Model Output Discussion

[cooling climate]

Unfortunately the upper flow of the ECM is very similar to the 00Z, (some good consistence from ECM).

The mega pacific buckle, which allows a very temperary jet diversion down into southern spain/Africa, allowing for a slight easterly.

This upstream buckle then quickly resets due to the fluidity of the northern hemisphere flows atm and we end up back to the typical jet through the UK routine.

IF and yes its a big if but if the models are underestimating the pressure rises to the north then the jet

will be further south with the UK in the cold zone.

[snowmadchrisuk]

ECM at t144.

Netweather charts are wrong then , your's is a day later to mine.

[West is Best]

Excellent early winter charts on the 12z runs. It just goes to show that a mild autumn is a total irrelevance. Like the flick of a switch we're suddenly in a much colder spell, with delightful northern blocking at least for a while.

As they might be saying on X factor, now the show really begins! And I'm back lol!

Edited November 29, 2009 by West is Best

[phil nw.]

Yes a tantalising ECM with good undercutting as our trough pushes well into Europe.

http://www.meteociel...68&mode=1&map=1

Caution at this stage though,look at GFS same time,

http://www.meteociel...carte=1&runpara=

Note the differences with the Atlantic high ,Lower pressure to our North East,going no where for cold.

Shows how quickly the models are growing apart because of the uncertainty upstream with the developing Pacific ridge.

Up to T120hrs.though and the trough still in situ with yet more embeded lows nearby with more rain coming Tues and then rain and showers

weds,thurs as another low resides on our doorstep.

http://www.wetterzen...cs/Rukm1201.gif

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

http://www.wetterzen...cs/Recm1201.gif

http://charts.netwea.../h850t850eu.png

Temps.staying lower but any snow i think will be confined to Northern High ground and more likely Tues.

Just a final note,the coldest night so far, tomorrow night, is forecast

http://charts.netwea...2/ukmintemp.png

I would think favoured frost hollows would be 2-3C lower than those at least.

Edited November 29, 2009 by phil n.warks.

[Alex95]

Depends what you regard as accurate because any chart out to that range is probably useless.

OK, but early FI can sometimes be looked at for trends (Up to Friday perhaps?) and I was wondering which one to use but I don't suppose why one would be more reliable. Also, the parallel run looks to be 24 hours behind the normal GFS - the northerly is predicted for Tuesday instead of Monday?

Edited November 29, 2009 by alza

[nick sussex]

I'd say if the models under estimate how far south the jet goes then its looking good, if conversely its the other way then it just looks wet and average to cool with any snow mostly over northern hills and mountains and seeing as most people don't share their living space with a mountain goat then at the moment all sledge orders should be put on hold, i'd say at the moment anything past 96hrs given the upstream uncertainty is FI, unfortunately this model drama has plenty of life left in it.

[reef]

I sometimes feel like Im reading different charts to everyone else when I look through this thread. The synoptics on offer arent the worst in the world (no Bartletts etc) but theres no sign of anything wintry in the reliable timeframe. Even if we do get this diving jet and northern blocking its pointless as theres just no cold air to tap into. I also urge caution on believing in northern blocking past T+96, history suggests it never turns out as suggested (especially if its high pressure over Greenland).

To me, after this short snap tomorrow it just looks like average or cool cyclonic weather for the next week or so, with nothing too mild but no real chance of anything wintry either.

[DAVID SNOW]

Excellent early winter charts on the 12z runs. It just goes to show that a mild autumn is a total irrelevance. Like the flick of a switch we're suddenly in a much colder spell, with delightful northern blocking at least for a while.

As they might be saying on X factor, now the show really begins! And I'm back lol!

Why have i now got that tune from star wars, when darth vader appears, in my head :smiliz19:

[phil nw.]

I'd say if the models under estimate how far south the jet goes then its looking good, if conversely its the other way then it just looks wet and average to cool with any snow mostly over northern hills and mountains and seeing as most people don't share their living space with a mountain goat then at the moment all sledge orders should be put on hold, i'd say at the moment anything past 96hrs given the upstream uncertainty is FI, unfortunately this model drama has plenty of life left in it.

