Stratosphere temperature watch - 2016/17

[knocker]

 

[feb1991blizzard]

48 minutes ago, knocker said:

 

Yes ive been worried about this for a while, the E-qbo cant make it down past 50mb, even worse the westerlies at the top of the strat are making their way steadily down by the end of the run.

[Cheshire Freeze]

1 hour ago, feb1991blizzard said:

Yes ive been worried about this for a while, the E-qbo cant make it down past 50mb, even worse the westerlies at the top of the strat are making their way steadily down by the end of the run.

I read something about this last week. Are we facing another E QBO that fails to establish?

[feb1991blizzard]

8 minutes ago, CreweCold said:

I read something about this last week. Are we facing another E QBO that fails to establish?

Its looking like it, The September 30mb zonal mean wind speeds have come out, still an increase in the Easterlies but only slightly, shame if this goes belly up, looks like a perfectly timed e-qbo to me, following similar pattern to 09/10 and nearing a solar minumum, Gavin Partridge said in one of his videos he thinks it wont fail this time but I'm not so sure,

https://www.esrl.noaa.gov/psd/data/correlation/qbo.data

[Yarmy]

It's not that unusual for the Easterly descent to stall for a few months. Berlin has yet to update for September, but you can see plenty of similar examples in the record:

Edit: I'd also say that we are on the wrong side of solar min for it to be a good match with 09/10. Geomagnetic activity lags a few years.

Edited October 3, 2017 by Yarmy

[Yarmy]

 

[feb1991blizzard]

5 minutes ago, Yarmy said:

It's not that unusual for the Easterly descent to stall for a few months. Berlin has yet to update for September, but you can see plenty of similar examples in the record:

Edit: I'd also say that we are on the wrong side of solar min for it to be a good match with 09/10. Geomagnetic activity lags a few years.

True but its still low solar activity even if you take lag into consideration, also that's all the more reason to hope the qbo pattern stays in sync because next year will be west qbo just before solar min so 19/20 could well be the jackpot winter. 6 months after weve hit solar min and e-qbo.

[cheeky_monkey]

30 minutes ago, Yarmy said:

It's not that unusual for the Easterly descent to stall for a few months. Berlin has yet to update for September, but you can see plenty of similar examples in the record:

Edit: I'd also say that we are on the wrong side of solar min for it to be a good match with 09/10. Geomagnetic activity lags a few years.

Plus we are heading towards a weak/moderate La Nina...09/10 was a weak El Nino

[blizzard81]

33 minutes ago, Yarmy said:

 

What is this showing exactly? 

[blizzard81]

1 hour ago, feb1991blizzard said:

Its looking like it, The September 30mb zonal mean wind speeds have come out, still an increase in the Easterlies but only slightly, shame if this goes belly up, looks like a perfectly timed e-qbo to me, following similar pattern to 09/10 and nearing a solar minumum, Gavin Partridge said in one of his videos he thinks it wont fail this time but I'm not so sure,

https://www.esrl.noaa.gov/psd/data/correlation/qbo.data

What caused the unprecedented delay over the last 12 months I wonder? And on top of this now a seemingly marked stall in proceedings. 

[feb1991blizzard]

Just now, blizzard81 said:

What caused the unprecedented delay over the last 12 months I wonder? And on top of this now a seemingly marked stall in proceedings. 

Not sure but I know last winters fail was extremely rare, ive seen qbo charts going back to the 50s (cant remember where) and it hasn't happened in the last 50 years I don't think, assuming ive read the charts properly.

[Yarmy]

28 minutes ago, blizzard81 said:

What is this showing exactly? 

It's the average AP index over time.  The AP index is a measure of geomagnetic activity on Earth. It follows the same pattern as the sunspot cycle, but lags it by a few years. Geomagnetic activity is thought to influence climate (although perhaps only on a regional basis). There are some links to papers way back in this thread.

Edited October 3, 2017 by Yarmy

[feb1991blizzard]

Here's one that goes back to 1930 as well which nicely illustrates the lag effect.

 

EDIT : I knew there was some kind of lag effect but what confuses me is when people talk about a sudden spike in solar activity scuppering a cold spell and the models collapsing a block over a couple of runs like 2012 December??

Edited October 3, 2017 by feb1991blizzard

[knocker]

 

[blizzard81]

1 hour ago, Yarmy said:

It's the average AP index over time.  The AP index is a measure of geomagnetic activity on Earth. It follows the same pattern as the sunspot cycle, but lags it by a few years. Geomagnetic activity is thought to influence climate (although perhaps only on a regional basis). There are some links to papers way back in this thread.

Thank you for your reply, much appreciated. 

[blizzard81]

1 hour ago, feb1991blizzard said:

Not sure but I know last winters fail was extremely rare, ive seen qbo charts going back to the 50s (cant remember where) and it hasn't happened in the last 50 years I don't think, assuming ive read the charts properly.

I'm getting that sinking feeling again for this winter lol. 

[summer blizzard]

7 hours ago, feb1991blizzard said:

Yes ive been worried about this for a while, the E-qbo cant make it down past 50mb, even worse the westerlies at the top of the strat are making their way steadily down by the end of the run.

