Stratosphere Temperature Watch 2012/2013

[Snowy Liverpool]

I don't think this one will become close to reaching the criteria for a SSW. However, could it be classified as a Canadian Warming.....?

Have you got a link to somewhere which has the temperature part of the criteria. I've read a lot of conflicting ones but in journals, "significantly higher than 10c" seems to be the favored one, though that's far too vague, it could be anything from 15 to 100.

[chionomaniac]

There is a link to an old paper a good few pages back. The problem with Canadian Warmings is that they don't seem to have the clear distinction in definition that Polvani et al gave to SSW's

[Lee Smith]

they dont happen to often

[snowking]

Wave 1 activity looks to wane a little, before some small signs of returning on the day 10 forecast:

http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/eczm.php?alert=1&forecast=all&var=ha1&lng=eng

SK

[Glacier Point]

06z GFS .... best strat forecast of the winter, admittedly at the very extended range but it demonstrates the evolution of the cut off lobe which is now reliably being modelled, as is the shift of the main body towards Siberian sector.

70 hPa

30 hPa

10 hPa

A very displaced vortex and we have a full on Canadian warming forecast there, which could very conceivably shift northward into the Pole and trigger a MMW. Based on this GFS output, MMW centred late December, tropospheric feedback mid jan with a possible earlier fast response similar to what we've seen in the last 2-3 weeks.

This is the GFS we're talking about, and there has been a great deal of uncertainty in these outputs w/r/t the eastward development of the warm pool in the middle and lower stratosphere, but the building blocks being put in place around the middle timeframe are worth keeping tabs on from run to run because this could be highly signifiacnt in terms of weather ramifications in January. Judah Cohen must be pleased.

Edited December 6, 2012 by Glacier Point

[Gael_Force]

Have you got a link to somewhere which has the temperature part of the criteria. I've read a lot of conflicting ones but in journals, "significantly higher than 10c" seems to be the favored one, though that's far too vague, it could be anything from 15 to 100.

I posted the old paper mentioned below - definition from that source:-

2.4 Canadian Warming

The fourth type of warming, a Canadian warming is actually a hybrid; a minor

warming disguised as a major warming. At first, a Canadian warming looks like a

major warming, in which the easterly winds replace the zonal westerly flow in the

polar latitudes. However, a closer examination of this phenomenon shows that the

westerly polar night jet has not really been destroyed, as in a major warming, but

is displaced south of 60°N and, usually, relocated over southern Siberia. Canadian

warmings set up when an intense strengthening of the Aleutian High forces the high

to build into northern Canada. The warm air and easterly winds associated with the

high displace the cold polar vortex, pushing it south into Siberia, causing easterly

flow in the high latitudes (Labitzke, 1977). When the Aleutian High weakens, the

polar vortex pushes northward and the stratosphere returns to its normal winter

circulation.

http://www.dtic.mil/.../u2/a227731.pdf

Another one from Karin Labitzke.

Canadian Warmings often happen in early winter. They take place when the Aleutian stratospheric high intensifies and moves poleward. The Canadian warmings can reverse the meridional temperature gradient and sometimes briefly change the zonal wind direction over the polar cap, but nevertheless they do not lead to a breakdown of the cyclonic polar vortex.

http://www.atmosp.ph...5_Labitzke.html

I'll just add this recent paper as the forecast GP has posted looks very akin to the illustrations.

https://docs.google.com/viewer?a=v&q=cache:eNxekOZyNaoJ:www-mete.kugi.kyoto-u.ac.jp/Kyoto2012/ppts/oral/Feb22/S01_Bancala.pdf+Labitzke,+1977%29.&hl=en&gl=uk&pid=bl&srcid=ADGEESjme56mDysC6MTDfyI7355TsOMFceBBHqho9LnnJcLWD_y3tlJV014ByrZgtYID5KmVCDOo_PxuVHEiaRTESGBn8GJs-0YCCEq9KKMpM2_rosPyRWgAMGQd3g8S8A2hoRgreaOo&sig=AHIEtbQfJtzaqENMkb8CWpXp6i56Ezau0w

Edited December 6, 2012 by Gael_Force

[Snowy Liverpool]

Thanks Gael Force that's perfect

[Glacier Point]

Cool, Atlantic blocking structure at day -15/-16 leading to increased Wave 1.

