Winter 2014-15 thread

[picog]

Will we see any SSW before mid January, reading Cohen's update on the Strat thread we may have to be patient ( I hate that word ). Still there's sod all you can do it about it except enjoy the weather you've got.

At least it is not hammering down and blowing a hooley! If christmas was like today, cold clear and frosty, I'd be OK with that.

[Dorsetbred]

Greetings from central Europe. This winter is, so far, even worse than 13/14 which is really remarkable considering there was no winter last year. I'm not optimistic about the future. 11C at 6AM, spring is here I guess.

Welcome to NW, can you include your location for us please?

[Hocus Pocus]

At least it is not hammering down and blowing a hooley! If christmas was like today, cold clear and frosty, I'd be OK with that.

Indeed, it's a beautiful day today and I'll be more than happy if it continues like this for the rest of winter.

[feb1991blizzard]

There is a stonking mean Atlantic ridge on the 6z GEFS.

[matty007]

Indeed, it's a beautiful day today and I'll be more than happy if it continues like this for the rest of winter.

 

As would I, Winter doesn't always have to be wet and windy. 

[I remember Atlantic 252]

Indeed, it's a beautiful day today and I'll be more than happy if it continues like this for the rest of winter.

 

Sadly a one off, windy again tomorrow and mild

[richardc1983]

Not mild! But does mild mean average for this time of year or actually mild!

[johnholmes]

Not mild! But does mild mean average for this time of year or actually mild!

 

depends whose version you read, some on here have their own agenda. If you read Met O outputs then the words mild, rather mild, cold etc all have specific values for each part of the country.

[Summer Sun]

The beeb are suggesting a chilly start and end to next week and milder around mid week

 

http://www.bbc.co.uk/weather/features/30462998

 

Matt Taylor also talking about westerly winds for Christmas week

Edited December 13, 2014 by Summer Sun

[Dorsetbred]

 

 

Matt Taylor also talking about westerly winds for Christmas week

I think that is line with a lot of folk, green is the scene...

[Geordiesnow]

The beeb are suggesting a chilly start and end to next week and milder around mid week

 

http://www.bbc.co.uk/weather/features/30462998

 

Matt Taylor also talking about westerly winds for Christmas week

 

And as we know, the weather can easily change so whilst the trend may be for Atlantic during the xmas period, it does not fully mean this will be the case. If you want to place a bet on a main city having a white xmas basing on the outputs, it would have to be Glasgow really, especially if we get a cold NW'ly. 

[feb1991blizzard]

I hate to say it but if the strat charts don't start improving soon (particularly but not exclusively referring to the parallel GFS run), then we can forget about anything until late January.

[Weather-history]

I hate to say it but if the strat charts don't start improving soon (particularly but not exclusively referring to the parallel GFS run), then we can forget about anything until late January.

I can't see why we can't have wintry outbreaks before any SSW/MMW event?

For instance why was January 1979 so cold? The SSW didn't happen until the end of February.

The bulk of the cold of winter 2008-09 occurred before the SSW event. I remember Glacier Point going for a frigid February because of the SSW event. Infact the second half of February was exceptionally mild. The mildest part of that winter was after the SSW event.

The coldest part of winter 1976-77 was before the SSW event, after it the rest of that winter was largely mild.

I think we are becoming too hung up on what goes on in the stratosphere. Not sure why it has become such an "in thing" in the last 5 or so years. Hardly anyone were talking about it 10 years ago.

Edited December 14, 2014 by Weather-history

[MP-R]

^^ Yep. All we need is more amplification of the current pattern and some of the recent northwesterlies could have been pretty wintry northerlies. We're not a million miles away but something needs to give. Who knows, we may get a SSW and a high pressure sat over us not wanting to move... aka February 2009.

[chionomaniac]

I can't see why we can't have wintry outbreaks before any SSW/MMW event?

For instance why was January 1979 so cold? The SSW didn't happen until the end of February.

The bulk of the cold of winter 2008-09 occurred before the SSW event. I remember Glacier Point going for a frigid February because of the SSW event. Infact the second half of February was exceptionally mild. The mildest part of that winter was after the SSW event.

The coldest part of winter 1976-77 was before the SSW event, after it the rest of that winter was largely mild.

I think we are becoming too hung up on what goes on in the stratosphere. Not sure why it has become such an "in thing" in the last 5 or so years. Hardly anyone were talking about it 10 years ago.

You're right WH, I think that too much get hung up on the SSW part - this is important because it dramatically increases the chances of cold as can be seen from this chart from this paper:

 

 

http://www.columbia.edu/~lmp/paps/butler+polvani+deser-ERL-2014.pdf

 

But it is not the be all and end all. It is a bit disingenuous picking out the SSW's that don't deliver to a small section of the NH (UK) when the above study shows how they will dramatically increase the chance of cold spilling to the mid latitudes, but you are right otherwise.

