General Model Output Discussion

[Optimus Prime]

Take a look at the Ensembles

Whoah you could fit a bus in that gap from the average line to the actual forecast observed temperature!

[phil nw.]

I can't see why everyone is getting excited to be honest. There is no point having a cold mainly dry 2 weeks.

It would be such a waste to have such an unusual cold spell to end up with no snow.

No snow = Rubbish winter

If you read earlier posts in here BB you may change your mind regarding dry.

In the cold NE flow about to be established for a number of days there should be chances of troughs and minor lows forming in the unstable flow.

Granted the north and east coastal counties are best placed but the models will not pick up on some of these mesoscale features that can crop up at quite short notice.

Look at this fax for example

A trough coming south,it may not give much for us in the centre and south west but it`s an example of what can happen.

Edited December 31, 2009 by phil n.warks.

[80sWeather]

I can't see why everyone is getting excited to be honest. There is no point having a cold mainly dry 2 weeks.

It would be such a waste to have such an unusual cold spell to end up with no snow.

No snow = Rubbish winter

Dont worry snow will turn up at short notice,its a deep cold flow from the NE. I think alot of peoples worrys stem from the fact that this is a very unusual set up,and we are used to atlantic based model forecasts that show fronts/ lows sometimes 5 days in advance,this spell is very different and remember it does not take a very active trough in cold weather to deliver alot of snow due to the type of precipitation ie roughley 1mm rain = 1cm of snow. I remember many a bbc forecast in this type of situation when snow was only forecast a few hours away.

[kent]

Looking good then for all hopefully in the possibility of some snow, but I always cringe when the more learned members talk of snow and those dreaded words AWAY FROM THE SOUTH COAST. Can anyone assure us down here in Poole Dorset that the conditions may be suitable for snow when and if it arrives. So many times we have to be content with hearing of snow reports just 20 miles north and west of us. Happy snowy new year to all.

Quick your mums calling you for your breast milk.

Totally agree and what a shame the weather may close the play schools.

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

Take a look at the Ensembles

Whoah you could fit a bus in that gap from the average line to the actual forecast observed temperature!

IS the red line 30 day mean? (My German isn't too good!)

Surely it's just the mean for this time of year?

[PB22]

ECM T+96:

ECM T+120:

A bitter north/northeasterly blast which would bring a good chance of snow for almost everyone as troughs would undoubtedly develop in that perishing flow.

[Nick.F]

30 year, for each day

Edited December 31, 2009 by Nick.F

[snowking]

IS the red line 30 day mean? (My German isn't too good!)

Surely it's just the mean for this time of year?

Thats the 30 year mean my friend

So well below average

SK

[Optimus Prime]

It's the 30 year mean...

[03jtrickey]

http://www.wetterzentrale.de/pics/Recm961.gif

+120 could be a cracking chart, the northerly looks better-aligned and stronger...

[wysiwyg]

Looking good then for all hopefully in the possibility of some snow, but I always cringe when the more learned members talk of snow and those dreaded words AWAY FROM THE SOUTH COAST. Can anyone assure us down here in Poole Dorset that the conditions may be suitable for snow when and if it arrives. So many times we have to be content with hearing of snow reports just 20 miles north and west of us. Happy snowy new year to all.

I share your pain Kent even though I'm further inland than you. Reality is that our coasts have a drastic effect on the local weather, warming, tides etc. My rule of thumb is that the colder it is the more likely that the cold will nulify any warming effect - looking at those ensembles the cold is looking good - it's just a case of now analysing the shorter term data 0-72hrs to start to put some detail on the overall synoptics being currently modelled.

( PS DO NOT FEED THE TROLLS!!!)

[Magadan]

@ John Holmes & wysiwyg, many thanks for the informative replies!

Yes, with aerodynamics it's non-linear equations that are trimmed down and require massive computing power (Computational Fluid Dynamics aka "CFD"). It's not the most accurate method and gets worse when dealing with turbulent flow, etc. So the weather, being a vastly scaled up version of this, complete with a huge range of thermodynamic factors as well, is clearly not going to be easily modeled with current technology and computing power, which is what got me thinking about a different, more statistical "matching" approach rather than taking fragmented / extrapolated data sets and feeding them into algorithms that essentially consist of non-linear equations that have been dumbed down into manageable linear ones! As things stand, it's low quality initial data fed into necessarily non-comprehensive equations, which is why (it now seems to me) a high level of accuracy beyond a few days is unattainable from the models alone.

I may indeed email the Met Office but I think they might be reluctant to let me know too much detail about their modeling as I'm guessing its proprietary information!??

