Model Output Discussion 1st January 2014-06z onwards.

[snowmadchrisuk]

The difference at 96 hours between GEM AND ECM/GFS is crazy . Gem has the Cold air in by +120 hours , GFS you have to wait till +192 hours and ECM it's still not properly in at +240 , Would imagine Gem will back down at least on timing later , but it has really impressed me lately, 

[Downpour]

Looks like the ECM op was a mild outlier but an op run cannot be discounted.

More runs needed etc etc

[The Eagle]

Oh dear....

 

 

UKMO 144

 

[Troubleatmill]

Looks about right to me? -6/-7 850's on the 17th?

Dont get that when i open it up its about -2 850 on the 17th :s, wierd, ill try booting it down and back up, cheers for saying its right on yours anyhow

[MisfitDog3]

I haven't posted much this Winter though been a member for a while. I must admit sudden changes in model output makes me reach for the 'caution pills'. From having a look at what the main models seem to be edging towards I can't help thinking we will be seeing the Atlantic influencing any cold spell slightly more than anything from the east. Fronts seem to be making more progress across the country in the current couple of days than forecast a few days ago. I suspect the 'train' will be hard to stop....

[Summer Sun]

UKMO still not interested in the real cold air out to t144, another big low at t144 brings the prospect of further wind and rain to all areas maybe wintry on high ground in the north and east but no widespread problems with snow for now

 

Edited January 9, 2014 by Summer Sun

[Cecil Hogmanay Melchett]

UKMO is a real spanner in the works!! Far to much energy going North east from the Atlantic.

[Gibby]

Good morning. Here is this morning's look at the midnight outputs from the NWP for today Thursday January 9th 2014.

 

All models show a brief respite in the recent wet conditions over the next 72 hours. However, even this is fraught with frustration for some as all models show further troughs moving in from the Atlantic tomorrow and again later on Sunday. Although tomorrow's front will not be particularly active there will be some heavy bursts of rain on it in the West and after a fine and colder day on Saturday a more active set of fronts moves in later on Sunday with a strong Southerly wind and heavy rain with flooding issues enhancing again. Then through Monday a more showery period develops as winds fall lighter but it looks like becoming colder as all models from quite early in the week bring colder air to the North and East with a growing risk of some of the rain turning to sleet and snow.

 

GFS then shows the middle week period with yet another active frontal system affecting the SW with further heavy rain. It's this feature as it moves SE that brings the colder weather in the North and East further towards the SW as the fronts hit the colder air and turns more and more of the rain to sleet and snow to all areas by the end of the week as cold Easterly winds develop over all areas. Then through the lower resolution part of the run the cold weather is shown to persist in the South with further risk of sleet and snow at times while the North sees the cold relaxing under a ridge of High pressure with sharp frosts and eventually becoming milder as milder Atlantic winds take hold over Scotland.

 

The GFS Ensembles show nothing particularly exciting temperature wise and only keep rather cold uppers for a brief while next eek before the mean brings values back up to closer to normal later. precipitation remains a feature throughout the period and some of this will be of snow in places for a time with not much evidence of anything particularly dry lasting for any length of time in any one place.

 

UKMO is not that interested in producing much in the way of cold next week with only the North and East at risk. Instead it shows Low pressure anchored in the Atlantic with a strong flow dragging fronts into the UK next week with some regularity, especially into those areas in the South and West that least need it.

 

GEM shows the weather turning colder quickly next week as high pressure to the NE becomes the driving force to our weather with increasingly cold winds from the East. With Low pressure to the SW and fronts close by here the risk of snow is a very real one from the middle of next week and beyond particularly in the South.

 

NAVGEM shows also High pressure over Scandinavia a week from now with a cold and unstable ESE flow over the UK dragging cold surface air across the UK from Europe with snow likely at times especially towards the South and near the East coasts of Britain.

 

ECM today is rather less wintry keeping Low pressure over the UK for longer before it slides away South later in the week. For flood stricken areas this model brings an awful lot more rain to those areas that least need it with spells of heavy rain and showers maintained through the week gradually turning more wintry in Northern and Eastern areas firstly and then to other areas too later in the week.

 

The ECM Mean Chart for 10 Days shows good confidence on High pressure biased towards Scandinavia  with a Low pressure trough stalled close to the UK. This is a typical classic Winter setup for the UK which can often bring some wintry weather to anywhere over the UK at times as cold continental surface air looks likely to be dragged across Britain from Europe bumping into frontal activity which looks strong over the UK with sleet and snow a real possibility for almost anywhere away from coasts.

 

The Jet Stream Forecast from GFS shows the flow migrating further South of the UK next week and East across Southern Europe. Later in the output the flow is shown to split with one arm maintained over the South of Europe while a Northern arm later puts pressure on the Scandinavian block by rounding it's Northern flank, sinking it South slowly later.

 

In Summary this morning it looks likely that next week's weather could go one of two ways. The Euros show that it looks likely to keep an Atlantic feed of air with spells of rain and showers continuing to pummel those areas of the South and West that least need it with the North and East likely to see some snow for a time as the fronts reach colder air here. The ECM Ensembles and the operational's of GEM and GFS are much stronger on their suggestions that the UK will turn much colder before the middle of the week with the risk of snow almost anywhere as low pressure troughs over or to the West of the UK disrupt and get forced SE into Europe allowing Easterly winds to flood over the UK. There will no doubt be a lot of ups and downs in this developing situation as we go through the outputs of the coming days and through the weekend before we know to what extent if any cold weather affects the UK next week but at least the best chance this Winter yet of snow and cold exists currently.

[jvenge]

UKMO is still not too shabby. I think a few people would have said yes please only last week. Hopefully that doesn't dump too much water. 

