Model Output Discussion - 05/01/2016 18z onwards

[nick sussex]

5 minutes ago, cowdog said:

Might be misremembering but they did chop and change a lot once the cold was shown to appear. Think it switched around 96 hours before a breakdown was expecting to switching to extending the cold, and it was that extension which provided the deepest cold (e.g. when they got almost -18c in Skipton.).

No but the initial cold blast was forecast well. We're not even in the cold bit yet! lol The disagreements within T96hrs is not something I ever remember seeing with this type of set up before.

[ALL ABOARD]

9 minutes ago, winterof79 said:

I have splinters in my fingers.The UKMO chart has more of a pronounced greenland ridge on its eastern flank looking at that.The s/e extent of the low toward s/w Greenland looks very similar on both

I agree that there is more of a pronounced ridge but IMO the ridge is better because the low heads n/e allowing a better ridge to form, I may be incorrect but that's my take on it.

If you fast forward to 144 on both you can see how the UKMO ridge is far better as the main energy has headed north east?

Edited January 8, 2016 by ALL ABOARD

[IDO]

4 minutes ago, Zakos said:

This is quite contradictory to a post you made last week...

 

The breakdown of the cold weather as shown by the GFS is a possible outcome , but my no means set in stone.

If it were to happen I highly doubt it will be as rapid as the GFS Is showing, I doubt the cold air entrenched over Europe will be swept aside as easily as shown

If we go right out to la la land at 384 hours, we still have a negative AO, both on the 00Z and the 06z.

so even with a potential breakdown this could well be temporary with further cold incursions possible.

I think some of us are on different pages here. Most of my posts and many others refer to the longevity of the Greenland block not the longevity and depth of the colder weather? What I have been saying is the trend is to have a brief GH and the 06z mean sums that up with a D5 to D8 block there:

I suspect the outlook till March will be as a whole below average temps, but I was referring to the last few days, where many were suggesting that we were in a locked in  block to the NW, with sustainable very cold synoptics. Do you believe that the Greenland block will be sustainable? Even the colder GEFS do not really support that (now down to less than 30% by D10). I agree we are probably heading for a cooler regime and within that some colder shots, but I was doubting the ~boom~ Greenland block charts!

[Interitus]

28 minutes ago, RachN said:

Can I ask a question about the current model outputs and the approaching change, which pretty much everyone agrees is coming, but the disagreements seem to be around, how big a change and how long it stays basically.    What did the models show in the run up to Dec 2010, did they show it coming at least 10 days out, and did they stay on track all the way through, or did they do as they are doing now, and shift/realign/downgrade/upgrade/all agree/all disagree.     I'm just interested as a very very amateur weather watcher, if the models are behaving as you would expect them too?

Good old meteociel has archives of the charts from 2010 - in the unlikely event the link is required - http://www.meteociel.fr/ - select model of choice, choose archives and input date and time of run required

Edited January 8, 2016 by Interitus

[swilliam]

12 minutes ago, nick sussex said:

No but the initial cold blast was forecast well. We're not even in the cold bit yet! lol The disagreements within T96hrs is not something I ever remember seeing with this type of set up before.

I remember it well - the GFS/UKMO were pretty solid then the ECM churned a couple of runs where the low that came southwards went SW and W based -NAO was shown. This then suddenly changed back again to dropping S.

[TSNWK]

big set of 12z. For the 1st time this winter I have planned my day around them. By 4:10 we will know what way the GFS is going..and by 4:20 the UkMet will have shown her hand. Stick or flick.. Who knows and why we love it here.

 

sit comfortable.. Pour a drink and enjoy.

Edited January 8, 2016 by TSNWK

[nick sussex]

Just now, swilliam said:

I remember it well - the GFS/UKMO were pretty solid then the ECM churned a couple of runs where the low that came southwards went SW and W based -NAO was shown. This then suddenly changed back again to dropping S.

Yes but the UK was already in the cold spell at the time. I remember that issue it was the PV chunk dropping south from Greenland. I remember moaning about that PV chunk dropping south too far west! lol

[Mapantz]

1 minute ago, Greenland1080 said:

Is there a full NH view of the UKMO T72 chart you can view please?

This one?

[Snow Run]

43 minutes ago, johnholmes said:

no correction needed you are pretty much spot on with what the AA and NAO are. 

Thanks, John. It would follow by definition that there would be NAO and AO index values for every model run (and current/past conditions). From what I've seen, those most often quoted are from NOAA. I have a rough idea that they are from the Azores to about Iceland for NAO, and from there to the pole for AO, but I'll do a bit more reading up!

