Model Output Discussion 26/10 2012 >

[Liam J]

It really is incredible. A day of relatively poor runs from the GFS (after weeks of predominantly cold and polar airflows) seems to convince people that the entire month of November, even as far ahead as Christmas, will turn out to be mild. Its amazing. Its as if somehow a predominantly mild (ish) chart will always turn out to be solid, undeniable fact, despite the fact that we are all WELL aware that they change on a daily if not an hourly basis.

I suppose you could also say that the same happens when a few GFS runs are showing cold evolutions out at T384?? But the difference is that they get ramped, over analysed and cherry picked to death regardless of how far into fantasy land they happen to be - ''another Winter 1962/63 is on the doorstep'' etc etc....

Edited October 31, 2012 by Liam J

[SMU]

http://www.meteociel.fr/modeles/ecmwf/runs/2012103112/ECH1-168.GIF?31-0

Excellent chart - primed for further cold-

the STJ over the SW states will take that energy North supporting higher heights to its east- should see a retrograde block develop over greenland from that-

S

[snowstorm445]

I suppose you could also say that the same happens when a few GFS runs are showing cold evolutions out at T384?? But the difference is that they get ramped, over analysed and cherry picked to death regardless of how far into fantasy land they happen to be - ''another Winter 1962/63 is on the doorstep'' etc etc....

Where have I said that they are different. Frankly the ramping over cold weather is just as bad if not worse in reality, but I think people are sensible enough not to take it seriously unless if happens to appear on runs for several days. But with mild runs, people act as if it is guaranteed to turn out the way that it is shown with that sort of "its just our luck" pessimism. It really is unbearable.

[legritter]

looking at todays charts and data etc , gives me plenty of hope for a real mixed bag of weather . plenty of[ Possibilities ]and the real possibility of surprises . it is increasingly probable that next week will see high pressure pushing up from the s/west but this could easily disappear over the next couple of runs . by this time friday the charts out to 168 hrs could be showing a fair cold shot ,as for some posters writing off a cold winter ,we dont know whats around the next corner .off to work now ,but will be back for new modell runs later .

[Ice BIast]

PV in pieces at 240h on the ECM

[Gibby]

Good evening. Here is my take on the 12zs from GFS, UKMO and ECM on this wet West Country Halloween night.

All models continue to illustrate a period of sustained unsettled and rather chilly conditions as a very deep Low to the North of Scotland carries a cold front slowly East over the UK this evening and tonight. Behind it skies clear as winds veer west and decrease. It will also become rather chilly with some showers spilling into western coastal counties later in the night. Tomorrow shows the UK in an unstable and rather cold Westerly flow with showery weather for most though some places in the East may stay dry. Through the following two or three days all models show the complex Low pressure continuing to locate over the UK with rain or squally showers continuing in rather cold conditions with snow on Northern hills.

GFS then shows a ridge of High pressure moving into the UK early next week but it will be Wednesday before any effects of this are felt in the far East. Any improvements are short lived though on the operational run as Low pressure returns from the West with rain returning by Thursday to the West. This Low sinks South affecting mostly West and SW Britain before a ridge takes hold from the North into FI. Through these latter days of the run the UK’s weather become s more and more dominated by High pressure building in off the Atlantic settling over the UK by the end of the run with fog and frost problems developing should skies clear.

The GFS Ensembles shows a period of slightly below average uppers before a slight recovery to near normal levels occurs next week. The pattern does still continue to show occasional rainfall as the Atlantic keeps a hold over the UK though not without some transient ridge of high pressure spells.

The Jet Stream continues to blow strongly to the South of the UK over the coming 4-5 days. Later it ridges temporarily North through the Atlantic before the ridged flow topples SE over Britain next week on its way to settling back to the South of the UK in FI.

UKMO at midday on Tuesday shows rising pressure over the UK in a cold Northerly flow left behind as the legacy of the current Low pressure having moved away East into Europe. A few showers could still affect the East with most other areas becoming dry.

ECM at the same time point shows a weak ridge toppling over the UK with a fine and dry day likely in a moderate NW flow. By midweek a stronger WNW flow develops with Low pressure’s well North of the UK affecting Northern and Western areas principally with some rain. Eastern and Southern areas would see little if any rain in temperatures somewhat higher than of late. As the run reaches its final days the pattern is a little bit of déjà-vu as Low pressure returns down from the NW bringing a return to rather cold, windy and unsettled conditions by day 10.