We are in quite a typical late November pattern really with the Atlantic driven weather but we are at least South of the jet.

I agree Nick that any snowfall in this cyclonic setup is going to be shortlived and marginal without a good feed of cold upper air.

However as more PM air filtrates into the trough, like tomorrow and Monday, then snow chances increase temporarily,mainly for high ground though.

I think i have commented before about alike this pattern of uk trough/southerly jet being akin to long periods during last Winter.

Look at these 2 charts,

http://www.wetterzen...00120081130.gif

http://www.wetterzen...cs/Rtavn001.png

So similar to this time last year.

I am certainly not suggesting that it continues throughout this winter but it is remarkable how the sypnotics appear to repeat.

We didn`t do too bad then with minimal N.Heights although much of the snowfall was marginal.

Edited November 29, 2009 by phil n.warks.

[SP1986]

I sometimes feel like Im reading different charts to everyone else when I look through this thread. The synoptics on offer arent the worst in the world (no Bartletts etc) but theres no sign of anything wintry in the reliable timeframe. Even if we do get this diving jet and northern blocking its pointless as theres just no cold air to tap into. I also urge caution on believing in northern blocking past T+96, history suggests it never turns out as suggested (especially if its high pressure over Greenland).

To me, after this short snap tomorrow it just looks like average or cool cyclonic weather for the next week or so, with nothing too mild but no real chance of anything wintry either.

I tend to agree with this, it looks cool, and remaining cool, but in fact it is actually going to be just below average. I suppose the potential longevity of the colder spell could be of note, but it's never going to be hugely cold. Furthermore, the longer this cold spell goes on into early winter, the greater the possibility that a milder pattern may take charge through mid-late Winter.

I can't see anything to get excited about at the moment, obviously some people do though - maybe our expectations are too high compared to others?

[DAVID SNOW]

Very much so Reef, they are nothing to get excited about even if they materialise. The North Sea is still warm at this time of year and Europe is also warm. Sliders, southerly tracking lows etc... wouldn't have any air cold air to run into.

At this time of year, if we are are wanting cold and snow then we should be looking to northerlies - and that is not what the models are showing. I think part of it as that the christmas pudding has conditioned people to expect the usual synoptics, which IMO could very quickly materialise out of this model confusion, that anything different provides a lot of undue excitement.

So are you still happy, confident, that this december will be the mildest in your modern vera, sorry era,as you said in your LRF?

[weather eater]

Whether something develops over the next few days is very up in the air at the moment, we have to wait and see, lord knows why so many people seem to expect the models to come up with a complete package from start to finish.

Furthermore, the longer this cold spell goes on into early winter, the greater the possibility that a milder pattern may take charge through mid-late Winter.

I can't see anything to get excited about at the moment, obviously some people do though - maybe our expectations are too high compared to others?

Nothing to get excited about if you take the model runs as gospel, I think the point is about hoping something better will develop from the earlier position, one way or another the models have most likely not got the FI part of their projections right.

Have you any evidence to back up the first statement Stephen that a colder start will lead to a warmer mid to late winter.

[azores92]

Furthermore, the longer this cold spell goes on into early winter, the greater the possibility that a milder pattern may take charge through mid-late Winter.

thats not always the case. many a winter have had the cold well spread out over the 3 months. irrespective of the fact the climate is somewhat milder these days, it can still happen

Edited November 29, 2009 by azores92

[J10]

It's been quite some time since we saw this type of output, has the PNA over in the USA and Canada ever been this positive since we've all become model anoraks? The gfs operational run really looks out on its own here and goes against the euros aswell as the gem and i think is another gfs special to meet the shredder!

If we look at the general pattern it looks reasonable to go with the azores high displaced, low heights remain over central europe, the jet tracking more nw/se towards western europe with weak height rises to the ne, the problem is a few hundred miles either way in terms of output means a huge difference with the polar front very close to the uk.

