Model Output Discussion

[SMU]

I would certainly like to see the GFS parallel come more into line with the UKMO and ECM, and would certainly give more consideration to its output now - we'll see what it comes up with in the next few minutes!

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=6&code=0&mode=0&runpara=1

Paul its out to 84 & its backtracked quite a bit on the easterly away from its 00z run- looking a lot more healthy @84-

A huge backstep on the 06z GFS -away from a milder return from the SW- HOWEVER - we would like something to encrouch from that area- ALL the best non convective snowstorms for the South / South west have been in this type of arena....

Big snow event for the SW/ Midlands & eventually the SE on the 192/204/216 charts of the 06z-

S

[SNOW-MAN2006]

Pic of the runs of the potent snowy N-ly afterwards will be the GEM/ECM.

http://91.121.93.17/pics/Rgem1681.gif

http://91.121.93.17/pics/Recm2401.gif

http://209.197.11.95/c9s4a5k3/cds/gfsimages/gfs.20091213/06/168/airpressure.png?dopvhost=charts.netweather.tv&doppl=0bb062f94094a769&dopsig=f08bf00150c2d3ef412e3b1e458fafa9

Similar agreement from the GFS 06z althogh 850's arent particularly cold....

SM06

[PB22]

Paul its out to 84 & its backtracked quite a bit on the easterly away from its 00z run- looking a lot more healthy @84-

A huge backstep on the 06z GFS -away from a milder return from the SW- HOWEVER - we would like something to encrouch from that area- ALL the best non convective snowstorms for the South / South west have been in this type of arena....

Big snow event for the SW/ Midlands & eventually the SE on the 192/204/216 charts of the 06z-

S

Yes, I think the GFS model is slowly being dragged, kicking and screaming, towards the ECM and UKMO.

Pure FI, but the GFS operational brings a Christmas Day whiteout for many!

http://www.wzkarten.de/pics/Rtavn2881.html

http://www.wzkarten.de/pics/Rtavn2882.html

[Cecil Hogmanay Melchett]

06z gfs is a stunner .

It keeps it cold out until the 25TH of DECEMBER. :lol:

Which ever has it right i dont really care,its going to get COLD.

:lol:

Happy days indeed.

[Frosty.]

Big snow event for the SW/ Midlands & eventually the SE on the 192/204/216 charts of the 06z-

S

What about the snow events for the north, it's not just a southern event steve.

The N'ly would be brutal if it verifies, the 6z gfs and 00z ecm give a prolonged N'ly blast and i'm sure there would be scope for polar lows in such a set-up.

[snowmadchrisuk]

Well the mood has changed in here this morning i'm glad to read. ECM going for a really tight Easterly flow that would bring endless showers and blizzards , Followed by a Northerly and then back to an Easterly again . This is a Classic block that would cause constant Easterly , NE'ly Northerly . If ECM is right then that is the best kind of block you can get for the UK.

[bluearmy]

the parallel isnt playing ball into the low res ......................

[SMU]

What about the snow events for the north, it's not just a southern event steve.

The N'ly would be brutal if it verifies, the 6z gfs and 00z ecm give a prolonged N'ly blast and i'm sure there would be scope for polar lows in such a set-up.

yes- your quite right- my post was geared towards the people in the SW as they dont usually get a mention in the outputs!!!

Obviously Scotland getting hammered-

I well & truly hope we get some snowcover thurs & friday- this will then guarentee some very cold day- sub zero......

Steve

[Snowyowl9]

I`ve never seen a battleground easterly on christmas day before not even on the models.

http://91.121.93.17/pics/Rtavn3001.png

Although russia looks to of warmed up with a S-ly

[kold weather]

VEry impressive 06z GFS and shows the value of having a slightly further south jet then on the 0z run, this is exactly the type of evolution I was looking for on...big snowfall event for midlands deeper in FI as well as the low pressure cannot get any further north...

the only problem with the run is the colder air from the north never really makes it down and makes every event probably very borderline in the south.

[Frosty.]

yes- your quite right- my post was geared towards the people in the SW as they dont usually get a mention in the outputs!!!

Obviously Scotland getting hammered-

I well & truly hope we get some snowcover thurs & friday- this will then guarentee some very cold day- sub zero......

Steve

Let's hope we all get some, the gfs 6z and ecm 00z are full of potential for widespread disruptive snowfalls and penetrating frosts with maxima barely above freezing, it really does look like a big chill ahead by later in the week onwards, i'm just hoping the N'ly doesnt get pushed too far west or east and hits us directly instead as shown.

