General Model Output Discussion

[The PIT]

This either needs to be pinned or another colour for the thread title. Took me ages to find it.

Looking that some will be lucky and have a white xmas this year. All depends how north that low gets as it still out in FI land at the moment. Tonight could be interesting depending on warm that warm sector is. We have to many of these these winters.

[Shunter]

latest 12z chart showing the front and areas of snow on and behind it along with a sat picc from Dundee-usually would use NW but this is perhaps better today.

I have posted many times on here that UK Met use ALL models, EC, GFS their own and various short and longer term specialist models of their own-rarely is one taken on its own.

The precipitation seems to losing insensity as it moves out of scotland. Is this expected or is it expected to re-intensify as it hits the colder air further south?

[Fozfoster]

any one watching the 12z !!!!

[nick sussex]

Upto 84 hrs on the gfs 12hrs and already large differences between this and the earlier gfs 06hrs run, cold spell looks like being extended and with slack low pressure and cold pooling some very cold night time temps. Also small lows may give further snowfall as they track ne but its very messy and complicated and liable to small changes which given the set up could make a big difference to snow, rain or just dry.

[swfc]

looking at the nh charts it would be a great set up if all that low pressure slipped sse.great blocking to the north.why wont the low pressure move away towards the east or se.????

[nick sussex]

It's quite strange really normally this thread would be busy but i think everyone is concentrating on todays possible snow but really these synoptics are very rare in recent winters.

That slack flow with no mixing out of the cold at the surface earlier on could produce some really low temps. The key here though is the flow remains slack.

[Rollo]

It really is a messy picture-I have never(well I certainly have no recollection of), pressure charts like this during a prolonged cold spell, perhaps(and I hesitate to say it) that this type of thing is what we will experience in the post christmas pudding.

Edited December 19, 2009 by Rollo

[SteveB]

It's quite strange really normally this thread would be busy but i think everyone is concentrating on todays possible snow but really these synoptics are very rare in recent winters.

That slack flow with no mixing out of the cold at the surface earlier on could produce some really low temps. The key here though is the flow remains slack.

It is strange, but as you said most are concentrating on there own patch in the separate threads. Plus I guess most aren't sure what's happening with an ever changing signal for turning mild or prolonging the cold, It's hardly worth looking beyond Thursday.

[The PIT]

FI downgrade for xmas although there should be snow showers around.

[swfc]

looks to be all over by 192 hrs,subject to change tho

[Mark Bayley]

Considering the amount of changes in the short term i wouldn't pay much attention to the medium, long term. Small changes mean big differences between rain and snow, cold and mild etc... Christmas day still looks cold with some snow on high ground and northern areas perhaps. Before hand it looks very cold, especially over night!

[philmes]

Hilarious low pressure system in the Atlantic by the end of the high resolution segment.

[johnholmes]

looks to be all over by 192 hrs,subject to change tho

it really is funny reading some of the posts on here-

'all over by T+192'

well that is over a week or is my maths truly appalling-some have had cold and even lying snow already for 2 days-that makes it 9

how many days do you realistically want or expect?

[Mark Bayley]

Here the diffrence between the UKMO and GFS at the T144, just shows the amount of uncertainty in the medium range!

[nick sussex]

Very good ukmo! the 144hrs is superb in terms of possible evolution to more very cold weather, if we see a strong signal to the ne to raise pressure then its game set and match to cold!

http://www.meteociel.fr/modeles/ukmo2.php?nh=&ech=144&carte=1021

[swfc]

it really is funny reading some of the posts on here-

'all over by T+192'

well that is over a week or is my maths truly appalling-some have had cold and even lying snow already for 2 days-that makes it 9

how many days do you realistically want or expect?

To be be honest it was a tongue in cheek comment but do what you will.lol.plenty of changes still to come beyond this weekend.Oh merry xmas john and watch out for them spirits paying you a visit thursday night.

Edited December 19, 2009 by swfc

[Sawel]

I don't think anyone really puts any faith in the UKMO at T144, it has performed dreadfully at that range over the last week, but that's certainly not to say that the GFS will be right either such is the uncertainty.

Why not? The ECM is the only model with a better verification record than the UKMO at 144 hours.

[southbank]

Very good ukmo! the 144hrs is superb in terms of possible evolution to more very cold weather, if we see a strong signal to the ne to raise pressure then its game set and match to cold!

http://www.meteociel.fr/modeles/ukmo2.php?nh=&ech=144&carte=1021

Excellent if only the ukmo was more reliable at 144 but who knows ! Interest to view the ECM 12z so if the t 72 - t 120 evoultion are closer to ukmo or gfs . Can't believe it's so qt in here with so much twist and turns to come . That's what makes weather so interesting that only 6 days away to be day and can end up with a whole number of outcomes

[Sawel]

That's what people say but I find it hard to believe. I feel that the GFS verification is let down by it's 06z and 18z runs. For me, and certainly during this cold spell the GFS 0z and 12Z have led the way.

I use the stats on this site-

http://www.emc.ncep.noaa.gov/gmb/STATS/html/acz6.html

The pecking order at 144 hours is ECM--> UKMO--> GEM--> GFS

It's the same order at 120 hours (5 days)

[kippure]

All the way from the north sea to newfoundland. Thats some northeasterly.

[timgriff99]

All the way from the north sea to newfoundland. Thats some northeasterly.

Absolutely fascinating- never seen anything like it!

Thanks for that

[January Snowstorm]

The ECM is a shocker leaving us all in a mild Southerly by Christmas day

[swfc]

ecm seems to be on the change again.?????.Beyond 36 hrs i dont think the models have a clue. :lol:

ecm seems to be on the change again.?????.Beyond 36 hrs i dont think the models have a clue. :lol:

[ChartViewer]

Actually I do think all models are indicating a breakdown cOme Xmas Eve/day.......Not mild but

slightly higher temps than we have seen last few days.

Suspect that will last up until New Year when possible FI Northern blocking starts to show its han d again...

Regards

CV

[bluearmy]

not sure we've seen this evolution from ecm. if the ridge doesnt come north, the run would probably evolve in a similar way to the 00z. wait for the ens before too much 'naval gazing'. would nt be a shock if the 00z was different again. the FAX T120 later will show if this ridging from iberia in this fashion has any ens support.

the northern blocking will 'win in the end' anyway.

Edited December 19, 2009 by bluearmy