Model Output Discussion - Sunday 20:35--->

[Paul]

Please continue the model discussion here.

All the latest model runs are available here on Netweather:

Model Viewer

GFS, Ensembles, Fax, UKMO, ECMWF, NMM + coming soon GEM all within a click:

http://www.netweather.tv/index.cgi?action=nwdc;sess=

Model comparison - compare the 'big 4'

http://www.netweather.tv/index.cgi?action=modelcomp;sess=

Please note that this is for discussing the models, not for general winter chat or cold weather craziness - a new ramping thread has been started if you want to have a bit of a ramp at the latest runs:

Please keep your posts on topic - and bear in mind the team will be removing the off topic ones whenever they see them.

[PB22]

As I just posted in the other thread:

ECM ensemble panel:

http://www.ecmwf.int/samples/d/inspect/catalog/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!168!pop!od!enfo!enplot!2009120612!!/

And the ECM ensembles for De Bilt:

http://www.knmi.nl/exp/pluim/Data/PLUIM_06260_NWT.png

Not too bad model output tonight, but a long, long way off and plenty can, and probably will, change. The odds remain against a significant cold spell affecting our shores.

[SMU]

Please continue the model discussion here.

All the latest model runs are available here on Netweather:

Model Viewer

GFS, Ensembles, Fax, UKMO, ECMWF, NMM + coming soon GEM all within a click:

http://www.netweather.tv/index.cgi?action=nwdc;sess=

Model comparison - compare the 'big 4'

http://www.netweather.tv/index.cgi?action=modelcomp;sess=

Please note that this is for discussing the models, not for general winter chat or cold weather craziness - a new ramping thread has been started if you want to have a bit of a ramp at the latest runs:

Please keep your posts on topic - and bear in mind the team will be removing the off topic ones whenever they see them.

Ok Guys- Now we have had the enjoyment of the 12zeds lets just bring it down to reality- & I want to run some GFS archive runs that show how this promising situation at 144 can go Jordons verticus-

However before that- Something thats been prevelent over the last few years is that when the UKMO 120/144 is not on board the GFS seems to follow & occasionally the ECM_

We have got a good ukmo tonight & indeed there is a stark reminder of this type of evolution from yesteryear- NOTE THE DATE THOUGH nearly 25 years ago-

http://www.wetterzentrale.de/archive/ra/1985/Rrea00119850101.gif

UKMO 144

http://www.wetterzentrale.de/pics/Rukm1441.gif

So the like for like comparison of Jan 85 V the UKMO output SHOULD be very encouraging, however shortwaves didnt seem to exist in them good ol days..

Lets cast our minds back to Xmas day 2008- Nick Sussex was tucking into his roast turkey & stratos ferric was setting up his new Scaletrix-

As they logged on the GFS rolled this xmas feast out..

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=0&ech=6&heure=12&jour=25&mois=12&annee=2008&archive=1

Wow thats a tasty run there- plenty of WAA up greenland, then the PV moving SW under the block & eventually west at the tail end of FI-

IIRC there was some tongues a wagging on the forum that day & indeed boxing day-

http://www.meteociel.fr/modeles/gfse_cartes.php?jour=26&mois=12&annee=2008&heure=12&archive=1&mode=0&ech=6 Especially note the T138 Chart & the 180 Chart-

THe greenland high scenario & subseqent bitter NE air is built all on the house of cards that is WAA up Western greenland eventually Running Parallel northwards-

Note the 138 chart-- ring any bells against todays GFS runs ( & ECM)

Now move on X2 days to the 28th Dec 2008 ( By then the forum is a buzz)

note if we are X2 days down the line then the ridging & block should be around T90.....

http://www.meteociel.fr/modeles/gfse_cartes.php?jour=28&mois=12&annee=2008&heure=12&archive=1&mode=0&ech=6

T90- http://91.121.94.83/modeles/gfs/archives/gfs-2008122812-0-90.png?12

Again- run the evolution & note the Greenland high scenario/......