[SMU]

VEry impressive 06z GFS and shows the value of having a slightly further south jet then on the 0z run, this is exactly the type of evolution I was looking for on...big snowfall event for midlands deeper in FI as well as the low pressure cannot get any further north...

the only problem with the run is the colder air from the north never really makes it down and makes every event probably very borderline in the south.

To be honest though- you wouldnt want the volution any other way=- ( all be it a bit further south)

Some people may want to visit trevor Harleys site over the next few days for some of the blizzards arriving in the SW of old- Huge depths of 40/50cms being blown about in an easterly gale.....

I think the very easy Summary for todays runs is- Easterly is now nailed- although the scope for snow is still under question, the northerly reload is becoming clearer & at somepoint the altlantic tries to move in- if its one system in the atlantic then its game over, however if we see an elongated trough develop then expect plenty of undercutting to develop- with the high chance of high pressure back building to the North east...

S

Edited December 13, 2009 by Steve Murr

[Duane S.]

As somebody said earlier on in this thread, don't expect the GFS to do a huge backtrack and suddenly follow the Euros. It rarely does that. But what we have here with the 06z is a great upgrade showing tentative signs of lower pressure to our South and it certainly has nudged towards the ECM/METO with this run IMO.

I'm sure it hs been asked but really, how often do we see 1070 progged in ANY HP system? Let alone a fully fledged GL high! I have to pinch myself sometimes but it is incredible, even moreso when you consider it is December for goodness sake!!!

Forget the details at this stage, with that beast building above we have a VERY interesting couple of weeks ahead.

[bluearmy]

To be honest though- you wouldnt want the volution any other way=- ( all be it a bit further south)

Some people may want to visit trevor Harleys site over the next few days for some of the blizzards arriving in the SW of old- Huge depths of 40/50cms being blown about in an easterly gale.....

I think the very easy Summary for todays runs is- Easterly is now nailed- although the scope for snow is still under question, the northerly reload is becoming clearer & at somepoint the altlantic tries to move in- if its one system in the atlantic then its game over, however if we see an elongated trough develop then expect plenty of undercutting to develop- with the high chance of high pressure back building to the North east...

S

the 00z NAEFS continue to show weak blocking to our north right out till T384 - they also show the mean jet staying very strong to our south but approaching n france by the last week of the year. might i suggest another old fashioned favourite of a mid country split N/S after xmas with somehwere approx n midlands being the change from slush to white: then it all comes s again (just added that last bit for effect!!)

[Whether Idle]

I think the GFS has got it all wrong as early as t72 wrt low pressure in the Baltic - run wont verify at t0 IMHO, and I will reconsider the landscape after ALL the 12zs are in

[Lewis]

I think this is a very important point KW, but perhaps it's not something we should get to hung up on for now. I'm still not entirely convinced that this GFS evolution in the medium term is all that wrong tho, despite the much more potent Easterlies being progged by ECM/UKMO and if it does prove right of

course the ability for the cold air to flood south early in the Xmas week will clearly be hampered.

Overall the pattern looks excellent and is absolutely choc full of wintery potential, no one can deny that, but I think we currently dismiss GFS at our peril.

Most sensible post of the day

The GFS has been the far most consistent of the models from day 1. The GFS has never backtracked and then gone the way of the EURO's, its the EURO'S that have back tracked to fall in line with the GFS, all but the odd run (ECM) for example.

For me the latest 06z introduced colder air a lot earlier, and on a wider basis, that's set the foundation for a potential and prolonged winter cold snap. With easterly's and northerly's.

Temps will be very cold, later in the week barely getting above freezing during the day.

The current GFS 06z is a messy run and opens up so many avenues to different scenarios then again the GFS is more progressive than the ECM and UKMO.

Let's just enjoy the ride, i honestly think the euro models and GFS will meet half way.

Lewis

[kold weather]

To be fair Steve I agree, I'd have thought there would be several big snow events if the GFS is right and it shows us what we need to get that which is no one big low pressure system in the Atlantic. The paralell shows how easily it could go wrong because the cold air never reach the south and the low is further north and strong which prevents the SE flow and instead we go to milder conditions quite rapidly, then we get a massive 945mbs low develop.

What the 06z op run shows though IMO is something that will start to crop up increasingly on the models, esp if the GFS keeps the Greenland block stronger for longer.

[Frosty.]

Oh Frosty mate!