GFS reacting to this ?

November meridional heat flux was also good in that respect:

If so, that will be a sustained wave 1 attack in 15-20 days time given this structure is likely to be in place for a good few days - takes us to around end December for MMW displacement type.

Edited December 6, 2012 by Glacier Point

[lorenzo]

MMW odds now?? Before end of month or early January... Exciting stuff.

Liked the ECM for a number of reasons, then thought about this double barrel signature on the upper Vortex.

Extreme FI at time range mentioned previously - The Aleutian Strikes Back from the GEFS Ens.

That should do the trick! I think I am more excited by January now than the present Beasterly saga !

Edited December 6, 2012 by lorenzo

[chris55]

MMW odds now?? Before end of month or early January... Exciting stuff.

Liked the ECM for a number of reasons, then thought about this double barrel signature on the upper Vortex.

What is an MMW, is it just another name for a SSW?

[Bishop Brennan]

What is an MMW, is it just another name for a SSW?

MMW = Major Mid-winter Warming

I believe it is simply another way of describing a SSW, I stand corrected if not.

Bish

Edited December 6, 2012 by Bishop Brennan

[lorenzo]

Yes Major Midwinter Warming / Sudden Stratospheric Warming.

SSWs: “a major midwinter warming occurs when the zonal mean zonal winds at 60N and 10 hPa become

easterly during winter, deï¬ned here as November-March (NDJFM)†- Charlton and Polvani, J. Clim. 2007

[Vertical Limit]

I don't think this one will become close to reaching the criteria for a SSW. However, could it be classified as a Canadian Warming.....?

Hi Chio, you made a predicition a few weeks back for a Canadian Warming to occur (just a little later than perhaps you were expecting) - a great call, well done.

The most notable year for a Canadian warming - 1962? I shouldn't have said that!

[Vertical Limit]

MMW odds now?? Before end of month or early January... Exciting stuff.

Liked the ECM for a number of reasons, then thought about this double barrel signature on the upper Vortex.

Extreme FI at time range mentioned previously - The Aleutian Strikes Back from the GEFS Ens.

That should do the trick! I think I am more excited by January now than the present Beasterly saga !

This seems to tie in very nicely with the NW winter forecast for a prolonged cold spell from about Mid January to early Feb.

Luvely jubbly!

[cooling climate]

This chart caught my eye today.

[lorenzo]

Just giving this paper a read just now. Looks like a good one.

http://elib.dlr.de/76823/1/acp-12-3659-2012.pdf

[MattH]

Morning, just a quick EC 32 update;

High confidence for the E'ly scenario next week, albeit a weak one, but it still manages to get cold air into place. The breakdown scenario for next weekend is anyone's guess. 'Slider lows' may become involved and from my experience more often than not models breakdown the block/cold air quicker than actually happens when the event in question gets nearer. So that's got high confidence and again 10 out of 10 to the EC32 for picking up this E or NE'ly scenario weeks back.

It keeps N blocking in place with lower pressure to the S or SW until the 23rd (ish) which, to me, suggests that any Atlantic intrusion next weekend is short lived on this model. However, week 3 has changed, Xmas week, which N blocking disappearing and low pressure becoming dominant just to the W or SW of the UK bringing a more unsettled spell, before a weak signal for a Greenland high into early Jan.

Going off recent posts in here this scenario may tally well, with a potential milder/more unsettled/Atlantic influence for a time later in December before a potential 'reload' into January. To be honest after what now looks like being a particularly cold first half of December at least, you would imagine (statistically) that a milder interlude would be likely at some point and if the EC32 is once again correct, unfortunately that may fall over Xmas now, but time will tell.

Overall given the extend outlook now into early January and the temp anoms, without question I believe this Dec will be either around if not below average in terms of CET and will be at least one month out of the 3 that will overall likely be on the cold side. I have a feeling, again given some of the comments in here, that future stratospheric developments will be crucial in determining January's synoptic trends, but I've believe a cold regime will continue into January.