Onto the 29th Dec- everyone is ramping up some kind of cold from the NE & Genuine Greenland high-

we should now be t72 & counting-

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=0&ech=6&heure=12&jour=29&mois=12&annee=2008&archive=1

t72-

http://91.121.94.83/modeles/gfs/archives/gfs-2008122912-0-72.png?12

looks good? _----- Wheres our greenland high at 144-

Oh dear shortwave spoiler through the block-

http://91.121.94.83/modeles/gfs/archives/gfs-2008122912-0-144.png?12

Ok so what happened in the end...

http://www.meteociel.fr/modeles/gfse_cartes.php?jour=1&mois=1&annee=2009&heure=12&archive=1&mode=0&ech=6

no block, nothing no greenland high- THe cold air stayed out into the North Sea....

Beware people the evolution with shortwaves is a deck of cards....... we have all been bitten so many times-

Steve

[West is Best]

ROFL ... just seen the 12z GFS!! And, indeed, the others. Blimey.

But we've been here before at this time range only to be cruelly denied. Steve's post is right!

[ChartViewer]

Ok Guys- Now we have had the enjoyment of the 12zeds lets just bring it down to reality- & I want to run some GFS archive runs that show how this promising situation at 144 can go Jordons verticus-

However before that- Something thats been prevelent over the last few years is that when the UKMO 120/144 is not on board the GFS seems to follow & occasionally the ECM_

We have got a good ukmo tonight & indeed there is a stark reminder of this type of evolution from yesteryear- NOTE THE DATE THOUGH nearly 25 years ago-

http://www.wetterzentrale.de/archive/ra/1985/Rrea00119850101.gif

UKMO 144

http://www.wetterzentrale.de/pics/Rukm1441.gif

So the like for like comparison of Jan 85 V the UKMO output SHOULD be very encouraging, however shortwaves didnt seem to exist in them good ol days..

Lets cast our minds back to Xmas day 2008- Nick Sussex was tucking into his roast turkey & stratos ferric was setting up his new Scaletrix-

As they logged on the GFS rolled this xmas feast out..

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=0&ech=6&heure=12&jour=25&mois=12&annee=2008&archive=1

Wow thats a tasty run there- plenty of WAA up greenland, then the PV moving SW under the block & eventually west at the tail end of FI-

IIRC there was some tongues a wagging on the forum that day & indeed boxing day-

http://www.meteociel.fr/modeles/gfse_cartes.php?jour=26&mois=12&annee=2008&heure=12&archive=1&mode=0&ech=6 Especially note the T138 Chart & the 180 Chart-

THe greenland high scenario & subseqent bitter NE air is built all on the house of cards that is WAA up Western greenland eventually Running Parallel northwards-

Note the 138 chart-- ring any bells against todays GFS runs ( & ECM)

Now move on X2 days to the 28th Dec 2008 ( By then the forum is a buzz)

note if we are X2 days down the line then the ridging & block should be around T90.....

http://www.meteociel.fr/modeles/gfse_cartes.php?jour=28&mois=12&annee=2008&heure=12&archive=1&mode=0&ech=6

T90- http://91.121.94.83/modeles/gfs/archives/gfs-2008122812-0-90.png?12

Again- run the evolution & note the Greenland high scenario/......

Onto the 29th Dec- everyone is ramping up some kind of cold from the NE & Genuine Greenland high-

we should now be t72 & counting-

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=0&ech=6&heure=12&jour=29&mois=12&annee=2008&archive=1

t72-

http://91.121.94.83/modeles/gfs/archives/gfs-2008122912-0-72.png?12

looks good? _----- Wheres our greenland high at 144-

Oh dear shortwave spoiler through the block-

http://91.121.94.83/modeles/gfs/archives/gfs-2008122912-0-144.png?12

Ok so what happened in the end...

http://www.meteociel.fr/modeles/gfse_cartes.php?jour=1&mois=1&annee=2009&heure=12&archive=1&mode=0&ech=6

no block, nothing no greenland high- THe cold air stayed out into the North Sea....

