Model Output Discussion 17th Dec.2013-12z onwards.

[Gaz1985]

Any Models showing surprise snowfalls in the next few days considering the slack flow and cold 850s??

 

GFS 

 

Ireland first midnight Tuesday

 

Then it moves east effecting parts of N England, Wales and Scotland by 6am Tuesday morning

 

Edited December 22, 2013 by Gaz1985

[nick sussex]

If they are, they wouldnt be a suprise shaky !Extended london ecm ens are at last showing some cold clusters in a fortnight. Slowly but surely. not convinced we have to take the first chance either nick.

That was just me being dramatic! lol Seriously though I'd prefer the quicker resolution shown by the GFS 12hrs run, I'd wager that we would get the favourable trough disruption on that set up come T0hrs. The longer route of course could get there eventually but we then have to hope the Arctic high remains resolute.

[Man With Beard]

Any Models showing surprise snowfalls in the next few days considering the slack flow and cold 850s??

Yes this is also in the back of my mind. Obviously most models are just on the wrong side of this except for high ground in the north, but I think it's going to be close. Bearing in mind the potential volume of rainfall this week, any surprise snowfalls could be quite spectacular too. Don't get your hopes up too much though!

[shaky]

If they are, they wouldnt be a suprise shaky !Extended london ecm ens are at last showing some cold clusters in a fortnight. Slowly but surely. not convinced we have to take the first chance either nick.

lol got me there bluearmy . I'm so desperate for snow that even if my location doesn't get any snow and there's a good snowfall elsewhere I will be really happy.

[UV-RAY]

That was just me being dramatic! lol Seriously though I'd prefer the quicker resolution shown by the GFS 12hrs run, I'd wager that we would get the favourable trough disruption on that set up come T0hrs. The longer route of course could get there eventually but we then have to hope the Arctic high remains resolute.

Indeed Nick, as the longer it takes the more chance of it going the way of the pear.

[Ali1977]

Some good ens by 240, still looking very positive for change towards cold

[Purga]

Looked at from above the far end of FI shows a touch of promise

But it's a long, long way off and still touch and go but at least it's a straw to clutch.

[Richie V]

Hard to believe reading page 43 that theres two of the most serious storms in the relaiable for 20 years approaching. Did someone say it was going to snow?!!

[Timmytour]

After tonight and then Boxing Day night i wonder whether this little feature running up the channel, which GFS 18z shows without any potency, will actually turn out to carry a wee bit more venom?

That said, it might disappear altogether!

[Iceni]

That was posted, I'm fully sure, with a large dose of sarcasm...

 

The first sentence wasn't. The DE isn't a multinational, it's a newspaper…

 

Wow

 

Well it might come as a surprise to some innocents on here, but it wouldn't be the first time a very talented amateur/semi-professional such as GP threatened the interests of those with a lot of investments. The classic way to shut them up is to offer them a job, money for 'research' (which somehow never gets published or implemented) and get them to sign a confidentiality clause.

 

I said I was being cynical, but I'm afraid it's the classic, time-honoured way multinationals operate. I wish GP every success, but will miss his brilliant, educational and informed comments.

Edited December 23, 2013 by Iceni

[TSNWK]

Morning folks. Gfs 00z appears to have dropped the idea of bringing us something colder by the end of the year, heights not nearly as good over the pole and the Norway gap is shut.....it does look chilly around the start of next week, but it fades away..

Met office looks a bit better at 144, heights over the pole are stronger and general profile looks better going forward, also there is cheeky little low presure 500 west miles of Ireland, which is not there on the gfs I wonder if that might go under us as it appears to have a negative tilt.

Cheers.

[That ECM]

Morning folks. Gfs 00z appears to have dropped the idea of bringing us something colder by the end of the year, heights not nearly as good over the pole and the Norway gap is shut.....it does look chilly around the start of next week, but it fades away..Met office looks a bit better at 144, heights over the pole are stronger and general profile looks better going forward, also there is cheeky little low presure 500 west miles of Ireland, which is not there on the gfs I wonder if that might go under us as it appears to have a negative tilt.Cheers.

The low you talk of on UKMO and not on GFS is shown on the ECM at t120 but at t 144 it goes north. Not able to post charts, sorry. Net result is a half way between UKMO and GFS. Shame it didn't go the way of the UKMO as t168 would have been interesting. Edited December 23, 2013 by That ECM

[IDO]

Some very good GEFS with potential for a colder spell for the UK. Looking at them it's apparent that pressure is building close to the UK:

 

 

We need some luck getting the right outcome but a zonal flow has become a lower risk. There are Iceland, Greenland, UK, Scandi Highs and variants on that theme.

 

The Control has the right synoptics. With the trigger low to our west:  

 

Allowing an upper trough to move south:  

 

This enables the next vortex low to fill the trough:   

 

WAA towards Greenland. Not quite there on this run as the high sinks, as energy from the vortex pushes the cold SE:

 

 

 

So plenty of options on the table; from missing out, from cool to cold, and some snowy charts.

 

19 is my fav:    

 

Cold for N, E and West Europe looking like a very high probability from week 2, it is whether the UK can grab some of those headlines.

[AWD]

With this;

and this;

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_ha2_f240.gif

forecast to take place in the Stratosphere over the next couple of weeks, I would expect many tasty but volatile, ens and FI operational charts to start appearing soon.

