Stratosphere Temperature Watch 2012/2013

[MR EXTREMES]

so is the strat event over now and are we likely to see ongoing effects or is this now the time to hang up the strat boots for another year?

[Tamara]

The stratospheric pattern does seem (so far) to be mirroring some previous recent years with a strong warming followed by a drop right back to relatively cold conditions, leading to above average Spring conditions and then leading to a summer soaking. Far too early to think about in terms of when the final warming comes, but I'd rather we'd give yet another summer soaking a miss this year though..

However, in the meantime, and in respect of the lagged effect of the stratospheric patterns on the troposphere, the warming still has a part to play - whether it does or doesn't affect the UK favourably for cold weather in February

Edited January 25, 2013 by Tamara Road

[Luisport]

Ryan Maue‏@RyanMaue

Currently at 995 mb -- 6-hourly pressure time series: 987, 980, 963, 935, 922, 919 at tau+36. 65mb/24hours is ferocious/extreme deepening

5 hRyan Maue‏@RyanMaue

GFS back to 919 mb with explosive cyclone off east coast that will move WNW of Iceland during next 36-48 hours. http://twitter.com/RyanMaue/status/294659035070861314/photo/1

Matthew Hugoâ€@MattHugo81

The low in the W Atlantic goes from 987mb to 938mb in about 18hrs! http://www.wetterzentrale.de/pics/bracka.gif http://www.wetterzentrale.de/pics/brack0.gif - A drop of 49mb! #wow

[summer blizzard]

The stratospheric pattern does seem (so far) to be mirroring some previous recent years with a strong warming followed by a drop right back to relatively cold conditions, leading to above average Spring conditions and then leading to a summer soaking. Far too early to think about in terms of when the final warming comes, but I'd rather we'd give yet another summer soaking a miss this year though..

However, in the meantime, and in respect of the lagged effect of the stratospheric patterns on the troposphere, the warming still has a part to play - whether it does or doesn't affect the UK favourably for cold weather in February

That stratospheric pattern is not responsible for the summer soaking (and infact summers 2009 and 2010 were warmer than average)..

[iceicebaby]

(and infact summers 2009 and 2010 were warmer than average)..

Global it might, but not regional Edited January 25, 2013 by iceicebaby

[Tamara]

That stratospheric pattern is not responsible for the summer soaking (and infact summers 2009 and 2010 were warmer than average)..

I seem to remember GP pointing out that strong negative zonal anomalies after very strong final warmings were attributable to the southerly tracking jet stream and high pressure across the pole that we have seen in various recent summers such as 2007, 2011 and last summer as well. I'm less sure about 2009 and 2010, although 2010 I think featured some blocking over the pole as well. Last summer for sure was exacerbated by the easterly QBO phase which encourages warmth over the pole and accentuates HLB and a southerly tracking jet stream - much as occured in 2007

Edited January 25, 2013 by Tamara Road

[summer blizzard]

I seem to remember GP pointing out that strong negative zonal anomalies after very strong final warmings were attributable to the southerly tracking jet stream and high pressure across the pole that we have seen in various recent summers such as 2007, 2011 and last summer as well. I'm less sure about 2009 and 2010, although 2010 I think featured some blocking over the pole as well. Last summer for sure was exacerbated by the easterly QBO phase which encourages warmth over the pole and accentuates HLB and a southerly tracking jet stream - much as occured in 2007

Ah right, i knew it was very low GLAMM that was the cause but was unaware that he had deemed the strong final warming as responsible.

[Tamara]

Ah right, i knew it was very low GLAMM that was the cause but was unaware that he had deemed the strong final warming as responsible.

As always, a combination of factors

[Zenarcher]

Updated yesterday shows temperatures are still on the rise I've made a zoom in on the image,

[lorenzo]

Second night on the bounce have spotted this in the lower res strat forecast at T300.

[summer blizzard]

Second night on the bounce have spotted this in the lower res strat forecast at T300.