Very hard to say how this will turn out, fingers crossed for a happy snowy outcome for the UK, here in sw France it looks wet and cool but positively very snowy for the Pyrenees.

Indeed some much needed snow is likely over the Alps and indeed Pyrenees over the next 48 hours or so. Recent charts also indicate some cool weather over the Alps, whihc may well give further snow over the next week or so, ill quite a bit of uncertainty about this though.

[SP1986]

Whether something develops over the next few days is very up in the air at the moment, we have to wait and see, lord knows why so many people seem to expect the models to come up with a complete package from start to finish.

Nothing to get excited about if you take the model runs as gospel, I think the point is about hoping something better will develop from the earlier position, one way or another the models have most likely not got the FI part of their projections right.

Have you any evidence to back up the first statement Stephen that a colder start will lead to a warmer mid to late winter.

Of course I can't find evidence but I can use experience - after a cooler episode milder weather always follows, and vice versa - as were in a cooler episode right now I would expect a warmer pattern to occur before the end of winter (unless of course we're destined to stay in coolness forever

Whether you take the runs as gospel or not, there's still not any suggestion of any significant cold weather on the horizon - if I believed there was, I'd be panicking by now.

[West is Best]

There's a bit of a tendency at this time of year to get polarised. When we get tease charts like these it almost becomes pantomime like: 'oh yes it is' vs 'oh no it isn't'!

No real reason why we can't just be a bit balanced.

The charts look good, and they might yield some nice cold snaps from this. There again, they might not. Only time will tell. There's not an awful lot of point anyone claiming to know for sure which way they will go.

Edited November 29, 2009 by West is Best

[Frosty.]

My summary of the coming week is as follows, cold on monday in most areas with showers scattered across the uk, wintry on higher ground, some sunshine and temps between 2-7c 36-45f north to south, a sharp frost mon night with lows well below zero especially over scotland where -7c 19f could be recorded, this means that tuesday will take a long time for temps to recover despite the early sunshine but a front will be approaching from the west with a band of rain which could initially fall as snow on it's leading edge, chiefly on high ground. Midweek looks a bit milder but not as mild as we are normally used to and with some rain around but winds tending to become lighter and we are still under the influence of slow moving low pressure, by friday and the end of the week it could be turning much colder in the northeast especially with max temps of 2-3c and a few wintry flurries as winds pull down from a NE'ly direction. As to what happens beyond that is currently unknown, by me anyway.

[Snowstorm1]

My summary of the coming week is as follows, cold on monday in most areas with showers scattered across the uk, wintry on higher ground, some sunshine and temps between 2-7c 36-45f north to south, a sharp frost mon night with lows well below zero especially over scotland where -7c 19f could be recorded, this means that tuesday will take a long time for temps to recover despite the early sunshine but a front will be approaching from the west with a band of rain which could initially fall as snow on it's leading edge, chiefly on high ground. Midweek looks a bit milder but not as mild as we are normally used to and with some rain around but winds tending to become lighter and we are still under the influence of slow moving low pressure, by friday and the end of the week it could be turning much colder in the northeast especially with max temps of 2-3c and a few wintry flurries as winds pull down from a NE'ly direction. As to what happens beyond that is currently unknown, by me anyway.

WOW that would explain for bbc update on 5 day but wow i would take that

[BLAST FROM THE PAST]

Very much so Reef, they are nothing to get excited about even if they materialise. The North Sea is still warm at this time of year and Europe is also warm. Sliders, southerly tracking lows etc... wouldn't have any air cold air to run into.

At this time of year, if we are are wanting cold and snow then we should be looking to northerlies - and that is not what the models are showing. I think part of it as that the christmas pudding has conditioned people to expect the usual synoptics, which IMO could very quickly materialise out of this model confusion, that anything different provides a lot of undue excitement.

I think that a cold pattern is developing for December, the Lps getting stuck out west/SW phase has moved on and that the following colder pattern is showing its hand [that'll be my initial favoured winter LRF scenario for Dec wrong but we aren't there yet]. However, the jet continues its propensity to remain on southerly track [which has been doing now for about 3 years due to the solar driven cycle] and which is one major feature I have looked at and the favoured set up pushed by Ian appears out of the window too as no model is entertaining the christmas pudding set up....and I don't think they will either. Because if a mild pattern was to develop it wouldn't be due to a Bartlett but because of a stalling situation as we have seen in Autumn.

