Model Output Discussion - 30th November onwards

[Methuselah]

infact the gem at t240 is what you call a good trend indeed with heights into eastern Greenland and deep lows that would most certainly be going southeast.

but its unlikely we will see Greenland blocking anytime soon but scandi block is a very realistic trend.

I think that that's where the validity, in citing previous winters' charts, comes into play...Given, say, the a chart for 3/12/62 (and somehow not knowing it was such!) how many of us would be able to make an accurate 10-15 day forecast? Air is a fluid, and can't really be compartmentalized into convenient blocks - not without encountering the obvious pitfalls associated with gross over-simplification, anyway...

 

God, I don't what it's going to be like in 10 days' time! 

[phil nw.]

I think we can be reasonably sure of a redeveloping high over W Europe after the brief Arctic surge has gone east.

We have seen this on all recent runs and ens- somewhere over the s.UK and France to begin with at the weekend.

http://www.meteociel.fr/ukmo/runs/2013120312/UN96-21.GIF?03-17

 

The 00z anomaly charts do show those heights relocating towarads Scandinavia by day 10 but they are not favourably orientated to bring upper cold from the east at that stage.

http://176.31.229.228/modeles/gens/naefs/run/naefsnh-0-0-240.png?12

http://www.meteociel.fr/modeles/ecmwf/runs/2013120300/ECH101-240.GIF?03-12

 

We would start to see surface cold drifting off the continent in a more se flow in that pattern though.

We do need to watch for the return of part of the pv back towards Siberia which would run over the top of the Scandi.high putting it under pressure.

This is what the 12z GFS has shown in later frames and is always possible.

On the other hand it's a good sign to see the Atlantic troughing stalling out west in the earlier output which shows the block is having an effect.

Edited December 3, 2013 by phil nw.

[johnholmes]

for the immediate future some may be interested in this and into the technical thread if you 'lose' it in here

 

The Thursday storm for the north

 

I did promise to give a link to useful sites to watch this form-deepen and track through Wednesday into Friday.

 

Also copied into the so called technical thread-don’t be put off by the title, it should remain easier to find than in here where no doubt by tomorrow it will be ‘lost’. Enjoy following and learning about the weather from this depression, have a look at the Net Weather Guides for more information on things you may not be clear about and of course ask questions.

 

The Fax charts

http://www.weathercharts.org/ukmomslp.htm

Satellite charts with the infra red movie version perhaps the best to track but others also very interesting, for the Dundee ones you need to register (it’s free and easy to do)

http://www.sat.dundee.ac.uk/auth.html

http://www.yr.no/satellitt/europa_animasjon.html

Actual weather, several places to bookmark

For actual weather on the Shetland Isles

http://www.shetland.gov.uk/icecast/default.asp

Regular hourly reports from sites all over the UK and abroad if you wish

http://www.xcweather.co.uk/

Track the low from buoy reports although many are south of its expected track

http://www.ndbc.noaa.gov/maps/United_Kingdom.shtml

 

Charts showing the progress of the low

Obviously 6 hourly updates from Exeter of their Fax charts

And this site, remember it is a computer generated chart and is at times not as accurate as the Fax for the same time. It is very useful to watch its general track, deepening etc.

http://meteocentre.com/analyse/map.php?hour=0〈=en&map=UK

for those that understand the WMO code this list all the stations in the UK in the SYNOP code with stations in Shetland and Orkney fromm03001 to about 03017, to see what the SYNOP for Torshavn north of the track is giving the type in 06011, all of them report every 6 hours, 00,06,12,18 and some every 3 hours

 

For forecasts-see above for Shetland and below the full UK Met including shipping areas

http://www.metoffice.gov.uk/weather/uk/uk_forecast_weather.html

[terrier]

Think Ian's comments are very interesting indeed. But let's not get too hung up on them. As he says they are a few opinions on the table and we just need to wait and see. Now back to the models tonight the winds on Thursday looks very nasty for a lot of the uk with Scotland seeing blizzard conditions. Then into the weekend things settling down thankfully.

[Tom Jarvis]

which model is the canadian model??  

just follow someone tha say it has the low in the us perfectly tracked

[Summer Sun]

The latest video from the beeb shows the milder air making its move during Friday pushing the cold air east

 

Tonight's UKMO

 

 

And the latest thoughts from the met office

 

 

I think the biggest concern over the next 3 days is the wind speeds for the north on Thursday

 

Edited December 3, 2013 by Summer Sun

[Frosty.]

I think the GEM has dropped the ball recently, it was the first model to pick up the signal for the upcoming cold snap but it seems to have had it's purple patch and is back down the rankings in mid table.

[Matty M]

Summary of result from the 2009-2012 study based on RMSE for Ireland is grid area.

 

Climate refers to a 30 year rolling climatology for each week period.

 

Of course this not peer reviewed!!

 

 

 

 

[Yarmy]

which model is the canadian model??  

just follow someone tha say it has the low in the us perfectly tracked

 

GEM

[johnholmes]

Summary of result from the 2009-2012 study based on RMSE for Ireland is grid area.

 

Climate refers to a 30 year rolling climatology for each week period.

 

Of course this not peer reviewed!!

 

 

 

 

thanks for that Matty-as everyone knows I do like to see factual statistical evidence. Unless I am mistaken the end data is worse than climatology or am I misreading your data for the sites in Ireland? It would seem probable that similar figures would be arrived at over much of inland UK?

[Purga]

Just got in & an atrocious run from GFS mild all the way through apart from a cool blip in the north - blink and you'll miss it.

High pressure anchored over Europe and a very cold cell over Greenland and Canada blasting powerful LP systems across the Atlantic and pumping up very warm uppers across the UK.