[03jtrickey]

WOW! http://www.wzkarten.de/pics/Recm1201.gif

Much better northerly flow, and cold uppers! <-8s over parts of the UK in 120 becoming widespread by +144

[PB22]

More snow at T+144:

Be interesting to see what happens next...

[weather eater]

I can't see why everyone is getting excited to be honest. There is no point having a cold mainly dry 2 weeks.

It would be such a waste to have such an unusual cold spell to end up with no snow.

No snow = Rubbish winter

That's easy for some of us the who are interested in all aspects of the climate, not just snow. I really cannot remember the last time I saw this kind of pattern emerge. If you want snow these kinds of synoptic evolutions are the best and most reliable way to get it. If you want instant snow gratification get on a plane to Finland or drive to Inverness. It may well be that many of us will not see bucket loads of snow, as I said earlier I can remember many freeze ups that did not involve major snow fall, indeed even 62/63 was noted for prolonged periods of freezing cold but mainly dry weather. This is an evolving situation so enjoy and save your anger for when winters over, if things snow wise have not improved.

[Lowestoft]

So even though the models are showing us a dry, cold period - over that timescale anything could happen.

So what is the point of the Models?

Now going to get ready for the night ahead, goodnight boys.

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

30 year, for each day

Thats the 30 year mean my friend

So well below average

SK

It's the 30 year mean...

OK thanks, my bad

Edited December 31, 2009 by RAIN RAIN RAIN

[PB22]

Pressure building over Scandinavia by T+168, with more snow showers for the east:

[Mark Parsons]

I share your pain Kent even though I'm further inland than you. Reality is that our coasts have a drastic effect on the local weather, warming, tides etc. My rule of thumb is that the colder it is the more likely that the cold will nulify any warming effect - looking at those ensembles the cold is looking good - it's just a case of now analysing the shorter term data 0-72hrs to start to put some detail on the overall synoptics being currently modelled.

( PS DO NOT FEED THE TROLLS!!!)

And once you are into Jan & Feb then quite often we have entrenched cold situations that do over ride our warm English channel, I can remember on several occasions seeing snow on the beach at West Bay in W.Dorset and once there were even snow drifts!!

Anyway we have to have the cold first to get the snow and troughs will develop, I can remember in the mid 80's a cold front from the NE which produced 10 inches of level snow down here by the coast!!

[TEITS]

Pressure building over Scandinavia by T+168, with more snow showers for the east:

Have to say im not very keen on the ECM +168 and to be honest the same applied to the GFS 12Z which is why I didn't comment.

Everyone knows I love a good E,ly but what is a concern is if the block sinks too far S with LP moving E bringing an end to the cold spell.

Much prefer the safer GH scenario.

[SMU]

Pretty Poor ECM tonight- which has taken the edge of the long term prospects-

At least for once we have a cold spell on our doorstep at t0 out to 144-

I also recall the ECM 12z on the december cold spell did this a couple af times where the retrogression didnt get to greenland- so I am pessimistic about this run- Its also at odds with the 00z- which generally is considered the best....

But as ever we will wait & see....

S

Edited December 31, 2009 by Steve Murr

[derrylynne]

Once the unstable NE air is established it is almost a certainty that trofs and lows will form as they move down. It is all but impossible for these systems to be picked up until very near to the event. I am one of the old ones here that well remembers the winter of 1962/3 and the very cold winters in the 80's. To give an example while in a prolonged cold spell such as this event about to come off the forecast was for dry and frost. A polar low formed rapidly in the cold air stream and I was snowed in by deep drifts for three days. This is the kind of thing that can happen.

These charts are the best seen since the old days - never in what has been termed the even larger teapot have we seen charts such as these. As a starting point you have to have an entrenched cold spell to establish a really good old fashioned snow event. I expect looking at the kinks in the isobars and the airflow that most will see snow at some point. Patience is the name of the game...

[bluearmy]

what gets here first - the noirthern arm or the easterly? for the time being, it will be the northern arm

[Optimus Prime]

Might not be as good for the longer term prospects of sustaining cold but it's a much wetter run.

[PB22]

Have to say im not very keen on the ECM +168 and to be honest the same applied to the GFS 12Z which is why I didn't comment.

Everyone knows I love a good E,ly but what is a concern is if the block sinks too far S with LP moving E bringing an end to the cold spell.

Much prefer the safer GH scenario.

Its come to something when a cold and snowy run isn't greeted with joy! But yes, I do see where you are coming from Dave. The longer term prospects on the ECM 12z aren't as good, but then again this cold spell won't last forever. Its just one run though and in the meantime there's still lots of fun and games to be had.

I'd advise coldies not to look at the ECM post T+168:

T+192:

Wonder where this one will stand on the ensembles later.