Model output discussion pm 13/01/2016

[winterof79]

She's sliding sir

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=102&mode=0&carte=1

Just track the precipitation

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=78&mode=2

[shotski]

2 minutes ago, Ali1977 said:

This should aid our block, sending more WAA into that area.

Is this the long awaited rocket :-)

expecting some crazy outputs tomorrow .

Edited January 13, 2016 by shotski

[Blake]

23 minutes ago, steveinsussex said:

0 always comes up when i Play

It's 35/1 but we'll forgive him for his input is valuable to many

Minor change in GFS 18z with precip marginally further east on Monday with frontal snow edging a bit further inland. 

[phil nw.]

Sensible model output discussion please guys.ta

[booferking]

Fax Charts look really good northerly at 120 with cold front coming down.

[nick sussex]

The GFS 18hrs run moves towards the UKMO in a chaotic sort of way. But you can see what its trying to do, if you look at T114hrs and T138hrs and compare that to the UKMO for T120 and T144hrs the overall patterns are very close.

[feb1991blizzard]

5 minutes ago, booferking said:

Fax Charts look really good northerly at 120 with cold front coming down.

I don't think that front will make it, it will weaken as it just runs up against high pressure and get shunted.

[booferking]

1 minute ago, feb1991blizzard said:

I don't think that front will make it, it will weaken as it just runs up against high pressure and get shunted.

Do you think the overall picture on the fax charts are good for prolonging the cold.

 

[Midlands Ice Age]

1 minute ago, feb1991blizzard said:

I don't think that front will make it, it will weaken as it just runs up against high pressure and get shunted.

Depends Feb

If we get the undercut in about 24 hours from there at would just suck all the cold air down from the Arctic (vis a potent re-load)!!

It is not an impossible eventual outcome as you can already see low energy going through Portugal into the Med

 

[Blake]

T+186

12z

18z

More precip nearby, Europe colder in general, blocking not as strong.

[feb1991blizzard]

2 minutes ago, Midlands Ice Age said:

Depends Feb

If we get the undercut in about 24 hours from there at would just suck all the cold air down from the Arctic (vis a potent re-load)!!

It is not an impossible eventual outcome as you can already see low energy going through Portugal into the Med

 

I think if we get an undercut (probably the outsider IMO) it would prop the high up tbh, so more likely we would be looking East then because the high would be further North.

[damianslaw]

UKMO has performed exceptionally well over recent days - sticking to the colder theme and keeping the atlantic at bay. GFS has moved closer and closer to the UKMO.

Heights are programmed to build through the country and more importantly northwards sufficiently to cause trough disruption early next week.

There are strong hints now heights will become a stubborn feature and could eventually ridge NW with trough activity forced underneath.

What a topsy turvy week its been, last Tuesday all models were suggesting a Greenland High scenario, we then saw the GFS backdown towards a more atlantic influence, whilst ECM teased us with an easterly, whilst UKMO maintained a NW flow, then various output over the weekend, with GFS and ECM bulldozing the atlantic through, UKMO holding steady with heights staying high close to the UK, we now have trough disruption..what next??

[edo]

no model had any precipitation near my location today, even the NMM midday chart had the precipitaion south of here yet i have had 4 hours of very decent snow, some of the posts about dry for 7 to ten days etc are a a bit premature. If the models cant track the route of a low at 6 hours people really should try and be less emotional about the output....i do however love the analysis of charts no matter how far in FI and people should stick to just that great analysis and less reverse pyschology 

 

keep up the great work

[feb1991blizzard]

5 minutes ago, booferking said:

Do you think the overall picture on the fax charts are good for prolonging the cold.

 

Its not bad but I cant see where PPN is coming from YET, we need more runs to see whether we can get a battleground, theres loads of options on the table, I'm just far from certain though that we are likely to get a widespread heavy snow event.

[Biggin]

47 minutes ago, shotski said:

Lovely stuff.

we have lift off !!!!

Another lower level torpedo into Greenland ??

[BLAST FROM THE PAST]

Intriguing tweets from Fergie.  I'm going to give 24-48 break from models and come back Fri for the 12z runs.  Very interesting to see where we go from mid next week.  Although I said mild to try and assert, I don't think it will win not for any lengthy time, just that block will be shifted from over us as trough scenario develops [similar to now] but more potent last week of Jan.  However it seems the blocking wants something to say about all this 

 

BFTP 

Edited January 14, 2016 by BLAST FROM THE PAST

[nick sussex]

Overall this evening a somewhat confusing picture emerging as to how things will develop next week.

The UKMO has the best solution in terms of snow chances and especially if you go by comments from Ian F then they're expecting shortwaves to track close to the south of the UK.

The ECM 12hrs was fine for cold and frost but really wouldn't deliver much snow if at all.

The GFS 18hrs run has trended towards the UKMO but you'll often find with it that the longer it goes out it reverts to type in trying to push too much energy ne, indeed if you look at the UKMO 12hrs run to T120hrs and the GFS 18hrs run to T114 hrs they're very close indeed.

So UKMO and the GFS

Both hold the PV lobe further nw and have a similar amplitude over the central USA.

