Stratosphere Temperature Watch 2014/2015

[KTtom]

What's the frequency of ssw events? i.e. How often do they occur? Are they relatively rare or relatively common?

Good question and one I have been trying to get answers to via little response ....If you look at this link they are very frequent, but I can't believe this can be accurate????

 

http://curriculum.pmartineau.webfactional.com/ssw-animations/

Edited December 29, 2014 by KTtom

[lorenzo]

Good question and one I have been trying to get answers to via little response ....If you look at this link they are very frequent, but I can't believe this can be accurate????

 

http://curriculum.pmartineau.webfactional.com/ssw-animations/

 

Couple of images that give a mean representation of frequency.

 

[Recretos]

Not much to add, the before mentioned GEFS Control which had an interesting trop. output, was nothing special strat wise.

 

 

GFS zonal wind profile is what you would expect. 

 

 

Now, JMA on the other hand, has at 264h 7m/s 60N zonal mean wind at 10mb with a strong wave 2.

 

 

 

 

 

Strong wave 2 is also evident on the vertical velocity profiles with the stronger wave breaking over the Canada/Atlantic sector. 

 

 

 

JMA seems over-optimistic, tho configuration-wise for the strat, it is the second best model, following ECM and leading before GFS.

 

So much for now.

Cheers

 

Edit:

Adding FNMOC Control:

 

Edited December 29, 2014 by Recretos

[Ffive]

GEOS-5 Analyses and Forecasts of the Major Stratospheric Sudden Warming of January 2013

 

 

 

 

http://gmao.gsfc.nasa.gov/researchhighlights/SSW/

[chris55]

"Now, JMA on the other hand, has at 264h 7m/s 60N zonal mean wind at 10mb with a strong wave 2."

 

So thats an official SSW forecast from JMA then? Or have i misinterpreted that?

 

Nonetheless it seems JMA and ECM are both keen on this warming. 

Edited December 29, 2014 by chris55

[bluearmy]

Has to be negative Chris. 7m/s slow but not negative

And Andrej is back so we can proceed with a SSW!

Edited December 29, 2014 by bluearmy

[Recretos]

And Andrej is back so we can proceed with a SSW!

 

Going away again for a few days (staying at girlfriends place), but I will try to setup the software on her computer.

 

Sorry for offtopic.

Edited December 29, 2014 by Recretos

[chris55]

Has to be negative Chris. 7m/s slow but not negative

And Andrej is back so we can proceed with a SSW!

 

Cheers Nick

[bluearmy]

Going away again for a few days (staying at girlfriends place), but I will try to setup the software on her computer.

Sorry for offtopic.

Women and model watching! Save for a few stars on here, never found it a great mix!

The EC 12z run consistent and the predicted 10 hpa split extremely marked with Tony's big distance between the vortices evident. Split at 30 and 50 hpa aswell though not as split as 10 hpa. Presumably that will happen with time on this model run evolution.

Don't want to get ahead of myself here but something is definitely happening.

JMA at day 8 quite crazy but not far at all from ECM at that timeframe

Edited December 29, 2014 by bluearmy

[snowking]

As per Nick's post above

 

ECM tops out at +228 at -7.7c, and by T+240 (with continued warming around -12c) breaks through the middle of the elongated vortex and obliterates the vortice in the vicinity of Greenland, forcing it well away to the West, and leaving the dominant player the Siberian/Scandi vortice instead...sound familiar? It should do for anyone who has seen the 12z ECMWF tropospheric output:

 

 

The easiest way I can say to you of visualising this is to look at the purple colours on the charts above and see what happens to their make-up and positioning. This is exactly what is born out at 10mb too.

 

Strong signs of a very quick downwelling phenomenon too down as far as 50mb by day 10 (unfortunately we don't get to see any lower than this as of yet on WxBell) with an almost identical geopotential height transition taking place at this level too - and quite evidently the same in to the troposphere too.

 

Still all out at day 10 right now, but the signs over the last 48 hours are that the warming and potential (2nd) split are not only ramping up, but becoming more and more favourable for the Atlantic profile too.

