General Model Output Discussion

[Tom Quintavalle]

Some very solid runs then tonight, which leaves us with a very promising outlook for cold weather freaks!

As Nick S. suggests, that t120/t144 period is a bit of a concern, as its still a little way off but steady as she goes at the moment.

As someone who's a bit long in the tooth, (A child of the 60s infact), lets get the cold weather synoptics in place first and worry about snow distribution later. Once the cold becomes entrenched, the snow will come and sometimes with a slack flow, it turns up in the most unexpected places!

Regards,

Tom.

Edited December 30, 2009 by TomSE20

[nick sussex]

any snow here for friday and next week?

also that ecm chart at 240 hrs, isn't exactly jaw dropping, but its a long way and i could be looking at it wrong?

If you were at the last supper would you be asking for ketchup? :lol: The ecm is a wonderful run and a throwback to years gone by, even at 240hrs it's still cold, don't worry about things that far out, the most important part of the run is around 120 to 144 hrs, we need to see that verify.

[kent]

F1? :lol: How long have you been here?

Long enough to have seen charts change dramatically even overnight.

[on the coast]

If you were at the last supper would you be asking for ketchup? :lol: The ecm is a wonderful run and a throwback to years gone by, even at 240hrs it's still cold, don't worry about things that far out, the most important part of the run is around 120 to 144 hrs, we need to see that verify.

Yep the 120 mark is the key. Keep it South and swiftly East please.

[nick sussex]

Ok it just seems to me that hardly no one has discussed prospects for this sort of area and the disucssion in here seems to be mostly on the south ( not trying to be funny about it)and i just wondered is it not looking any good for here? we did really well last week and with around 11 days of snow and a white xmas, i would hate to just have a freezing cold spell without the white stuff though.

For your area the ecm if it verified would definitely bring snow and some very low night time and day time temps. It's a great set up but don't get the sledge out for a few more days, we need to overcome a little hurdle before then but if that passes okay then yes no need to worry you will get some snow.

[snowlover2009]

Long enough to have seen charts change dramatically even overnight.

that doesn't answer the question. whatever is in FI, no one is going to ignore it. you would be wondering to yourself why no one was discussing FI if no one spoke about it. it also doesn't mean we should ignore it either. it is nice to look at and bette rthan mild charts.

For your area the ecm if it verified would definitely bring snow and some very low night time and day time temps. It's a great set up but don't get the sledge out for a few more days, we need to overcome a little hurdle before then but if that passes okay then yes no need to worry you will get some snow.

Thanks for that, thats very reassuring now . I can understand a cold chart, but its understanding where the ppn is and what type of low holds the most ppn.

[SMU]

Some very solid runs then tonight, which leaves with a very promising outlook for cold weather freaks!

As Nick S. suggests, that t120/t144 period is a bit of a concern, as its still a little way off but steady as she goes at the moment.

As someone who's a bit long in the tooth, (A child of the 60s infact), lets get the cold weather synoptics in place first and worry about snow distribution later. Once the cold becomes entrenched, the snow will come and sometimes with a slack flow, it turns up in the most unexpected places!

Regards,

Tom.

Hi Tom- some *POSSIBLE* heavy & prolonged snow in the SE corner - days 4-9 on the ECM- I wouldnt worry about the track of the low) London & the home counties has a good 100 miles to spare even if it moves North- as long as the core central point goes to our south were OK-

I dont think there will be much scope for Northward movement ( if anything more chance of sliding south which would be a disapointment)

This is because the trough that moves SW from Norway is pinning the track of that atlantic s/wave within a small coridoor- + the wind flow comes of the SE- which is pants for convective snow, but perfect in undercutting situations - thickness are VERY favourable- Plus once we get snowcover down... well you know the rest-

Thickness from the SE at 120 is 524 DAM- thats very good-

Shooters hill on alert from freezing hair at 240 + 264 as winds fall light northerly.... :lol:

S

Edited December 30, 2009 by Steve Murr

[sebastiaan1973]

the temperatures at the De Bilt based on ECM 12

31: -1/-1

1: -1/-5

2: -3/-7

3: -2/ -5

4: -7/-12

5: -6/-10

6: -3/-7

7: -1/-6

8: -1/-5

9: 0/-2

[Frosty.]

A lot to look forward to once the remnants of mild air is swept away from the southwest and south with bitterly cold air then gripping the nation until the end of next week if the ECM 12z verified, only at T+240 hours does it look as though it would topple with high pressure nudging in from the west but plenty more changes ahead. We have the luxury of choosing between Arctic and Polar Continental air for around the next 10 days (possibly even longer). If anything, my pick of the models tonight is the ukmo 12z which looks even more potent than the gfs & ecm @ T+144.

Edited December 30, 2009 by Frosty039

[andy_leics22]

Actually people laugh when someone says F1 instead of F.I but I think it can sum the late stages of model runs up well :lol:

F1... It zooms in and out of the charts like an F1 car, so maybe F1 is just as good as calling it F.I (Fantasy Island) :lol:

[Tom Quintavalle]

Hi Steve,

Yes Steve, the ECM is a peach of a run for the SE, IF verifying should produce some notable snowfalls for the SE.

I see the METO have the Xmas tree out for East Kent as early as Friday.

http://cache.netweather.tv/fax/PPVI89.png

The fabled East Kent streamer, hopefully temps should be ok for some snow showers, esp. over North Downs east of Canterbury/Ashford. Snow chase to Dover/Folkestone way Steve?

Dont want to be too IMBY, some troughs showing further up the coast too.

http://cache.netweather.tv/fax/PPVG89.png

Regards,

Tom.

[phil nw.]

Yes another set of cold runs tonight.

The Scandi trough is the driver going forward and the way it extends and orientates next week would drive colder Polar continental air towards us.

Usually this will bring with it developing minor features or shortwaves as the cold air picks up some instability over the warmer North Sea.

N. and E.Scotland and parts of NE England are likely to be hit first as one such feature shows it`s hand in the short term,here on tonights fax,

If ECM T144hrs.is anything close to what happens then more of these small features would appear in that Very cold flow.

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

As Nick S and some others have said we just need confirmation that the next low to our SW approaching at T120hrs.doesn` t get any further North than here

GFS http://www.wetterzen...s/Rtavn1201.png

ECM,UKMO and GEM all keep much further South and keeps away any mild incursions.

Very promising overall for a long cold spell now.

Edited December 30, 2009 by phil n.warks.

[Paul]

Reminder - this thread is for the discussion of the model output..

For more light hearted chat about the models (for instance 'it's an upgrade' or 'wow it's going to be cold going by the ecm' etc etc), please use the model moods and chat thread:

For non model related chat, there is the winter discussion and all of the regional discussions among other threads, so please use those.

[Iceberg]

I've just gone through the 00 to 240 likely precip from the ECM.

One word....Stunning.

It takes a band of precip to the south of the M4 between 96hrs and 168hrs (starting in the southwest).

Then widespread snow for pretty much everyone from 168 to 180 and then more widespread snow 180 to 198 across England.

Fanbloodytastic.

[yamkin]

JMA 12Z 120h to 192h. Here comes the Channel Low

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

I've just gone through the 00 to 240 likely precip from the ECM.

One word....Stunning.

It takes a band of precip to the south of the M4 between 96hrs and 168hrs (starting in the southwest).

Then widespread snow for pretty much everyone from 168 to 180 and then more widespread snow 180 to 198 across England.

Fanbloodytastic.

Can we see those charts? or a link to them?

[Ben_Cambs]

Can we see those charts? or a link to them?

http://www.meteociel.fr/modeles/ecmwf.php

[winter watcher]

JMA 12Z 120h to 192h. Here comes the Channel Low

Would like it that little bit further south and east for me. As nick says that is the key area to get proper old school conditions. Its ok but not dizzy heights stuff.

[Cheese Rice]

Only just viewed the GFS, looks great, especially for the North East of England, looks like the snow will piling up there. Looks like alot of organized showers will be moving in as early as tomorrow morning in Yorkshire/NE.

[yamkin]

Would like it that little bit further south and east for me. As nick says that is the key area to get proper old school conditions. Its ok but not dizzy heights stuff.

JMA is right behind the likes of ECM. I am looking forward to the GFS 18Z.

