Model Output Discussion - 21st - 28th November

[Mark Neal.]

You won't be wrong, it'll be all change again in the morning and those that are up now will be down again then... that as you know is the nature of this particular beast.

Very true, but thats why people have to take it as a pinch of salt and not increase there expectations that way they won't be as dissapointed.

With the winds strong towards the end of the week, blizzards for the highlands, or will they have calmed down by then?

Mark.

[ZONE 51]

GFS 18z - An interesting run then!

Here is the GFS potential storm on thursday,

For the future cold im going to remain positive like the ao/nao at the moment..

By the end of the week we could be seeing wintry stuff over the higher Northern areas, i would imagine mountains are certainly going to get some sking conditions from this,

850s chart showing -5C cold line(thats what i call it)

which is enough for high tops snowfall i would say.

Is this run of cold weather just a one night buzz?, or will it be there on the next run..

Edited November 21, 2011 by ElectricSnowStorm

[A Winter's Tale]

I think the latest run is better for the shorter term:

At 120 hours, -5C line reaches parts of N, W Scotland and NI and it sticks around until 132 hours. This would mean some snow over the higher ground and in the coldest places in the NW there could be some wintryness at lower levels at times.

At 159 hours, a notherly arrives with the -5C line in Northern Scotland. At 168 hours, the -5C line goes further south and colder uppers enter Northern Scotland and the -10C line isn't all that faraway from the Shetlands. This would increase the chances of lower level snow. Now the potential for wintry weather within the reliable time frame seems to have improved and at the very end of the reliable timeframe just 6 days away from now there is an even greater potential for some snow in the north.

Now after 168 hours anything could happen but colder uppers suitable for snow spread further south the -10C flirting with the Northern Isles.

It's still a long way off but a little more promising than of late.

[Hedgehog]

I know its in "FI" but it does look like we will be moving into "Winter" around 240-240hr (End of the month) with things moving into place. Before then just expect just typical autumn weather. I hope this makes sense!!!!

[summer blizzard]

]

I know its in "FI" but it does look like we will be moving into "Winter" around 240-240hr (End of the month) with things moving into place. Before then just expect just typical autumn weather. I hope this makes sense!!!!

In the more traditional sense it would appear so.

I personally (and many other people) have their own personal definitions.

For me, Autumn begins with the first sub-20C maxima two days in a row during August while winter begins with the first sub-10C maxima for two days in a row during November.

In my mind, we are already in winter.

[Cecil Hogmanay Melchett]

Very poor models again this morning.

GFS and ECM out to 12oh look very zonal with a positive NAO.

I would imagine any optimism from yesterday will vanish rapidly.

[ronan]

Lol this forum really does amaze me! It's one run!! Chill out!! The models will obviously chop and change!

[Iceaxecrampon]

So lets see, the ecm was on the mild side and is not supported by the mean and then gfs throws us into deep cold. Notice my other posts a few pages back about lows undercutting, which is what we should look for. If we get undercuts of secondary lows you get runs like tonights 18z, incredible. Here is a few:

Wintry showers to the north and feeling cold and raw in the wind:

http://hw.nwstatic.c...117/h500slp.png

http://hw.nwstatic.c...7/ukmaxtemp.png

http://hw.nwstatic.c...141/h500slp.png

One of those days where the temperatures get colder through the day and rain turning wintry in the north:

http://hw.nwstatic.c...5/ukmaxtemp.png maxes of 1 to 5c in the north and wind making it feel bitter and raw

http://hw.nwstatic.c.../h850t850eu.png

http://hw.nwstatic.c...hgt500-1000.png

http://hw.nwstatic.c...0/ukmintemp.png a very cold night -5 in some parts with a chart like that

http://hw.nwstatic.c...180/h500slp.png

FI:

http://hw.nwstatic.c...228/h500slp.png stormy and cold with cold winds

Remind you of something, go back to the end of November/december 2010. Of course we have a way to go yet and the heights are not as good, but the low over the UK is nearly spot on:

SNOW/BLIZZARDS for the north and east http://hw.nwstatic.c...252/h500slp.png

Severe frost: http://hw.nwstatic.c...2/ukmintemp.png

http://hw.nwstatic.c...384/h500slp.png Not perfect, but it is there and nice to see

Wow, what a ramp. Great signs after the benign autumn, things can only get better. Wintry showers possible end of the week and the weekend in the north if verified! Wow! Lets just say that is an amazing for cold and snow fans, if we don't get close to this, we should by far get something seasonal or more normal this coming week and to start December IMO.

Also, a new thread, new pattern. Great

Still chopping and changing going on unsure about SNOW/BLIZZARDS on the 00Z

Reliable hopefully for this weekend sleety mix but hopefully more consolidated ppn at higher altitudes.

Quite a drop in the Cumbrian ensembles.

