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Stratosphere Temperature Watch 2012/2013


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then the date give or take a day or 3 is the 14th of Jan 2013 for our biggest shot of COLD so far this winter.

( Obviously this is for our little neck of the wods at 50N)- move closer to 90N & the propergation will be quicker-

So look for a reversal of zonal winds at 70/80n for day 10, & that to extend south further in time.....

Anything that appears before then is a bonus.

Excellent post Mr MURR. I find your zooming in of 14th Jan quite/no very interesting, in the seasonal thread before Xmas I have proposed a potential rather large winter [notably cold/snowy] period for 16-22 Jan [nowt to do with any strat forecast]. I have anticipated the jet stream to take a big shift south as the Atlantic gets blocked from high latitude block ridging south towards the UK.

Great informative post.

BFTP

Edited by Paul
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Why is this thread in need of a 'reality check'?

We have a major SW on the cards, and we all know that whilst this does not guarantee any cold weather (and, to the best of my knowledge, nobody's ever claimed that it does) it is a straw to clutch - it does increase the probability...

What am I missing?

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Why is this thread in need of a 'reality check'?

We have a major SW on the cards, and we all know that whilst this does not guarantee any cold weather (and, to the best of my knowledge, nobody's ever claimed that it does) it is a straw to clutch - it does increase the probability...

What am I missing?

You can't get excited about cold weather on this site, apparently excitement is the same thing as guaranteeing a record breaking cold spell for the UK. The simple fact of the matter is that almost all cold spells come from SSWs and it's rare to get a cold spell without an SSW. People have every reason to get their hopes up for an SSW, would you not get excited in a poker game if you got a card that turns your chances of winning from 10% to 70%? To associate every SSW with cold for the UK is naive and of course patience is needed to wait and see where the northern blocking develops in the troposphere before making any assumptions, but the simple fact is the chances of cold are much more favorable with an SSW than without one.

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Anyone got any ideas yet re BA's question regarding the momentum flux. I sense the lack of replies suggests we've hit a brick wall!

I've looked through lots of research and it is so complicated that I'm beginning to get a physics induced migraine!

From what I've read the EP flux vector direction results in two outcomes meridional heat flux or meridional flux of zonal momentum, now looking at a SSW's the delivery is not just down to the momentum flux wave but normally works in conjunction with the heat flux to help propogate the effect into the lower atmosphere.

I will continue to dig around for some clearer answers after my brain has recovered!

On a separate note I found this interesting article re SSW's, its a very good explanation of the key things to look for. Chiono et al may have this but anyway heres the link:

http://www.atmosp.ph...P26_A47_Coy.pdf

Edited by nick sussex
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You can't get excited about cold weather on this site, apparently excitement is the same thing as guaranteeing a record breaking cold spell for the UK. The simple fact of the matter is that almost all cold spells come from SSWs and it's rare to get a cold spell without an SSW. People have every reason to get their hopes up for an SSW, would you not get excited in a poker game if you got a card that turns your chances of winning from 10% to 70%? To associate every SSW with cold for the UK is naive and of course patience is needed to wait and see where the northern blocking develops in the troposphere before making any assumptions, but the simple fact is the chances of cold are much more favorable with an SSW than without one.

Agreed and while I feel confident of getting one or two decent cold shots out of this we could see something much more noteworthy with late January and February to see the best response of this warming as far HLB's are concerned. Edited by cooling climate
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Propagation seems to be a hot topic today and some fantastic analytical posts also. Going to be great to see so many folk keen to examine where this SSW leaves us within the next 2-3weeks, am sure with more questions than answers but that's the fun !

In relation to wave propagation have this one bookmarked, interesting abstract and summary which some folk may enjoy, vitally it recognises the small dataset which kind of highlights how we are learning every year with SSWs.

http://journals.ametsoc.org/doi/full/10.1175/1520-0442%282002%29015%3C0781%3ADPTAIT%3E2.0.CO%3B2

Off to read some of the linked papers

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Some good posts in this thread today. I remember reading a very good paper can't remember who by which discussed the effects of different types of stratospheric warmings in recent years. It was interesting to note that nearly all SSW's precedeed cold weather of various degrees, with the cold taking different lengths of time to establish itself.

I became aware of SSW's back in late Jan 09 when we had that sudden SSW which quickly established in the space of days the cold snowy start to Feb 09, even the BBC mentioned it..

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Posted Image

Hmm, the second GFS run to establish a secondary warming around the Greenland area. This outcome could be very helpful in shifting the odds in our favour with regards to a decent tropospheric pattern developing after the initial SSW.

