Model Output Discussion - 30th November onwards

[bluearmy]

But sticking with ukmo means we can't look more than a week ahead - BORING!

I just trawled through the 00z and 12z gfs op for this thurs/fri/sat from mid last week onwards. To give it credit is ludicrous. It's like thanking Switzerland for helping us win WWII ! Ukmo was the best model and even then, is early efforts when it saw the timescale were not great. The ens means have proved the best guidance on this. as with the previous cold shot, ECM was too amplified (slow off the eastern seaboard) and gfs too flat and quick. just a note that gem op, having picked the general pattern earliest, dumped the northerly first but then went uber flat. The fact that we have ECM, gem and jma all heading the same way should give confidence that this is the direction the nwp will head over the next few days. Will something then change to alter the direction of travel? Perhaps but then that's the beauty of all this.

And btm, I that think things would get interesting before Xmas if the easterly drift is still in place by mid month.

[Hotspur62]

Just a quick question. Does the UKMO have any plans to extend their outlook(to Jo Public) to say 192hrs?With all the technology they have it would be great if they would extend their model accordingly. Even then, it would be less than what ECM and GFS do now but it would be nice to compare the 3 main models at a slightly longer range. Apologies if wrong thread and please put in appropriate one if this is not the one!!

[swfc]

But sticking with ukmo means we can't look more than a week ahead - BORING!

I just trawled through the 00z and 12z gfs op for this thurs/fri/sat from mid last week onwards. To give it credit is ludicrous. It's like thanking Switzerland for helping us win WWII ! Ukmo was the best model and even then, is early efforts when it saw the timescale were not great. The ens means have proved the best guidance on this. as with the previous cold shot, ECM was too amplified (slow off the eastern seaboard) and gfs too flat and quick. just a note that gem op, having picked the general pattern earliest, dumped the northerly first but then went uber flat. The fact that we have ECM, gem and jma all heading the same way should give confidence that this is the direction the nwp will head over the next few days. Will something then change to alter the direction of travel? Perhaps but then that's the beauty of all this.

And btm, I that think things would get interesting before Xmas if the easterly drift is still in place by mid month.

My point was aimed at the new members who get slightly carried away and confused with the eye candy in fi.I also said its good for looking at trends and good to look at even if not at all reliable

[Nick F]

Gee whiz, that's one long southerly draw at t+192 on the 12z ECM, all the way form Morocco and the Canary Islands if I'm not mistaken. Though ECM does have a tendency to over amplify the upper flow at times.

 

Really need to see either Atlantic troughing/upper energy divert further SE into SW Europe, or Atlantic troughing to stall/amplify out west and allow height rises north across the UK while cold pooling to the E and NE moves SW over northern Europe - if we are to have any hope of getting an easterly. Hints in F.I. of this perhaps happening, but it's a long road, with the flow upstream perhaps or perhaps not playing ball. 

 

If only the models were as good at predicting easterlies as they are northerlies!

Edited December 2, 2013 by Nick F

[TSNWK]

Good ole ECM 3rd time lucky I hope. Ensembles are out, not bad, not bad at all. Always nice to see the grid dropped a level to capture a cheeky -10 run

[Grimsby Snow Lover]

Compared with yesterday's forecast the NAO looks like going negative as we head towards the middle of December if today's run is anything to go by. Something worth keeping an eye on as this could suggest a blocked Atlantic.

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif

[nick sussex]

Just a quick question. Does the UKMO have any plans to extend their outlook(to Jo Public) to say 192hrs?With all the technology they have it would be great if they would extend their model accordingly. Even then, it would be less than what ECM and GFS do now but it would be nice to compare the 3 main models at a slightly longer range. Apologies if wrong thread and please put in appropriate one if this is not the one!!

The UKMO operational goes upto 168hrs, we only get to see upto 144hrs though, the reasons for that are beyond me! I'm not sure cost wise how much this would add to their budget if they went out to say 240hrs like the ECM or even 192hrs like the JMA. Even if they did extend it I doubt it would be open for public view.

[Jason T]

But sticking with ukmo means we can't look more than a week ahead - BORING!

I just trawled through the 00z and 12z gfs op for this thurs/fri/sat from mid last week onwards. To give it credit is ludicrous. It's like thanking Switzerland for helping us win WWII ! Ukmo was the best model and even then, is early efforts when it saw the timescale were not great. The ens means have proved the best guidance on this. as with the previous cold shot, ECM was too amplified (slow off the eastern seaboard) and gfs too flat and quick. just a note that gem op, having picked the general pattern earliest, dumped the northerly first but then went uber flat. The fact that we have ECM, gem and jma all heading the same way should give confidence that this is the direction the nwp will head over the next few days. Will something then change to alter the direction of travel? Perhaps but then that's the beauty of all this.

