Snowy L
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Posts posted by Snowy L
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Sink to where exactly? There's nowhere it can feasibly sink to? Looks like going down the GFS route to me with a renewed attempt at a Greenland/Icelandic high as we get towards day 10.
It's being drawn in by the Southern Russian high
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PV is still very much intact, the last 2 frames aren't going to be nice imo, I can see that high sinking.
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ECM makes it, surrounded by lows to the south so it can't sink.
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Also good WAA towards Greenland on that 144 chart.
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Looks like it's going to make it based on t144...
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We have retrogession
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168 shows -8 uppers crossing northern Scotland
That's a nice line of lows building up in the Atlantic, I hope that aids the retrogression of high pressure to our Northwest.
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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.
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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.
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Stronger Iberian low, could be so important for a reload.
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Well I didn't see that one coming...
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Weird looking 18z, high pressure in the Atlantic is very weak but low pressure doesn't seem to want to claim the area either.
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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:
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Storm of the century in FI GFS, those isobars over Greenland have formed a solid white line
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HI Phil - I disagree with the assumptions you are making in this post- almost Ian Brown esque-
What you are intimating is that due to the fact that the stratosphere is cooling that vis a vee there cannot be any cold or any polar blocking, & because the models aren't modelling any warming or any abate of the zonal wind there cannot be any cold either-
Well, that is why annoyed me with the stratosphere thread from last year - Everyone has gone stratosphere mad, sure is part of the system, however it doesn't have total control of the weather-
For example take the stratospheric profile for November 2010
http://www.cpc.ncep.noaa.gov/products/stratosphere/temperature/archive/50mb9065_2010.gif
Below the norm getting close to getting to the bottom of the range-
but what chart do we see in that month?
http://modeles.meteociel.fr/modeles/reana/2010/archivesnh-2010-11-25-0-0.png
The stratosphere will indeed continue to have its periods of cooling & hopefully as we head into Winter we will see a warming like last year where the temp anomaly goes off the scale- we can of course then take some confidence into a cold -AO forecast.
There is however nothing to assert though that because there is no blocking now there can be no blocking in say 10-15 days time.
We should be keeping the options open looking at how things develop- & no one can say with confidence that there will be no blocking in 10 days, just because the stratosphere doesn't seem to be playing ball or because we currently have a period of zonal conditions....
I notice Ian piped up- his zonal forecast for more than 10 days of zonal conditions have finally come to fruition- hes only been forecasting them since 2008-
S
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.
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A couple of interesting FI charts from the GFS 12z run,firstly at 30mb with the polar vortex shifting east of the N.pole...
...and then at 100mb with what looks like a scandi trough and ridge towards Greenland.
Obviously at the outer realms of FI but worth watching all the same.
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.
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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?
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Any figures on how this year's index performed and how it compared to good years like 2009?
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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!
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Trying to post the link but not working.http://www.solen.info/solar/
Solar effects the stratosphere no one is arguing there but a few days of moderate
activity will not have an almost immediate effect on troposphereic weather it does not
work like that. You would have a lag effect which would start in the upper atmosphere
and work its way down effecting the tropics first I would have thought and then down
stream effects elsewhere.
There is no way the Sun would have played any part in the intensity of the storms tracking
across the atlantic when the sun's activity went from low to moderate in the last few days.
Activity is now moderate to high by the way.
Last years failed beasterly also had nowt to do with a small uptick in solar energy.
Ozone over the northern hemisphere and the Arctic has been above normal all year
and the deviation from normal at this present time can be seen below.
This is one of the reasons among several that I think we will see a negative AO this
winter along with a negative NAO.
I know I'm not using it to forecast storms I'm using it for stratospheric forecasts.
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Trying to post the link but not working.http://www.solen.info/solar/
Thanks, so we are above 150 solar flux at the moment, good news seeing as we are in West Phase QBO.
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Solar influences on the stratosphere are well researched. Dr Karin Labitzke is the key author on the subject at the Free University of Berlin. Resume Brief here
There are many papers newer than this, however this is a good one to have a flick through.
ftp://geosp-server.aquila.infn.it/isss/ASSE06/Labitzke.pdf
With respect to the impact of solar activity on the precise location of the Polar Vortex with respect to increased solar flux, not something I have seen studied in a paper yet.
Are there any sites that give current observations for solar flux 10.7cm?
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Solar max is a somewhat nebulous arithmetic concept anyway: where's the max here?
Rest assured we are in the current year(s) of peak activity. The poles have flipped recently as we can see here:
I'm pretty dubious about solar-climate connections to be honest, especially at the short range.
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.
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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,
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Model Output Discussion 13/11/13 >
in Forecast Model Discussion
Posted
I should add though that I don't buy this run at all. There is no way the vortex will be that much intact in 10 days time. We will see gaps appear which will aid our high pressure to stay to our North, unlike the end of todays 12z run.