If the cold pattern does embed itself mostly through Dec then we are in for one hell of a time...as stormy this winter will be and in a cold pattern?

Model output is very encouraging thus far

BFTP

Edited November 29, 2009 by BLAST FROM THE PAST

[Alex95]

The thing which I find very encouraging is the amount of northern blocking predicted so early in the season! Usually there is much more northern blocking in February than in December, so whilst the upcoming spell may not give snow it could well be a good sign for later on the winter. Of course that may be wrong but it is my take on the situation anyway.

Also, my LRF for a mild December is looking more and more busted judging by the models, a good chance of cool, 'slightly below average' weather for another week or so even if it doesn't get cold and snowy. Certainly not the very mild and wet weather which I feared would happen around this time, similar to what we experienced around the 20th November.

[weather eater]

Of course I can't find evidence but I can use experience - after a cooler episode milder weather always follows, and vice versa - as were in a cooler episode right now I would expect a warmer pattern to occur before the end of winter (unless of course we're destined to stay in coolness forever

Whether you take the runs as gospel or not, there's still not any suggestion of any significant cold weather on the horizon - if I believed there was, I'd be panicking by now.

I see we have different experiences, its perfectly possible (although not likely these days) to get a cold winter throughout, its also possible to have a cold period followed by a warmer one, then another cold, and so on. The way your post was worded was that if we have a cold period now, that might be our lot for the winter, Of course m maybe I’m just being grumpy, having fled the living room from the karaoke tosh that is X-factor.

My point about cold weather on the horizon was that I think most people recognise that the models show no real cold at the moment, but that they hope the models will develop something better over the next week, it might be a forlorn hope or even a fools hope, but at least the models show some potential at the moment.

[SP1986]

Hope is fine of course, if you have this opinion then I cant fault it.

I have however this week seen references to 1981 and 1982 - so basically I've developed a little cynicism along the way but I get what you mean - In my virtually short lifetime though winter often goes through a few patterns, rather than continues the same throughout.

I would expect during December a milder pattern to take hold - obviously I may be wrong but it's a good bet based on previous years (although we havent, other than last year, really seen a cold start to winter).

We'll see anyhow.

I just hope people dont get disappointed

[chionomaniac]

Very much so Reef, they are nothing to get excited about even if they materialise. The North Sea is still warm at this time of year and Europe is also warm. Sliders, southerly tracking lows etc... wouldn't have any air cold air to run into.

At this time of year, if we are are wanting cold and snow then we should be looking to northerlies - and that is not what the models are showing. I think part of it as that the modern era has conditioned people to expect the usual synoptics, which IMO could very quickly materialise out of this model confusion, that anything different provides a lot of undue excitement.

That may well apply to you Ian, but as far as I have seen the vast majority on here are basing their expectations on the what the models are actually showing and what the teleconnections may have to offer alongside this. I believe UK troughing giving wet but average temps, as suggested by GP, is the most likely outcome over the coming weeks but that there still remains the possiblity that a colder burst may be possible - and more so than a Bartlett.

Ian, if the stratosphere was running a lot colder than average, I am sure that you would have mentioned how this would be bringing us strong polar vortex 'modern era' synoptics. It isn't, so, if you base a lot of your modern era theory on this being so, and it isn't, then surely you should mention this. But you don't - why is this?

c

[snowlover2009]

bbc forecasting snow and 1c on friday! take a look your self!

[I remember Atlantic 252]

There is the potential for some very mild weather into the second week of the month as we could well see deep troughing in the Atlantic allied to a pressure rise over Europe, putting us in SSW/Southerlies.

yeah most likely in the christmas pudding, been tragic really not seen a sub zero temp yet, still autumn I know but, got northerly wind now and my temp is 5.1°C, would have been less before 2000?