In Summary the weather remains in typical Autumn mood with rain and showers for all in the next week before a drier phase moves in towards the middle of next week. It’s longevity is undecided between the models as GFS throws a depression South to the West of Britain before building High pressure over the UK while ECM looks like returning us to where we are now with rather cold and wet conditions at times. Apart for some snow on Northern hills over the coming days there is little sign of anything too wintry anywhere in the next two weeks although should it verify ECM raises a few eyebrows at day 10.

Edited October 31, 2012 by Gibby

[AWD]

A quick run through the GFS 12z operational shows no "zonal" flow to me at all.

The next few days look unsettled and on the cool side with snow possible on the highest ground in the north at times;

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=48&code=0&mode=0&carte=1

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=48&code=0&mode=1&carte=1

The Jet Stream tracking over southern England;

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=48&code=0&mode=5&carte=1

Then next week HP starts building in the Atlantic, slowly but surely settling things down somewhat, although this is a slow process;

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=144&mode=0&carte=1

Again, remaining on the cold side with further snow possible on the highest ground in the north;

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=144&code=0&mode=1&carte=1

The Jet remaining to the south of the UK in general;

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=144&code=0&mode=5&carte=1

HP stays in the Atlantic for most of next week & into the following weekend with rather benign conditions over the UK, showery and still remaining on the cool side would be best used to describe the weather then;

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=192&mode=0&carte=1

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=192&code=0&mode=1&carte=1

Now as we enter the realms of FI we see the HP in the mid Atlantic becoming more assertive and start to edge further east over the UK;

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=240&mode=0&carte=1

The PV starting to tighten over Greenland & more especially over Russia ( the latter not all that bad in terms of PV situ for winter ).

Even here, by day 10 temps are still below average for the time of year;

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=240&code=0&mode=1&carte=1

The Jet starts to intensify over southern Greenland as it is pushed north by the Mid Atlantic HP;

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=240&code=0&mode=5&carte=1

Settled with temps around average, perhaps very slightly above at the surface as the Mid Atlantic HP influences our weather;

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=300&code=0&mode=0&carte=1

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=300&code=0&mode=1&carte=1

Notice how, although the vortex continues to strengthen, it as shifted the core of intensity over Russia & Scandinavia, not necessarily a bad thing in the long run for UK cold prospects.

At the very end of the GFS run, and at this stage this is purely conjecture, we have a strong PV over Russia, very cold weather here and in Eastern most parts of Europe;

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=384&code=0&mode=0&carte=1

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=384&code=0&mode=1&carte=1

In the UK, temps around average, perhaps very slightly above at the surface, and settled with a HP cell sitting over us, with hints of it nudging towards Greenland during the last few frames.

Nothing overly mild showing & nothing what I would call zonal showing in the GFS output.

The GFS Ensembles show the operational run to be at the mild end of its members in FI, both at 850hpa & 500hpa, with the mean trending close to uppers of 0c throughout;

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=306&y=141&ville=Londres

The GFS operational more or less an outlier in terms of pressure throughout FI.

http://www.meteociel.fr/cartes_obs/gens_display.php?x=306&y=141&run=12&ville=Londres&runpara=0&type=1&ext=1

Like the GFS, the UKMO 12z output shows unsettled and cool conditions for the remainder of this week, strong winds at times too;

http://www.meteociel.fr/modeles/ukmo2.php?nh=1&ech=48&carte=1021

http://www.meteociel.fr/modeles/ukmo2.php?nh=1&carte=1007&ech=48&archive=0

Becoming less unsettled next week as HP starts showing its hand in the Mid Atlantic;

http://www.meteociel.fr/modeles/ukmo2.php?nh=1&ech=144&carte=1021

The GEM is similar to both the UKMO & GFS for the reliable future, it does however, bring the Mid Atlantic HP closer to our shores a little more quickly on its 12z run, settling things down somewhat by next week;

http://www.meteociel.fr/modeles/geme_cartes.php?&ech=144&mode=0&carte=1

The ECM 12z again showing wet, windy and rather cold conditions for the rest of this week, with snowfall possible on the highest ground in the north at times;

http://www.meteociel.fr/modeles/ecmwf.php?ech=48&mode=1&map=1&archive=0

http://www.meteociel.fr/modeles/ecmwf.php?ech=48&mode=0&map=1&type=0&archive=0

By next week the ECM starts to assert HP in the Mid Atlantic bringing less unsettled conditions to the UK, temps still on the cool side though so perhaps some crisp frosts and fog in this setup;

http://www.meteociel.fr/modeles/ecmwf.php?ech=144&mode=1&map=1&type=0&archive=0

http://www.meteociel.fr/modeles/ecmwf.php?ech=144&mode=0&map=1&type=0&archive=0

ECM then goes a different way then the GFS, in that it sinks the HP down to the SW of the UK, and at the same time strengthens the PV over Greenland introducing a typical zonal pattern over the UK.

