Winter Model Discussion - Cold Hunting -12Z 03/01/13

[Cheshire Freeze]

Oh dear, feel like I'm going to be compelled to stay up for the 0z again tonight! Good job I'm on annual leave from work!

[Panayiotis]

As much as I want cold/snowy weather, I see too many folk saying "this run won't happen or "this model clearly hasn't read the strat forecast" just because the model doesn't show what they want or expect.

While this may be a rogue run or an eventual incorrect outcome, it seems some people never learn!

It's worth remembering that a SSW does not guarantee cold for the UK.

Yes you are right it doesnt guarantee cold for us, but the NH profile on the 18z (in the medium-longer term) doesnt fit what a SSW essentially does and that is to destroy the PV, thats why many are dismissing the 18z. Edited January 4, 2013 by Panayiotis

[Weather Boy]

As much as I want cold/snowy weather, I see too many folk saying "this run won't happen or "this model clearly hasn't read the strat forecast" just because the model doesn't show what they want or expect.

While this may be a rogue run or an eventual incorrect outcome, it seems some people never learn!

It's worth remembering that a SSW does not guarantee cold for the UK.

True, but unless the theory's is completely wrong, it is highly unlikely that a SSW would result in a raging PV as shown by the 18z. I therefore think that it is reasonable to say that this run is a bit bats and it will be surprising if it is well supported by its ensembles. Probably a whacky run for the bin unless supported by further runs over the weekend.

Edit: in effect payoitis beat me to it, but more succinctly!

Edited January 4, 2013 by Weather Boy

[JP1972]

Yes you are right it doesnt guarantee cold for us, but the NH profile on the 18z (in the medium-longer term) doesnt fit what a SSW essentially does and that is to destroy the PV, thats why many are dismissing the 18z.

Despite all the background signals and favourable hemispheric patterns, recent history tells us that we are perfectly capable of missing the boat.

Just saying, feet on the ground all that.

[Jason M]

The end of the run is bonkers, I think someone needs to hand the 18z a copy of the strat forecast! It just seems to bin this and goes into mid-winter default mode, blowing up the PV.

In teems of the nearer future, the problem seems to be the persistence of high pressure to our south. This was part of the problem last feb from memory.

In terms of the 18z though, probably one for the bin (even though I hate saying this). It is doing exactly what the met have predicted the NWP models would and has gone a bit loopy. Expect the kitchen sink to be thrown by the GFS in the next few days.

Your right about the pressure to our south. Not only did it wipe out Feb last year, it did the same for the latter part of Jan and all of Feb in 2011. Once pressure rises over Iberia its a devil to get rid of. That said, doesnt mean it will happen this time so fingers crossed.

Jason

[Radiating Dendrite]

As much as I want cold/snowy weather, I see too many folk saying "this run won't happen or "this model clearly hasn't read the strat forecast" just because the model doesn't show what they want or expect.

While this may be a rogue run or an eventual incorrect outcome, it seems some people never learn!

It's worth remembering that a SSW does not guarantee cold for the UK.

It does not guarantee cold no, but after a strong warming and then second warming, the vortex would not simply regroup over the pole in a few days, precedent shows us this.

[SP1986]

Im not dismissing the 18z because of anything technical, but when you have an FI that shows widespread -9C at the surface with an 850hPa profile of +1 to +2C, that kind of thing only happens on a continental landmass, it simply doesn't happen on an island! But if anyone has any examples, Im ready to be proved wrong for sure.

[Catacol]

Blasted Azores/Iberian high - it really is a bane for us coldies isn't it?

As I posted earlier GP's composite for the coming period has low pressure to the south. Mind you, so did his composite for December, and that went haywire.

Anyone know what the sun is doing?

[Weathizard]

What on earth has happened with the GFS here? Looking at temp charts -9 with 2 degree uppers? Really?

Edit: already posted above. Bizzare though.

Edited January 4, 2013 by Weathizard

[Cheshire Freeze]

Anyone know what the sun is doing?

Providing the nation with page 3 goodness?

[LomondSnowstorm]

If there was a single credible bit of evidence to support the rapid reformation and strengthening of the PV just a week after the SSW then it might be worth taking seriously. As it is, it's just a standard crazy FI solution on the GFS and I'm surprised we haven't seen even more incoherent nonsense lately at this range to be honest. Shorter term it continues to look interesting but the basic outlook remains the same: heights building from mid latitude to high latitudes with some kind of cold block to our north by days 8-10.

[Panayiotis]

Despite all the background signals and favourable hemispheric patterns, recent history tells us that we are perfectly capable of missing the boat.

Just saying, feet on the ground all that.

Could you give me some examples? We are 'perfectly capable' and more likely to get a colder outcome if the hemispheric pattern is favorable and thats what most of us are looking for.

[MrSunshine]

Providing the nation with page 3 goodness?

Wouldn't wipe my I have a problem with that rag.

[Polar Maritime]

As I posted earlier GP's composite for the coming period has low pressure to the south. Mind you, so did his composite for December, and that went haywire.

Anyone know what the sun is doing?

