Stratosphere Temperature Watch 2011/2012

[Partholon]

Matt Hugo's latest ECM 32 day update was as he put it the best he's seen for northern

blocking since December 2010 with a clear indication from the model of easterlies from

23rd to 29th then Greenland blocking and north/northeasterlies 6th to 12th Feb.

The dates are unimportant its the fact their sounds of though their was a strong signal

for northern blocking.

Considering how accurate the ECM 32 dayer has been I find it strange that given the strong

indications of a cold outlook (this is the second update to show this) he has downplayed

this with no blogs on netweather and only a couple of references on (TWO) and now he is

talking of a stronger signal for a +NAO.

Could the GFS profiling of the stratosphere with a much more +NAO and stronger Vortex

be proving correct I wonder.

The UKMO in their extended outlook yesterday made no mention of blocking. That may suggest they are backing the GFS on what happens in the stratosphere and its effects lower down.

If so maybe that's why he's downplaying the ecm 32 day update?

[LomondSnowstorm]

Matt Hugo's latest ECM 32 day update was as he put it the best he's seen for northern

blocking since December 2010 with a clear indication from the model of easterlies from

23rd to 29th then Greenland blocking and north/northeasterlies 6th to 12th Feb.

The dates are unimportant its the fact their sounds of though their was a strong signal

for northern blocking.

Considering how accurate the ECM 32 dayer has been I find it strange that given the strong

indications of a cold outlook (this is the second update to show this) he has downplayed

this with no blogs on netweather and only a couple of references on (TWO) and now he is

talking of a stronger signal for a +NAO.

Could the GFS profiling of the stratosphere with a much more +NAO and stronger Vortex

be proving correct I wonder.

We don't know yet which one will prove correct. However, others have picked up on the GFS showing major vortex weakening at the 30hpa level by the end of January http://cdn.nwstatic.co.uk/gfsimages/gfs.20120115/06/288/npst30.png (this was with zonal wind reversal at lower levels over the pole shown on the ECM http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwfzm_u_f240.gif so there are some positives out there for further vortex disruption, potentially favourable for us, in the foreseeable.

[karyo]

I don't like how brief the warming is at the 30hpa level. Within a few days it goes back down to below average.

http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/ts.php

Karyo

[chionomaniac]

I don't like how brief the warming is at the 30hpa level. Within a few days it goes back down to below average.

http://wekuw.met.fu-...ww/wdiag/ts.php

Karyo

Look again and check out the EP- flux

[nick sussex]

Look again and check out the EP- flux

Thats a big change since yesterday, can I ask how much effect will the weakening of that EP flux have, also Chiono from your previous posts the nw tilting EP isn't good as its towards the Equator so today we've got it going in the other direction not north towards the pole, would I be right in thinking thats more towards Scandi and hence any blocking is more likely to appear there or am i way off!!!

[chionomaniac]

Thats a big change since yesterday, can I ask how much effect will the weakening of that EP flux have, also Chiono from your previous posts the nw tilting EP isn't good as its towards the Equator so today we've got it going in the other direction not north towards the pole, would I be right in thinking thats more towards Scandi and hence any blocking is more likely to appear there or am i way off!!!

Can't give full answer now. But ep flux forecast far better for any downwelling negative anomalies

[nick sussex]

Can't give full answer now. But ep flux forecast far better for any downwelling negative anomalies

Thanks well that is good news as we try to see off that PV!

[karyo]

Look again and check out the EP- flux

Today it shows the 30hpa bouncing up again in a few days. It's good but it shows that even the stratospheric forecasts can vary considerably from day to day.

Karyo

[picog]

Temperature up by 30C at the 30 hPa level over the past few days— currently well above average, but from the comments, it may not stay there too long.

[phil nw.]

Looking through the ECM data today the mean zonal wnd speeds continue to fall.Forecasts show speeds of between +20 and -10m/sec.at the higher latitudes incl.the N.Pole.

http://wekuw.met.fu-...mwfzm_u_a12.gif

http://wekuw.met.fu-...mwfzm_u_f96.gif

http://wekuw.met.fu-...wfzm_u_f240.gif

This is in the lower levels which should help to further weaken the vortex.

Edited January 16, 2012 by phil n.warks.

[chionomaniac]

Looking through the ECM data today the mean zonal wnd speeds continue to fall.Forecasts show speeds of between +20 and -10m/sec.

http://wekuw.met.fu-...mwfzm_u_a12.gif

http://wekuw.met.fu-...mwfzm_u_f96.gif

http://wekuw.met.fu-...wfzm_u_f240.gif

This is in the lower levels which should help to further weaken the vortex.

The last few GFS runs have been flirting with the idea of a split as well Phil.

[phil nw.]

The last few GFS runs have been flirting with the idea of a split as well Phil.

Yes i noticed that Ed.It would be nice to see those yellows within the Arctic circle soon though.

[mountain shadow]

Yes i noticed that Ed.It would be nice to see those yellows within the Arctic circle soon though.

I'd rather see the yellows over Greenland to be honest.

[damianslaw]

On average isn't the polar vortex much weaker in Feb than during Dec and Jan any way regardless of how the stratosphere is behaving. Its been rampant for so long now and near record levels in December the natural progression must be for it to weaken markedly. - Feb is not a month renowned for rampant westerlies.