This is important because less energy will spill towards Greenland, the ECM is flatter over the central USA and has the PV lobe exiting the ne USA coast and those purples towards the south of Greenland:

These might at first hand look like minor differences but they do impact more as you move forward.

Ordinarily you'd put the ECM as the top dog and its verification would support that however each model can go through good and bad periods.

So in terms of the outputs you have the UKMO least progressive, the GFS next and then the ECM. This is quite strange because its normally the GFS which would often be the flattest and quickest upstream. The fact that its moved towards the UKMO on its 18hrs run shouldn't go unnoticed.

We'll see in the morning what happens.

 

 

 

 

 

 

 

[Man With Beard]

At least a week under 5C in London according to ECM ensembles. A warmer phase follows but do I notice the hint of a drop off at month end?

[Mildcarlisle]

And having a look at the jet-stream modelling, Tuesday 19th Jan. seems to be pivotal with energy moving out of Eastern U.S.A. resulting in cyclogenesis which would appear to move things on,such that by Saturday 23rd, the 'layabout' synoptics we have just now will have changed likes.

Edited January 14, 2016 by Mildcarlisle

[Mucka]

First of all let me say this post is more fueled by insomnia than passion but it is an honest opinion on model bias

There is only one thing more likely to cause forecast error than bias within models and that is projecting our own bias onto the output.

A few days ago GFS was beating the UKMO comfortably  run after run as UKMO repeatedly massively over estimated the strength of Atlantic blocking and was a thousand miles too far East with the trough and also much to deep with it. 00z 144 comparisons with actual and this is not cherry picking, this was the theme over several runs.

UKMO

GFS

 

Roll forward and see  what the projected for 16th 3 days ago with current output and we see the roles are reversed with UKMO coming out comfortably on top.

UKMO

GFS

 

So what is the reality here?

That UKMO has consistently shown a bias to over amplify the pattern while GFS has consistently shown a bias to flatten t the pattern - perhaps it is just luck as to whether that over progressive bias or over amplified bias wins out in these type of situations rather than skill of the model?

Of course GFS gets to play villain because it will show the less cold options and just as we like to jeer the opposition star player in a football game when he fires a shot wide, so we simply shout encouragement to our own star player when he misses the target. It is all pantomime and currently we cheer UKMO and boo and hiss at GFS, "He's behind you!". All good fun so long as we don't take it too seriously. Just take on board the models have bias and the UKMO will tend to trump GFS once blocking is in place but GFS will often trump UKMO on the formation of blocking - luck or otherwise.  Also GFS for the same reasons will likely model a breakdown of any blocking before UKMO both rightly and wrongly (not much help that except GFS will often see an attempted breakdown first but likely overplay it)

With that in mind GFS is very likely still over progressive despite inching toward UKMO run after run like a cartoon character dashing between trees hoping not to be noticed but UKMO has backed away slightly from the strong Atlantic blocking in favour of a weaker ridge while ECM has flitted somewhere between the two extremes and so overall a nearly but not quite scenario may be correct with some undercut and the cold somewhat prolonged but the block ultimately doomed to fail and sink a slow death. I hope that is incorrect because while it keeps things colder and drier for a couple more days or so it doesn't offer any hope of a reload of cold and has very limited snow chances - GFS solution much the same but milder and less settled quicker.

So UKMO is the form horse over GFS in this current situation and has largely led the way on the potential undercut, reload and further snow chances, (although I might add I was able to use GFS output several days ago to describe the potential undercut we now see modeled)

Bah what the hell, come on UKMO! 

Edited January 14, 2016 by Mucka

[Mucka]

GFS swinging back toward a more progressive breakdown this morning if anything but at least gives a breakdown snow event by way of send off for our cold snap/spell

 

...enter UKMO stage left to loud cheers, that is an amazing difference for just 96h UKMO left GFS right

UKMO 120 very cold and largely dry under a UK high - no breakdown signaled there at all.

144 still cold but spoke too soon,

all the energy moving NE so slow death of the high likely from there. I thought there would be some undercut looking at the 120 chart. I think I would prefer a GFS type breakdown if we can't sustain a cold pattern though obviously UKMO has better prospects for sustaining cold and we want it to be on the right track at 96h but just with more undercut.

Edited January 14, 2016 by Mucka

[The Beast From The East]

Good morning Mucka, I'm not so good at reading the models but am I right in thinking that the UKMO is backing down slightly and instead of a undercut the Atlantic is trying to go over the high pressure. Which I'm guessing is not so good longer term? 

Thanks.

[Ali1977]

FI from the GFS looks interesting, not far off something epic here.

[shaky]

Not good model runs this morning!!!ukmo solid as ever with the undercut but ecm and gfs are sinkers!

[TSNWK]

Sorry folks! But there really seems to have been a massive flip overnight towards ending the cold spell middle of next week.

UKMET is kinda of keeping it chilly with a high slack bang over us at 144. GFS has a mushy breakdown around 120 and I cannot even bring myself to comment on the ECM 168

just as it was looking so good and the professionals were suggesting it would be decent duration, the models have flipped hugely.