Model Output Discussion - 21st - 28th November

[kold weather]

Pattern isn't actually all that bad on the models for the medium term. Ok its not anything like the last 2 winters but we broadly hang onto an active and set-up with LP close by at most times and a generally NW airflow.

Eventually we should see a Euro high type pattern re-emerge so make the most of the cooler/active pattern whilst its here.

[TonyH]

Odds are that the perceived 'cool zonality' will prove more of an 'average zonality '

As others have mentioned it will obviously be 'cooler' due to the ridiculously warm Autumn!

[stewfox]

Whilst I agree with your last sentence I suspect most people in here won't be happy with a pattern change that still doesn't deliver low level snow widely across the UK.

For me a proper pattern change would be one that saw the PV weaken and split, whilst those low heights remain to the north its very difficult to see a way the UK can get extended cold and low level snow.

Surely this obsession with snow shouldn't effect what has happen ?.

A High over or near us for 4 weeks + now we have the Atlantic back with a series of deep depressions crossing the country with storm force winds particulary in the North.

Could you get more of a 'pattern change', or is a pattern change only accepted if it puts us in the deep freezer ? So much 'weather' going on this week but its all ignored.

[Cecil Hogmanay Melchett]

Pattern isn't actually all that bad on the models for the medium term. Ok its not anything like the last 2 winters but we broadly hang onto an active and set-up with LP close by at most times and a generally NW airflow.

Eventually we should see a Euro high type pattern re-emerge so make the most of the cooler/active pattern whilst its here.

I'd say thats a probabilty Kold,until we see some relaxing of the PV then the natural progression at some point is for HP to build over Europe again.

[TonyH]

Hi Blast, I think the models this morning are looking more promising for a really cold blast in the next 7-10 days, judging by the angle of the jet with lows attacking from the northwest..do you agree? and i'm a bit surprised by some of the negative comments given how excellent FI is looking for cold and snow.

Uh?

cool zonal? there will be blizzards for the uk in the next 7-10 days if the gfs and ecm 00z verify.

And Uh once more!

[Frosty.]

Frosty I'm not saying theres no chance of snow just that its hard to have too much faith in the output past 144hrs because of their general bias in these situations. If you're looking for that possible northerly then look out for that troughing in the eastern USA, it makes no difference what the outputs show for Europe if you don't get an amplification of the troughing there you won't get a temporary ridge developing over Greenland and won't get the necessary downstream amplification in Europe to pull a polar nw/n flow down.

I'm just trying to be positive about the latest trend of the models, it's been such a dismal autumn for model watching over the last 7 weeks but now we are seeing a more traditional late autumn / early winter pattern with increasing risk of hill snow for the north and a lot of much needed rain for the south with the potential for a cold snap in early december.

[TonyH]

Lol! What on the top of Ben Nevis!

Thats a bit like me saying here in the Pyrenees there will be blizzards above 1,500m, you don't need anything particularly cold for snow at higher elevations.

I do admire your glass half full perspective, maybe I've just become a misery!

As I mentioned earlier there is a small chance of a northerly toppler and that could give some snow a little further south before the jet rolls over the top and sinks it.

It does however look good for the Scottish ski resorts, and a little better for European ski areas but until I see snow forecast within 96hrs then I'm loathe to dust off the skis!

Quite. A bit of perspective here.

[shedhead]

yes it's looking a lot more promising for cold fans for the first time this autumn, hope the models stick to the current trend of repeated polar maritime incursions and then a blast from the north pole.

That is like saying January will be colder than June.

Of course things look better, but if these progs had come out 12 months ago they would be called absolutely disasterous, such was the potential at that time.

As others have said PL your glass half full attitude is nice to see in one way, but given this mornings outputs it's both misleading and plain wrong to suggest the likelyhood or blizzards away from high ground in the north across the next week or so, in fact it's almost akin to saying somewhere will see 20c+... ie not impossible, but unlikely in the extreme.

Edited November 27, 2011 by shedhead

[Frosty.]

Uh? And Uh once more!

I said blizzards for the uk, I didn't say where in the uk but scotland would have blizzards in the set up shown on the 00z runs although can't rule out snow further south, shame it's in FI but for weeks and weeks there was nothing of interest in FI.

[nick sussex]

Surely this obsession with snow shouldn't effect what has happen ?.

A High over or near us for 4 weeks + now we have the Atlantic back with a series of deep depressions crossing the country with storm force winds particulary in the North.

Could you get more of a 'pattern change', or is a pattern change only accepted if it puts us in the deep freezer ? So much 'weather' going on this week but its all ignored.

I thought I mentioned the unsettled and often windy conditions in my first post of the day, so I wasn't ignoring the current weather!

Generally the majority of the people in here want to see a pattern change to something properly wintry so I'm free to highlight that the change we see is not a pattern change in the key area of the Arctic in terms of the PV!

So yes there is a pattern change for Europe, but there isn't one over the Arctic!

[Summer Sun]

Pleased to see the very deep lp system for next weekend (3rd & 4th) has downgraded a hell of a lot.

Looks very interesting from the 8th onwards.

http://www.null/ds/gfs.htm

[Frosty.]

That is like saying January will be colder than June. Of course things look better, but if these progs had come out 12 months ago they would be called absolutely disasterous, such was the potential at that time. As others have said PL your glass half full attitude is nice to see in one way, but given this mornings outputs it's both misleading and plain wrong to suggest the likelyhood or blizzards away from high ground in the north across the next week or so, in fact it's almost akin to saying somewhere will see 20c+... ie not impossible, but unlikely in the extreme.

I have only said what the models are showing, if we are allowed to talk about FI...FI is cold with a risk of snow and after the benign and very warm autumn it is worth discussing a possible cold snap, i'm not trying to mislead anyone and I apologise if I have but this very warm autumn has dulled some of our hope of anything cold occuring.

[shedhead]

Pleased to see the very deep lp system for next weekend (3rd & 4th) has downgraded a hell of a lot. Looks very interesting from the 8th onwards. http://www.null/ds/gfs.htm

Gavin, as I know others have pointed out to you on numerous occasions there is simple no point in looking that far ahead, but for the record it only looks interesting from the 8th if mild/very mild is you weather of choice.

I have only said what the models are showing, if we are allowed to talk about FI...FI is cold with a risk of snow and after the benign and very warm autumn it is worth discussing a possible cold snap, i'm not trying to mislead anyone and I apologise if I have but this very warm autumn has dulled some of our hope of anything cold occuring.

In that case PL all I can conclude is you have access to a different GFS and ECM than me, or indeed many others on here. Edited November 27, 2011 by shedhead

[SilverWolf]

I said blizzards for the uk, I didn't say where in the uk but scotland would have blizzards in the set up shown on the 00z runs although can't rule out snow further south, shame it's in FI but for weeks and weeks there was nothing of interest in FI.

Sounds like you're wanting cold and snow as much as me, but won't the models show more cold and snow in FI partly because we are heading more into winter? Excuse my ignorance if it doesn't work that way, proper novice here.

[Frosty.]

Gavin, as I know others have pointed out to you on numerous occasions there is simple no point in looking that far ahead, but for the record it only looks interesting from the 8th if mild/very mild is you weather of choice. In that case PL all I can conclude is you have access to a diffent GFS and ECM than me, or indeed many others on here.

so you can't see the potential cold snap then?

[TonyH]

I guess that they will show more in the way of cold and snow potential in December yes.

[Snowstorm1]

so you can't see the potential cold snap then?

I see it too so its not only you im honestly at loss with all the negativity in here

[TonyH]

Sounds like you're wanting cold and snow as much as me, but won't the models show more cold and snow in FI partly because we are heading more into winter? Excuse my ignorance if it doesn't work that way, proper novice here.

I guess they would yes.

Edited November 27, 2011 by TonyH

[Frosty.]

Sounds like you're wanting cold and snow as much as me, but won't the models show more cold and snow in FI partly because we are heading more into winter? Excuse my ignorance if it doesn't work that way, proper novice here.

I only have 6 years experience of posting on here and I can honestly see a cold snap affecting the uk in the next 7-10 days but it seems that only a few on here agree with me. I have tended to be as sceptical about cold potential up to now but I do think we have a chance of something wintry although nothing that will last as there is no sign of blocking in the atlantic..as last dec.

[shedhead]

so you can't see the potential cold snap then?

