Winter Model Discussion - The Hunt For Cold -12z 14/12/12

[blizzard81]

I haven't posted on here for a few weeks, been checking the model runs every few days and at the moment, they are absolutely hideous for cold and snow lovers! I hope january and february show signs of turning a lot colder. the ensembles make for bad viewing at the moment!

Well with a quote like that, could you please not post for another few weeks, lol Only yokin!!

The only thing giving me hope at the moment is we still have time for the models to revert back to cold in time for Xmas. However,

only another 24 - 48 hours at most.

[Froze were the Days]

Very poor models outputs this morning in my opinion, at least on the upside it looks like we are slowly going into a pattern change with more of a SW/NE tilt of the jet and both ECM and GFS looks like they agree with this in a week or so's time, maybe poor in the short term but better in the longer outlook as we aren't exactly getting anywhere with that Siberian High pressure at the moment.

As mentioned towards the back end of next week could be pretty mild but at least conditions will be more mobile and we have to look for cold elsewhere.

[snowking]

A few observation from me for the 0-192 period on the 6z ensembles:

1) Almost all are in broad agreement for the overall pattern, with the azores high tilting the jet SW-NE by the end of the period

2) A strong signal for a brief E'ly incursion next saturday as LP dives SE into the continent

3) IF the projected pattern is indeed correct, then the next area of interest for me is what we can do with the azores high. I think its better for all that if its going to turn a bit milder, it turns drier too in order to help those at constant risk of flooding at present. Something such as this:

Is not out of the question for me, and would at least be dry and cooler for most.

We are making assumptions at present that the GFS is modelling the atlantic energy correctly - something which I have never been convinced of in ANY winter.

SK

Edited December 15, 2012 by snowking

[karyo]

I've just viewed the models I wish I hadn't to be honest! The GFS in particular is a horror show but even the ECM manages to bath us in a warm southwesterly flow!

The pressure rise in Iberia and then central Europe is a particular concern as it joins with the Russian high and can lock us in a very mild pattern for a very long time!

I think Christmas is unlikely to be anything else than green now it is just a question how much longer this mild pattern lasts.

Karyo

[Weathizard]

Very poor models outputs this morning in my opinion, at least on the upside it looks like we are slowly going into a pattern change with more of a SW/NE tilt of the jet and both ECM and GFS looks like they agree with this in a week or so's time, maybe poor in the short term but better in the longer outlook as we aren't exactly getting anywhere with that Siberian High pressure at the moment.

As mentioned towards the back end of next week could be pretty mild but at least conditions will be more mobile and we have to look for cold elsewhere.

I wouldn't say that's an upside, just my opinion but a Bartlett-Azores/NW-SE jet tilt is exactly what we don't want. I've seen winters frittered away slowly and painfully with this pattern. I am hoping beyond hope we can stop that azores high rising, the signal for this is growing ever stronger, but if this happens we are in a whole heap of trouble I feel. Don't get me wrong, I don't think this is a done deal by any means but the growing trend for that wretched AH is worrying for our longer term, as well as shorter term prospects.

[Uncle_Barty]

The trend for height rises over Spain and France continues apace this morning at least on the opps.

If this carries on for much longer the easterly options amongst the ensembles will really start to fall away. Whatever happens it looks like either a blowtorch or winter wonderland Christmas. It's not going to be boring over the next few days.

Rather than looking east we need to look to our south as its what happens here that's going to determine the end result in our part of the world. The trend has been clear though recently, which unfortunately is for ever stronger signal for high pressure just where we don't want it.

Noticed we have an uncle Barty posting. Will he be staying for Christmas and new year though?

Jason

Jason

Oh, I'm always around!!

Despite the mild outlook in the short term, I don't think we are going to see a Bartlett setup any time soon.

More worryingly, there are some signs of some heavy rain Weds/Thurs in the areas that really doesn't want it.....

[snowking]

As for xmas day itself:

1) Strongest cluster is actually for a NWly incursion, with the Control and the OP also broadly in agreement with this

2) 12 out of the 20 Perturbations have a cold 850 pool either over or above to move over the UK

SK

Edited December 15, 2012 by snowking

[itsnowjoke]

I wish i hadnt looked on here now who wants a green christmas bah humbug

[Frosty.]

The GFS in particular is a horror show

Karyo

It's not bad at all, yes we have a mild spell but that was always likely and then christmas week currently looks colder and more seasonal with some frosts and even some snow around, towards new year could trend even colder.

[johnholmes]

Just a chart with an explanation on it to try and correct the wrong idea that the European high is causing the jet to...

It is actually the other way round

[karyo]

It's not bad at all, yes we have a mild spell but that was always likely and then christmas week currently looks colder and more seasonal with some frosts and even some snow around, towards new year could trend even colder.

Brief flirting with returning polar maritime air is hardly inspiring and gets watered down as we approach t0.

Let's hope that the pressure rise over the continent will not continue to gain momentum as it can waste several weeks of winter!