How this will propagate down into the troposphere and more importantly how it will affect the UK pattern, if at all, remains to be seen. Therefore, I wouldn't get too attached to FI output for the timebeing yet, no matter what it shows!

Interesting times for sure though. January looking a lot more interesting than December for the cold weather lover.

[That ECM]

The interesting thing IMO is that at t144 on the big three there is much disagreement. Often the case when pattern changes are taking place. Clearly doesn't mean we will be entering a winter wonderland but better than looking at a flat pattern from t0 to t 384.

Edited December 23, 2013 by That ECM

[Polar Maritime]

Yes AWD, at what with these 2 powerful storms incoming, it will only to add to the complications in FI. Some interesting model watching over the next few days.

Edited December 23, 2013 by Polar Maritime

[TSNWK]

ECM also not playing this morning, heights have leaked away towards the end of the run and it all looks very purple up over the arctic.

In summary I think we have taken a few steps back this morning for cold.

Edited December 23, 2013 by TSNWK

[winterof79]

GEFS mean still has heights over the pole at 144 even this is FI i feel

 

http://modeles.meteociel.fr/modeles/gens/run/gensnh-21-1-144.png?0

UKMO same time frame

http://www.meteociel.fr/ukmo/runs/2013122300/UN144-21.GIF?23-06

ECM

http://www.meteociel.fr/modeles/ecmwf/runs/2013122300/ECH1-144.GIF?23-12

 

But all three are progging the lows differently so it is futile to go further

http://www.meteociel.fr/ukmo/runs/2013122300/UW144-21.GIF?23-06

http://www.meteociel.fr/modeles/ecmwf/runs/2013122300/ECM1-144.GIF?23-12

http://modeles.meteociel.fr/modeles/gfs/runs/2013122300/gfs-0-144.png?0

The loss of heights over the pole after 144 on the ECM goes against the majority of the GEFS.

Edited December 23, 2013 by winterof79

[IDO]

ECM also not playing this morning, heights have leaked away towards the end of the run and it all looks very purple up over the arctic.In summary I think we have taken a few steps back this morning for cold.

19 of the GEFS at T240 still have heights close to the pole. ECM sinks the polar high to the US. Only a couple of GEFS have that solution. At the moment the ECM looks like an outlier. ECM op tend to run with a pattern for several runs, be it amplified or flat, before it goes with the ensembles. I would say a change is likely, but yes the ECM op is also viable but the mean and ens should tell us more.

[shaky]

In the shorter term the ecm gives a little low pressure across the south of England at 72 hours in a relatively cold slack flow.so you never know some people might get snowfall over the next 2 or 3 days even in the south.one thing I have noticed is the low pressure in the atlantic is going south all the while but very deep.

[Severe Siberian icy blast]

In the shorter term the ecm gives a little low pressure across the south of England at 72 hours in a relatively cold slack flow.so you never know some people might get snowfall over the next 2 or 3 days even in the south.one thing I have noticed is the low pressure in the atlantic is going south all the while but very deep.

Iv been watching this , surprised know one's mentioned it, a kink In the isobars moves across southern areas , I heard it mentioned some days ago , but it's even dropped since. Not sure why ? Edited December 23, 2013 by Severe Siberian icy blast

[bluearmy]

Iv been watching this , surprised know one's mentioned it, a kink In the isobars moves across southern areas , I heard it mentioned some days ago , but it's even dropped since. Not sure why ?

Steve m mentioned it during the ECM run yesterday evening. Not sure about it tbh. looks a bit unconvincing at the moment but there is time. fi output very questionable for the time being, especially the ops.

[Captain Shortwave]

The ECM kind of shows why me and a few others wanted the GFS to be right yesterday. If you have the high over the pole, you might as well use it at the first opportunity because we don't know what will happen to it afterwards. It could remain in situ, fade away or move to another part of the pole. The ECM splits the high with half going towards Canada and the other towards Siberia, leaving us in the status quo. Meaning

Another storm.

Still time for change though.

So;

Today - Very wet and very windy in the south, strong winds elsewhere.

Tomorrow - Stormy in the northwestern third of the UK, slightly better elsewhere.

Christmas day - Calmer with showers in the west, snow over modest elevations perhaps.

Boxing day - possible system moving through southern England, again snow over the hills.

27th - Next storm, possibly as bad as todays.

Beyond - who knows.

Have a good day everyone and stay safe.

Those in the south, watch out for the squall line probably hitting some areas at rush hour this evening. Could be very nasty.

[Cecil Hogmanay Melchett]

UKMO pick of the output this morning but one does get the feeling its going to be a while before even the chance of some decent HLB.

ECM in particular is woeful for cold prospects even out to day 10 with intensely low heights to the North west.

[IDO]

As previously stated the ECM op looks an outlier with respect to the Arctic High migrating to the conus.

 

The mean at T240 (strong polar high anomaly) :  

 

This also shows a slacker zonal flow to the N/NE so opportunity for heights to build given the right ingredients.  Compare to the T168 chart which has a zonal flow (low heights anomaly) to our north:  

 

Its a waiting game and may take several shots before the cold seeps south and to where?

Edited December 23, 2013 by i'm dreaming of...