says , the weather will do what it wants not what we want or the models want ..

[SnowObsessor90]

My personal thoughts yesterday were that we probably wouldn't see anything interesting in the output emerge until some point next week at the very earliest and I really haven't much since then to suggest otherwise. I suspect the scenario that ECM has been toying with will end up being somewhat of a red herring at least for now but we'll see...

[Methuselah]

Because if you look over the last 14 days , the P/V is moving East not West and this hasn't changed. Strat forecasts have been pretty much spot on , The fact that the UK has been unlucky with snowfall doesn't change that ... There is no raging P/V over greenland currently , and the pattern is just a little far East currently for our part of the world, But with time them SW's should start to move South and that gives the Russian High a chance to back West , Main point is the P/V is not going to setup over greenland as powerful as the 12z shows and all the other signals simply over ridden .. But thats my opinion and as I think it is you that often says , the weather will do what it wants not what we want or the models want ..

Are you saying that the starting data are wrong too, then? Having asked that, I don't have a great deal of faith in anything that goes much past 5 days anyway...

[nick sussex]

Well the GFS 12hrs run is a horror show, the UKMO is okay, the rest are just a bit beige.

There are marked differences upstream and this again ties in with earlier comments by NOAA so we'll have to see what the ECM does.

[chris55]

All eyes on ECM then!!

GFS looks a little progressive, but you never know.

The hints at the undercut and possible easterly was shown on the 6z GFS yesterday for the first time on an op run . ECM has had two runs on the trot with such a scenario. We really do need the ECM to stick with this trend if we are to have any chance of such a set up.

UKMO at 144 looks neither here nor there, and the 144 chart is usually open to change on that model.

It's all about the daddy tonight and with the gears setting in motion earlier in the run I'd trust ECM over the other models tonight.

IMO it's the barents sea Low we need to see pushing south east through the Russian high thats the Key, without this the Scandi block just gets pushed east again as we have seen before, having energy slicing to the east allows pressure to remain higher between Norway and the UK. This results in a separation between the Russian high and our developing Scandi high (on the 00z ECM) and this is what holds the Atlantic back..

Id add to that although the Azores high looks like the joy killer on the GFS12z I think it's upstream patterns (to the east) that allow the Azores beast to rear it's ugly head.

Edited December 14, 2012 by chris55

[EML Network]

I'm trying to remain optimistic with the various models and runs, but I am really struggling , I think FI sits at about 4-5 days presently.

With the Russian High standing ground and the complex set up over the Atlantic I guess anything can happen.

THAT BEING SAID...My problem with this set up is that the Azores high never really gets an opportunity to have it's energy transfer North of West of the UK, which is where we'd really need to see it, to stop those Lows bombarding the UK, instead it gets flattened out and is forced East and some of the runs are truly awful from a cold lovers perspective, with some of the runs placing + 12 UPPERS in parts of the UK

Other runs have the Azores nosing up over the UK, which allows some of the Lows to feed a North Westerly in as they pass by.

What we really want to see is the Azores to move West and then one of these lows can act as a trigger , diving South and East or East and then we could possibly tap into a more North or North Easterly feed.

The Russian High is largely to blame for this current set up we find ourselves in as well, I can't see it making in roads far enough West to put the UK under an Easterly feed.

IMO we'll likely be stuck in the sort of pattern were now in, give or take a few days in between where the Azores noses into the UK, I just can't see a way of this as things stand

Edited December 14, 2012 by EML Network

[bluearmy]

more crazy NH polar pattersn being painted on the fi GEFS members. not sure what the back end of dec and beyond has in store but not convinced mobile zonal will be too much in evidence unless we are exceptionally unlucky

[Frosty.]

The Gfs 12z op run looks like a mild outlier to me, i'm sticking it in the shredder with the polar vortex. The ukmo 12z looks more realistic and i'm sure the ecm 12z will be better.