[lorenzo]

From watching this chart meander around the norm for so long pleasing to see this spike, and it's moving in a more favourable direction.

Much discussed but am celebrating the demise of the resident Vortex !

[bluearmy]

within a couple of degrees of a technical ssw at T144 on the berlin update.

[Radiating Dendrite]

within a couple of degrees of a technical ssw at T144 on the berlin update.

Are the zonal winds forecast to change then?

Also, is this one well set up in terms of maximum impact on the troposphere?

[Cecil Hogmanay Melchett]

within a couple of degrees of a technical ssw at T144 on the berlin update.

Yes for all intents its a SSW if this doesn't splatter that relentless PV then nothing will.

TIme lag etc now critical because the clock is ticking towards Feb now.Incidentally im speculating that the METO lads are posibly taking this into account with their colder Feb chances.

[chionomaniac]

Well - good and bad news today.

The good news is that we are almost at that technical SSW and if it was measured at 58N then it is forecast to be achieved as shown below. The mwean zonal mean winds drop to less than 2 m/s at 10hpa and 60N.

Not that I think it makes too much difference whether or not we have a technical SSW at this stage ( one for the history books) - the affect of the warming is going to be the same now.

In previous events we have seen the negative mean zonal winds drop down the stratosphere close to the North Pole (or rise up close to the pole). This event is different in that the negative mean zonal winds are being diverted equatorwards - probably as a result of the unfavourable E-P flux.

How this effects the mean zonal winds in the lower stratosphere and troposphere around polar regions remains to be seen. Presently it looks like the reformation of the polar vortex in the upper stratosphere could be favourable to a negative AO in the lower stratosphere with an area of weakened vorticity situated here.

However looking ahead to the next 6 weeks it is very unlikely that we will return to the vortex Intensification conditions seen earlier this winter and that we are likely to enter a period that is more conducive to high latitude blocking, the such of which we are seeing on the other side of the hemisphere currently.

The not so good news involves the short to medium term forecasts at the lower level of the stratosphere. We are seeing both the ECM and GFS agree at the 100 hPa level that the polar vortex is shifting back towards Greenland. It is weakened but will still be enough to stop blocking occuring there in the medium term - ite certainly needs monitoring.

c

[nick sussex]

I'm beginning to think the idea of blocking over Greenland is not what the UKMO are seeing, their outlook seems to be blocking to the ne which is still possible with that segment of the weakened PV.

If the Canadian high amplifies the downstream pattern then that troughing to the west may eject energy under higher pressure to the ne, surely given the split PV aided by that strat warming thats a possible scenario, for this reason I think we need a negatively tilted trough near the UK.

I keep thinking about last nights ECM 144hrs or something similar in terms of trend as a way to get to that to colder option of the UKMO.

[sebastiaan1973]

Chio. Thanks for the update. Nice to see we are close to a SSW. Congrulations with you forecast in which you told us, a SSW would perhaps come in January. It is still 144h away, so it could turn to a real SSW as well. Concerning those 192h charts of GFS and EC. Are they not highly uncertain?

[chionomaniac]

I'm beginning to think the idea of blocking over Greenland is not what the UKMO are seeing, their outlook seems to be blocking to the ne which is still possible with that segment of the weakened PV.

If the Canadian high amplifies the downstream pattern then that troughing to the west may eject energy under higher pressure to the ne, surely given the split PV aided by that strat warming thats a possible scenario, for this reason I think we need a negatively tilted trough near the UK.

I keep thinking about last nights ECM 144hrs or something similar in terms of trend as a way to get to that to colder option of the UKMO.

I think that the metoffice have seen an uncertainty and this is why their update yesterday gave two options. I would be looking east/ NE first when looking for any potential cold spell, given the latest 100 hPa forecast charts.

Chio. Thanks for the update. Nice to see we are close to a SSW. Congrulations with you forecast in which you told us, a SSW would perhaps come in January. It is still 144h away, so it could turn to a real SSW as well. Concerning those 192h charts of GFS and EC. Are they not highly uncertain?

Thank S.

I would agree that the 100 hpa charts are less reliable during events - we have seen a loty of twoing and froing recently - but the current forecast has been stable for a couple of days now. I will keep an eye on it though.

[nick sussex]

I think that the metoffice have seen an uncertainty and this is why their update yesterday gave two options. I would be looking east/ NE first when looking for any potential cold spell, given the latest 100 hPa forecast charts.

Thank S.

I would agree that the 100 hpa charts are less reliable during events - we have seen a loty of twoing and froing recently - but the current forecast has been stable for a couple of days now. I will keep an eye on it though.

If you agree with me Chiono then thats good as you are the stratosphere king!

[chionomaniac]

If you agree with me Chiono then thats good as you are the stratosphere king!

I wouldn't quite say that but I do agree with looking east.

[Yorkshiresnows]

I wouldn't quite say that but I do agree with looking east.

Guys,

I'm always looking East ... and dreaming of Feb 91, Jan 87 etc etc

(This thread is great though CC. Now come on lets reel in that Easterly / North Easterly / Northerly ... any of these will do)

Y.S