And btm, I that think things would get interesting before Xmas if the easterly drift is still in place by mid month.

 

 

15TH Dec CFS, Should please the eye BA, As for faith I know, I know, But it's there in a Cold wash of Winter tsunami.

 

[SMU]

Evening All-

 

 

Ive not replied to anything today- so sorry if ive missed anything important.

A juicy post to get your teeth into before the 18z.- An honest evaluation of the model performance this week.

 

So we are there now ( all but) - but the wide variations between the models have been removed & finally we have some unity with the best of it seemingly here at T84.

 

http://www.meteociel.fr/modeles/jma/runs/2013120212/JN84-21.GIF?02-12

http://www.meteociel.fr/modeles/jma/runs/2013120212/JN84-7.GIF?02-12 into 96.

 

Within this short window of 18-24 hours there is the prospect of storm force Northerly winds & heavy snow showers packing into Northern Scotland, western Scotland, NI & possibly NE Scotland-

Im sure we will see a line of snow showers glancing the extreme east coast- but all staying offshore.

 

 

Perhaps now we have allignment of sorts - todays a day to reflect on the Rollercoaster that has been the model output of the last few days.

 

ECM-

Very very strong consistency from the ECM, showing the Northerly pattern - in-fact the ECM has had the correct pattern type on Nov 26 @ 00z & 12z - but really got its act together on the 27th-

 

Here are the ECMs for the last 5 days running 216 - 192 - 168 - 144 - 120

 

00z + 12z 216 chart 27th

http://www.meteociel.fr/modeles/ecmwf/archives/2013112700/ECH1-216.GIF?00 SPOT ON

http://www.meteociel.fr/modeles/ecmwf/archives/2013112712/ECH1-240.GIF?12  VERY GOOD

 

00z + 12z 192 Chart 28th

http://www.meteociel.fr/modeles/ecmwf/archives/2013112800/ECH1-192.GIF?00  SPOT ON ( 100 miles to far west though) possibly slightly over amplified

http://www.meteociel.fr/modeles/ecmwf/archives/2013112812/ECH1-192.GIF?12  EXCELLENT

 

00z + 12z 168 Chart 29th

http://www.meteociel.fr/modeles/ecmwf/archives/2013112900/ECH1-168.GIF?00 V Close but to amplified at the SW Greenland tip

http://www.meteociel.fr/modeles/ecmwf/archives/2013112912/ECH1-168.GIF?12 V Close but to amplified at the SW Greenland tip & to far west.

 

00z + 12z 144 chart 30th

http://www.meteociel.fr/modeles/ecmwf/archives/2013113000/ECH1-144.GIF?00 V Close but as above- slightly to amplified & to far west 200 Miles.

http://www.meteociel.fr/modeles/ecmwf/archives/2013113012/ECH1-144.GIF?12 V Close but eastward correction 100 miles - still to amplified.

 

00z + 12z 120 01st

http://www.meteociel.fr/modeles/ecmwf/archives/2013120100/ECH1-120.GIF?00  Spot on barring the over amplification

http://www.meteociel.fr/modeles/ecmwf/archives/2013120112/ECH1-120.GIF?12  Correction East, angle of amplification more NE instead of North-  Looks to be spot on.

 

00z + 12z 96 2nd today

http://www.meteociel.fr/modeles/ecmwf/archives/2013120200/ECH1-96.GIF?00 SPOT ON

http://www.meteociel.fr/modeles/ecmwf/archives/2013120212/ECH1-96.GIF?12 12 hours later spot on....

 

 

ECM Summary :

 

If you look at the GLOBAL Picture- back across the last 12 runs you will see it nailed it on the 26th - some 9 days out at 216.- that's the ridge in the Atlantic, Deep low digging south over the North sea,

Aleutian Ridge moving SE downstream & a split flow over the states with a low in the Midwest.

 

The ONLY area of fault on the NEW updated ECM has come from the area around the SW tip of Greenland & the speed of the solution- being slow & amplified, in-fact its not 'quite' been there & that subsequent swing to a faster solution has taken the amplification past the point when it no longer goes North, but ENE traversing the coast of southern Greenland.

HERE

 

What we are talking is an UNDER estimation of the Jet by a maybe a FEW M/S -

 

The net correction is a 'slightly flatter pattern, a slightly eastward jog (200 miles is nothing in weather terms- but Massive for the UK) & of course 1 full less day of cold as there is no high pressure to traverse around the high but through it.