Karyo

[TEITS]

As for xmas day itself:

1) Strongest cluster is actually for a NWly incursion, with the Control and the OP also broadly in agreement with this

2) 12 out of the 20 Perturbations have a cold 850 pool either over or above to move over the UK

SK

Yep that is what I was hinting at to Steve M last night with regards to xmas.

So ECM ensembles suggest a split between an E,ly or a SW,ly and the GEFS mean suggests a W/NW,ly.

Good luck to the Pro forecasters for Xmas day.

[Timmytour]

The models are giving us every prosect of a White Christmas

A White Hot one that is!

[Frosty.]

Brief flirting with returning polar maritime air is hardly inspiring and gets watered down as we approach t0.

Let's hope that the pressure rise over the continent will not continue to gain momentum as it can waste several weeks of winter!

Karyo

There will always be bumps in the road as this is the uk and we can't avoid mild weather but I can take some positives from today's output so far, I think the mild spell won't last long and christmas/new year will become rather colder with a more southerly tracking jet again.

[Uncle_Barty]

Just a chart with an explanation on it to try and correct the wrong idea that the European high is causing the jet to...

It is actually the other way round

Thanks for this, John.

Did you mean 'to the right of the jet entrance' in the graphic. Positions of the circles you put in suggests right rather than left?

I've always assumed that the surface patterns are the result of the upper air ones, rather than vice versa? Which is way I usually scratch my head when I see something like "that shortwave is stopping the blocks from meeting/moving east" or whatever, whereas I always thought "the shortwave is there because the position of the blocks allows it to be there.."!

Edited December 15, 2012 by Uncle_Barty

[BOMBHEADS]

not forgetting TEITS has £10 on a white christmas, i hope your right

[johnholmes]

Thanks for this, John.

Did you mean 'to the right of the jet entrance' in the graphic. Positions of the circles you put in suggests right rather than left?

I've always assumed that the surface patterns are the result of the upper air ones, rather than vice versa? Which is way I usually scratch my head when I see something like "that shortwave is stopping the blocks from meeting/moving east" or whatever, whereas I always thought "the shortwave is there because the position of the blocks allows it to be there.."!

Yes your final para is correct as far as I am concerned and any advanced book on meteorology will show this.

re the position of the area for building pressure; it might be better if I give the positions for building surface pressure in writing. In strict correctness it is to do with the thermal trough but it is not that far away from being just the same with the actual upper trough at the 300 or 200mb heights.

The trough must be diffluent, by that it means with air flowing more slowly OUT of it than INTO it. Pressure tends to rise to the left of the jet/wind flow behind the trough. It does the reverse with a diffluent upper ridge; ie. ahead of the ridge and on the lower side of the ridge.

hope that clear things up?

[Summer Sun]

You have to laugh at GFS today it goes from this

to this in 24 hrs

[Scorcher]

It's not bad at all, yes we have a mild spell but that was always likely and then christmas week currently looks colder and more seasonal with some frosts and even some snow around, towards new year could trend even colder.

Am I looking at the same charts as you? Christmas Eve looks very mild indeed on GFS although Christmas Day does indeed look a bit cooler. In the reliable time frame it's mild and it looks like remaining so right up to Christmas Eve, although even that is still in FI. I wouldn't be averse to snow on Christmas Day but it's not looking great at the moment.

[Buriedundersnow]

could someone plz tell me what happened to the pv setting up shop in eastern siberia?

[Frosty.]

Am I looking at the same charts as you? Christmas Eve looks very mild indeed on GFS although Christmas Day does indeed look a bit cooler. In the reliable time frame it's mild and it looks like remaining so right up to Christmas Eve, although even that is still in FI. I wouldn't be averse to snow on Christmas Day but it's not looking great at the moment.

I have no idea which charts you are looking at but this is what is shown after the mild BLIP and also what I have been talking about this morning, the gfs goes from mild to cold and we could have a nwly or nly during christmas week.

[Mr Frost]

A fair number of IMBY posts in here so I will add mine.

After 12 days of harsh frosts and 3 separate snowfalls to start Winter I am not fussed about any mild weather! It makes a nice change to see some rain and hear wind! Also, White Christmas looks in with a shout for a number of places in the North of the UK going by the models and thoughts of the met office.

Winter will come to most parts at some stage during the next 3 months, be patient and look for trends/read the strat thread. No point constantly whining about how crap it looks currently. If you are that depressed about it book a trip to Lapland or a return flight to Scandanvia for a long weekend.

Early days for us in the UK, plenty of time for Winter wonderlands.

Edited December 15, 2012 by Mr Frost

[snowking]

could someone plz tell me what happened to the pv setting up shop in eastern siberia?

I really don't mean this in a patronising way, but can you see on there where the polar vortex is?

Its the large purple mass, based centrally around NE SIberia

SK

[Buriedundersnow]

I really don't mean this in a patronising way, but can you see on there where the polar vortex is?

Its the large purple mass, based centrally around NE SIberia

SK

yeah i know its there today but in quite a few runs towards the end it brings part of it back to canada or greenland and we r told to look out for trends and that would be a trend now when someone says setting up shop to me that means it going there and staying there for an extended period

[johnholmes]

some of you may wish for a little white sorry light relief with the pdf link below