Dead as a dodo.. And has been for months, taking into account it's solar max..

http://www.space.com/19131-sun-solar-space-weather-2013.html

Edited January 4, 2013 by Polar Maritime

[BlueSkies_do_I_see]

If any of you accessing this through a mobile, here is a link to Ian Fergusson's forecast. I couldn't get the one posted earlier to work.

http://news.bbc.co.uk/weather/hi/news/newsid_7760000/7760862.stm

Edited January 4, 2013 by BlueSkies_do_I_see

[Bobby]

Despite all the background signals and favourable hemispheric patterns, recent history tells us that we are perfectly capable of missing the boat.

Just saying, feet on the ground all that.

Here's something from earlier about the SSW and the statistics on whether it brings cold weather, he statistics suggest SSW's actually turn things warmer on average, read into that what you will

From a total of 54 SSW events compared with 1940-2012 CET anomalies

1-20 days following SSW is 0.038°C warmer than the 20 days preceding SSW.

7-28 days following SSW is 0.116°C warmer

15-45 days following SSW is 0.089°C warmer.

http://forum.netweat...80#entry2463540

Edited January 4, 2013 by Bobby

[Catacol]

Quick check of solarham reveals a quiet December and relatively quiet still, at least in terms of flares though there are currently 12 spots. For those wondering why I am talking about the sun... GP believes it is what put December's forecast out of whack. Certainly the solarham archive reveals that the latter half of November saw some proper solar activity. So while we all get excited about the accepted science of SSW, half an eye on the more controversial aspect of solar impact on global circulation may be no bad thing...

Dead as a dodo.. And has been for months, taking into account it's solar max..

It was not dead in last half of November - check the solarham archive. Link to December failure?

Edited January 4, 2013 by Catacol_Highlander

[on the coast]

Well another take from another run. My gut feeling is we are going to have a very cold dry spell with severe frosts. High pressure seems keen to stay near by on all runs so far. Model runs early next week may tell a different story?

[JP1972]

Here's something from earlier about the SSW and the statistics on whether it brings cold weather, he statistics suggest SSW's actually turn things warmer on average, read into that what you will

http://forum.netweat...80#entry2463540

Thanks Bobby.

It just goes to show that SSW doesn't necessarily mean the veritable feast of ice and snow we all crave in the UK.

I hope I'm proved wrong (I genuinely do) but until the models are singing from pretty much the same hymn sheet it would be foolhardy to assume we're about to enter the next ice age!

As many have already said the models may well continue to throw up various solutions until T0, so until something is nailed I'm of the opinion anything can happen.

Edited January 4, 2013 by JP1972

[Polar Maritime]

Quick check of solarham reveals a quiet December and relatively quiet still, at least in terms of flares though there are currently 12 spots. For those wondering why I am talking about the sun... GP believes it is what put December's forecast out of whack. Certainly the solarham archive reveals that the latter half of November saw some proper solar activity. So while we all get excited about the accepted science of SSW, half an eye on the more controversial aspect of solar impact on global circulation may be no bad thing...

It was not dead in last half of November - check the solarham archive. Link to December failure?

Off topic here sorry mods.. Yes a burst was all we got, we are in solar max, this solar max is very quite compared to those of late. Look it up.. this is in our favour to regarding cold weather.

Edited January 4, 2013 by Polar Maritime

[microclimate]

Normally we have epic charts to look at that fail to deliver (Dec 12 springs to mind along with every other failed easterly!) but this time we are waiting for something that hasn't shown it's full hand yet. Lot more interesting in my view.

[TEITS]

I haven't looked at the ensembles yet except the mean but I tell you what the +168 mean is miles better than the last time I checked.

The more I look at the model output the more mistrusting I become and FI for me is now +96/+120. At the moment im not convinced the models are handling that LP S of Greenland correctly and how far E this will be. A knock on effect of this is the HP that develops to the N of the UK. Lastly if a SW develops off the main LP in the Atlantic will this track SE or NE. If this tracks SE and undercuts the developing HP then bingo you could have a cold E,ly.

Still the potential for a sudden E,ly to develop and what I mean by this is a shift in the model output with this appearing at +72/+96.

[mulzy]

Hmmm, quite a few ensembles in the day 6-8 range (yes, I know it's FI) show a Scandi High. Interesting...

[Jason M]

Ensembles out to 192, very strong signal for Scandi High now emerging on majority of members. They are not all well positioned but plenty of cold runs in there and not at T30000 hours either.

Very encouraging but no guarantees of course!!!

Jason

[Catacol]

Well another take from another run. My gut feeling is we are going to have a very cold dry spell with severe frosts. High pressure seems keen to stay near by on all runs so far. Model runs early next week may tell a different story?

I think this is a definite possibility in January (though for us in the SW a little "brush" with a slider low would be nice... :-)

If I understand the more experienced posters on here I think they are expecting the frosty high to our north to move to the west thus introducing chances of N / NE flow. GP has mentioned in his long term forecast that in Feb the high may retrogress so far west that we end up in a westerly NAO pattern, and that is not good. RJS sees it presumably staying in Greenland for a while as he has called a very cold Feb overall. However the gist of this is that frosty to start may become less settled as time goes on, especially if heights lower to our south as the composites suggest.

All of this of course is subject to influence from the Stratosphere. The longer it remains split and shattered the better... and it would appear that we are on course for a long term vortex annihilation. Presumably once this happens then mean wind reversal and lack of arctic circulation in general will encourage long term high pressure maintenance.

It all sounds like good news... but the collapse of the teleconnections in December still leaves me cautious. I hope the sun remains fairly quiet, and hope that mean wind reversal can survive as long as possible.