 

We need to be clear though the ECM has never promised sustained HLB, just over amplified the ridge towards Greenland.

Incidentally the ECM made a similar mistake the other week, that is- totally lick the GFS in the overall pattern but mistake the over amplification- which again has big repercussions for the UK-

this was the model output ECM

 

http://www.meteociel.fr/modeles/ecmwf/archives/2013111412/ECH1-144.GIF?12 

Notice ridging into Greenland

ACTUAL Varification:

http://www.meteociel.fr/modeles/ecmwf/archives/2013112312/ECH1-48.GIF?12 -

 

Notice the flatter upstream pattern- right in the place it hurts for us.

 

What to take away from the ECM for the rest of Winter,  ECM is the leading model over the GFS, it licked the 500 MB pattern 9 days in advance & has stuck with it run after run all the way through, however around the Iceland region it 'sees' more ridging than perhaps is going to happen-

there's not many places in the globe that the extra amplification matters, however at the southern tip of Greenland there comes a cut off where systems all of sudden STOP going North & suddenly start going East- this through an angle of 90 degrees.- so a SMALL error / bias which would normally swing from say 10 degrees to a ever so slightly flatter 20 degrees to the North is suddenly swung from 0 degrees North to nearly 90 degrees East.

This pattern change has a direct impact on the sustainability on UK cold as it shortens the cold & reduces the westerly penetration of cold-

 

This small error is some peoples eyes is a huge error- hence the calls for the ECM being trounced / its failed its followed the GFS etc etc-

No the model error is small but the visible impact to the UK is huge.- so the perception is skewed towards a thought process that the model is rubbish.

 

Its not- its king with a bias just like nearly all the models.

In terms of the rest of the Winter wit the ECM I will generally STILL run with this model - why? because the Hemispheric pattern for the last 4 years has been heavily loaded towards Northern blocking so fortunately the ECM bias hasn't been visible due the conditions actually supporting the bias, however this winter thus far that bias has made it look a little foolish - when actually its performed superb.

So for Future budding cold spells look towards Southern Greenland to see if there is any low pressure or shortwave action that is the key trigger - as this may be to slow & to far west in the ECMS eyes- then as it corrects east the low slips east of the tip rather than South.

 

SW GREENLAND = CRUCIAL TO THE UK COLD.

 

The GFS model... ( Links are the 12z & 00z model only)

 

What can I say about the GFS  ..... well in the name of balance when the ECM at 216 was picking up the pattern for spot on the GFS was here-

 

216 00z & 12z

http://modeles.meteociel.fr/modeles/gfs/archives/gfsnh-2013112700-0-216.png?0 Very good but to flat with the US pattern

http://modeles.meteociel.fr/modeles/gfs/archives/gfsnh-2013112712-0-216.png?12 VERY GOOD

 

192 00z & 12z

http://modeles.meteociel.fr/modeles/gfs/archives/gfsnh-2013112800-0-192.png?0  Pretty good but upstream Midwest low very fast ejecting out to pole

 

http://modeles.meteociel.fr/modeles/gfs/archives/gfsnh-2013112812-0-192.png?12 AWFUL AWFUL

look at the eastward bias in all its glory our northerly it over into Germany

 

168 00z & 12z

http://modeles.meteociel.fr/modeles/gfs/archives/gfsnh-2013112900-0-168.png?0  Not bad- pretty close upstream

 

http://modeles.meteociel.fr/modeles/gfs/archives/gfsnh-2013112912-0-168.png?12  POOR AGAIN- look at that bowling ball low to the NE- but like all the other runs to Greenland ridging

 

144 00z & 12z

http://modeles.meteociel.fr/modeles/gfs/archives/gfsnh-2013113000-0-144.png?0 V Poor but very flat- +4c isotherm across England some 14 degrees to warm @ 850.

 

http://modeles.meteociel.fr/modeles/gfs/archives/gfsnh-2013113012-0-144.png?12  Poor again- to far EAST - England has zero cold air. - Eastward bias evident again.

 

120 00z & 12z

http://modeles.meteociel.fr/modeles/gfs/archives/gfsnh-2013120100-0-120.png?0 Pretty good ticks all the right boxes.

http://modeles.meteociel.fr/modeles/gfs/archives/gfsnh-2013120112-0-120.png?12 Slightly to far east again but catching up & westward correcting.