Also, a brilliant post by Steve earlier, the wealth of knowledge on here is something to behold and long may the constructive discourse continue.Posted Image

Edited by LomondSnowstorm
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I have been following you guys since last week. Just starting to wrap my head around this phenomenon. I read some interesting studies regarding SSWs and the frequency of them occur during Neg QBO coupled with low solar activity (minimums) and Pos QBO coupled with higher activity (maximums) since we are technically nearing maximum, but a very low SSN cycle, I would dare to say we could agree the Neg QBO proxy would work in this case. My point is, As long as the QBO hangs east, we'll continue to have more SSWs which would make me think is the driver behind global cooling. But i guess that could be a long stretch of logic, made sense in my head. lol

http://link.springer.com/article/10.1007%2Fs11214-011-9797-5?LI=true#page-1

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The GFS model (one below is for Reading) now extends to the 13th and clearly the temps at 850 and 500 mb are plummeting.

http://meteociel.com/cartes_obs/gens_display.php?ext=1&lat=51.45&lon=-0.97

and 2m temps follow suite.

http://meteociel.com/cartes_obs/gens_display.php?x=&y=&run=0&lat=51.45&lon=-0.97&runpara=0&type=3&ext=1

Interesting as someone suggested ssw on 4th would be felt lower down in the trop around the 15th or so.

Edited by muppet77
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Posted Image

Hmm, the second GFS run to establish a secondary warming around the Greenland area. This outcome could be very helpful in shifting the odds in our favour with regards to a decent tropospheric pattern developing after the initial SSW.

Also, a brilliant post by Steve earlier, the wealth of knowledge on here is something to behold and long may the constructive discourse continue.Posted Image

Once a warming is identified, no day within 20 days

of the central date can be defined as an SSW. The

length of the interval is chosen to approximately equal

two radiative time scales at 10 hPa (Newman and Rosenfield 1997).

This condition prevents the algorithm from counting the same SSW twice, as the zonal

mean zonal winds might fluctuate between westerly and

easterly values following the onset of the warming

http://journals.ametsoc.org/doi/pdf/10.1175/JCLI3996.1

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Bingo, once more. Not at the 4-1-2012 (altough by a margin!) but the fifth of januar.

Critically Sebastiaan the ECM is forecasting more of a split scenario with a further warming. This is also a propagating scenario more akin to 2009 and could deliver an easterly down the line.
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I have been following you guys since last week. Just starting to wrap my head around this phenomenon. I read some interesting studies regarding SSWs and the frequency of them occur during Neg QBO coupled with low solar activity (minimums) and Pos QBO coupled with higher activity (maximums) since we are technically nearing maximum, but a very low SSN cycle, I would dare to say we could agree the Neg QBO proxy would work in this case. My point is, As long as the QBO hangs east, we'll continue to have more SSWs which would make me think is the driver behind global cooling. But i guess that could be a long stretch of logic, made sense in my head. lol

http://link.springer...?LI=true#page-1

I've been of the thinking for a while the the -QBO has been and is a big driver this winter. Certainly in helping keep stronger zonal winds from propogating downwards to the middle of the strat (not that it has helped us so far but it could well be a big player in our favour in the upcoming SSW). The QBO is heading back to a positive state but should hold out hopefully

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I have read through the last few pages of the thread. A couple of questions:

1. The SSW is still currently only a forecast and not something that will definately happen? (whether it propagates or not)

2. When is SSW forecast to happen, around the 4th Jan? Has this date been consistant or has it been continually pushed back or forward.

Edited by latitude
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I have read through the last few pages of the thread. A couple of questions:

1. The SSW is still currently only a forecast and not something that will definately happen? (whether it propagates or not)

2. When is SSW forecast to happen, around the 4th Jan? Has this date been consistant or has it been continually pushed back or forward.

An SSW is forecast only, but is very likely to occur.

Around the 5th-7th Jan seems a likely date, what is more important is how the vortex reacts and the increased influence of the Polar high.

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I have read through the last few pages of the thread. A couple of questions:

1. The SSW is still currently only a forecast and not something that will definately happen? (whether it propagates or not)

2. When is SSW forecast to happen, around the 4th Jan? Has this date been consistant or has it been continually pushed back or forward.

It's very likely to happen as the stratosphere is nowhere near as variable as the troposphere, so is much easier to forecast. 7 days out (the time when the SSW is expected to happen) is still a very reliable time-frame for the stratosphere.

At the moment zonal winds expected to just about still be positive at midday on the 4th of Jan, so I would say the SSW will happen on the 2nd half of the 4th of Jan or the 5th of Jan. The date has been pushed back very slightly, it's almost negligible.

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For several days the SSW has been forcast between the 4th and 5th.

Trying to get an idea myself of when we would likely see the first real signs of H5 HLB's

in the models looking through the temperature profiles down through the stratosphere.

It is 6 days until we see strong warming over the pole at 10mb then another 3 days until

it propagates down to the 30mb level. Thats 9 days and then it has to propagate down

through the tropapause which would take seveal more days taking us to the middle of

January at the earliest before we saw the first signs of any blocking showing up.

With the strongest effects seen in the latter part of January and on through February.

post-10506-0-01565500-1356780971_thumb.g

post-10506-0-41621500-1356781073_thumb.g

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Silly question but do SSW's or any warmings for that fact only occur in the winter?

If not, what is their effect in the summer or is it coolings we look for in the summer toi generate possible heat for the UK?

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Silly question but do SSW's or any warmings for that fact only occur in the winter?

If not, what is their effect in the summer or is it coolings we look for in the summer toi generate possible heat for the UK?

Jayces, the strat cools in the autumn and warms in the spring. There are no warmings in the summer.

Edited by bluearmy
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