Winter 2012/13 - Chat

[chionomaniac]

Well that's sort of what happened last year. It was so cold that when when the warming came, it was very marked indeed. Technically, there wasn't an SSW though as no reversal of mean zonal winds occurred at 30hpa (just)

(It's 10 hPa and 60ºN for an SSW, ba)

[bobbydog]

(It's 10 hPa and 60ºN for an SSW, ba)

hi chio, what do you make of my earlier post? (#21) do you agree? disagree? or am i talking rubbish? lol

[tcc]

Am I right in thinking that even if there is a PV forming due to record cold strat etc, it still requires it to set up over Greenland to have a big effect on our weather? Isn't it feasible that we could still get cold with a strong vortex as long as it's not over Greenland? I'm sure I remember winters in the past (5 or 6 years ago) where there was a strong PV but it lifted out of Greenland (and the northern jet with it) which allowed a Scandi block to develop and we got some easterly action!

[chionomaniac]

hi chio, what do you make of my earlier post? (#21) do you agree? disagree? or am i talking rubbish? lol

I don't think that you are talking rubbish at all.

SSW's are the daddy's of stratospheric warmings, but I would like to see a warmer stratosphere per se.

Yes, they are more common in easterly QBO's especially coinciding with an ENSO event. They are not totally unexpected though - it is just a matter of recognising the tropospheric precursors that can lead to SSW's.

[Grimsby Snow Lover]

Am I right in thinking that even if there is a PV forming due to record cold strat etc, it still requires it to set up over Greenland to have a big effect on our weather? Isn't it feasible that we could still get cold with a strong vortex as long as it's not over Greenland? I'm sure I remember winters in the past (5 or 6 years ago) where there was a strong PV but it lifted out of Greenland (and the northern jet with it) which allowed a Scandi block to develop and we got some easterly action!

Do you mean like this? http://www.wetterzen...00119910207.gif

There was a strong PV then but as you say this was not over Greenland and thus allowed us to feel the full force of a Scandi high.

Edited November 10, 2012 by Grimsby Snow Lover

[Snowy Easterlies]

What is causing the strat to cool rapidly, this happened last year as well, i hope its not a trend for future autumn and winters, also will we get a strat warming this winter?

[bobbydog]

I don't think that you are talking rubbish at all.

SSW's are the daddy's of stratospheric warmings, but I would like to see a warmer stratosphere per se.

Yes, they are more common in easterly QBO's especially coinciding with an ENSO event. They are not totally unexpected though - it is just a matter of recognising the tropospheric precursors that can lead to SSW's.

thanks chio, i'm obviously learning something then! in which case, as i mentioned in my post, with an easterly QBO, high N Atlantic SSTs, and the (average) bi-annual frequency, an SSW is more likely than not this year?....

[tcc]

Do you mean like this? http://www.wetterzen...00119910207.gif

There was a strong PV then but as you say this was not over Greenland and thus allowed us to feel the full force of a Scandi high.

Ah yes GSL, just like that! Good find, I'm sure there was another one in the last few years as I remember Steve M talking about the PV moving to Baffin Island etc but yes that is what I meant!

[Cloud 10]

Saved this chart from the 17th of January this year which shows well the big warming event

in the stratosphere.

In comparison,this is how it looks at the moment.

[Grimsby Snow Lover]

For what its worth one of Marc Vogan's followers have seen something to suggest a tanking NAO and SSW during December. Im not sure what he has seen but sounds promising non the less. He did seem quite confident in his post.

Edited November 10, 2012 by Grimsby Snow Lover

[snowstorm445]

For what its worth one of Marc Vogan's followers have seen something to suggest a tanking NAO and SSW during December. Im not sure what he has seen but sounds promising non the less. He did seem quite confident in his post.

You actually that site? It's so full of rampers and trolls. Loads of them have absolutely no clue on how the weather works and the moment they see a northerly on a chart, no matter how far out, there are cries of "1963 winter on the way looks really cold mark yay snow".

It really makes you cringe at times.

[Robbie Garrett]

You actually that site? It's so full of rampers and trolls. Loads of them have absolutely no clue on how the weather works and the moment they see a northerly on a chart, no matter how far out, there are cries of "1963 winter on the way looks really cold mark yay snow".

It really makes you cringe at times.

As well as the fact that he now charges a lot of money for amateur armchair opinions. When I can come on here, interact with you guys and have a good discussion about it all. Without having to break the bank.

[Gavin P]

Morning all,

Heres the sixth winter 2012/2013 round-up video;

http://gavsweathervids.com/

Again exploring things like SST's, snow cover extent, solar, etc...

Hopefully next week I'll have the final seasonal model round-up, then the week after that I'll put the round-ups and seasonal models together with the NAO forecast from June and try to make a forecast for the winter of 2012/2013.

As ever thanks for your support.