[Zakos]

2 minutes ago, IDO said:

I think some of us are on different pages here. Most of my posts and many others refer to the longevity of the Greenland block not the longevity and depth of the colder weather? What I have been saying is the trend is to have a brief GH and the 06z mean sums that up with a D5 to D8 block there:

I suspect the outlook till March will be as a whole below average temps, but I was referring to the last few days, where many were suggesting that we were in a locked in  block to the NW, with sustainable very cold synoptics. Do you believe that the Greenland block will be sustainable? Even the colder GEFS do not really support that (now down to less than 30% by D10). I agree we are probably heading for a cooler regime and within that some colder shots, but I was doubting the ~boom~ Greenland block charts!

I believe the block could be sustainable yes. I do not have the expertise to say for sure, But yes judging from purely from the models I'd say there is a decent  chance. We will have a much better idea once the block sets up IMO.

Personally i dont see a completely blocked scenario such as Dec 2010. I think the Atlantic will attack on occasion. I dont buy the rapid return to mild westerlies though.

[karlos1983]

So if my understanding is correct, at around +84 hrs is when we need to be watching where the energy goes, highlighted on the below graphic from the GFS 06z output. Hopefully not SE, we want it to go N. 

Exciting 12z to come regardless of the outcome.

 

 

One question I do have, regarding the above, surely the GFS is better at getting to grips with detail in it's own backyard in comparison to the UKMO for example? or is that wide of the mark?

Edited January 8, 2016 by karlos1983

[Wilxy]

Hello Everyone the 12z runs are upon us so lets all relax and put the toys away its still looking cold for a time next week the models will always struggle with cold set up's and yes perhaps there will be some changes to the outlook by the end of next week but that is still a very long way off especially in a complex set-up that is showing currently and I can't wait to see the roller-coaster arrive this evening as I feel it will surprise us again whether that be a colder or less cold outlook.

So what are we looking for to a backtrack to something remarkable, better wave activity heading up to Greenland and further east like UKMO output, less short wave drama around Iceland, and most importantly how the Azores low/Tropical storm behaves.

Again I'll share the ECM ENS and also the GFS Ensembles. Clearly there is more uncertainty than yesterday but that is to be expected really even at the range of the uncertainty in a cold set-up and the ECM operational was at the top of the milder ensembles, same as the GFS operational and control run so going by this evidence its a case of waiting for more cross agreement across the models before we start to panic.

Anyway enjoy the charts/models and be happy that we are finally seeing something a bit more seasonal at least for next week.   

[radiohead]

2 minutes ago, karlos1983 said:

So if my understanding is correct, at around +84 hrs is when we need to be watching where the energy goes, highlighted on the below graphic from the GFS 06z output. Hopefully not SE, we want it to go N. 

Exciting 12z to come regardless of the outcome.

 

Even before that point, we want to see the ridging further east and stronger, over the tip of southern Greenland rather than going up to the west of Greenland.

We are running out of time to see these kind of changes though I think.

[TSNWK]

No change at plus 6 not liking this at all..

[nick sussex]

At T60hrs this looks a bit better than the 06hrs run.

[karlos1983]

Just now, nick sussex said:

At T60hrs this looks a bit better than the 06hrs run.

Agreed, but shortwave Drama risk goes up from this point on. nail biting stuff.

[TSNWK]

1 minute ago, nick sussex said:

At T60hrs this looks a bit better than the 06hrs run.

What you seeing there Nick?

[northwestsnow]

1 minute ago, nick sussex said:

At T60hrs this looks a bit better than the 06hrs run.

Needs to look a lot better to satisfy my lust nick cant see much change nyself

[radiohead]

12Z is going the way of the 06Z during this initial period at least.

[nick sussex]

The shortwave is further east but the GFS is still determined to develop that which we don't want to see at T84hrs.

[phil nw.]

The odd post is still being removed unfortunately containing banter rather that model discussion.

Now the 12z run is rolling out it will become very busy so please help us by staying on topic.

Cheers all

[karlos1983]

10 minutes ago, karlos1983 said:

Agreed, but shortwave Drama risk goes up from this point on. nail biting stuff.

 

5 minutes ago, northwestsnow said:

Well im on my phone so cant watch the charts, i will assume the silence is a bad sign ?

I think I will be retracting my earlier comment, it is now looking like the 06z, But i must stress, I could be wrong.

12z v 06z

Edited January 8, 2016 by karlos1983

[tight isobar]

@catacol.

Its on course for Somerset. ..

And regarding the outsider in the national. ..if that shortwave gamble was in one of my lucky 15 accumulators..of late its going seriously t#ts up...

[TSNWK]

6 minutes ago, northwestsnow said:

Well im on my phone so cant watch the charts, i will assume the silence is a bad sign ?

Early stages NWS - I sometimes do that on my phone.. so understand where your coming from.. but lets not worry for now.

[TSNWK]

At +84 there is new shortwave just to the West of Iceland - effects of which I dont really know, but I guess it might well fall under the Short wave Drama catergory.. which is not good.

Edited January 8, 2016 by TSNWK