 

96 00z & 12z

http://modeles.meteociel.fr/modeles/gfs/archives/gfsnh-2013120200-0-96.png?0 SPOT ON

 

http://modeles.meteociel.fr/modeles/gfs/archives/gfsnh-2013120212-0-90.png?12 SPOT ON.

 

GFS SUMMARY

 

Why do I personally Hate the GFS- because its always playing catch up to the EUROS, Its always flat when the Euros show an amplified pattern so is wrong nearly every time we get a Scandi or Greenland high.

 

We get 4 runs a day- which If I overlaid all the other 12 runs would show a multitude of scenarios, some at the extreme eastern end of the range, some over amplified ( looks like the 18z is usually the pub run) & some just on some wild tangent- usually the 06z.

 

Should I dismiss it- well I'm going to change my tact on GFS, what the faster flat pattern helps to show is usually the opposite of the pendulum, If the ECM is at the slowest amplified end then you can bet your bottom dollar that the GFS will be the flattest, with this in mind quite often the final solution is a blend of each- the halfway house- but normally not quite halfway to the GFS, more like 1 third to the GFS & 2 thirds of the EUROS-

 

From this you could generate a predicted forecast, but with one very difficult element & that is does the 2 third house create any pinch points that could change the final pattern so drastically for the UK-

 

2 main areas arise from this- ( For UK cold)-  Southern tip of Greenland energy is 1 & the other is when we are setting up Easterlies & low pressures are projected to move south then SW whilst the ridge builds above.-

The fast solution ( GFS ) will throw the low pressure further into Europe - but the bigger impact on the long-wave pattern is instead of a Scandi High you see a 'Sceuro' high, with the UK in a southerly or SE flow & the jet to flat on top.

Then as the Easterly approaches its how far does the GFS move to ECM where the Sceuro is suddenly a Scandi high again because the solution was in-fact slower.

 

This example is VERY evident tonight.

 

GFS SCEURO HIGH- http://modeles.meteociel.fr/modeles/gfs/runs/2013120212/gfsnh-0-192.png?12

JMA Scandi high -http://www.meteociel.fr/modeles/jma/runs/2013120212/JN192-21.GIF?02-12

 

This all comes from FAST v SLOW solutions.

 

Anyway, what to take away from the GFS-

 

12z Eastward bias. IGNORE- if its significantly FLATTER or EAST than the ECM.

6z/18z  . IGNORE - if its significantly different to the ECM.

 

00z- do not discount- I cannot find to many faults with the 00z GFS- not biased in many ways & generally the most consistent.

What we can also take away is the GFS will find the weaknesses in the blocking first ( usually) because its primed for a faster solution- so that can support us going forward with comparisons with the ECM.

 

 

The model that's come out best again is the UKMO- resilient & Smooth, seemless & minimal fuss.

In this case it started at 144 with the 2 thirds house & has never changed since.

 

 

 

 

The Scandi High..........

 

I'm pleased that I presented this idea first ( even Mr Holmes questioned the 500 heights not following ANY ridging to Scandi)

 

The forecast was driven by the angle of the jet coming out of Canada & the subsequent split flow-

It is now appearing in the models-

 

So what would be tonights forecast- based on the ABOVE model inconsistencies.

 

GFS- 12z 240- Slight amplification -

http://modeles.meteociel.fr/modeles/gfs/runs/2013120212/gfsnh-0-240.png?12 

But a Euro high- 

 

Mild SW winds for the UK.

 

 

ECM 240 12z Much better amplification

http://www.meteociel.fr/modeles/ecmwf/runs/2013120212/ECH1-240.GIF?02-0  KEEN ESE wind & very cold at the surface, -

JMA 192-   Run of the day

http://www.meteociel.fr/modeles/jma/runs/2013120212/JN192-21.GIF?02-12  Easterly @ 216

GEM 240 - AWSOME

http://modeles.meteociel.fr/modeles/gem/runs/2013120212/gemnh-0-240.png?12 

 

But... the Best suite of the day is the ECM 15 day.

 

00z Chilly

http://www.knmi.nl/library/php/resample_image.php?filename=/exp/pluim/Data/pluim_06260_0_00_60.png&width=692 day 11/12 mean around 4c.

 

12z very much colder

http://www.knmi.nl/library/php/resample_image.php?filename=/exp/pluim/Data/pluim_06260_0_12_60.png&width=692 ( swop to 12z) Day 11/12 mean now down to 2.5c & the control + op very cold.