[shedhead]

With milder air pushing into much of Scandi and almost as far east as the Urals across the next week or so, it unfortunately looks as though Eurasian snow cover will reduce significantly. Much the same could be said across N America, which also looks to become somewhat less cold from Wednesday, so something of a backward step developing for N H snow cover at least.

[BLAST FROM THE PAST]

Talk of write off? Hopefully I see the next couple of weeks as part of the winter plan...whatever it may bring I know its not model related but NOAA have called off their Nino watch......neutral at best/worst expected by them. Anyone got analogues for -ve QBO, neutral ENSO etc

BFTP

[garbagebags]

Am I right in thinking everything is in place for a -NAO/AO and blocked cold winter EXCEPT the strat temperatures?

And could someone tell me, what causes the Strat to suddenly warm?

[bluearmy]

(It's 10 hPa and 60ºN for an SSW, ba)

doh - i knew it was 60 or 70N but honestly remembered it being at 30hpa !! doesnt look like i'll need to remember for a fair while at the moment !!

[CanadaAl]

Am I right in thinking everything is in place for a -NAO/AO and blocked cold winter EXCEPT the strat temperatures?

And could someone tell me, what causes the Strat to suddenly warm?

Yeah that does seem the case, that's why i don't think we can jump the gun over the strat temps. I was told the strat doesn't influence the CFS, so i'm wondering what it's picking up on giving us constant mild runs... Airing on the side of caution i guess.. I believe strat warming is caused by sudden wind reversal occuring at the pole. thus having a domino effect on the strat (I could be completely wrong haha) Watching gav's vids, i do still think it's too early. could go either way.. the met are sticking to their end of nov cold forecast

[Ian Brown]

Am I right in thinking everything is in place for a -NAO/AO and blocked cold winter EXCEPT the strat temperatures?

And could someone tell me, what causes the Strat to suddenly warm?

The Strat is a complex subject which I don't fully comprehend and it's significance is open to debate.

The NAO is a variable that is very difficult to predict; a theory as good as any is that once it has defaulted to a +ve position in the winter period (ie now) that it becomes very hard to shift, certainly that has been the case over the last 25 years or so.

There is, I think, looking at the American interpretation of the ENSO, very little signal either way. So on balance with the NAO having gone positive and those deep blues now appearing over Greenland, I don't really think there will be anything to significantly shift this pattern much over the coming months.

I think the chap who posted the video (Glacier ?) looks to have a far greater knowledge of all sorts of factors than I've seen even from some of the US guys but just my opinion is that you start at the general default winter pattern and need really good reasons for saying that something different is the offing, and I don't really see that it is.

[shotski]

Anyone looking at the current output and writing off early winter needs to look back at November 2010, the 11th November and the charts look very un-interesting for cold and by the 14th November they probably look worse.

By the 18th we have a build of pressure into scandinavia which is very similar to what is being shown for the end of the month.

20th & 22nd of November we have retrogression to Greenland and the rest is History as they say.

Edited November 11, 2012 by shotski

[Ian Brown]

Thanks Shotski, certainly does show how things can flip. I would have been in the US at the time so don't recall, but pretty exceptional set-up ending up the end of November for the UK.

[feb1991blizzard]

Tide beginning to turn in our favour, even if we miss out first go that maybe better news, at least a build up of cold pooling possible ready for the killer blow, remember what GP said about waxing and waning, as long as that block is there, we will hit the jackpot eventually!!!

[bobbydog]

The Strat is a complex subject which I don't fully comprehend and it's significance is open to debate.

The NAO is a variable that is very difficult to predict; a theory as good as any is that once it has defaulted to a +ve position in the winter period (ie now) that it becomes very hard to shift, certainly that has been the case over the last 25 years or so.

There is, I think, looking at the American interpretation of the ENSO, very little signal either way. So on balance with the NAO having gone positive and those deep blues now appearing over Greenland, I don't really think there will be anything to significantly shift this pattern much over the coming months.

I think the chap who posted the video (Glacier ?) looks to have a far greater knowledge of all sorts of factors than I've seen even from some of the US guys but just my opinion is that you start at the general default winter pattern and need really good reasons for saying that something different is the offing, and I don't really see that it is.

yes, that chap "Glacier" does know a thing or two about the weather- he's a senior professional forecaster for Netweather!

anyway, there's a lot of uncertainty regarding the strat at the moment, the best way to find out whats going on is to watch the MOD thread along with the strat thread and the actual model output itself.

[keithlucky]

El Nino watch is over neutral conditions now all helps for a colder winter with a better chance of snow.

[I remember Atlantic 252]

first signs of an easterly on GFS? deepest FI but could be start of trend, although dosent look cold

Terry not Ian Brown by the way, people think he is on model thread and USA does not mean upper stoke area lol!!!!

Edited November 12, 2012 by ihatetherain