Model Output Discussion

[claret047]

Good evening Folks

This is my first post although I have been reading the site avidly for a number of years.

The charts are currently showing a great deal of potential and is very reminiscent of the lead up tp the 1962/63 set up although as someone mentioned earlier that the continent was much colder at that time.

My concern at the moment is what will happen to the shortwave. If we can get enough umpth from the east (thats a good technical term!) to get it push over us in the southeast I will be more than happy as long as do not end up in a warm sector.

Perhaps Paul may be able to help me with the following:

Is the anticipated set up conducive to the Thames Streamer and if so could it extend from the Cockle sheds as far as Chelmsford.

I look forward to continue to view the daily excitement and also hope to post from time to time although I am nowhere near as knowledgeable as TEITS, BFTP, Paul RJS etc and of course the master himself John Holmes.

Heres looking forward to a good ECM later on this evening

Kind Regards

Dave

Edited December 10, 2009 by claret047

[kold weather]

Ensembles are all pretty much cold, the few that do bring the temps up above -5C at 850hpa before the 20th are the ones that bringing the shortwave across the UK. Just about anything could happen past 144hrs, indeed we still haven't got great agreement on the intial easterly shot so I suppose we shouldn't get too into the set-up after 144hrs, but of course we will anyway!

[chrisbell-nottheweatherman]

From what I've now seen of the ECM surface pressure chart, it seems to take the high away to the NNW. What effect/effects is that likely to have if true?

[NorthantsSnow]

Not sure what to make of the GEM. Initial easterly shot not half as cold as the GFS, but could deliver a better second shot? Hard to tell when for some reason its evening run stops at T120.

[Long haul to mild]

ECM at T96 still not really interested in much of an initial Easterly shot....

ECM 96

And quite different from the GFS at T120

ECM 120

Edited December 10, 2009 by Chalk Serpent

[NorthantsSnow]

Quite a poor ECM out to T120. Looks very similar to the 00z so far.

[kold weather]

ECM doesn't get the upper high nearly as far north as the other models have, really struggling to get that upper high over Iceland even by 120hrs, wil lbe most interesting to see where this run goes. I can't imagine it'll be as good as some of those ensembles though tbh...

[The Eagle]

ECM is nowhere near as good as either the GFS or UKMO at 120hrs. At the very least a significant delay in much colder weather and I would not be supprised if it ended up something worse then that in later stages of the run. A bit worrying.

[Long haul to mild]

So, big differences between the models as early as T+96. ECM sticking by its 00Z guns.

Based on previous experience, which model usually predicts these potential E'ly setups most accurately?

[Harsh Climate]

Whats wrong with the ecmwf??

http://www.wetterzentrale.de/pics/Recm1441.gif

looks terrific to me!

[Lewis]

So, big differences between the models as early as T+96. ECM sticking by its 00Z guns.

Based on previous experience, which model usually predicts these potential E'ly setups most accurately?

It does not work like that, but in general the ECM is very consistent in the more reliable time frame (1-5 days out) and the GFS is just better at the time, and also better for shortwave development.

I'm going with the ECM on this one i'm afraid. Still not that bad though.

Lewis

[Nick L]

Whats wrong with the ecmwf??

http://www.wetterzen...cs/Recm1441.gif

looks terrific to me!

Agreed! I think it is a case of comparing them to the absolute belters we have had of late causing a bit of a disappointment. If we had 3 days of runs showing blowtorch southwesterlies then these charts would cause a meltdown in here.

[chrisbell-nottheweatherman]

Whats wrong with the ecmwf??

http://www.wetterzentrale.de/pics/Recm1441.gif

looks terrific to me!

Aren't the geopotentials too high and the HP in the wrong place?

[Reading FC]

So, big differences between the models as early as T+96. ECM sticking by its 00Z guns.

Based on previous experience, which model usually predicts these potential E'ly setups most accurately?

I normally find the ECM to be the more reliable one at this time range. Personally I'm hoping it verifies although that goes against what most others here would like to see. Looking at the evolution it's very plausible, however so are the other models as well. It's still anyones guess as to what the finer details will be and I do find as things get nearer the most reliable will usually be the fax charts as they have human input.

