Snowy L

ECM makes it, surrounded by lows to the south so it can't sink.

Also good WAA towards Greenland on that 144 chart.

Looks like it's going to make it based on t144...

We have retrogession

That's a nice line of lows building up in the Atlantic, I hope that aids the retrogression of high pressure to our Northwest.

ECM and UKMO still keep some form of link between the Atlantic High and North Pole High. GFS in typical fashion says no to that and ramps up the low pressures to the North of our block.

Looks like we're going to get high pressure moving into Greenland in FI again. We need to keep an eye on that Atlantic high that joins in after our toppled high of the initial cold spell.

Stronger Iberian low, could be so important for a reload.

Well I didn't see that one coming...

Weird looking 18z, high pressure in the Atlantic is very weak but low pressure doesn't seem to want to claim the area either.

Hmm, I'm not sure if this is an error, but the ECM has suddenly picked up on a massive increase in wave-2 breaking in 7-10 days time. I'm skeptical because this was nowhere to be seen in forecasts in the previous few days. Can't post images yet sorry: http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/eczm.php?alert=1&forecast=f240&var=ha2&lng=eng

Storm of the century in FI GFS, those isobars over Greenland have formed a solid white line

I'm quoting Chionomaniac on this but the stratosphere did indeed play a part in that cold spell: "There is still a lot to learn about this subject and on the surface the stratospheric conditions were nothing too out of the ordinary in late autumn in 2010. However, at that time of year, the vortex is yet to gain the kind of strength that a prolonged winter cooling would lead to and so is vulnerable to attack. And this attack came in the form of the rare tropospheric led Greenland wave break, which broke into the lower reaches of the stratosphere creating a split, which in turn reinforced the Greenland high. Later on in the season, these types of tropospheric waves will be suppressed by the vortex if it has cooled and strengthened sufficiently. So enhanced tropospheric wave activity was enough to split the lower stratospheric vortex before the stratospheric vortex had increased to it's full winter strength. Quite rare." In fact it bares a few similarities to what I think is our current situation. The vortex is strengthening and will continue to strenghten with strong zonal winds, however wave breaking is expected to begin next week, which some models, the GFS in particular, are forecasting to affect the lower stratosphere. There was an interesting GFS chart posted in the strat thread which shows a split in the lower vortex, albeit in FI, which if becomes reality we could be looking at some form of Northern blocking. This of course being started by the big height anomaly in the Aleutian Islands in the troposphere. The stratosphere isn't the main contributor to winter weather, but I think the troposphere>stratosphere>troposphere is by far and away the main cause of winter set ups.

GFS has picked up on this a lot more than the ECM models. Still too early to say but that massive enhancement of wave-2 breaking thanks to the Aleutian High was always going to have some sort of effect. It won't affect the higher strat but you would expect it to make an impact in the strat lower down. The whole idea of Canadian Warmings is that the higher strat continues to cool whereas lower down we see a warming in Canada that shifts the lower vortex east of the North Pole, as seen in those GFS charts. The fact that it's forecasting a smaller section to split away over North America ties in nicely with the fact that it's caused by wave-2 rather than wave-1.

Yeah it can be seen in the PNA it's expected to dive into a strong negative phase, which suggests strong blocking over the North Pacific. Anomalous high pressure over this region brings enhanced wave-2 activity and this can be seen for the first time on the Berlin models. We're looking at some pretty strong wave breaking in 7-10 days just after the wave-1 activity begins to weaken. http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_ha2_f216.gif Some small bursts of warming over Canada in the lower stratosphere have already put wobbles into the the lower vortex and I'm guessing they're the reason for the change to cool zonal, even very brief meridional patterns. Edit: Can we not post picture files from our computer anymore?

Any figures on how this year's index performed and how it compared to good years like 2009?

The attack on the stratosphere continues...wave 1 activity expected to increase in 10 days combined with an increase in wave 2 activity. Is this combined effort the reason why there's a credible rise in temperatures forecast for the other side of the north pole in a couple of weeks? Hopefully we get a minor warming out of this and we see a situation similar to early December last year, though with us being on the right side of blocking this time!

I know I'm not using it to forecast storms I'm using it for stratospheric forecasts.

Thanks, so we are above 150 solar flux at the moment, good news seeing as we are in West Phase QBO.

Are there any sites that give current observations for solar flux 10.7cm?

I think it's safe to say that we are past solar maximum now. Also the solar maximum was a very low one. The correlation between solar cycle/QBO/SSWs is more based on actual solar flux 10.7 cm rather than solar maximum/minimum. So even though we are close to a solar maximum, the actual solar flux is low as this has been a very weak solar maximum. I wasn't a great supporter of solar-climate links either, but the soalr cycle/qbo links have shown some good correlations in experiments, particularly solar max/qbo west links. http://strat-www.met.fu-berlin.de/labitzke/moreqbo/MZ-Labitzke-et-al-2006.pdf Page 8 shows the graphs and it shows a decent positive correlation between West QBO, Solar flux and SSWs, though the correlation is weaker when it comes to East QBO and solar flux. Edit: Forgot that they're measuring 30hpa Geopotential height at the North Pole, not SSWs. But greater heights at the North Pole implies displaced/split/weakened vortex.

I was feeling optimistic about an SSW this winter with us being at solar maximum with a west QBO (SSWs are more common under these conditions than in an east based QBO during solar minimum). However, the solar cycle has been very weak this year and it's gone against predictions of a maximum this year. 2011 is now considered to be the maximum and in fact we've seen a sharp drop in sun spot counts to levels last seen in the mid 2000s in the last few weeks. Snow is advancing nicely below 60 degrees and we've already seen a few wobbles in the temperature profile in the stratosphere. I'm hoping we will see a minor warming or 2 to give us a shot at a cold spell in late November/December. Wave-1 activity is set to increase in the next few days, but while it will give a warming it doesn't look like anything too strong and I doubt it will disrupt the vortex too much,

It's a big area of interest at the moment, this is a great read as well http://www.tellusa.net/index.php/tellusa/article/view/19375/html They mention a new observation to keep an eye on, November sea ice cover over the Siberian seas. It's on a short timescale so I'm thinking could it be linked with these early season disruptions to the polar vortex that we have seen in recent years. Ice cover has been low for a decade now, but near the Barents sea (the main observation area) it's been pretty much non-existent. As far as I remember we have seen weakening of the vortex in November/December in 2009,2010 and 2012 in the last few years and these have all had very low Siberian sea ice cover, particularly 2009 and 2012.

It happened last year apart from the first few days? Or was that just in my area.

Very warm (mean temperatures >5C above normal 10% Have we ever had a winter that's been 5c above average? Seems like a very high percentage for something I don't think we have ever seen.