With talk like that you'll have me thinkink that we have been relocated to the USA

This cold period has been modeled fairly consistantly now for the last week and a half though, so well done to all you guy's who work tirelesly on looking at the possible outcome

Big Innes

Hi mate,

From what I can see, the 6z gfs and 00z ecm will give the whole uk some snow during the next 7-10 days with the south most at risk from the E'ly and then the north having it's turn with the N'ly, they both kind of merge in FI and the most important aspect is that if we can get deep cold over the uk, there is a good chance that the mild breakdown could be delayed or we may keep the cold block over christmas, that would be the best present ever.

Edited December 13, 2009 by Frosty039

[cooling climate]

I cannot stress enough that this cold spell is going to be way different to what we have experienced in recent years.

Very much agree with your post especially this sentence because as you say we normally get a three day window of

opportuniity during a cold snap where hopefully we can get some snow.

This is completely different where we will have opportunitiy's from the east and north for snow over a period of at

least a week with daytime temperatures at or below freezing possibly(no fear of any lying snow thawing). If the

Euro's are on the money then perhaps this very cold spell coming up will last over or at least into the Christmas

period.

[Guest North Sea Snow Convection]

I think the GFS has got it all wrong as early as t72 wrt low pressure in the Baltic - run wont verify at t0 IMHO, and I will reconsider the landscape after ALL the 12zs are in

I agree - I don't see any point in looking beyond the latter part of the week until the easterly is completely agreed upon. The broad trend suggests an extended cold spell but as far as the GFS is concerned there is not much to be gained by looking beyond the point (and certaintly not FI!)where it diverges from the euros until there is agreement there

[Paul Sherman]

I think it is worth mentioning with regards the Models that different Models Perform better or worse at different stages on their Output. I will give you a for instance and this is regularly used by NOAA When we Chase Tornadoes in the States.

GFS - Better for spotting trends at further range from about T168 To T240

We then use the ECMWF & UKMO For a better idea of finer details within the 2-5 day range and so do NOAA & The SPC

ECMWF & UKMO Better for T48 To T120

Then over in the States everyone discards those 2 Models for the RUC for the Mesoscale and Finer details from T0 To T48

Maybe the Models we use here should/could be interpreted in the same way ??

Just a suggestion for all the wrist slitting that goes on when everyone pins their hopes on 4 GFS Runs a day

Paul S

[Iceni]

06z gfs is a stunner .

It keeps it cold out until the 25TH of DECEMBER. :yahoo:

Which ever has it right i dont really care,its going to get COLD.

Happy days indeed.

I've kept fairly stumm partly because although I'm begining to get the idea of how what's shown the models works, I still rely on GP JH TEITS and SM to explain them technically — keep up the good work guys , but I'm a great believer in the weather 'balancing' itself which this autumn it's proved to have done: bone dry September/October, followed by the wettest November on record without a single frost so far in my locality. All week I've had a gut feeling this projected cold spell is going to go the distance and deliver proper cold to balance all the mild mush we've had.

Two good things about this cold spell — I'll be able to wear my sheepskin coat which I've only worn for a week in January (and it's 5 years old!), the garlic in the garden will produce another bumper crop and the slug population will be decimated so my veg will stand a chance next summer. :clap::cold:

[Methuselah]

I must admit, I'm more interested in the overall evolution than in the day-to-day/run-to-run fluctuations in individual model output...But, the potential certainly exists, IMO, for something 'quite special' to unfold...

ATM, there are no concrete indications of when the eventual return of the mild mush might ensue; and, that provides a massive window in which snowfalls can occur (1981, 1995, 2000 perhaps)...When was the last time we saw such potential for attack from both the N/NE AND the S/SW - with cold air already in place here and abroad???

All-in-all the only view is optimism. And, it's been many years since I last said that!!

[moses]

ECM control run is even colder than the operational!

http://www.knmi.nl/exp/pluim/vijftiendaagse/Data/15DAAGSE_06260_NWT.png

Back to the GFS and if this is going to trend towards the UKMO/ECM don't expect this to happen in one run. I have found in the past that if the GFS does trend towards the Euros then its a slow backtrack with each consective run.

As the period in question is between +96/+120 I don't expect this to be resolved until tomorrows 12Zs. However lets hope the Euros remain with this trend because the longer they do the more likely the GFS will backtrack.

Re: Control Run Briefly, what is it and how does it differ from the operational.....

[kold weather]

The ensembles are very strongly agreed upon a mild breakdown by the 22-23rd of December, I think there can't be more then 2-3 runs that are cold after that date as nearly all of them pump up the Atlantic low to at least 960mbs and make it a very large system...

However they aren't going to see shortwaves that will likely siphon off quite a bit of the energy that the model shows going into the main Atlantic low...I suspect they are also under doing the strength of the upper high...