Beware people the evolution with shortwaves is a deck of cards....... we have all been bitten so many times-

Steve

Hi Steve,

Blimey thats an amazing turnaround at T72. Pesky Shortwaves!......What also makes me nervous

is the Chart shown By The Eagle on the previous thread which actually shows a warm sector mixed in and to be honest how many times also have we seen Easterlys arriving....Think the one in Feb 2005 (i think) was a classic example where we had warmer air mixed in from the South East which meant rain not snow.

But no denying it charts at moment are corkers......Roll on 18z......

Also I still am to be convinced by the Ensembles to be honest.

[kold weather]

Very true Steve but I think you've gotta think we are going to get some cold now, even if it does end up being through the standard inversion style.

The 12z ECM ensembles look good to me, can only see 3-4 of them that wouldn't be cool/cold at 168hrs and most will probably evolve into a much colder pattern down the line.

Still early days, that point of veiw I quite agree with!

[bluearmy]

i recall it well steve but i dont think conditions in the arctic were so beneficial at the time.

meanwhile, the eagle made a decent call re the temps from the 12z ecm. a bit of a surprise that de bilt isnt sub zero at days 9 and 10 with a continental flow but then the uppers arent that low at this point despite thicknesses mid 520's.

[ISAAC]

Far too much excitement on the model discussions today. There's going to be a lot of broken hearts if the ramping continues.

This is simply why i take anything past T+72 as a pinch of salt simply due to thenumbe let downs in the past, especially when it comes to easterlies

'Trends' in FI are nice, but we are still in the process ofseeing genuine trend. One stunning 12z UKMO with backing on GFS and ECM does bring excitment to be fair but im going to wait till the end of Tuesday before i get my hopes up.

[SP1986]

Can you link me to those ensembles please KW? I always forget to save the web address to my bar!

[Leigh]

Sorry,a bit off topic but what time does the 18z come out?

[SP1986]

starts roughly 21:30, finishes about 22:30 for the reliable timeframe and 21:45 for the 180-384 hour period.

[stewfox]

Far too much excitement on the model discussions today. There's going to be a lot of broken hearts if the ramping continues.

This is simply why i take anything past T+72 as a pinch of salt simply due to thenumbe let downs in the past, especially when it comes to easterlies

'Trends' in FI are nice, but we are still in the process ofseeing genuine trend. One stunning 12z UKMO with backing on GFS and ECM does bring excitment to be fair but im going to wait till the end of Tuesday before i get my hopes up.

Agree 20 pages of ramping but not much detail

Its ok to keep posting charts at T168 or T180 or T240 and their fun to see, but it seems everyone has joined the band wagon. However thats all F1

I want to see how things evolve up to T72 , THEN we will have a much better idea . Just remember what we had 24 hrs ago cf 48hrs ago.

[David-kig]

Hi Steve,

Blimey thats an amazing turnaround at T72. Pesky Shortwaves!......What also makes me nervous

is the Chart shown By The Eagle on the previous thread which actually shows a warm sector mixed in and to be honest how many times also have we seen Easterlys arriving....Think the one in Feb 2005 (i think) was a classic example where we had warmer air mixed in from the South East which meant rain not snow.

But no denying it charts at moment are corkers......Roll on 18z......

Also I still am to be convinced by the Ensembles to be honest.

oh yes feb 2005 easterly brought a day of sleet turnt to rain then to snow in the evening across southern england. that were forecast for alot of snow across southern areas and that wat warm sector does breaks hearts and see sleet alll day long lmao

[nick sussex]

Another great post from Steve M, i'm sure i speak for everyone in saying a big thankyou to him for all the incredible work he does on here.

Yes his post certainly shows why i have an aversion to shortwaves! to me they just add complications to an already difficult route to cold but when they do come off the results can be very good as we've seen from this evenings output.

Certainly the point SM makes about the ukmo was very evident a few years back, i'm sure some members remember the gfs going for an easterly, the ecm followed for a couple of runs and the ukmo didn't want to know, the end result was tears and cancelled sledge orders and the ukmo right.And yes folks that was another shortwave fiasco!