[sebastiaan1973]

My link

Amazing ENS! 10 icedays, and bitterly cold

[nick sussex]

The ecm De Bilt ensembles show the operational run with good support throughout, the control run is actually colder and the operational run for days 8-10 is actually one of the milder options. Hard to say what the others have synoptically but yes folks the ecm at the end for at least the Netherlands could almost be said to be a mild outlier!

http://www.knmi.nl/exp/pluim/Data/PLUIM_06260_NWT.png

In terms of upstream there is still some uncertainty regarding the eastern USA trough remembering that this is important for events downstream in Western Europe,

KEPT REASONABLE CONTINUITY FROM OVERNIGHT ISSUANCE... WITH A

GENERAL 00Z ECMWF/CANADIAN BLEND EARLY BEFORE BRINGING IN THE

WELL-PERFORMING 00Z ECMWF ENSEMBLE MEAN. MODIFICATIONS INCLUDED

DEEPENING THE SYSTEM OFF THE MAINE COAST IN LINE WITH MANY OF THE

OPERATIONAL MODELS AND NUDGING ITS POSITION AS WELL.

12Z MODELS CONTINUE TO WOBBLE AROUND WITH THE SFC/UPPER LOW

PLACEMENT/STRENGTH OFF THE NORTHEAST... AND HPC IS STAYING LARGELY

IN THE MIDDLE OF THE PACK.

So although you can obviously tell i'm quite excited about the ecm output but will temper this with some caution. This is not a done deal yet, we need a couple of more days to be really sure. Just another quick note it is good news that the Maine low is deepened this is what we want, this will help it track more ne, we dont want a weak system as this will find it easier to slide eastwards.

Edited December 30, 2009 by nick sussex

[yamkin]

Latest from Ian Fergusson (South West Thread)

Re the latter - no special thoughts, for now. General view from our medium range forecast gurus is for snow risk to be largely N/NE/E/England + Scotland and with low SW risk, but they stress a caveat of organised snow PPN bands proving more widespread and persistent. We'll keep powder dry until further runs.

Speculation / ramping on a website is, of course, not subject to scientific peer review (neither are Ghost, Loch Ness Monster or UFO 'factual' authors) and so forgive me while I'll await the scientific consensual modelling......!

But bear in mind: The expert model analysis on some threads needs to be discriminated from the fluff, and it's very evident that those threads are blessed with some very real, talented and diligent folk who know what they are talking about.... so yes, certainly one to watch. An interesting spell awaits.

There's sufficient short-term forecast problems to not bother (from my perspective, at least) fretting about the T+84/96/144 frames and indeed beyond that, into the realms of GFSpeculativeSpuriousAndDefinitelyNotCertainScience hyperventilation zone. That's meandering into the realms of speculative blah, but clearly it's all worthy of proper, qualified discussion and learned speculation. (NB: I'm not isolating GFS for critique - just those who follow it slavishly, like some Weather Modelling Bible).

[Paul]

Reminder - this thread is for the discussion of the model output..

For more light hearted chat about the models (for instance 'it's an upgrade' or 'wow it's going to be cold going by the ecm' etc etc), please use the model moods and chat thread:

For non model related chat, there is the winter discussion and all of the regional discussions among other threads, so please use those.

Repeating the above as the level of off topic posts is getting a little ridiculous at the moment - already some serial off topic posters have found themselves stopped from posting as a last resort - we don't want to take that course of action, but it gets to the point where we have little choice...

[kold weather]

Well once again some pretty impressive outputs. The 12z ECM isn't quite as good as the 0z as the upper high weakens, however since it is on the milder side of the ensemnbles its quite possible most sustain the high somewhat longer.

EVentual evolution though is starting to become in better agreement IMO and thats for the Greenland high to eventually be forced south-eastwards as the PV to our east slowly rotates away to our NE and the canadian vortex tries to take over...in this evolution your not going to see any quick breakdown, heights would probably in the end be forced to rise again near the UK/Scansinavia and possibly in the long run back to an easterly flow.

The 12z GFS is once again one of the most stunning runs I've ever seen but maybe just for once is going over the top with the blocking over Greenland, still it is picking up the idea of heights being forced back northwards past 240hrs again, something which I'm sure would happen eventually in the ECM output as well.