General Model Output Discussion

[VillagePlank]

Wow hang on, the feature I've circled...that's interesting!!

Yes, the Scandi high development seemed, to me, like the logical development of current synoptics (here) Unfortunately, the next best guess, I think, is a howler of a February, given polar temperatures,and it's expected effect on ramping up the jet-stream, and moving th jet-stream north.

Still, in these modern times, cold zonality can occur ... can't it?

[KTtom]

Yet another great output this morning, the ECM is an absolutely stunning in the longer term as heights build to the north again with a block from Scandi to Iceland.

Fax charts also look great medium term with prospects of more widespread snow on Tuesday/Wednesday.

[West is Best]

Yet more great overnight runs, with superb ensembles.

Into the depths of this cold spell now. Precipitation will be a question of following the fax charts more than the other outputs I suspect, together with Met Office forecasts. Some places will undoubtedly catch a fair bit, as has happened already. Wales, the North East and Scotland have seen heavy snowfall in places.

[Frosty.]

AWESOME 00z runs, the only model i'm hoping has lost the plot is the GEM 00z which is nowhere near as promising as the gfs, ecm & ukmo 00z which are full of potential. A bitterly cold Arctic flow will blast south during monday and the cold air will become entrenched for the whole week and hopefully the following week as well, the snow that falls during next week should be powdery and frosts will become severe and penetrating, most of the snow looks like being in northern and eastern britain but anywhere could get snow showers.

[Rob K]

nowhere near as promising as the gfs, ecm & ukmo 00z which are full of potential.

I have to disagree about the UKMO 00Z - it's a much worse run than we've seen recently. It shows no sign of the all-important linkup to Scandinavia, so no long-fetch easterly. It's a sinker, pure and simple.

Compare UKMO: http://www.wzkarten.de/pics/Rukm1441.gif

to ECM: http://www.wzkarten.de/pics/Recm1441.gif

and look at the pressure over Scandinavia. Or scroll through the evolution here: http://www.meteociel.fr/modeles/ukmo2.php?carte=1021&ech=84

Worrying development, but only one model - let's hope it disappears on the 12Z!

[snowmadchrisuk]

AWESOME 00z runs, the only model i'm hoping has lost the plot is the GEM 00z which is nowhere near as promising as the gfs, ecm & ukmo 00z which are full of potential. A bitterly cold Arctic flow will blast south during monday and the cold air will become entrenched for the whole week and hopefully the following week as well, the snow that falls during next week should be powdery and frosts will become severe and penetrating, most of the snow looks like being in northern and eastern britain but anywhere could get snow showers.

The Gem doesn't look to bad to me Frosty , The main point being is that it tries to go for the linkup to Scandi. This part is going to take a few more days to model properly , but can see signs of an Easterly for southern England at least.

[nick sussex]

Well it's all systems go this morning! The ukmo backs down and good agreement for how the Scandi trough sets up, the models then go for an easterly of varying degrees. The gefs ensembles are fantastic again this morning, will be interesting to see what the ecm ones are like later but if you're a cold and snow lover in the UK it doesn't really get any better than this.

Edited January 2, 2010 by nick sussex

[londonsnow]

awesome synoptics. with regards to the arctic flow progged for early next week, i guess its the usual scenario. the sticking out bits of the uk and northern scotland will benefit. but as wib said all eyes on those fax charts for a trough or two

[TEITS]

Well incredibly the model runs are just as good as last nights. Pretty good agreement that around +96 we're going to see the Scandi trough sink S with very cold, unstable NE,lys on its N Flank. Beyond the models continue to hint at a prolonged E,ly but for now im going to focus on +96/+120.

This morning im not going to focus on the SE/E Anglia because to be honest in an unstable NE,ly much of the UK is at risk and at this range precipitation is going to be difficult to pin down.

The general trend based on the fax charts is a cold front will move S on Mon/Tues and its behind this cold front that widespread heavy snow showers will spread SW to many regions. This will begin by affecting the N including N Ireland but slowly the risk extends further S.

On a personal note I love the regional Met O forecasts. Heavy prolonged snowfall for Tues/Wed in my region and thats a forecast I haven't seen since the 1980s. I will also add that during today and overnight the risk of snow moving S could affect many regions. However as is always the case you're better off checking the radar for the developments of this.

[nick sussex]

I have to disagree about the UKMO 00Z - it's a much worse run than we've seen recently. It shows no sign of the all-important linkup to Scandinavia, so no long-fetch easterly. It's a sinker, pure and simple.