 

I remain cautious but increasingly optimistic

 

SK

 

EDIT: NAVGEM wants to join the party too, and I am more than happy to let him:

 

Edited December 29, 2014 by snowking

[ITSY]

So if we're talking about the severity of warming it seems as though we're looking at ECM, JMA and NAVGEM against the GFSOp and GFSP. What i'm unsure about is if even the first three of these models, which are forecasting this drastic rise in temperature in areas favourable to us, are actually showing either SSW or the prelude to SSW? It all seems highly unusual to have discrepancy of this sort at relatively medium term range for the strat - not sure whether that fills me with optimism or pessimism!

[snowking]

So if we're talking about the severity of warming it seems as though we're looking at ECM, JMA and NAVGEM against the GFSOp and GFSP. What i'm unsure about is if even the first three of these models, which are forecasting this drastic rise in temperature in areas favourable to us, are actually showing either SSW or the prelude to SSW? It all seems highly unusual to have discrepancy of this sort at relatively medium term range for the strat - not sure whether that fills me with optimism or pessimism!

 

This tweet from Eric Webb might be relevant in answering this:

 

 

 

Eric Webb â€@webberweather  1h1 hour ago

@DTVaWeatherman @MattHugo81 @Recretos @chionomaniac 500mb last 10 days nearly verbatim Garfunkel's precursor pattern pic.twitter.com/XnXTnyjF54

 

 

 

 

In short, take note of the image at the bottom right (theorised precursor pattern to an SSW) and the composite above it showing the 500mb anomaly pattern over the past 10 days

 

SK

Edited December 29, 2014 by snowking

[ITSY]

This tweet from Eric Webb might be relevant in answering this:

 

 

 

 

 

In short, take note of the image at the bottom right (theorised precursor pattern to an SSW) and the composite above it showing the 500mb anomaly pattern over the past 10 days

 

SK

Fascinating - thanks for this.

 

From what I can tell it would seem then that we could be anywhere form several days away to several weeks away (ie the last 2 process frames) from  SSW and this is at the core of the difference between the GFS and the other models. the GFS being the model which wants to delay the onset of SSW further away and the others wanting to bring it forth into a matter of days not weeks, perhaps even developing a SSW outright if the JMA is to be believed.

 

[Skin]

Just something I noticed. There is a pattern of warming every 4-5 weeks, it seems once we get to the strat season. So  just extrapolating, the next one would be end of Jan, beginning of Feb. gaining more heat each time. 

 

[Penrith Snow]

Bloody hell reading this thread hurts my brain, although it us compulsive reading and thanks for all the posts guys.

It doesn't seem long ago when all this stuff wasn't talked about in weather forecasting, I don't remember anyone mentioning MJO,s SSW or Pacific ridges in 1979, we just had some very cold easterlies and it snowed!

Life is so complicated these days.

Andy

[Snowman.]

CMA also in there not as strong as the others but not like the GFS

 

 

NCMRWF

 

 

 

GFS looking very much on its own of shifting it east then back west.

[Trom]

Just something I noticed. There is a pattern of warming every 4-5 weeks, it seems once we get to the strat season. So  just extrapolating, the next one would be end of Jan, beginning of Feb. gaining more heat each time. 

 

Trouble is a trend without a theory is just data mining potentially.  Still has not stopped the masses in the financial worlds believe in chartism.

[Skin]

Trouble is a trend without a theory is just data mining potentially.  Still has not stopped the masses in the financial worlds believe in chartism.

Makes me think the signal is MJO related. 

[KyleHenry]

Wave 1 has produced much higher temps at the 1 hPa level than forecasted

http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/winterdiagnostics/index.html

Dec 27th. 25C, Dec 28th 35C and Dec 29th 35C.

Would be good to see the same result for wave 2.

Up the 192 hours the split and elongation of PV is there for all level before forecasted to rejoin.

So far so good and good things to come

[bluearmy]

Slight changes on the ECM this morning. The splits at 10, 30 and 50 Hpa have gone by day 10 but the vortex remains under great pressure with its Canadian elongation stretched out the higher you go. The temps profile fairly consistent with yesterday's runs. The ECM perhaps not quite as agresive with the pinch on the vortex as it was yesterday.

