Model Output Discussion

[phil nw.]

Very funny Ian saying that something amazing must be happenning that is the first time this winter he has said something positive about cold

Indeed,A most unexpected comment,one to save for posterity.

Good on you Ian,it`s good to know you can consider the dark(cold)side.

[LomondSnowstorm]

Came home expecting the usual mild spell talk only to find that last night's 18Z has actually been fairly closely matched by the 00Z and the 12Z, with the euro high bringing a bitterly cold easterly! While the spell is nothing like set in stone, the last few models have been fairly consistent and shown a very similar evolution, despite it being in FI.

[clark3r]

Yeah Iceberg it is a more realisitic evolution, one that has happened before, though granted the only one that managed to complete the evolution through to its logical conclusion (which is a Greenland high, and a roaring southerly jet) was Feb 2005, it'd probably be a strong enough set-up to see us through xmas if it happened. Still I have a big doubts given the models have been too far west in the last 2 weeks with many different things.

i have doubts too! but then again southern britain hasnt had any decent snow before christmas in years and are well over due so maybe the modells we are seeing may deliver!

[SP1986]

whoops posted this in the wrong one before...

I know this a broken record thing but the run up to FI is so disorganised around eastern Europe and Russia, it is nothing like the easterly runs that were there before. The low over Scandinavia just doesn't seem to be like it's plausible evolution would be an easterly - I'm pretty sceptical of this evolution... however if that low was to be moved a little to the west then I so believe an arctic northerly would occur and it may have a little more plausability to it.

For me to accept this run as plausible with regards to an easterly I would have been looking for defined and well organised height rises over Eastern Europe/Northwest Russia, and also preferably the low over Scandinavia either being further west or a little less significant. I do believe the GFS programs too much chaos into the area where the source would come from, therefore I'm pretty sceptical of the 12z (personally)

[Matt12345]

I'll add my two penneth.

Wow what a run. Xmas coning early and the north pole shifting to Leeds

After the last couple of runs this is a belter. Memories of '63 indeed

I'm going out to celebrate

Here we go again. Hope your not disappointed by later runs!

[cyclonic happiness]

GFS parallel is also looking good !

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=192&code=0&mode=1&runpara=1

Interesting times ahead, but caution required !

the parallel run brings the easterly in a bit earlier than the 12z normal, at 168+ or next friday!!

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

Just to look that far out is amazing to see, sod the rest of the run

[karyo]

The UKMO looks reasonably similar to the GFS at 144 hours

12Z UKMO: http://www.meteociel.fr/modeles/ukmo2.php?nh=&ech=144&carte=1021

12Z GFS: http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=144&mode=0

Karyo

[snowmadchrisuk]

the parallel run brings the easterly in a bit earlier than the 12z normal, at 168+ or next friday!!

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

Just to look that far out is amazing to see, sod the rest of the run

The High actually starts building across eastern Britain next Tuesday in 4 days time . If we can get that far it's a start and changes the patten that were in now.

With the exception of run 17 , all Ensemble members have high pressure over the whole country at +180 with at least half extending the high into Greenland.

Edited December 4, 2009 by snowmadchrisuk

[clark3r]

whoops posted this in the wrong one before...

I know this a broken record thing but the run up to FI is so disorganised around eastern Europe and Russia, it is nothing like the easterly runs that were there before. The low over Scandinavia just doesn't seem to be like it's plausible evolution would be an easterly - I'm pretty sceptical of this evolution... however if that low was to be moved a little to the west then I so believe an arctic northerly would occur and it may have a little more plausability to it.

For me to accept this run as plausible with regards to an easterly I would have been looking for defined and well organised height rises over Eastern Europe/Northwest Russia, and also preferably the low over Scandinavia either being further west or a little less significant. I do believe the GFS programs too much chaos into the area where the source would come from, therefore I'm pretty sceptical of the 12z (personally)

hello,

what do you think are the chances of us getting these easterlies?

[MR EXTREMES]

this setup has been showing in every fi chart for over a week still not likely to happen.

remember gfs has been the poorer model out of the big 3 for sometime.

i reckon something cooler maybe on the horizon but by far not as cold as people are thinking,

looking as far as FI is just not good and will end up in dissapointment and i eat my hat if the ECM progs a similar idear to the gfs.

also very much expect tomorrows gfs outputs to be alot different than todays bringing a deluge of dissapointed.

[phil nw.]

The UKMO looks reasonably similar to the GFS at 144 hours

12Z UKMO: http://www.meteociel...=144&carte=1021

12Z GFS: http://www.meteociel...&ech=144&mode=0

Karyo

Yes the first step is the High to our South starting to ridge and the Atlantic trough hit`s the wall as soon as T96hrs.

http://www.wetterzentrale.de/pics/Rtavn961.png

Notice by T144hrs. the Low in S.Europe developing,another step in the right direction to hold the High up and start to send the cold air westwards,something that Steve M posted about earlier.

http://www.wetterzentrale.de/pics/Rtavn1441.png

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

We are not there yet re.getting the cold flow to the UK but good first steps are showing within the near term.