[mountain shadow]

Agreed Ian. Classic zonal ensembles. Some windy and wet weather coming up, more so towards the north west. Any snow confined to the mountains.

I would say we are at least three weeks away from any chance of lowland snow, even then nothing in the teleconnections to hint at that outcome.

[Isolated Frost]

Next 2 weeks looking at the jet energy, polar vortex movement and stratospheric warming/cooling signals do seem very zonal. The odd northerly toppler as the 18z prescribed, along with a maximum dosage of atlantic-dominated weather (polar and tropical). Uppers may pass 5c at times but will generally be between 0c-4c in Tm spells and -5c--1c in Pm spells. I'd imagine if there if enough energy in the arctic to warrant an outbreak with the jet running on top of any mid-latitude high, it won't be extremely potent, nothing more than -8c/-9c, which would still probably deliver widespread showers to the east coast, east anglia and much of scotland/ireland/w wales and sw england.

I'd probably say temperatures alternating with dominating Tm air being a couple of degrees above the average, with Pm air around or slightly below and them northerly topplers that could bring temperatures a couple degrees below.

A very mixed, mod*rn wintery outlook. Very mixed with uppers of 5c and -5c possible in the range of 2-3 days in the same location at times. Average overall. Interesting however, definitely no raging southwesterlies, but no southerly jet and potent polar airstreams.

[Mark Neal.]

Models look crap for cold and snow lovers this morning, looks like the south westerly may well be back! All to play for and its just ONE run, but last night's pub run may have got a few people a bit over optimistic.

Mark.

[Frosty.]

Some short lived wintry spells for scotland on the gfs 00z this morning with wintry showers and westerly gales but soon being mixed out by milder, wet and windy spells but with polar air digging in behind the cold fronts..for the majority of the uk it looks generally mild but with some periods when temps are closer to average, a generally unsettled spell ahead of us with gales at times, plenty of rain but most of the rain this week will arrive on thursday in nw britain with a risk of severe gales and then a brief spell of rPm air with wintry showers across the far north before milder, wet and windy weather arrives next weekend, so for the northern half of scotland it looks mild, cold, mild etc, everywhere else it looks mild, average, mild etc.

[cyclonic happiness]

I think it's all very encouraging and with all the extra snowcover in the northern hemisphere (must be 15-20% up on average) we're sure to get something good soon, probably cold zonality.......cold enough for lowland snow imo.

[Great Plum]

Cold lovers and mild lovers alike... Do not panic... I've been on here 8 years and when runs and their ensembles shift from run to run like they have been doing, this seems to be systematic of a pattern change - it seems that it takes a while for the models to 'settle down'. FI in these sort of periods is t96 - t120.

So what will happen? I'm no expert but look at the upstream signals, don't take each run as gospel and for what the weather will do in the future, look at the met office further outlook. In this instance, they probably have it close.

Write off December based on one run of charts when winter is still 10 days away? Don't be daft!

[nick sussex]

No surprise to see the GFS drop its better lower resolution output and deliver just plain old zonality, the ECM looks zonal and doesn't deliver anything of interest until right at the end of its run.

It's a shame the GFS 18hrs run decided to go awol as that raised expectations and I fear the thread will be filled with alot of disappointment, however if you ignore that rogue run overall the models today are ever so slightly better than yesterday in terms of a possible PM incursion. Given most of the charts yesterday you could say the horror rating has fallen slightly!

The UKM0 at 144hrs probably looks best of the big 3 at that timeframe.

The ECM ensemble mean still pulls the Euro high westwards from 168hrs, but overall nothing too exciting for cold and snow lovers within the 240hrs timeframe.

Edited November 21, 2011 by nick sussex

[Frosty.]

No surprise to see the GFS drop its better lower resolution output and deliver just plain old zonality, the ECM looks zonal and doesn't deliver anything of interest until right at the end of its run. It's a shame the GFS 18hrs run decided to go awol as that raised expectations and I fear the thread will be filled with alot of disappointment, however if you ignore that rogue run overall the models today are ever so slightly better than yesterday in terms of a possible PM incursion. Given most of the charts yesterday you could say the horror rating has fallen slightly! The UKM0 at 144hrs probably looks best of the big 3 at that timeframe. The ECM ensemble mean still pulls the Euro high westwards from 168hrs, but overall nothing too exciting for cold and snow lovers within the 240hrs timeframe.

Despite what you say, at least the far north of the uk does have some cold interludes between the mild spells and it's not all bad further south, some spells of near average temps will remind people it's late november, for most of this month it has felt more like april with temps frequently approaching 60f.

[wolvesfan]

Morning all,

ECM showing the mid atlantic high pressure retrogress again then build slightly towards greenland,it's done this on quite a few runs now.not expecting it to bulid any further north but it could be more favourable for NW incursions for the uk.also might help dent the SW flow and help to get troughing into central europe as the jet amplifies.deffinatly a more exiting spell of weather coming up.