http://www.meteociel.fr/modeles/ecmwf.php?ech=192&mode=1&map=1&archive=0

Temperatures likely to be average to above average as milder "westerly air" takes hold over the UK.

http://www.meteociel.fr/modeles/ecmwf.php?ech=192&mode=0&map=1&type=0&archive=0

I believe this pattern the ECM is suggesting for next week is something similar to what the Met Office are suggesting too, if I read the earlier posts from Ian Fergusson correctly.

Into ECM FI, and the ECM starts sending some WAA up the south western side of Greenland, which starts to displace the PV somewhat here and pushes the core intensity of it east into Scandinavia and possibly Russia (if the run went beyond day 10), similar to the GFS scenario.

This in turn pushes the Jet Stream on a more NW/SE axis, introducing some colder air to the UK again after the brief milder spell.

By day 10, the UK becomes unsettled and rather cold again, with snow possible to even modestly high levels in the north if the below verified;

http://www.meteociel.fr/modeles/ecmwf.php?ech=240&mode=1&map=1&type=0&archive=0

http://www.meteociel.fr/modeles/ecmwf.php?ech=240&mode=0&map=1&type=0&archive=0

So in summary, the foreseeable future looks likely to be unsettled & on the cold side with rain for all of us at some time, snow on the highest ground in the north. Then we have HP trying to make grounds to the UK from the WSW. The models diverge here as to whether it becomes a Mid Atlantic HP, it sinks southwards and we end up zonal, or it engolfs the UK settling things down. The ECM does bring a zonal pattern in briefly, but even this model then alters the axis of the Jet to a more favourable position of colder air, and thus brings temperatures back down to below the seasonal norm again.

What I don't see is a mild zonal pattern setting up shop, and definetly not a stubborn mild zonal pattern. Cold zonal at times yes, but that's as it. The outlook is rather cool for November, with typical amounts of rain & wind expected this time of year. There is more below average weather showing than there is above average.

Enjoy all, there isn't a blizzard showing, but IMO there is some very interesting weather possible in the coming days, with interesting trends POSSIBLY emerging in FI.

Edited October 31, 2012 by AWD

[A Winter's Tale]

Good evening everyone and happy Halloween and I can say that UK shouldn't experience horrific weather through this evening and through the night, however it may well prove to be a little atmospheric with heavy, overcast skies and some persistent and heavy rainfall combined with some gusts across parts of England and Wales this evening as a band of rain should move eastwards and clear into the north sea by dawn Thursday morning but many in England and Wales should see rain from this band during the next 10 hours. In Scotland, skies may remain mostly on the cloudy side - the Outer Hebrides and far north west may see some clear night skies - with showers - particulary in western areas - and these should be wintry on the mountains. In Ireland there should be showers here too - particulary in the north and some some clear spells. Minimum temperatures should be 3 to 9C.

Thursday morning should see cloud cover increase from the west in Ireland as a group of more organised, widespread and quite heavy showers arrive but skies should clear in the afternoon and evening. Scotland should see some sunny spells throughout Thursday with showers in the west and some of which reaching inland but the organised area of showers affecting parts of Ireland in the morning should arrive in the late afternoon and early evening and widespread and quite heavy showers should be around the coasts of Western England and Wales and earlier in the afternoon the channel coast may be at threat with some showers and these could make their way a fair bit inland. However Thursday should be a mostly sunny day for England and Wales and parts of Ireland and Scotland. Maximum temperatures of 5 to 10C. Showers should persist across parts of Scotland and the seas to around west coast of the British Isles overnight and skies shouldn't be particulary clear with some cloud cover with a few breaks. Minimum temperatures of 0 to 7C.

Friday is looking like another showery day with plenty of sunny spells for many. The south and east of England should escape the showers with decent spells of sunshine here but northern and western areas most at risk of catching showers with some sunny spells. Maximum temperatures of 7 to 11C. However, Friday night should see reduced activity of showers with south western coastlines at risk and some light precipitation in the sea to the west of Ireland. A mostly dry night with some decent clear night skies - particulary in southern and eastern parts of England. A cold night too with lows of 0 to 8C.