The main difference with gfs op heights is that on ECM, the Siberian is the master whilst on gfs, it's the Canadian. At day 10, the Siberian master on ECM getting closer to the pole with the Atlantic and pacific ridging squeezing in the Western Hemisphere.

Both models look similar out to day 7. Thereafter, ECM ramps up the temps and split whilst gfs puts the split back together.

looking at Berlin, it seems we have two lots of wave two. One coming from the upper strat and one from the lower (perhaps trop induced). It would seem to me, that on yesterday's run, gfs doesn't see this renewed wave two coming from the top. The gefs definitely won't see it as they don't go that high. The ECM ens should do but the implications of this second wave would likely be post two weeks down here.

So to summarise where we are this morning - perhaps the previous three ECM runs are a tad aggressive in the mid/upper strat with their split and the gfs are probably not aggressive enough.

Interestingly, the NH height profile on the gfsp in two weeks looks similar to the ECM day 10 50hpa with the Asian master stretched out towards Canada.

If ECM is in the right ballpark and there is going to be a fairly quick reaction, expect in two weeks in the trop, to see the low heights begin to drain away from Canada and a fair size vortex setting up just the Asian side of the pole with Atlantic and Alaskan ridges. Of course, that sets it apart from it ens mean suite in the trop.

I would settle for that, given where we are.

EDIT: looking through the gefs , they are clearly now reacting to the general warmings higher up as many members have disrupted vortexes heading through week 2.

 

also, the berlin site hasnt updated any of the charts for yesterday. my analysis of the wave 2 data based on the run from midday sunday

Edited December 30, 2014 by bluearmy

[Interitus]

Yesterday's GEOS was within a whisker of an SSW by day 10 with reversed flow at roughly 7mb and above at 60°N - 

 

This is a broad area of reversed flow at many latitudes, not just confined to near the pole as has been seen so far with the forecast split (and seen in earlier stages of this run).

Interesting are the charts for the 1mb / 1800K levels which gives a different option. In comparison to lower levels where the initial wave 1 becomes wave 2, the wave breaking strips off so much vorticity that the original Asian geopotential heights are reduced by mixing and the secondary Atlantic height rise becomes a wave 1 from the opposite side.

The result is more of a displacement than a split, shown nicely in the animation - http://acdb-ext.gsfc.nasa.gov/Data_services/arctic/anim_EPV_1800.html

 

Index of GEOS plots - http://acdb-ext.gsfc.nasa.gov/Data_services/arctic/index.html

 

 

 

 

 

[Paul123]

In order to better understand the mechanism of the stratospheric warming, I have made a sequence of this mornings EC Wave 2 (geopotential) forecasts (+24/48/96/144/198/240):

 

 

It is obvious that the warming reaches its peak in about one week.

 

Before that I notice a warming in the upper troposphere that lifts into the stratosphere.and consequentily joins with the initial upper stratosphere warming.

 

I assume this is the process of wave breaking, that I often read about on this forum.

 

(The troposphere geopotenial heights are driven by a (shallow) Atlantic Rossby wave.)

Edited December 30, 2014 by Paul123

[bluearmy]

Yesterday's run Paul (the charts are duplicated on today's supposed data for yesterday's 12z)

But I doubt much changed on the wave forecasts

[Paul123]

Yesterday's run Paul (the charts are duplicated on today's supposed data for yesterday's 12z)

But I doubt much changed on the wave forecasts

 

Okay, thank you.

 

The point is that given the driving forces of the wave 2, the stratospheric forecasts quite a lot depend on the tropospheric output, more than usually appears to be the case.

There is still quite a lot uncentainty in the strat. progs.

 

No way clear, the size of the coming (ongoing) warming. 

Edited December 30, 2014 by Paul123

[mountain shadow]

Decent warming where we want it on PGFS 30HPA.

http://max.nwstatic.co.uk/gfsimagesnew/gfs.20141230/12/222/npst30.png

Will it work its way down to 500H though?