As there's no colour what are you showing?

[Interitus]

As there's no colour what are you showing?

There's ridging to the northwest with low pressure over Scandinavia, if the troposphere mirrors this then we could be looking at cold northerly based flow.

[lorenzo]

Thanks !

Was busy attempting to add some colour.

Going to dream about a stratopsheric omega vortex block now..

[Interitus]

I see your interpretation is a bit more ambitious than mine haha!

edit: but also see on the Scottish thread that you found an ensemble member that at least goes with the northerly.

Edited January 26, 2013 by Interitus

[chionomaniac]

We are seeing an interesting and consistent signal at 10 hPa from day 10 which is likely to have a bearing on the troposphere thereafter.

Firstly, the mean zonal winds at this level are still negative - but this is likely to reverse back to weak positive by the 28th.

Note the position of the upper ridge - over the Pacific/Alaskan sector where it has resided for most of January since the SSW. As this fills the vortex position is beginning to change and from day 10 the clear trend is to shift the vortex towards Siberia.

It is likely that there wiill be a tropospheric response to this and that the Polar vortex that has dominated the Atlantic sector will have the opportunity to shift.

I don't think that I have ever seen such a disconnect with the MJO forecasts and tropospheric pattern in the Atlantic sector since I have been monitoring them.

With the MJO in strong amplitude phase 7

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml

we would expect to see the Atlantic dominated by a ridge

not the strong vortex currently forecast.

It appears that the stratosphere is overriding the MJO signal here.

However, with the upper vortex shift then we could expect to see some sort of realignment in that pattern - though it may take some days for this to become apparent in the tropospheric model output. I can't see anything popping out of the blue in the next 10 days, but once the upper pattern change starts then we are more likely to see a more amplified output over the Atlantic - fitting in with the ECM 32 day projections.

[bluearmy]

we have seen several attempts this winter to drain the canadian vortex and each time it has reformed, stronger than it was. my concern, as ever, is that whilst energy is on the move, we cannot get a decent block to advect cold towards nw europe. if this upcoming movement of the upper strat vortices verifies then i would not be surprised to see the canadian vortice reform thereafter. will that be hudsons, baffin or maybe further west ? if it repeats and continues to flood the far nw atlantic with energy, our only hope of feb cold is via a scandi block or a repeat of the pattern we have just been through. that wouldnt surprise me.

[lorenzo]

I thought about the same bluearmy, and wondered if the Canadian Warming of the vortex Nov/Dec set up an almost default background pattern that has remained with us across this Winter, if not a pattern then a pre-disposition to return to the Atlantic drainage base state. Was also wondering if NAO state prior to the SSW event created any definitive pattern throughout the period of time where the zonal winds reverse.

From the Berlin list here are the dates featuring Canadian Warmings rolled forward, again the height anomaly that is suffering from disconnect remains. As C notes - Strat killing the MJO , is the signal bouncing back and setting up this wave train of furious lows across the hemisphere, if not where is the energy that would normally be associated with setting up the ridge heading?

Interestingly the mean Atlantic elongated trough seems to be another response of some SSW cases.

One thing I am certain of is that the NWP will flip at some point, the lifting out of the mean Vortex took 48-72 hrs to pull through on the modelling from when it was measured on the Strat charts, for this reason would not be surprised to see a chart flip akin to that ECM disappearing, perhaps this time a re-appearance..

[snowking]

As Lorenzo points out, the last few GFS runs have been very consistent with the 100mb stratospheric ridge initially based over the UK, but retrogressing with time.

The 6z is very aggressive with the idea:

And then by day 15:

More runs required, but this ties in much better with a February MJO Phase 8 projection.

Incidentally, the ECM32 from Thursday:

Very consistent with its output from the previous run:

Everything other than shorter range NWP pointing towards a return to the cold around 7-10 days into February at this stage

SK

[chris55]

Thanks SnowKing nice to have the 32day ens from EC. Is this just a one off, as I didn't think us mere mortals could access the ec 32?

