314 replies to this topic

[bluearmy]

nick sussex, on 17 January 2012 - 13:32 , said:

It's not available to the general public but its output is often reflected in the UKMO extended outlook.

this is where i'm confused nick. the update they have made isnt the extended one, its the 14 dayer which should reflect current ecm ens data. where is the cold cluster days 10-14 ??? maybe the 32 day run is very clear in its thinking and it is the second run to show this scenario. i guess they feel its a base they have to cover if they are going to talk about possibilities of cold in early feb when the 30 day release is done.

[Zakos]

bluearmy, on 17 January 2012 - 14:13 , said:

this is where i'm confused nick. the update they have made isnt the extended one, its the 14 dayer which should reflect current ecm ens data. where is the cold cluster days 10-14 ??? maybe the 32 day run is very clear in its thinking and it is the second run to show this scenario. i guess they feel its a base they have to cover if they are going to talk about possibilities of cold in early feb when the 30 day release is done.

This indicates that the Met have binned outputs such as the GFS. This I do not blame them for as they have obviously grown tiresome of its inconsistency.

Edited by Zakos, 17 January 2012 - 14:17 .

[m1chaels]

smich, on 17 January 2012 - 12:04 , said:

Can anyone explain why the GFS operational continues to have so little support from it's ensembles? It's been going on for weeks now and happens almost every run, 0z, 6z, 12z pub run - the lot.

It's really very curious. I'm not saying it's an outright outlier, it just seems to be a very mild run at some stage time after time.

Any thoughts anyone?



Steve Mich

I was wondering if it related to the op being run in higher resolution (is this correct?). I think it is fairly generally agreed that the reason that cold synopics in FI often do not come to fruition is that at longer range the models can not pick up the small pertubations that become short waves that then modify the cold synoptics. If the op is run in higher resolution then it may model some of these modifying short waves that the lower resolution ensemble runs do not pick up - hence they show the cold FI solutions when the OP does not? Just a thought from an observer and I am sure the more experienced and knowledgeable of the models will be able to expain why I am wrong.

[Active Weather Dude]

Perhaps they are basing it on the CFS Output! Lol!

http://www.meteociel...&carte=0&run=10
http://www.meteociel...&carte=0&run=10

http://www.meteociel...&carte=0&run=10
http://www.meteociel...&carte=0&run=10

[kate1]

Zakos, on 17 January 2012 - 14:17 , said:

This indicates that the Met have binned outputs such as the GFS. This I do not blame them for as they have obviously grown tiresome of its inconsistency.

Think we should all have done the same thing a couple of weeks ago and saved ourselves a lot of anguish!

This seems to be the most positive the MetO have been this winter about the prospect of real cold. Which leads me, as a newbie, to ask: now that they have said this, what changes are we ( hopefully) likely to see in the models in the coming days, if this prediction is to verify within the suggested timescale?

[Frosty039]

shedhead, on 17 January 2012 - 13:16 , said:

That has to be the main hope now Frosty if we are to salvage anything at all from January, otherwise it will be 11 down and 4 to go, but being as it's a leap year we do at least get an extra day of official winter... I think the lack of activity in the MOD pretty much says it all regarding tangible prospects for cold in the foreseeable future, Thurs and early Fri's snow showers across N and W Scotland apart that is - still plenty of potential, but to be fair we've been saying that all month and probably will continue to do so for some time yet.

Hi shedhead,

There could still be enough time for the weekend pattern to shift further west as some of the models showed yesterday so it's still possible we could have a cold and unsettled weekend, especially for the north and east with a risk of snow showers although I think the best chance for cold air digging further south will be early next week.

[bluearmy]

bluearmy, on 17 January 2012 - 14:13 , said:

this is where i'm confused nick. the update they have made isnt the extended one, its the 14 dayer which should reflect current ecm ens data. where is the cold cluster days 10-14 ??? maybe the 32 day run is very clear in its thinking and it is the second run to show this scenario. i guess they feel its a base they have to cover if they are going to talk about possibilities of cold in early feb when the 30 day release is done.

which is exactly what has happened.

in the red corner, we have the ecm 50 day ensembles whilst in the blue corner we have the ecm 32 dayer. so far this season, the 32 dayer is undefeated with only a couple of draws whilst the ensembles are currently coming off the back of a pretty poor run of form. anyone want to offer odds on this. looks like another blackburn at utd job to me !!!

[mulzy]

May not be particularly on-topic but the MetOffice 16-30 day forecast has been updated:

"The forecast for the first half of February is very uncertain. As with the day 6 to 15 forecast, there appear to be two main scenarios, each equally probable, but which are very different. It is also fairly likely that the prevailing weather type at the end of January will continue into February. The first scenario consists of a changeable westerly or southwesterly type, with rain at times (amounts greatest in the west), and with temperatures noticeably above average for early February, with only occasional frosts. The alternative scenario is that very much colder weather, with winds from an easterly or northeasterly quarter, will prevail well into February, bringing widespread frosts, and snow to some areas. In this scenario it would be the east that was most vulnerable to snowfall"

Seems like there is a slightly less than 50% chance of cold weather in early February - ties in with some of the ensemble model output I guess....

Edited by mulzy, 17 January 2012 - 14:52 .

[legritter]

its time for a new chapter gang , it will be very interesting uk met 144 hrs and ECM 168 hrs . as i hinted yesterday we could see a migration south of some good cold air . met office must be pretty confident , i will scram of now before im deleted , cheers

[kate1]

The MetO have now updated their 16-30 day outlook too... Stating two likely scenarios, one with above average temps and rain, the other - a coldie's dream! Take your pick!

kate1, on 17 January 2012 - 14:51 , said:

The MetO have now updated their 16-30 day outlook too... Stating two likely scenarios, one with above average temps and rain, the other - a coldie's dream! Take your pick!

Mulzy, you beat me to it.

[smich]

Thanks to all who replied re. my question on GFS operational vs ensembles. I'm still curious - no matter what the "tweak" to each ensemble member, they nearly all diverge away from the operational at a certain point?

Also, if that point is at the resolution change, fine. But why hasn't this happened with such consistency before? It's wierd. I can only assume it's to do with a major pattern change, with a lack of actual data coming from the crucial area ie the Arctic.


Thanks again

Steve Mich

[Catacol_Highlander]

Seven of Nine, on 17 January 2012 - 08:49 , said:

Looks very much like January will go out as how December started, I have too say something is amiss with either the models or teleconnections. For all the favourable synoptics in our favour, we just can't get any decent height rises to our North.

... thought it is important to point out that the big 2 winter forecasts (GP and RJS) both pointed to little at all up until mid January and then winter arriving. RJS hasnt quite got his timing right - no NE direction yet, but GP was very clear that the timing of the change was hard to pinpoint. Here we are on Jan 17 and that is exactly what is happening.

Plenty of time yet. I have faith in both these guys, and GP in particular. If he says a change is on its way - and last night he mentioned a 10 day time frame approx - then let's not throw all hopes into the bin yet.

[West is Best]

shedhead, on 17 January 2012 - 10:34 , said:

I know what it suggests, but I'll be extremely surprised if come Friday morning it verifies anything like that chart depicts - as ever time will tell tho.

Nothing in the GFS 06 to suggest it's beginning to pick up and respond to the wider hemispheric changes either, at least not within the low res section,
so IF this run verifies it's hard to see how all hopes won't have to be pinned on Feb for any sustained cold.

Good post.

Re. someone's comment about the GFS, actually it's been very good. The problem has been a lot of wishcasting in the meantime, which is very understandable given the background of the 'winter' so far. There's been a bit of a tendency to latch on to FI outputs as if they are significant, and to minor ensemble members as if they someone are more likely than the operational (which shows the likeliest scenario).

I still fail to see much hope in the model outputs of any sustainable cold and will stick for now with what I posted a few days back, namely that the models are showing a bit of wintry precipitation further north especially for those on higher ground. That alternates with a lot of Atlantic driven weather some of which will be very mild.

Which is about it right now. Things can change, and fairly quickly, but at the moment January is heading out with little snow to show for it, certainly down south.

[Osbourne One-Nil]

I'm sure we're all getting sick and tired of the off topic posts in this thread, so why not go and be off topic in the new one?

http://forum.netweat...n-january-17th/

[Zakos]

mulzy, on 17 January 2012 - 14:49 , said:

May not be particularly on-topic but the MetOffice 16-30 day forecast has been updated:

"The forecast for the first half of February is very uncertain. As with the day 6 to 15 forecast, there appear to be two main scenarios, each equally probable, but which are very different. It is also fairly likely that the prevailing weather type at the end of January will continue into February. The first scenario consists of a changeable westerly or southwesterly type, with rain at times (amounts greatest in the west), and with temperatures noticeably above average for early February, with only occasional frosts. The alternative scenario is that very much colder weather, with winds from an easterly or northeasterly quarter, will prevail well into February, bringing widespread frosts, and snow to some areas. In this scenario it would be the east that was most vulnerable to snowfall"

Seems like there is a slightly less than 50% chance of cold weather in early February - ties in with some of the ensemble model output I guess....

I would not like to be a met office forecaster at this time. Things must be hectic at the HQ. You can tell as the 16-30 day was released later than normal.

I agree very much with this output. Its now, or never

If the block does form in a favourable position for cold (I presume they think a Scandi block)

It is very likely that it will be strong enough to completely hold off the Atlantic, allowing for a very prolonged notable cold and perhaps snowy spell.

If it forms in a non-favourable position for us or perhaps does not form (unlikely IMO), then zonality will rule for the foreseeable.

As to which is more likely, I will side with GP and others and say cold is more likely.

Remember, if they went with cold, it would most likely be all over the news. They dont want to scaremonger.