The lobe just of 50hpa has actually weakened substantially in strength and is probably just a residual pocket of westerlies. 

The westerly QBO in the upper stratosphere is actually fairly normal as the next wave develops months in advance. Remember that the chart does not space equally.

[summer blizzard]

10 hours ago, Singularity said:

Another key aspect last winter was long periods of moderate-strength stratospheric warming with positive height anomalies frequently having some but not a lot of influence on tropospheric patterns... yet still enough to - ironically I suppose - interfere with the vertical wave activity needed to produce a bigger, more effective warming event.

Or at least, that's what J. Cohen deduced from how things panned out.... he's not had the best track record these past few winters so there's no guarantee that this is an entirely valid theory. What do others make of it? TIA 

If it does hold truth then I will have some concern if the vortex is consistently very weak from early on as this seemed to be what facilitated the long-duration-yet-weak-magnitude warming tendency of last winter. Just my take on things though!

I recall some suggestion in the past of a kind of elastic band effect whereby to get a larger fall in mean zonal winds you need an initially stronger vortex. With that being said though 2005/2006 was a great example of a winter where the vortex never really got going but was pretty cool.

https://acd-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra2/wind/u60n_10_2005_merra2.pdf

[Yarmy]

Just further to the above discussion:

Structure of the QBO

The time-height section derived from these data in Fig.30 shows the observed structure of the QBO at equatorial latitudes:

• alternating easterly and westerly wind regimes propagate downward with time;
• westerlies move down faster and more regularly than easterlies;
• the transition to easterlies is often delayed between 30 and 50 hPa;
• easterlies are generally stronger (30-35 m/s) than westerlies (15-20 m/s);
• maximum amplitudes of both phases typically occur near 20-hPa;
• the average period is about 27 months;
• both period and amplitude considerably vary from cycle to cycle.

 

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

[knocker]

 

[Devonshire]

16 hours ago, Yarmy said:

Edit: I'd also say that we are on the wrong side of solar min for it to be a good match with 09/10. Geomagnetic activity lags a few years.

Tentatively - isn't current solar cycle position a good match for cycle 19 (i.e., Winter 1962/63)?! Although we could do with QBO going strongly easterly and La Nina being rather weak for a better match. (It is interesting to note also that the cycle 19 minimum came off the back of a VERY high maximum - unlike current cycle). For what all these things are worth.

[Singularity]

11 hours ago, summer blizzard said:

I recall some suggestion in the past of a kind of elastic band effect whereby to get a larger fall in mean zonal winds you need an initially stronger vortex. With that being said though 2005/2006 was a great example of a winter where the vortex never really got going but was pretty cool.

https://acd-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra2/wind/u60n_10_2005_merra2.pdf

Interesting to note the weak vortex spell in October that year too. It would take a lot to prevent a recovery to near-average at some point which from the looks of things ought to be enough for a sufficient magnitude of breakdown. Looking for a nice clean split for a change rather than the messy developments of last winter and the unhelpful displacements of the one before that (we sure have been through a lot of frustrating shortfalls in recent winters...).

[Norway Nut]

2 hours ago, Devonshire said:

Tentatively - isn't current solar cycle position a good match for cycle 19 (i.e., Winter 1962/63)?! Although we could do with QBO going strongly easterly and La Nina being rather weak for a better match. (It is interesting to note also that the cycle 19 minimum came off the back of a VERY high maximum - unlike current cycle). For what all these things are worth.

Umm, I heard it was a good match for, I think, Solar cycle 12 or 6 or even 5. 

"In terms of overall solar cycles we continue to trend very closely to the weaker soar cycles of 5, 6, 12, 14 and 16. Out of all these cycles SC12 has and remains the closest to SC24." http://www.gavsweathervids.com/sc24-25.html

Edited October 4, 2017 by Norway Nut
Source documentation for what it is worth

[Devonshire]

2 hours ago, Devonshire said:

Tentatively - isn't current solar cycle position a good match for cycle 19 (i.e., Winter 1962/63)?!

I might have phrased this better: I believe we are at a similar pre-minimum stage in the cycle as winter '62/'63 (cycle 19) - in response to Yarmy's point about geomagnetic energy lagging solar cycle (and implication that most favourable solar-related conditions for harsh UK winter are a little post-minimum). Our harshest winter in last 100 years came just pre-minimum.

[Interitus]

17 hours ago, knocker said:

 

Yes, there have been record weak wind speeds in the MERRA 2 dataset, from 50 mb and below related to troposphere circulalion, but some have been getting a bit carried away with the significance of this, and the upper level vortex has been developing as normal.

A weak vortex in October is a poor predictor for strength later in the winter, at least as measured as measured by 10mb wind speed (NCEP reanalysis). There is a weak correlation by persistence to the strength in November (0.27) but none for other months. Persistence leads to higher correlation for consecutive months November-December (0.42), December-January (0.54) and January-February (0.41) but no correlation for lead times more than a month apart. The stopping the plate spinning analogy doesn't seem to apply.