[Snowmad79]

So uhm, the example of last years epic failure HP retrogression was nothing to do with the fact that PV was stuck on or near to greenland with too much shortwave energy coming off it ? where as this years it appears to be split and away from that greenlandish position of last year so in theory shouldnt shortwaves or LP systems be less of a problem this time around ?

I guess what I'm really saying is I think this time there will be less in the way of spolier activity for this possible upcoming event

[mountain shadow]

Further to what Steve Murr was saying regarding short wave spoilers.

I would argue that we haven't seen such projected northerly block in a long long time, with AO tanked negative and massive disruption of the Polar Vortex especially so early in the season.

I hope that logic would dictate that the disrupted vortex would lead to a less powerful jet stream which would in turn reduce the likliehood of spoiler short waves.

But then that's logic for you.

[Cloud 10]

Can you link me to those ensembles please KW? I always forget to save the web address to my bar!

ecm ensembles :o

[SP1986]

Thanks for that, it does look at least on these ECMWF ensembles despite the fact it's too far out to be 100% certain there are more ensembles between -5C and -10C at 850hPa.

[Paul]

18z just starting to roll in now, for those who haven't used it yet, you can use the gfs viewer on nw to compare it to the last run, just load a second chart by selecting it from the right hand side drop down menu, then click the prev button next to it, you can then see the two runs alongside eachother and the system displays the same timeslots so you're looking at like for like charts:

http://www.netweathe...tion=nwdc;sess=

[Fozfoster]

All the usual suspects amassing for the 18z .

[nick sussex]

This evenings mean height comparisons give us an almost text book omega block on the ecm.

http://www.meteo.psu.edu/~gadomski/ECMWF_12z/hgtcomp.html

For those newer members it looks like the greek letter omega, those positive red anomalies from greenland southwards, basically for cold lovers its the equivalent to foodies of 3 star Michelin cuisine.

[Duane S.]

Is it just me or the better the charts get the more cautious and pessimistic I become? Most strange because I am normally so bullish about things. Maybe because I have been bitten so many times before by 'dream synoptics' only for it to trip over the final hurdle.

Yes shortwave activity is the normal culprit BUT I do feel this time is different (like I did every other time for some other reason no doubt :o ). But this time we don't have a great big shortwave producing PV machine sat over greenland, there is a real genuine opportunity for this to happen.

The fact that the 3 main models are so much together on this tells me we could be on the verge on something very special. To have the GFS, ECMEF and most importantly, IMO, the METO, on our side for such an cold and unusual pattern right out to +144 is extremely unusual. Add to that the Parallel which has been consistent throughout and even the most staunch sceptics on this forum must be raising an eyebrow over the way these charts are going.

Steve explained very well indeed on the previous thread why the ensembles are to be taken with a small pinch of salt at this stage although they will take on a much greater relevance as we head nearer T+0

NOTHING is nailed on and won't be for a considerable amount of time yet. Somebody posted earlier that the only way now is down. I'm afraid that is probably the harsh reality. DO remember that there is virtually NO WAY the charts are going to continue showing this sort of setup from now until the event. Downgrades are inevitable, let's just hope that when they occur, and they will, that they are only a small little fruit fly in the ointment and not a whacking great ugly bluebottle messing everything up!

[winter watcher]

I know i said the ecm was a cruical run for todays fantastic output and it turned out brilliant thats the main three models on board now. However i would not be suprised if the 18z decided to play things down a bit as long as we still have a trend to go by. I know its known as the pub run but its got to have had a heel off alot off vodka to top off the previous runs we have seen thus far. Heres hoping

[Roadrunner]

You've only gotta look at the amount of users online to know Winter could be back with a bang. Lets hope the 18z continues the trend and plays ball. I think Mr Sussex had better stock up on the prozac for the next few days, could have a few customers!

[chionomaniac]

One of the critical favourable changes that we have seen in the modeling has been the transfer of ridging from the Pacific to the Atlantic following the vortex split. This was noticeably absent following the vortex split earlier on in the year. The reduction of Pacific heights I believe will aid retrogression of the pattern and can be traced out on the blocking forecasts.

c