[snowmadchrisuk]

Not a great +144 UKMO tonight , it just doesn't want to show any Northern Blocking.

[SP1986]

The UKMO model if it were to run past 144 hours would most likely give a similar pattern to the GFS 6z - the high pressure of the UK is indicative that the UKMO would send easterlies down into the Balkans rather than over the UK. What this suggests is the building pattern by 144 is still wide open and not necessarily conducive to an easterly. However the different needed to either produce southerlies or easterlies in this case is very small, either could happen, but it's about whether the pattern evolution is realistic or not.. well find out.

[Duane S.]

The rollercoaster is in full flow ATM and for those that missed the cracking 18z pub run last night will be able to find solice in the equally good 12z. This morning's parallel run was good (haven't looked at the latest parallel run yet). Now, could we get the ECM to show it's support please? Don't forget, the ECM came up with a couple of cracking operationals about 5 days. What we are seeing is the almost inevitable northern heights building being reflected on the charts.

I doubt we will end up copping for it as good as the 12z would have us believe but the trend is building for a pretty special pre-xmas treat.

Whatever happens from here on in, VERY VERY interesting model watching days ahead.

[cooling climate]

A very quick flick through the ensembles on meteociel and a good few show a easterly or

northeasterly etc with blocking to the north.

I wonder if Steve Murr is going to give an in depth view of the 12z or perhaps he is

hedging his bets until the ECM run is in.

I myself am very confident that the ECM will back up the 12z GFS run.

With such a strong signal coming from the models now I think we are only a couple of days

away from the models just dealing with the details rather than will it or wont it turn much

colder.

[Geordiesnow]

A far better run from the 12z GFS, the key thing is not what happens with any easterly it shows after 180hrs, but more to the point that the high gets far enough north to give us settled and hopefully inversion based weather.

I agree, i still think more runs are needed to know for sure that there is potentially a euro high link up with heights further North. Of course, until we know that will occur or not then for now, it's not about whether if we see any easterlies in the model output.

To be honest, the outlook is not that bad regarding temp wise. Tuesday looks like being the only day we will see widespread double figures. It's going to be quite wet and windy at times in places but it is December after all.

[karyo]

There is a good downward trent in the 12z ensembles from the 14th onwards

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

Karyo

[cooling climate]

Not a great +144 UKMO tonight , it just doesn't want to show any Northern Blocking.

The heights to the north are there, look on the n/hemisphere charts and then compare to the operational

GFS run.

By t144 on the UKMO run the low in the atlantic is already backing west as pressure rises to the south,

another good run.

[Backtrack]

This is the strangest chart I have ever seen the GFS produce...

[Iceberg]

I agree CC the 12Z ensembles are pretty decent with an approx 60-40 split, with 40% of them going for the cold.

I am still awaiting the ECM 12Z before full judgement (the 18Z is pretty irrelavent, except I would hope for more Ensemble support for the key 144 timeframe.)

ATM still only a 25% chance from me.

[Backtrack]

This is the strangest chart I have ever seen the GFS produce...

It didnt post..

Here ya go!

[Dingwantssnow]

It means 'warm air advection' - basically a plume of warmer air moving from one place to another.

GFS 12z looks promising and would be very snowy if it were to materialise. The building blocks are there and easterlies are quite common in El Nino Decembers (aka 1997, 2002). It will be interesting to see the ensembles whether it has support.

Thanks for that Reef:)

[bluearmy]

the NH plot of the UKMO at T144 isnt far from GFS way to our ne which is significant. IF ecm heads in this direction on the 12z, i'm not sure the seasoned cool heads on here will be able to control the masses. of course, many have posted that if an easterly does come within a decent timeframe, it will often be a surprise. this one is rather a shock having appeared at a timeframe similar to the one originally shown by ECM T240 at the start of the week, only to dissapear and only recur on this weeks GFS runs beyond T300.

[Geordiesnow]

Not a great +144 UKMO tonight , it just doesn't want to show any Northern Blocking.

In terms of Northern blocking, it look's very similar to the 12Z GFS does it not? The high is slightly further east on the UKMO but whether that makes a difference or not, we will never know unfortunately.

There does appear to be a trend that high pressure might take over soon but it's very difficult to know whether the high will lead to a cold spell down the line or not.

Also, don't be disappointed if the ECM does not follow suit, you can't expect all models runs to look the same at such a lengthy timescale. conversely, don't expect an easterly to be "nailed on" if it does incredibly shows something like the GFS.

[Iceberg]

They concur Karyo 8 of the 20 runs have -10 850's at some point during the run for Dorset !.