 

We seem to have a model disagreement at the moment. Is it the GFS who is going to redeem itself in the eyes of coldies? ;-)

 

Still though, no models showing a return to mild. Just disagreements on timing, how cold and how much snow. But what would this forum me without a rollercoaster? The last 4 days seem to have been a mixture of doom and cheer, sometimes changing twice a day :-D

 

[Jason T]

which model is that jason?

 

Sorry CHM Poor previous reply. Here is the link.http://meteocentre.com/models/get_ensemble.php?mod=ncep_geps&run=00&stn=PNM&hh=000&map=eur〈=en

[Cheshire Freeze]

I think some people are over reacting to that UKMO run. You can see by the final frame that forecasters would face a nightmare in predicting what would fall from the sky. -2/-3 uppers, a front straddled across the country and a whiff of a continental undercut with some frigid uppers not that far out east......says a dumping of snow for somewhere in my book.

[The PIT]

Still very much in the air this cold snap. ECM much poorer this this morning. GFS downgrading closer to time but upgrading further out. So nothing nailed on the trend at the moment is for cooler weather however it's still possible that everything will be placed further east, north, south or west. This will have a more effect on how or if the cold air reaches us.

Don't be fooled by any posts saying it's certain to happen it will need to get a lot closer than T144. The changes already shown should indicate a level of uncertainty.

[carinthian]

Hello, here is our latest thoughts from Central Europe. Looking specifically at this same time next week. The expectancy is for a low pressure system to be in place over the Southern Alps with an alignment to a developing upper trough towards Scandinavia. This should produce snowfall in our location on Tues/ Wed. Stronger Scandinavian High, possibly pushing westwards, this will enhance low heights to the Southwest of the British Isles to link with the low pressure system over Europe. This circulation may develop quicker and hold further south than some of the other models are hinting. So the main thrust of cold could be towards Southern Britain with the main threat of snow coming from the westward push of the developing upper trough linked with the European Low circulation.

Should get another up -date this afternoon.

C

[Purga]

UKMO is a real spanner in the works!! Far to much energy going North east from the Atlantic.

It's the shape of the approaching LP that's the problem

 

The block isn't strong enough and the LP too intense and 'round' shaped. It needs to elongate (trough disruption).

 

Anyway, it's only one run & there will be many more ups & downs..

 

 

Edited January 9, 2014 by Purga

[bobbydog]

UKMO is a real spanner in the works!! Far to much energy going North east from the Atlantic.

 

i don't think so

 

at t96 we see a big LP system heading north-east but towards slack but building high pressure.

 

 

at t120, the HP has organised into a block and the LP system 'crashes on the rocks'

 

 

then at t144, the LP reforms and starts heading south-east. - under the block. the only way it can go really, as its not going through it!

 

 

all going to plan it seems.....

[Cecil Hogmanay Melchett]

I think some people are over reacting to that UKMO run. You can see by the final frame that forecasters would face a nightmare in predicting what would fall from the sky. -2/-3 uppers, a front straddled across the country and a whiff of a continental undercut with some frigid uppers not that far out east......says a dumping of snow for somewhere in my book.

Well maybe im reading the UKMo wrong but that run looks like dumping a lot of rain for the vast majority.

[bobbydog]

It's the shape of the approaching LP that's the problem

 

The block isn't strong enough and the LP too intense and 'round' shaped. It needs to elongate (trough disruption).

 

Anyway, it's only one run & there will be many more ups & downs..

 

as tommy cooper would have said....

 

 

"just like that"

[Jason T]

Well cold has arrived in Germany  Claims from twitter. Temps look pretty cold.

 

Cold of winter arrives the first time in Germany.

 

http://goo.gl/Z5m6F8         http://goo.gl/6yISw

[Cheshire Freeze]

Well maybe im reading the UKMo wrong but that run looks like dumping a lot of rain for the vast majority.

 

I presumed the same until I saw the uppers....they're fine. Poss rain readily changing to heavy snow as dew points lower.

[tight isobar]

Morning.we have still to reach the pinnacle point of evolution, this is now (as suspect) a highly complex situ. Getting an easterly flow on board the mods is one thing! Establishment is another. Overall things still look good going for cold this morning.however we are now at a juncture where complications are a bound certainty.but as again we are fast approaching the critical stage. And if todays 12z firm on or stick, then im personaly going to have a larger dose of confidence.....keep taking the tablets!;-)

[jvenge]

I presumed the same until I saw the uppers....they're fine. Poss rain readily changing to heavy snow as dew points lower.

You reckon from around Yorkshire up? Thats what my eyes say, but I'm a newbie.

[Cecil Hogmanay Melchett]

You reckon from around Yorkshire up? Thats what my eyes say, but I'm a newbie.

UKMO screams rain to me all the way to 144h maybe the exception being NE Scotland.

Cant see the dews but looks to be more Atlantic then continental air....

[Summer Sun]

8 day temperature anomaly from GFS, becoming colder for all but the south west and parts of the south coast, significantly colder for Scandinavia as well 12c below for some places

 

 

Normal temps left expected temps right

 

 

Across the pond in the USA the severe cold has gone

 

[cooling climate]

The UKMO does not inspire a lot of joy. The trough to the west would probably disrupt

somewhat but the cold would be kept further north over Scotland I would have thought.

Nothing is certain yet though and still all to play for.

Edited January 9, 2014 by cooling climate

[mountain shadow]

UKMO screams rain to me all the way to 144h maybe the exception being NE Scotland.

Cant see the dews but looks to be more Atlantic then continental air....

 

How can you make that determination from the H500 charts?, unless you have access to the dew point data, 850hpa, 950hpa data, precipitation data etc..

 

If you have that information, please post it for us.

 

Thanks.