[SNOW-MAN2006]

ecm looks great i think, high pressure further east so more of a low pressure influence and hence more percipitation.... cold eastern flow to.... :/ why is everyone so glum i do not comprehend why?

[Harsh Climate]

Agreed! I think it is a case of comparing them to the absolute belters we have had of late causing a bit of a disappointment. If we had 3 days of runs showing blowtorch southwesterlies then these charts would cause a meltdown in here.

ye certainly would. What I like about this chart is that slack low in the north sea moves south allowing more of an easterly and Im sure the cold will advect further west as a result.

[kold weather]

12z ECM at 144hrs does look like its trying to introduce a weak ENE flow but its very poor compared to the models.

Really doesn't want to raise heights at all over Greenland and instead focuses it just south of Iceland instead, a real pain in the butt type of run that has us just getting enough cold to not be a total waste of time!

You've gotta wonder whether the ECM is onto something or not though, but on the otherhand as long as the GFS/UKMO agree on the same set-up occuring and timing, its still more then possible to discard it as a model outlier for now with respect to what it does with the upper high...but it has been very stubborn for quite a few runs not to take it as far north as the others suggest.

[Long haul to mild]

It does not work like that, but in general the ECM is very consistent in the more reliable time frame (1-5 days out) and the GFS is just better at the time, and also better for shortwave development.

I'm going with the ECM on this one i'm afraid. Still not that bad though.

Lewis

I have a feeling you may be right; it's just interesting that there's such a disagreement over the initial E'ly shot with GFS showing plenty of wintry precipitation for the SE on Monday / Tues, but the ECM just sits the high much closer to the UK.

Still, the ECM at 144 is a bit more like it..............

Edited December 10, 2009 by Chalk Serpent

[Nick F]

Whats wrong with the ecmwf??

http://www.wetterzentrale.de/pics/Recm1441.gif

looks terrific to me!

Does look ok by t+144 - with the now familiar low dropping down sinking south faster than other output, which allows a NE'erly to develop, though coldest air still locked up over NE Europe.

We just don't want the ridge to our NW sinking SE like the 00z.

[Harsh Climate]

Aren't the geopotentials too high and the HP in the wrong place?

I wouldnt worry about that too much, I think the high will shift north westwards as another disturbance pushes down through scandanavia..

[snowray]

Whats wrong with the ecmwf??

http://www.wetterzentrale.de/pics/Recm1441.gif

looks terrific to me!

Not as cold, not much PPN both from the almost non existant Easterly and then the SW just clipping the East.

[SNOW-MAN2006]

Right so just to put things into perspective, the intial cold spell over this weekend isnt looking great but the potential for next weekend is fantastic, yes its ages away but the is a general consenus between the models.... GFS has the low at 144 much further to our NE whereas the ECM bring it into the north sea.... and a freezing easterly.NEly to accompany it.... brill i think

[kold weather]

Would be VERY marginal indeed even inland on the 144hrs chart from the 12z ECM, probably would be cold enough overnight. Also I suspect temps would probably not be that cold, probably between 4-6C on that chart during the daytime.

Also could reload later on as well...but its nowhere near in the same league as the 12z GFS/UKMO that much is clear as day!!

Even the easterly cannot be disagreed upon, it seems clear all models have the same evolution but the ECM holds the upper high further south then the GFS, so who wins the war with regards to the easterly flow on Monday will win the war overall IMO.

Edited December 10, 2009 by kold weather

[Harsh Climate]

Does look ok by t+144 - with the now familiar low dropping down sinking south faster than other output, which allows a NE'erly to develop, though coldest air still locked up over NE Europe.

Ye that does seem to be a reccuring problem, the real cold just doesnt want to move into western europe . I think it would require major developements for that to happen within 180h, maybe the arctic high nudging south is whats needed..

[MR EXTREMES]

theres a possibility of the ecm keeping the high pressure bang over us,

with a possibility of it sliping back south east allowing the alantic back in.

so could well be settled and slightly below average but not extreme.

Edited December 10, 2009 by badboy657