Model Output Discussion 13/11/13 >

[chionomaniac]

Time for a new thread.

 

Please keep on topic - no off topic posts, no gif obsession and please do remember the zero tolerance policy.

 

To start us off here is the 6-10 day NAEFS ensemble mean anomaly. Impressive Atlantic ridge heh?

 

 

 

What seems most likely is that the ridge pushes east, flattens and undercuts - the all important southern Europe low heights help this occur- and these show no signs of abating on the 11-15 anomaly charts - though the Atlantic ridge does.

[SMU]

Someone in the old thread asked me why I did think the ECm 12z was correct-...

 

 

I think its a LITTLE over progressive with the high shearing east - with to much emphasis on a ridge thrown to Scandi, I expect to see more troughing towards Svalbard not allowing the ridge to get that far-

 

Either way though the solutions are good-

 

also ECm day 10 AGAIN-

http://www.meteociel.fr/modeles/ecmwf/runs/2013111312/ECM1-240.GIF?13-0

 

Who remembers 2010 & again 2013 when the big cold spells have arrived via a GH you see in the day or 2 running up to the big throw of WAA - 2 low pressures in the western atlantic getting spread south & north -

 

We have gone from tentative signs of blocking at day 10 to a slightly more solid level of confidence of blocking at day 10-

 

If I was doing the superensemblemean tonight none of it would include the GFS 12z suite.

 

Dont expect to many miracles from the 18z- the only caveat to that is if it 'sees' the split energy at 168 over SW greenland- if it doesnt the energy moving east will phase & flatten the high

If however it does continue to wake up & smell the coffee expect a stella dendrite run!

 

S

[radiohead]

Impressive.

 

[BlueHedgehog074]

A really good post by Weathermaster in the previous thread. (Just something else to help start the thread off along with some of the other great posts above, but it does go to show that even at 144 hours, the models aren't 100% certain on the positioning of the Low over the UK (although it does look like some sort of general flow from the North is likely). Also encouraging that the ECMWF operational model is following the ECMWF ensemble mean. Both of which show low heights to the South-East of us. Is good news if you want the cold to continue. Probably do, however, still need to be aware of what the GFS shows with its eagerness to flatten out the pattern as this cold spell could still end up to be a Northerly toppler (even though re-loads of the pattern are possible), although it's possible the GFS could start falling more in line with ECMWF's ideas on future runs and further strengthen the confidence of the European's model outlook. (Edit: although Steve Murr mentioned that the ECMWF's output tonight could be being a bit progressive/quick with one or two of its ideas, so a fair number of changes could obviously still be expected - at least probably until the models get an even better handle on the pattern).

My view on the models this evening and where each one stands,

Firstly the next 3 days (72 hours),

Thursday -

24.png

A large area of high pressure sits to the West of the UK but there is a low to our far North East and with the UK in the middle it will give very strong winds. Gale to severe gale force along Scotland and Northern parts of Ireland and England. Overall it will be a cloudy day with showers for many but Eastern and South Eastern parts of England will see some sunshine. Minimum temperatures on Thursday evening and into the night will get down to -1c to 3c in Northern parts.

254T.png

Friday -

48.png

High pressure covers most of the UK giving cloudy but dry weather everywhere with winds easing down. Scotland may see a few showers passing through and gale force winds will stay over the far North of Scotland. Minimum temperatures on Friday morning will be widespread ranging from -1c to 2c across inland parts in Scotland and England.

48t.png

Saturday -

72.png

High pressure stays over England and Wales but lower pressure moves in over Scotland and Ireland. The weather will be the same as the day before cloudy, dry and dull although Northern parts of the UK may see some sunshine in the late afternoon. Showers will also stay in the North. Saturday morning will be cold across England and Wales especially in the South East of England with temperatures going down to 0c to 2c.

72t.png

Now onto the outlook between 96 to 144 hours using GFS, ECM, UKMO, JMA, GEM, NAVGEM and CMA.

96 Hours Sunday -

Most of the models are starting to agree on the track of the big storm over Northern Norway although GEM and the CMA both place the center of the low in a completely different place to the other models.

The good news today is that most of the models do seem to make a better attempt with the high in the Atlantic in getting it to go up North to Greenland.

Comparing the models side by side the ECM seems to have good agreement along with the GFS, UKMO and a few other models backing it up.

ECM96.gif

120 Hours Monday -

Each model does begin to struggle here none of them entirely agree with each other so I wouldn't take anything past this point too serious for now.

To show the differences,

Six models apart from the GFS agree on a low to the North of the UK none of them really know where it will be yet or how deep it is,

UKMO is a good example,

UKMO120.gif

Next the models aren't sure on how much PV will be to the North of Norway after that big storm moves on,

The differences between GEM below,

GEM120.png

And NAVGEM show the ranges of PV in that area,

NAVGEM120.png

Finally in the Atlantic all the models apart from the CMA make an attempt to build pressure towards Greenland and to add to the mix the models are asked to predict what the low entering the Atlantic is going to do when it meets this large high pressure system.

The GFS, ECM, UKMO, JMA and GEM all do show something similar in that area so good agreement to some degree,

JMA shows what 5 models show in some way,

JMA120.gif

NAVGEM and the CMA look like the odd ones out here and the CMA is the only one that looks flat out of all of them.

144 Hours Tuesday -

Big differences between the models now but most of them do show a large area of high pressure in the Atlantic.

ECM144.gif

The UKMO seems the most keen on building pressure the most to Greenland,

UKMO144.gif

NAVGEM and the CMA both go their own ways at this point but the majority left do show some cold charts at this point despite their differences. The low I mentioned at 120 hours gets handled differently between each model and how it interacts and affects the high pressure in the Atlantic. The models show this evening we don't know yet since they all do something different but the good news is despite this they do show colder weather.

Overall - The models in the past 24 hours have got a better hang of the large storm over Northern Norway although two models are still struggling with it. Next most models show a low to the North of the UK but there are differences between them at this point and even in the Atlantic on how the high reacts to the changes around it. By Tuesday most models do show cold charts and there does seem to be decent agreement among those who do. I would say the changes we have seen in the past 24 hours have been good.

Edited November 13, 2013 by DiagonalRedLine

[bobbydog]

not an expert opinion by any means, more of a 'flying by the seat of my pants' observation of the models on a hemispheric level over the past few weeks.

now, the big aleutian high has been an ever-present feature in the models for some time now and here it is-

 

 

 

to expect huge snowfalls in the UK in november is a little optimistic to say the least.

 

however,.... i have a feeling that this big HP on the other side of the pole, is the 'brick in the washing machine'. (the washing machine being the tropospheric polar vortex. it has tried to balance itself with the atlantic ridging we keep seeing modelled.

 

as it winds itself up for its winter spin-cycle and gets faster and faster, it will eventually shake itself to pieces.....

 

and as steve murr might say-..... BOOM!.....

Edited November 13, 2013 by bobbydog

[bluearmy]

Impressive.

 

 

 

certainly appears to show a propensity for higher heights further north though the shape and movement if you follow the run  could well be indicative of a wide variation of solutions, some of which could be where we have deep depressions running around the top of a uk block. i note the end of naefs again showing a signal for a se greenland height rise on the spreads - fairly weak at the moment but then we are looking for signs of a reload. all in all, a pretty cold outlook and who knows, we could even see a november snowfall before the month is out.

[shaky]

The ecmwf 10 day mean is brilliant.its showing practically a ridge in the atlantic going up into greenland.for a mean chart that's pretty impressive. Have a feeling where going to wake up to a wonderful ecm tomorrow morning

edit:its way better than this mornings aswell.

Edited November 13, 2013 by shaky

[Cloud 10]

A steady decline in temperatures on the 12z ECM long range ensembles as the troughing

in Europe establishes.

 

 

 

Nice to see the -10 appear on the scale!

[Paul]

For those who may be wondering where to view the models - you can look at all the major ones here:

 

Model links:

GFS

Ensembles

ECMWF

GEM

Met Office

Fax

Compare the big 4

[Frosty.]

Ecm 12z ensemble mean is even colder and more wintry than the 00z..very impressive looking mean for the time of year from a coldies perspective. So it now looks like an Arctic blast next week is locked and loaded and snow will fall in various parts of the uk and frosts will become widespread and locally severe, especially for those areas which have snow cover, it's like a throwback to nov 2010 if the Ecm 12z mean or anything like it verifies, a very cold spell next week with ice, snow and frost dominating the forecasts, lovely jubbly.

[nick sussex]

Impressive.

 

Whats more interesting is the 850 spreads over Greenland which interestingly show a big range at day 8 but which lessens between days 9 and 10 while at the same time theres a narrow range across the UK.

 

The suggestion here is still uncertainty regarding how far north any high gets initially but even with some toppling the cold flow is maintained across the UK. So its looking like our friendly low heights over northern Italy aren't going anywhere soon.

[Snowman.]

CFS has just given us this...

 

 

 

[SMU]

More amplitude on the +PNA Pattern from the 18z at 114 ( digging the trough further south) plus a slower area of vorticity in the atlantic-

 

Because the 12z GFS phased these 2 together ( due to timing ) then I expect another nudge towards the euros on this run-

 

Can we get a fully blown decent GFS run - well that remains to be seen-

* ignore the ensembles..

 

S

[radiohead]

18Z GFS doesn't look like following the ECM, notice the difference between the low pressure in the Med on the ECM, and the low off Newfoundland too. (T138)

Edited November 13, 2013 by radiohead

[Cloud 10]

More amplitude on the +PNA Pattern from the 18z at 114 ( digging the trough further south) plus a slower area of vorticity in the atlantic-

 

Because the 12z GFS phased these 2 together ( due to timing ) then I expect another nudge towards the euros on this run-

 

Can we get a fully blown decent GFS run - well that remains to be seen-

* ignore the ensembles..

 

S

 

That's gonna be tough to do if it churns out stuff like this. 

 

[swfc]

Looks like gfs is sticking to its guns?As sm said tho it does seem to be out of kilter with the euros so see how tom goes.Reverse psychology may work btw

Edited November 13, 2013 by swfc

[Allseasons-Si]

Not been posting for a while due to family issues,although i have been viewing in here frequently,who wouldn't

 

there has been some fantastic outputs in the last few days and not forgeting the input too

 

back to MOD,i have just looked at the 18z from gfs and at just 96hrs,that shortwave N of scotland is a lot more deeper than the 12z at the same time frame,

 

12z18z

 

just a question for the more expierenced,would this give more amplification to the hp to the west,i have a hunch that it would.

[radiohead]

18Z GFS overall quite consistent with the 12Z GFS out to T168 except the cold uppers are gone a bit quicker this time.

[nick sussex]

Sadly the GFS 18hrs goes downhill even after a more positive start. It throws too much energy into Greenland and then decides to bring more shortwave drama into the mix by throwing this east/ne whereas the ECM phases this with low pressure moving out of Canada.

 

Oh well it wouldn't be the same without some drama, the GFS just loves the attention, its like the NWP version of Paris Hilton! that makes me sound old, lets say Lady Gaga, all style over substance!

 

Should make the morning model runs essential viewing, will the GFS be right and therefore avoid the cat litter tray or will this just be another GFS fiasco?

[Cheshire Freeze]

Sadly the GFS 18hrs goes downhill even after a more positive start. It throws too much energy into Greenland and then decides to bring more shortwave drama into the mix by throwing this east/ne whereas the ECM phases this with low pressure moving out of Canada.

 

Oh well it wouldn't be the same without some drama, the GFS just loves the attention, its like the NWP version of Paris Hilton! that makes me sound old, lets say Lady Gaga, all style over substance!

 

Should make the morning model runs essential viewing, will the GFS be right and therefore avoid the cat litter tray or will this just be another GFS fiasco?

 

The GFS makes for painful viewing. Nice to know the ECM and UKMO are in some form of agreement though.

 

Just watch it throw out a brilliant FI.

Edited November 13, 2013 by CreweCold

[SMU]

another fail from the GFS- just another one in a long line-

 

lets try it tomorrow 12z...

 

night

 

S

[swfc]

Seems wev been down this rd over the last couple of winters regarding the euros looking solid and gfs being out on its own and brandished being poor ete.24 -36 hours later big change to gfs!!Im in the euros corner but it does come to mind.Anyway biblical blocking awaits in f1

[Frosty.]

I'm not concerned what the GFS 18z shows because we have a stunning ECM 12z ensemble mean and op run and likewise the ukmo and gem..and we even have darren bett saying we are in for a strong cold blast and snow..so, 18z won't spoil a fantastic day and night of cold golden charts..more upgrades tomorrow please. : - )

[Cloud 10]

Does anyone have a decent link to the latest fax charts?  The meteociel ones have stopped updating.

[radiohead]

Does anyone have a decent link to the latest fax charts?  The meteociel ones have stopped updating.

 

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