Have a good weekend, Matt.

[lorenzo]

Thanks again for the update Matt, I have shared the thoughts on the EC32 in the Model Discussion thread, huge audience in there who will appreciate this info.

[Glacier Point]

Finger print activity in the upper stratosphere suggesting that wave 1 activity is likely to increase in the next 20 days.

GFS again picking up the idea of a strengthening stratospheric ridge extending into Alaska and Northern Canada, now at t348. This extends all the way up to 1hPa but not so discernible below 30hPa which does suggest wave 1, as does the total displacement of the pv.

Still looking very possible for a major warming going into the New Year. GFS currently bounding around in outputs but last week of December forecast to be well above average at the North Pole, something akin to current values which would be 10-15C above normal.

Still a few days before this hits ECM timeframe, outputs around 13th December should be of interest to see if we get some idea of cross model agreement although the causal effect (and pattern right now) looks to be sound in terms of timing and spatial modelling.

Edited December 7, 2012 by Glacier Point

[Nick F]

I'm no expert on the stratosphere, but the chart below suggesting a warming already taking place in the strat?

http://acdb-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra/t60_90n_70_2012_merra.pdf

[Pixel]

I'm no expert on the stratosphere, but the chart below suggesting a warming already taking place in the strat?

http://acdb-ext.gsfc..._2012_merra.pdf

Nick that post helps a lot.. it's so good to have something to compare to. I'm trying to learn the content in here but the you have to know the language.

A before/after -and/or- previous/present graphical presentation helps so much. Just got to join the remaining dots (-:

Edited December 7, 2012 by Pixel Precipitation

[lorenzo]

Yes Nick, being thrill seekers we are now searching for the next wave of warming. All fingers point to early January now and bits and pieces coming together.

Here is the temperature profile for the Northern Hemisphere of the 70hpa level where you can see this temperature change reflected.

This sequence from the ECM run shows the predicted temperature and height movement for the next 10 days as the vortex goes off on it's travels across the pole. Core low heights show the Vortex position relocating from the Davis Strait to the Laptev Sea.

[Ice BIast]

I found this 30 HPa chart interesting.

As well as showing the main part of the PV moving towards Siberia, it also shows a lobe of PV near Iceland, tracking quickly east. Once this lobe has cleared east, towards Scandinavia, that would open the door for height rises to the NW would it not?

[karyo]

I found this 30 HPa chart interesting.

As well as showing the main part of the PV moving towards Siberia, it also shows a lobe of PV near Iceland, tracking quickly east. Once this lobe has cleared east, towards Scandinavia, that would open the door for height rises to the NW would it not?

A shortwave will probably come into play again to prevent the cold from reaching us!

[lorenzo]

As Stewart wrote a couple of posts back looking at 13th onwards for the ECM for this to filter in. Been looking at this re-loacting vortex this morning and just observing random things out of interest as never really analysed what happens here.

First thing I spotted was the zonal wind profile ramping up again , perhaps in a similar manner to the increase prior to the wave 2 split..

Also some evidence of continued heat flux down the line, looking at the recent Wave 2 warming, this estimation at 240 hours has increased quickly near day 0 and was under projected.

This screen shot depicts the movement of the lowest Geopotential heights at 70hpa from now to day 10. A google map of the relocating vortex.

Chart I liked this morning was this one at 100hpa from ECM at just 72 hrs, the vortex nearly in 3 fragments at this level, a stratospheric shortwave ! Some comedy / irony in there.

Vacating vortex displaying a mind scrambling picture at just 72 hrs on the ECM run at 100hpa. The route of travel very close to the Scandi Block in respect of the discussion on model thread.

Reading some of the comments about Stratosphere and impact on models etc, totally appreciate that viewpoint. Perhaps it highlights the infancy of the monitoring and many papers that examine what is happening to the Stratosphere.

One of which is this published in October 2012 by the Met Office, reading the abstract qualifies the benefits of continued examination in this area, one I will still continue to enjoy.