Saturday at the moment could have some features across Scotland bringing light rain for a time for places and the south coast of England may be more at risk of a more persistent and heavier feature in the channel. Inland and eastern parts of England should remain dry however with sunshine and Ireland should see some good spells of sunshine too. Maximum temperatures of 5 to 10C. Overnight, the best for dry conditions and clear skies would be eastern and central parts of England whilst the southern coastlines of Wales and England and the western parts of Ireland remain at risk of some light rain and showers. Northern Ireland and parts of western Scotland could be at risk of seeing a feature bringing heavier rainfall and more persistent rainfall for a time in places but a cold night further north and east in Scotland and indeed a cold night for many with lows of 0 to 7C.

Much of Ireland, Scotland, Wales and northern and western England could have a mostly cloudy day on Sunday with some light precipitation around coastline and more inland across Scotland. Eastern England could remain drier with some sunshine. Maximum temperatures of 5 to 11C. Sunday night also looks showery for many western and northern areas and the south coast and some rain also leaving eastern areas overnight before clearing into the north sea. Behind this feature could be drier and clearer weather for inland parts of southern England and southern Ireland away from the showers. Minimum temperatures of 2 to 9C.

[johnholmes]

A quick run through the GFS 12z operational shows no "zonal" flow to me at all.

what a first class post whether you be a cold fanatic or not, well presented with plenty of charts to help explain AWD's view-thanks again

[Biggin]

A quick run through the GFS 12z operational shows no "zonal" flow to me at all.

Wow thanks for that Someone without an axe to grind, and no cherry picking. Weather wars are getting boring, plus thnks to Gibby to for his no nonsense to the point updates.

Edited October 31, 2012 by Biggin

[SMU]

hi so no one seems to be mentioning the weekend snow event the met office are pedicting for parts of cumbria mainly the lakes .read this evening weatherline update posted at 6pm today forecast provided by the met.saturday has snow at all levels by the afternoon .they must have picked up on something not spotted by the other models

I thought I was mentioning it days ago

S

[I Cumbria Marra I]

hi so no one seems to be mentioning the weekend snow event the met office are pedicting for parts of cumbria mainly the lakes .read this evening weatherline update posted at 6pm today forecast provided by the met.saturday has snow at all levels by the afternoon .they must have picked up on something not spotted by the other models

could you post a link please pal

[Nick B]

http://www.meteociel...H1-168.GIF?31-0

Excellent chart - primed for further cold-

the STJ over the SW states will take that energy North supporting higher heights to its east- should see a retrograde block develop over greenland from that-

S

Nice Halloween ghost in green on this saved chart.

[Liam J]

hi so no one seems to be mentioning the weekend snow event the met office are pedicting for parts of cumbria mainly the lakes .read this evening weatherline update posted at 6pm today forecast provided by the met.saturday has snow at all levels by the afternoon .they must have picked up on something not spotted by the other models

Nothing on the Meto site regarding a snow event, even the location forecasts have temps 7-10c across the lakes, wintry showers over high ground. The MWIS forecasts I print at work mention sleet/snow over high ground tomorrow, nothing unusual in November.

Are you a fellow Cumbrian?

MET -

Outlook for Friday to Sunday:

Unsettled throughout. Bright spells and showers, wintry over high ground, with a risk of hail and thunder at times. Often windy and rather cold with an overnight frost risk.

Updated: 1520 on Wed 31 Oct 2012

Weatherline -

Saturday

A bright but chilly morning, with sunny spells in the east, and a few scattered showers in the west, falling as snow over the tops. Cloud will increase through the day with showers becoming heavier and more frequent during the afternoon, falling as snow down to low levels. Moderate southwest winds will increase through the day with a risk of gales over the tops. Feeling cold in the wind.

These are mountain area forecasts, low levels does not mean down to sea level.

Edited October 31, 2012 by Liam J

[gottolovethisweather]

hi so no one seems to be mentioning the weekend snow event the met office are pedicting for parts of cumbria mainly the lakes .read this evening weatherline update posted at 6pm today forecast provided by the met.saturday has snow at all levels by the afternoon .they must have picked up on something not spotted by the other models

Touch and go at best, I would say.

I'm not sure if that's what is called, but the air appears to get mixed out during a period from between 0300GMT and 1800GMT on Saturday. A large swathe of the Central England belt, including Ireland early on, are entrenched in t850s of -4c.

I SHALL DO THIS ONLY ONCE AS THE BOSS MIGHT BE WATCHING.