Compare UKMO: http://www.wzkarten.de/pics/Rukm1441.gif

to ECM: http://www.wzkarten.de/pics/Recm1441.gif

and look at the pressure over Scandinavia. Or scroll through the evolution here: http://www.meteociel.fr/modeles/ukmo2.php?carte=1021&ech=84

Worrying development, but only one model - let's hope it disappears on the 12Z!

I have to disagree here the ukmo is perfectly fine, low pressure over southern europe, the next frame would show high pressure from Scandi, the jet to the far north is running west to east, its impossible for a Scandi high not to form, the col over the UK is simply the ukmo slightly slower with the evolution.The southern european low isnt going anywhere fast, the Atlantic trough is disrupting, the jet to the north is perfectly fine , the only thing thats sinking is your argument here!

Edited January 2, 2010 by nick sussex

[leroys35]

agree with you nick regarding ukmo on the 120 chart low out of usa tracks up the greenland seas by 144 there is no way the high will sink waa

[Iceberg]

Completely agree Nick, the METO is simply a little slower. as it forms a extra shortwave which slows the evolution up, (quite likely IMO).

Looking at today, the showers down the Chesire Gap and into the west midlands are far heavier than anticipated by the models, snow currently down ti Birmingham, maybe getting as far as Leicester in the next few hrs, also heavy snow in the Manchester region. The models always seem to under play the penetration of showers in these set ups.

The more organised band in Scotland which is due to move south looks heavy than progged as well just 24 hrs ago.

[If Wishes made Weather]

Nice radar loop this morning clearly showing an eastrly kicking to the northern side of the little low running down the North Sea. Eastern Scotland being affected by the clouds and showers. Road cameras in Grampion and Highland are now showing what appears to be 50 cm + of snow in places. Note how the slightly longer fetch out of the Skagerrak produces something streamer like.

http://www.sat24.com/Region.aspx?country=gb&sat=ir&type=loop

Completely agree Nick, the METO is simply a little slower. as it forms a extra shortwave which slows the evolution up, (quite likely IMO).

Looking at today, the showers down the Chesire Gap and into the west midlands are far heavier than anticipated by the models, snow currently down ti Birmingham, maybe getting as far as Leicester in the next few hrs, also heavy snow in the Manchester region. The models always seem to under play the penetration of showers in these set ups.

The more organised band in Scotland which is due to move south looks heavy than progged as well just 24 hrs ago.

Interesting point here - the models prog showers on the very coastal fringes in the East later in the week at most. Experience would seem to suggest that given a fair wind, showers easily get more than 50 miles inland.

[snowking]

Well really something for everyone from thus mornings runs

Generally agreement for most of this coming week for a NE'ly flow very unstable in nature sending periods of snow SWwards across the UK - id imagine monday-weds we should see up to 5cms fairly widely, with of course north-eastern areas taking the heaviest falls.

This then reverts to an easterly, giving our south eastern members (and lets remember despite all the talk of purposeful bias towards the SE on this thread, theres a bloody good reason - a majority of the population in the UK is in the SE!) something to get very excited about....and to be honest even further west. I can see this panning out like feb 09, only with a much larger window for the easterly conditions will become even more severe further and further west with time. The M4 I could see taking a battering all the way along

Anyway all that still uncertain in terms of snowfall, the certainty now looks like that pattern, which is going nowhere fast

SK

[Frosty.]

I have to disagree about the UKMO 00Z - it's a much worse run than we've seen recently. It shows no sign of the all-important linkup to Scandinavia, so no long-fetch easterly. It's a sinker, pure and simple.

Compare UKMO: http://www.wzkarten.de/pics/Rukm1441.gif

to ECM: http://www.wzkarten.de/pics/Recm1441.gif

and look at the pressure over Scandinavia. Or scroll through the evolution here: http://www.meteociel.fr/modeles/ukmo2.php?carte=1021&ech=84

Worrying development, but only one model - let's hope it disappears on the 12Z!

Yes the ukmo 00z is not as good as the gfs & ecm runs, I would say the ecm 00z is best because it would bring an easterly to the whole of the uk rather than just the south but there is pretty good ensemble support for a prolonged bitterly cold spell in all areas with snow at times. The ukmo has an interesting trough feature for the north next friday.