 

What is important though, is that we don't have an exceptionally cold stratosphere with the associated VI, because that does more or less rule out any significant cold for the UK. Northern blocking to the NW will not occur in these conditions. So far this year we have escaped VI and the outlook on that front is good.

 

Perhaps, the reason that the stratosphere is such an 'in thing' is because (rightly so) a lot of people are realising the important role it plays in the dynamics of the winter tropospheric conditions. We can still have a good cold Jan/Feb this winter without a SSW because we have already seen enough evidence suggesting that the stratospheric and tropospheric vortices are very malleable this autumn/winter and this bodes well for the rest of the season. 

Edited December 14, 2014 by chionomaniac
grammar

[Hocus Pocus]

I think a fair assessment would be that the odds are stacked against prolonged cold if the PV is well organised starting off the winter, however as WH highlighted it's not the be all and end all and sometimes it can diminish our cold prospects  again highlighted by WH above.

[cheeky_monkey]

I can't see why we can't have wintry outbreaks before any SSW/MMW event?

For instance why was January 1979 so cold? The SSW didn't happen until the end of February.

The bulk of the cold of winter 2008-09 occurred before the SSW event. I remember Glacier Point going for a frigid February because of the SSW event. Infact the second half of February was exceptionally mild. The mildest part of that winter was after the SSW event.

The coldest part of winter 1976-77 was before the SSW event, after it the rest of that winter was largely mild.

I think we are becoming too hung up on what goes on in the stratosphere. Not sure why it has become such an "in thing" in the last 5 or so years. Hardly anyone were talking about it 10 years ago.

Probably becuase people will hang their hat on anything that is percieved to be a pre-cursor to cold and snow...we have had SSTs, SSW, La Nina, Siberian Snow Index, OPI , Polar Vortex, NAO, AO , Solar Activity and the list goes on .Each year there seens to be something new that correlates to cold winters some how or some where even if the link is very tenious...lets face it it diesnt get too cold too often in this country and thats a fact and that wont ever change..unless there is a polar shift sometime soon.

[Hocus Pocus]

Probably becuase people will hang their hat on anything that is percieved to be a pre-cursor to cold and snow...we have had SSTs, SSW, La Nina, Siberian Snow Index, OPI , Polar Vortex, NAO, AO , Solar Activity and the list goes on .Each year there seens to be something new that correlates to cold winters some how or some where even if the link is very tenious...lets face it it diesnt get too cold too often in this country and thats a fact and that wont ever change..unless there is a polar shift sometime soon.

Unless we see Maunder/Dalton minimum from the current low solar output then no one can really argue with that assessment, and even during those episodes there were mild/wet winters. We have to be realistic and accept that the Atlantic will scupper many a winter for cold, embrace that idea and you'll never be disappointed.

[Weather-history]

I think a fair assessment would be that the odds are stacked against prolonged cold if the PV is well organised starting off the winter, however as WH highlighted it's not the be all and end all and sometimes it can diminish our cold prospects  again highlighted by WH above.

Yes I think a sudden stratospheric warming event is something you want if you are stuck in an unfavourable rut and hope it will knock you out of it. It gives you a chance.

However I'm not convinced if you are in a weather pattern that is delivering the goods that you would want a SSW event to pop up because it could knock you out of that pattern and into an unfavourable one.

[Ninman]

Interesting FI output - AO looks to go deeply negative and NAO looks to turn neutral

 

 

GFS-P 12z looks dump snow across scotland and notherrn england between xmas and new year:

 

 

No doubt this will change come tomorrow!

[feb1991blizzard]

Striking changes on the GEFS  18z suiteand not for the better either so far.

 

 

EDIT  :  Im going to be wrong here, its now looking like an upgrade!!!!!

Edited December 15, 2014 by feb1991blizzard

[Danielvn]

Interesting FI output - AO looks to go deeply negative and NAO looks to turn neutral

 

 

 

GFS-P 12z looks dump snow across scotland and notherrn england between xmas and new year:

 

 

 

No doubt this will change come tomorrow!

Correct me if I'm wrong, but is this not a snow RISK map rather than how much snow? Obviously common sense dictates that you're probably more likely to get more snow where there's higher risk, but it could also mean just a flake or two.

[No Balls Like Snow Balls]

From Weather Network UK

Temperatures to fluctuate widely over the next few days. Highs of 15C are possible by Thursday.

[Ninman]

Correct me if I'm wrong, but is this not a snow RISK map rather than how much snow? Obviously common sense dictates that you're probably more likely to get more snow where there's higher risk, but it could also mean just a flake or two.

Well yes, I didn't say how much snow, but if its at 100% then its likely it will be more than a few flakes. Either way its likely to change nearer the time.

6z gfs-p shows heights building in to Greenland at the end of the run with a cold northerly developing

[Hocus Pocus]

The MEtO 16-30 Dayer has now deleted the chance of much colder weather devolving later in the period. Not a good sign and they must be confident of no sustained cold spell on the horizon.

Edited December 16, 2014 by Hocus Pocus