[johnholmes]

Looking at the 500mb anomaly charts over the last few days, weekend output accepted from NOAA, they are still not showing anywhere near identical charts but they all 3 are trending into a flow that suggests some meridionality. GFS keeps, this morning, some sign of the Euro ridge and +ve area, neither NOAA (last evening) nor the ECMWF version this morning do. All 3 are building the +ve area off the eastern states with indications its heading towards Greenland, or at least part of it. Both NOAA and ECMWF pull the upper trough a bit further east, both suggest a largish -ve area over the UK suggesting a fairly cold pool of upper air there by T+240.

Its far from done but there is about a 30% prob I would suggest of a reasonably coldNW outbreak by the month end after a spell of almost zonal mix with Tm and Pm air, with the Pm air tending to become more frequent and deeper with time and extending further south.

Far from clear but the signs are there, regardless of the further out teleconnections not being very favourable.

Hopefully that is a fairly constructive post and not too weighted to the coldie fraternity on here.

[nick sussex]

Despite what you say, at least the far north of the uk does have some cold interludes between the mild spells and it's not all bad further south, some spells of near average temps will remind people it's late november, for most of this month it has felt more like april with temps frequently approaching 60f.

It depends what baseline you use to compare things, compared to some of the output yesterday todays is better.

However it's still far from great and snow on a mountain in Scotland isn't going to be much use to the majority of the UK. It is good of course for the Scottish ski industry.It goes to to show how utterly tedious the output has been from a cold perspective that average is a bit of a victory.

[johnholmes]

Cold lovers and mild lovers alike... Do not panic... I've been on here 8 years and when runs and their ensembles shift from run to run like they have been doing, this seems to be systematic of a pattern change - it seems that it takes a while for the models to 'settle down'. FI in these sort of periods is t96 - t120.

So what will happen? I'm no expert but look at the upstream signals, don't take each run as gospel and for what the weather will do in the future, look at the met office further outlook. In this instance, they probably have it close.

Write off December based on one run of charts when winter is still 10 days away? Don't be daft!

excellent post Great Plum

[snowmadchrisuk]

Despite what you say, at least the far north of the uk does have some cold interludes between the mild spells and it's not all bad further south, some spells of near average temps will remind people it's late november, for most of this month it has felt more like april with temps frequently approaching 60f.

Despite what you say, at least the far north of the uk does have some cold interludes between the mild spells and it's not all bad further south, some spells of near average temps will remind people it's late november, for most of this month it has felt more like april with temps frequently approaching 60f.

Sign's of a pattern change are in the air this morning ... GFS Op one of the Mildest runs , Control one of the Coldest , always a sign that something is about to change. More Cold members than Mild. ECM not bad as it keeps trying albeit failing to build height's out West and it does actually get there on it's later Charts . I note what Phil said last night but I do believe we can still get Cold patterns into the Uk even with a colder than average Stratosphere , If you put it into reverse we had the massive warming in early Jan and it came to nothing for the UK . It's kind of like a job application , warming Stratosphere preferred but not essential .

[Isolated Frost]

Widespread snow showers above 200-250m across much of western parts, good snowfalls in the lake district, pennines and highlands likely.

[nick sussex]

The ECM ensembles show a cooling trend in the extended range, the control run looks interesting.

http://www.weerplaza...?type=eps_pluim

The synoptic maps upto 168hrs for every ensemble member have a few more interesting solutions:

http://www.weerplaza...?type=eps_pluim

If we can actually see the Euro high pulled west then things could start to look a bit better, we need to see that verify, at that point the further output might hold much more interest.

Edited November 21, 2011 by nick sussex

[Airedalejoe]

Despite what you say, at least the far north of the uk does have some cold interludes between the mild spells and it's not all bad further south, some spells of near average temps will remind people it's late november, for most of this month it has felt more like april with temps frequently approaching 60f.

You keep quoting 60f, you may live in a little tropical micro climate but here in the NE most days have been nearer 50 than 60, just a little above average. Yesterday it reached 45f.

[wolvesfan]

It depends what baseline you use to compare things, compared to some of the output yesterday todays is better.

However it's still far from great and snow on a mountain in Scotland isn't going to be much use to the majority of the UK. It is good of course for the Scottish ski industry.It goes to to show how utterly tedious the output has been from a cold perspective that average is a bit of a victory.

Hi Nick,

Were we ever going to see a speedy descend into winter from the euro high scenario,mods gave us a fast track solution for a time but the overall pattern has worked against this,i agree with your point that the average conditions are a victory,our descend into winter might just have to be a little slower than what we would like,but at least we may now be heading in the right direction.cheers.

Edited November 21, 2011 by wolvesfan