The Gem doesn't look to bad to me Frosty , The main point being is that it tries to go for the linkup to Scandi. This part is going to take a few more days to model properly , but can see signs of an Easterly for southern England at least.

The GEM looks great for much of next week chris but then it kind of loses it's way although it still shows a cold anticyclonic outlook beyond next week, let's hope it makes the scandi link up on later runs and more importantly that the gfs and ecm keep the 00z trend intact.

[Rob K]

I have to disagree here the ukmo is perfectly fine ... The southern european low isnt going anywhere fast, the Atlantic trough is disrupting, the jet to the north is perfectly fine , the only thing thats sinking is your argument here!

OK well I'm quite happy to be wrong in that case!

[snowking]

In terms of anyone looking at things later this evening, dew points actually looking a little marginal on the Hi-Res NMM south in a line from birmingham to the wash in association with the troughs later on - could be something to keep an eye on as the evening wares on

The hi-res GFS output not so keen on this

SK

[nick sussex]

OK well I'm quite happy to be wrong in that case!

No worries it's probably a nerve shredding time for many members with the chance of the best wintry spell for over 30 years so close.

The actual high is really a red herring here, what delivers the Scandi high is the ridge backing west coupled with the southern european low, the Greenland high actually will sink and become absorbed in all the output, it looks on first sight on some of the output that this high edges ne, it does indeed just act as a buffer to the west, with the jet pattern northern arm right the way north running west to east, the southern arm with good energy in it as can be seen by that southern european low and the Atlantic trough disrupting, its a split flow pattern.

http://www.meteo.psu.edu/~gadomski/ECMWF_0z/hgtcomp.html

If you look here notice how the jet splits to the west of the UK with the energy distributed between the northern and southern arms of the jet.

Edited January 2, 2010 by nick sussex

[TEITS]

Stunning ensembles once again from the ECM.

http://www.knmi.nl/exp/pluim/vijftiendaagse/Data/15DAAGSE_06260_NWT.png

The control run brings a new ice age and is probably the coldest I have ever seen.

[yamkin]

Completely agree Nick, the METO is simply a little slower. as it forms a extra shortwave which slows the evolution up, (quite likely IMO).

Looking at today, the showers down the Chesire Gap and into the west midlands are far heavier than anticipated by the models, snow currently down ti Birmingham, maybe getting as far as Leicester in the next few hrs, also heavy snow in the Manchester region. The models always seem to under play the penetration of showers in these set ups.

The more organised band in Scotland which is due to move south looks heavy than progged as well just 24 hrs ago.

I've seen this sort of Cheshire Gap streamer before where it intensified & actually made it all the way down to London. This streamer may intensify as it heads in the direction of London.

[Geordiesnow]

Good model runs on a biting easterly blast for next week with increasing signs that the easterly may not even sink at all!

Still a bit of uncertainty how long any easterly blast will last for but this mornings runs(apart from the UKMO) has extended the easterly for my location and NE Scotland.

Hopefully the 06Z will continue the upgrades.

[yamkin]

Stunning ensembles once again from the ECM.

http://www.knmi.nl/exp/pluim/vijftiendaagse/Data/15DAAGSE_06260_NWT.png

The control run brings a new ice age and is probably the coldest I have ever seen.

TEITS, are my eyes deceiving me, that's almost -20c

[East Herts Snow]

Stunning ensembles once again from the ECM.

http://www.knmi.nl/exp/pluim/vijftiendaagse/Data/15DAAGSE_06260_NWT.png

The control run brings a new ice age and is probably the coldest I have ever seen.

The control is one of the warmest runs mid range, but becomes a very cold outlier towards the end, unless it is picking up on an even colder evolution trend? That could be record breaking cold, but must be a cold outlier.

NB - Off topic, but look how cold North America is going to be this week, even in central Florida night time lows look to be -3 by mid week.

Edited January 2, 2010 by North Londoner

[Cloud 10]

The control run brings a new ice age

I suppose every ice age has to start somewhere...

ECM GFS MEAN

Good agreement between the ecm operational and the gfs mean for an easterly,although the ecm op. was towards the coldest of its ensembles at that timeframe.

On a personal note,i'm getting very familiar with my snow shovel at the moment!:blink:

[East Herts Snow]

In the short term is looks a better run for Western areas, with PPN pushing down through Wales and Western England between +78 & +96 hours.

This run is slightly different, in that a second low forms and slides down Western areas and into NW France by +96 hours.

Edited January 2, 2010 by North Londoner