No PL I genuinely cannot, disappointing as that is. Yes it's going to be cooler than of late and yes there will be blizzard conditions at times, but only on ground above 200-300m in the north, 500-600m for central areas and above any tops in the south. Cold snap is a misleading term imo, we are entering a much more zonal phase, in which the current model output suggests average or perhaps a little below in the north and average to mild in the south. Edited November 27, 2011 by shedhead

[kold weather]

I wouldn't use the word cold snap, but for sure it will be colder and BELOW average for most of us in the first week of December (I'm willing to bet even the south is a little below)

What I will say is its going to feel very cold compared to recent weeks, the wind and the cooler air is going to make a very big difference to the feel of the weather that is for sure.

PS, GFS would suggest snow almost to sea level in Scotland, ECM restricts it to higher ground.

[Backtrack]

I see it too so its not only you im honestly at loss with all the negativity in here

If you're talking about the one around the 5th December - it's into FI, and it lasts for about 24 hours before getting blown away by the Atlantic. We just don't have the right ingredients for sustained cold just yet.

The best you will see from the models at the moment are brief topplers, and teasers in FI.

Regarding December 5th's 'cold blip', I can't see anything really for lower levels, away from Scotland. Not like there's much precipitation on there anyway.

Last night's 18z run was a great run for that cold spell, but it's getting shunted back and downgraded as we move towards the reliable, I wouldn't be surprised to see it disappear all together.

If you're talking about the brief NW'erly incursions before December 5th, then there's no snow on there away from mountains & hills.

Edited November 27, 2011 by Backtrack

[ribster]

That is like saying January will be colder than June.

Of course things look better, but if these progs had come out 12 months ago they would be called absolutely disasterous, such was the potential at that time.

As others have said PL your glass half full attitude is nice to see in one way, but given this mornings outputs it's both misleading and plain wrong to suggest the likelyhood or blizzards away from high ground in the north across the next week or so, in fact it's almost akin to saying somewhere will see 20c+... ie not impossible, but unlikely in the extreme.

Could he be allowed to discuss what the models are showing, which is the point of this thread after all. The likelihood of them coming to fruition or not is neither here nor there, unless that has become a caveat of the discussion recently?

[ukpaul]

If you want to be pedantic then yes, the introduction of zonality represents a pattern change, but going from exceptionally mild to average to mild it's unlikely to engender much interest - at least not amongst the coldies that make up 90% of this forum.

Most people aren't extrapolating what is showing now as being what will remain for the rest of the Winter. The relentless negativity from some because they aren't getting an exact repeat of last year would be cured by them looking at the actual output and casting their minds back fifteen years and more ago as to the variations on what winter can bring. Winters are different to each other. In any case, Britain isn't uniform, there's been a massive change for many this week and some of us might have to wait.

The output of the models has shown a marked change recently and there are more changes to come.

[nick sussex]

The thread seems to have descended into two polarized vew points this morning regarding prospects for colder conditons.

Both of them have their merits.

If you look at the positives and negatives:

Positives:

Azores high likely to edge into the Atlantic allowing a more nw/se tilt to the jet near the UK.

The upstream pattern is likely to amplify .

Negatives:

This amplification may only be temporary.

Low heights over the polar regions mean any colder weather is likely to be in shortish bursts.

Generally when you have a strong PV to the north the models often overamplify the jet in output past 144hrs, they also are not good at picking up shortwaves near Iceland which can cut off any PM flows.

The main point of uncertainty at the moment is when the Azores high will try and ridge into Europe, this is effected by the amplification of the pattern over in the USA and Canada. You cannot sustain a more cooler zonal pattern if the jet flattens out, before we get to that point the models may give a chance for a northerly toppler, this will be decided at around 168hrs.

The models are in general agreement upstream but vary on what they do with troughing there, if we can squeeze enough amplificaton at that point then this may lead to a northerly toppler.

The UKMO further outlook suggests the Azores high ridging ne later and this is the favoured option at the moment, however this is still well out into FI.

I suspect that for those looking for a proper but likely brief shot of wintry weather it needs to come within the next 10 days.

In terms of PM incursions these could give some wintry showers for northern areas but theres still uncertainty as to how far south we can get this colder air.

The GFS although not my favourite model overall is often quite good at picking those northerly topplers, although it does tend to overblow the depth of cold. At the moment theres not a great deal of support for this in its ensembles so I'd put it at a lowish chance for the moment.