 

Therefor the updated forecast based apon the model bias today is-

 

Northerly toppler, for 24 hours, high pressure ridging over the top but contrary to the GFS no WAA getting into the UK barring the extreme NW -

The SE staying cold-

day 8 -9 look for Energy dropping south into scandi in the form of a shallow low- with rapid pressure building NE, the UK sitting at the extreme western end of blocking for day 9/10.- light Southerly or SE tug.

Then energy getting underneath tugging the winds easterly & increasing day 12.

 

 

Look out for the Maps for 13/14 December.

 

best regards

Steve

 

 

 

 

 

 

[Matty M]

A really striking back-end windfield there about to hit Scotland.

 

Look at the gradient. A severe warning for Scotland if that worked out as progged.

 

[Cloud 10]

Maybe the NASA model has picked out a new trend at just 120 hrs.

 

[SW Saltire]

Just a quick question. Does the UKMO have any plans to extend their outlook(to Jo Public) to say 192hrs?With all the technology they have it would be great if they would extend their model accordingly. Even then, it would be less than what ECM and GFS do now but it would be nice to compare the 3 main models at a slightly longer range. Apologies if wrong thread and please put in appropriate one if this is not the one!!

 

 

I think if it did our opinion of it would be changed significantly. I mean even the GFS would not be so persistent with it's opposition to blocking as it would have 240 less hours to be wrong! 

[Matty M]

Yikes for Scotland and then into parts of North Sea coasts, even more so for Denmark, Holland, north Germany.

 

A real vicious storm.

 

[stratty]

 

 

Look out for the Maps for 13/14 December.

 

best regards

Steve

 

Stunning write up Steve - thank you!

[Hotspur62]

The UKMO operational goes upto 168hrs, we only get to see upto 144hrs though, the reasons for that are beyond me! I'm not sure cost wise how much this would add to their budget if they went out to say 240hrs like the ECM or even 192hrs like the JMA. Even if they did extend it I doubt it would be open for public view.

Thanks Nick. Suppose with all the cuts over last few years it sort of makes sense but it would be nice if they could show the world globally how good they are as in the Long Run if they proved to be successful it might bring its own  financial rewards

[Matty M]

Powerful jet-streak . If this were to hit London, we'd have a Red Alert out!

 

[Mucka]

Slightly better amplification than the 12z with energy going a little more NE than just E but not sure it will be enough as yet

 

Edited December 2, 2013 by Mucka

[stratty]

Slightly better amplification than the 12z with energy going a little more NE than just E but not sure it will be enough as yet

 

 

Wow! I think northern coast of mainland Europe could be in a spot of trouble with flooding!

[Hotspur62]

I think on behalf of most of us on MOD thread thanks SM for your your last post. Must have taken you a while but put it in a way that those like me who are still learning can understand(I think).Got a headache now though lol!!

[SMU]

Thanks for the comments ( around 2 hours for the post)

Anyway- changes afoot on the GFS- Major- the jet looks like going over the Scandi low as opposed to under it this time around....

 

It will alter the post 192 projections - but possibly still to flat for a big easterly....

 

S

[Gavin Hannah]

18Z showing an ever so slight upgrade with the cold shot.  Slightly further west with the cold uppers, but the differences are so minuscule, it will hardly be noticeable.

Looks like the the cold shot will last two days max (three at a push) starting with some stormy weather for the north of scotland bringing blizzard conditions especially to the high ground.

The -5 uppers start leaving the UK the early hours of sat morning. 

Edited December 2, 2013 by IBTHToThoseShortwaves

[radiohead]

80+mph gusts possible for northern areas early Thursday with blizzard conditions possible on high ground.

 

[nick sussex]

GFS 18hrs run is certainly moving towards the ECM here, we await the low moving east across Canada now to help sharpen the down stream trough, please GFS don't mess around!

[Geordiesnow]

Yikes for Scotland and then into parts of North Sea coasts, even more so for Denmark, Holland, north Germany.

 

A real vicious storm.

 

 

GFS a few days ago did to some extent projected a rather tightly packed isobar low pressure system but was toned down but now even the ECM has toned the low up quite a bit. 

 

Once again, another Northerly looking more sorry for itself with any ridging is so half hearted it may not of even bothered trying but due to the strength of those winds, we actually could get some pretty cold air heading our way but it be those winds during  Thursday which may cause the most disruption, certainly one to keep an eye on. 

 

Brief window for convective snow showers in places so if your in one of those areas in the firing line for snow showers, then enjoy them whilst it lasts is the main message. 

[AWD]

12z NAEFS showing strong hints of a block to our E/NE but perhaps not far enough north for the golden gem. South Easterly rather than easterly?

Nevertheless, the trend continues though.

Edited December 2, 2013 by AWD