It just goes to prove we are under cool zonal conditions right now and seemingly out to the realms of FI, which are probably at t+96 right now.

Let us not, take our eye of the more immediate timeframe, whilst we all still have the option of looking further ahead as well.

Edited October 31, 2012 by gottolovethisweather

[phil nw.]

hi so no one seems to be mentioning the weekend snow event the met office are pedicting for parts of cumbria mainly the lakes .read this evening weatherline update posted at 6pm today forecast provided by the met.saturday has snow at all levels by the afternoon .they must have picked up on something not spotted by the other models

Welcome to the forum Blackdog it would be good if you would enter your location in your avatar.

There does look a chance of some snow at the weekend for some northern elevations as rain moves into a pool of cold air although it does look like a brief event as slightly higher uppers follow in from the Atlantic.

[Gael_Force]

could you post a link please pal

The GFS has snow for the day in the NW -maybe computer generated forecast?

[Liam J]

Potential for a dusting at higher elevations briefly on Saturday morning, low to moderate risk of snow accumulation above 400m (200m in Scotland) The higher res NMM will be covering this time scale by tomorrow with more detail.

ECM restricts the potential to Scotland.

Edited October 31, 2012 by Liam J

[gottolovethisweather]

Potential for a dusting at higher elevations briefly on Saturday morning, low to moderate risk of snow accumulation above 400m (200m in Scotland) The higher res NMM will be covering this time scale by tomorrow with more detail.

Could still be one to watch. Thanks Liam.

As I said, whilst we remain in a cool zonal flow, there will continue to be occasional glimpses of wintry potential, for the more prone areas.

[Duane S.]

I've only skipped briefly through today's posts so I may have missed some comments but I'm surprised more isn't being made regards the ECM 12z post +144. The subtle trend has been there for a few days for the strengthening vortex to be broken up and shuffled over towards Scandinavia. We haven't yet seen an op run showing a full-on WAA surge into Western Greenland (in FI or otherwise) yet but I wonder if we are going to see that show up more and more for Mid - the last third of November over the coming 10 days? Certainly the ECM @ +240 seems to be screaming potential. And the propensity to maintain a meridional flow is very interesting...

[Geordiesnow]

I think we are going to head into a period of where the PV will be at its strongest so far this Autumn season so I don't see any significant cold on the horizon(by that I mean hpa of -5 or below heading into the UK) but the ECM has hinted as people have shown that the heights over the Arctic may rise again, a few ECM runs have indicated this if albeit at quite an unreasonable timeframe.

The outlook is a cool one but its a bright and showery one, with frontal activity limited but potential for more general outbreaks of cloud and rain is there for Sunday in Southern areas whereas the NW of the UK will see convective showers whilst those sheltered from high ground should see lengthy sunny spells.

One thing to note, there is potential for some gusty winds in the coming days, especially those in the lee of high ground and in any showers.

[bluearmy]

Hadn't looked at the ECM ens chart for London for a few days but very noticeable how the mean max post nov 10 drops off to around 7c. Knock out the scatter higher up and thats prob nearer 6c. Chilly!!!

[Cheese Rice]

Liking the ECM and GFS.

Both show a decline in the PV at around day ten. After an initial strengthening between the 3rd/8th it quickly diminishes from its usual place over the Arctic as heights attempt to build.

Cold Zonal appears to be conituning well up to mid November. I'd expect an increase in Northerly outbreaks packing quite a punch over the next few weeks.

Edited November 1, 2012 by Cheese Rice

[IDO]

The above post highlights the trend, maintained this morning, GFS refusing to allow the PV to regroup, other than transitionally. At T384 on GFS 0z:

npsh500.png

So opportune for some colder topplers between the cool zonal main synoptics. At T252, a case in point:

h850t850eu.png

In FI, so plenty of time for his to pass us by, but potential, however only minor support on the ensemble members:

t850London.png

So probably unlikely. The mean is flat at 0c 850pHa so cool zonal must be the most likely after the LP centric 5/6 days, with the south more likely to be under the HP regime and changeable further north:

h500slp.png

Cold shots not ruled out though.

The LP's forecast for the next few days are currently likely to affect the Channel south, rather than Southern England, as per the 8 day rain chart:

gfsopuktotpcp192.gif

This Autumn is living up to its name.

Edited November 1, 2012 by i'm dreaming of...

[weather_it_will]

Possible snow chance around T228/T240 on GFS as long

as low pressure remains NE of Scotland and the HP stays over the Azores to produce a northerly.