Just look at all the cold bottled up in the Arctic courtesy of a strong tight vortex and toasty uppers over GB

 

UKMO equally wretched with the vortex relocating over Greenland by 144hrs

Uppers very warm as well

Can ECM pull us out of a hopeless situation??

Edited December 3, 2013 by phil nw.
removed sarcastic comments -no more of those thanks

[garbagebags]

This is a Bartlett high, giving us mild air.

 

This is a Scandi High giving us cold air.

 

 

Just making that clear. 

Because there sure as damned seems to be a lot of confusion in here tonight...

[UV-RAY]

To be honest I really can't see anything other than a Rex block at best in the 10-14 day timeframe and even then I would be hesitant. I think we could be looking at more of the same really with heights if anything slowly sinking SE.

[CanadaAl]

Sifting through the charts from 4 years ago, it did seem that the GFS was really all over the place until the 11th. I know "No two years can be the same" but it does give us some hope as to what may unfold. In the case of that cold spell, the 18Z seem to of had a better grasp of things of what was to come. 

 

Keep smiling folks  

[Catacol]

Matt Hugo on Twitter:

 

"CFSv2 supports EC32 in terms of pressure patterns with a really strong signal for high pressure to the N/NE of the UK"

 

 

Very interesting. This type of cold solution is the form horse today it seems. If we manage to get a solid block to the north this side of Xmas with the background signals what they are then this winter could turn out to be really something - I'm still holding on to the possibility of some vortex shredding later on especially with the continued strength of the aleutian high and if that happens with high pressure already in situ then we better all go buy some anti freeze and a shovel. It would be ironic if the gutter press ended up somewhere close to reality bearing in mind their headlines are based on pure fantasy. 

 

Maybe - after all - dreams do come true!

 

[steps off the box labelled "ramp" and sits back down...]

[swfc]

Sifting through the charts from 4 years ago, it did seem that the GFS was really all over the place until the 11th. I know "No two years can be the same" but it does give us some hope as to what may unfold. In the case of that cold spell, the 18Z seem to of had a better grasp of things of what was to come. 

 

Keep smiling folks

???years

[Matty M]

thanks for that Matty-as everyone knows I do like to see factual statistical evidence. Unless I am mistaken the end data is worse than climatology or am I misreading your data for the sites in Ireland? It would seem probable that similar figures would be arrived at over much of inland UK?

At week 3 and week 4 the forecast is marginally better than a forecast using climatology but not by much.

Of course this is an overall average and would disguise any periods of increased accuracy & skill.

 

ACC is a measure of skill. (incorporates climatology)

RMSE .. accuracy. 

 

I would assume the results would be broadly similar for England.

Edited December 3, 2013 by Matty M

[Cecil Hogmanay Melchett]

GEFS 12z are mild and are pretty unambiguous in their appraisal of HP anchored to our SE with presumabley the jet way to our north.

[That ECM]

http://images.meteociel.fr/im/4666/ECM4-48_kim5.GIF

Wow!!

[Matty M]

http://images.meteociel.fr/im/4666/ECM4-48_kim5.GIFWow!!

Ingredients there for a severe wind event for certain with an intense jet-streak overhead.

 

Winds at 925hPa and 850hPa are frightening ad could get to the surface in parts. Would not like to be on the summit of Cairngorm.

[pip22]

Look how tight is the isobars!!

 

 

That is one beast of the storm. Worst than St Jude's? probably or perhaps not. I really think our northern counterparts will get used to it.

Edited December 3, 2013 by pip22

[NorthernRab]

 

I think the biggest concern over the next 3 days is the wind speeds for the north on Thursday

 

 

 

Alongside the heavy snow and subzero temperatures which will follow accompanied by very strong gusts leading to potential blizzard conditions for much of Scotland, surely?

[SW Saltire]

 

 

 

 

These winds could cause slight problems if they were the 'gust' speeds never mind the mean! I'm confident at least 100mph will be recorded somewhere and i'd hate to be on cairngorm summit, a bit breezy might sum it up

EDIT : snap Matty M!

Edited December 3, 2013 by SW Saltire

[SW Saltire]

GEFS 12z are mild and are pretty unambiguous in their appraisal of HP anchored to our SE with presumabley the jet way to our north.

They tend to have characteristics of what Blair's 'poodle' MPs. i.e nodding dogs with the operational and tend to flip drastically and uniformly. Hence, i was suprised to see as many as 11 members this morning supporting some kind of easterly

[Snowman.]

Just got in & an atrocious run from GFS mild all the way through apart from a cool blip in the north - blink and you'll miss it.

High pressure anchored over Europe and a very cold cell over Greenland and Canada blasting powerful LP systems across the Atlantic and pumping up very warm uppers across the UK.

 

 

Just look at all the cold bottled up in the Arctic courtesy of a strong tight vortex and toasty uppers over GB

 

 

UKMO equally wretched with the vortex relocating over Greenland by 144hrs

 

Uppers very warm as well

 

Can ECM pull us out of a hopeless situation?

We're in no bad situation the models today have been decent just because it isn't showing a roaring easterly doesn't mean its bad.

 

12z GFS can change within and instant after all its the GFS and you're worrying about something 192+ which is in the far depths of FI.

 

Here are some positives:

 

- MetO (Thanks to Ian) seem to also be sniffing out and pressure block somewhere to NE.

 

- Anomaly charts are showing something very impressive developing over Scandinavia.

 

- CFS being bashing them heights N/NE.

 

What you're doing is glancing at models then over exaggerating about them.

 

Today is today tomorrow is tomorrow each day having copious amounts of runs and plenty of time for change.

 

Considering we're slipping into a possible battleground scenario there is going to be a lot of uncertainty coming up soon.

Edited December 3, 2013 by SN0WM4N