[Snowman.]

Can someone tell me what this is? I would expect warming towards the end of Feb but I don't know if this is true?

[Glacier Point]

The really interesting aspect to this warmig event is the distortion to the hemispheric U-fields that is occurring, and helping to heavily accentuate a pattern of tropical waves.

At 70 hPa, the tropical stratosphere is at record low levels and almost certainly bringing about strong cooperation with the tropopause to shift and develop deep tropical convection.

Upper sigma relative angular momentum anomalies depict a -ve zonal wind anomaly in the mid to high latitudes in the NH and quite strong -ve wind anomaly just south of the equator (corresponds to lifted tropopause and development of taller thunder clouds). This is likely to stress the U-field setting up a poleward shift in eddy flux.

Overall relative angular momentum in the middle and lower layers is registering a massive increase in westerlies, in excess of +3 SD. That would be impressive in an El Nino winter, let alone an ENSO neutral winter. This increase being principally over the tropics, for the time being.

Meantime, are we seeing a nodal propagation of temperature anomalies through the polar stratosphere?

Likely tropospheric response continues to be anomalous mid and high latitude ridges in response to eddies developing off the sub-tropical ridges.

[Catacol]

I don't think that I have ever seen such a disconnect with the MJO forecasts and tropospheric pattern in the Atlantic sector since I have been monitoring them.

Exactly the question or issue I raised a few days back, and certainly the same answer I was drifting towards. The fact that the vortex can override the MJO phase is more evidence still of the importance of strat warming disruption to the vortex in terms of winter synoptics. It does also rather reinforce the point that a SSW does not automatically mean cold, and as we are seeing now if can actually fire energy towards us just as effectively as a strong vortex undamaged by SSW can do.

We have been a bit unlucky really. Had the vortex moved over to the pacific side then all the major height rises could have been with us, and then very blocked synoptics indeed would have been the result.

[Glacier Point]

..but notably the Global Wind Oscillation being held back in a more phase 5 orbit due to the manifestation of the extra-tropical measures in this oscilation compared to the MJO which has a tropical compenent only.

As we see the GWO signal 'mature', more of a signal to develop that disrupted flow in the Atlantic.

[cooling climate]

We are seeing an interesting and consistent signal at 10 hPa from day 10 which is likely to have a bearing on the troposphere thereafter.

Firstly, the mean zonal winds at this level are still negative - but this is likely to reverse back to weak positive by the 28th.

Note the position of the upper ridge - over the Pacific/Alaskan sector where it has resided for most of January since the SSW. As this fills the vortex position is beginning to change and from day 10 the clear trend is to shift the vortex towards Siberia.

It is likely that there wiill be a tropospheric response to this and that the Polar vortex that has dominated the Atlantic sector will have the opportunity to shift.

I don't think that I have ever seen such a disconnect with the MJO forecasts and tropospheric pattern in the Atlantic sector since I have been monitoring them.

With the MJO in strong amplitude phase 7

http://www.cpc.ncep....clivar_wh.shtml

we would expect to see the Atlantic dominated by a ridge

not the strong vortex currently forecast.

It appears that the stratosphere is overriding the MJO signal here.

However, with the upper vortex shift then we could expect to see some sort of realignment in that pattern - though it may take some days for this to become apparent in the tropospheric model output. I can't see anything popping out of the blue in the next 10 days, but once the upper pattern change starts then we are more likely to see a more amplified output over the Atlantic - fitting in with the ECM 32 day projections.

Very much doubt that the blocking we are likely to see during February has anything to do with what is

happening at 10mb level in the coming days. We have seen a quick response and lucky for us fairly prolonged cold (very cold spell at times ) from the SSW. The blocking in February which is likely to be much more pronounced is the warming that has been propagating down through the layers with at least hree weeks of warming and reduced zonal winds at the 30mb level to still affect the troposphere.

Edited January 27, 2013 by cooling climate

[iceicebaby]

One for the archive: