Stratosphere Temperature Watch 2011/2012

[phil nw.]

Thanks Mr C - any idea how reliable the forecasts are - are they based on ensemble forecasts from things like GFS/ECM?

Hi C,

Is this just another way of presenting yesterdays ECM 12z run of mean Heights but showing the mean flow of the Jet at 100-200hpa?

Edited October 26, 2011 by phil n.warks.

[chionomaniac]

Thanks Mr C - any idea how reliable the forecasts are - are they based on ensemble forecasts from things like GFS/ECM?

Hi Ben,

I have found that in the upper levels of the stratosphere the forecasts are reliable but this reduces as one nears the troposphere. If a stratospheric event is occurring then the forecasts are quite reliable in forecasting the event but not as accurate in detailing the specifics.

Hi C,

Is this just another way of presenting the yesterdays 12z run of mean ECM Heights but showing the mean flow of the Jet at 100-200hpa?

Yes, this is yesterdays 12Z ECM forecast but including the stratospheric output. This can be very frustrating when wanting up to date information the same day! The GFS forecasts are taken from the 00Z run and released the same day.

c

[Snowmad79]

The good thing is though, in the context of the more reliable timeframe the jet stays roughly 41deg north lattitude (London is 51) averaged out as you describe, so these charts are as reliable as the FI of the models they come from and to be taken with a pinch of salt in the latter stages as with all models.

Must admit, its pretty cool to follow the jet from this alternate perspetive. Thanks for that maniac

[phil nw.]

Hi Ben,

I have found that in the upper levels of the stratosphere the forecasts are reliable but this reduces as one nears the troposphere. If a stratospheric event is occurring then the forecasts are quite reliable in forecasting the event but not as accurate in detailing the specifics.

Yes, this is yesterdays 12Z ECM forecast but including the stratospheric output. This can be very frustrating when wanting up to date information the same day! The GFS forecasts are taken from the 00Z run and released the same day.

c

Yes i see thanks.

I note that the core of the strongest zonal winds at the top of the Strato. trend South by day 10 but at the lower level go slightly north as you say.

Would the trend at the top downwell to the lower level later thus forcing the jet stream south again.?

I am probably reading this incorrectly but just trying to learn the significance or not of this chart.

Thanks for your patience.

[karyo]

I suppose we should soon start seing some signs of pressure rise in Scandinavia based on Stuart's early thoughts?

That may save us from the zonal train for the first half of winter.

Karyo

[Radiating Dendrite]

I suppose we should soon start seing some signs of pressure rise in Scandinavia based on Stuart's early thoughts?

That may save us from the zonal train for the first half of winter.

Karyo

I think the pressure rise in Scandi will not happen for a few months yet if I am interpreting what GP said correctly?

[karyo]

I think the pressure rise in Scandi will not happen for a few months yet if I am interpreting what GP said correctly?

Months? GP said December and January so I would expect this showing on the stratospheric forecasts by late November?

Karyo

[Radiating Dendrite]

Months? GP said December and January so I would expect this showing on the stratospheric forecasts by late November?

Karyo

Probs early December.

To be fair, he said the signals are very mixed.

This could all change again by the time the actual forecast is released.

[Glacier Point]

More like January - the upper vortex will only show its true hand by mid to late December although we are seeing the zonal winds increase and expand between 80N and 40N on a daily basis, which is very much in line with those analogues I was discussing in the winter preview.

[karyo]

More like January - the upper vortex will only show its true hand by mid to late December although we are seeing the zonal winds increase and expand between 80N and 40N on a daily basis, which is very much in line with those analogues I was discussing in the winter preview.

Thanks. So we should be expecting an Atlantic dominated Nov and December? My optimish from yesterday has just faded! :-(

Karyo

[beng]

Hi Ben,

I have found that in the upper levels of the stratosphere the forecasts are reliable but this reduces as one nears the troposphere. If a stratospheric event is occurring then the forecasts are quite reliable in forecasting the event but not as accurate in detailing the specifics.

c

Thanks very much - makes sense :-)

[chionomaniac]

Yes i see thanks.

I note that the core of the strongest zonal winds at the top of the Strato. trend South by day 10 but at the lower level go slightly north as you say.

Would the trend at the top downwell to the lower level later thus forcing the jet stream south again.?

I am probably reading this incorrectly but just trying to learn the significance or not of this chart.

Thanks for your patience.

Hi Phil,

I think you are reading things correctly.

I have indicated with the box on the first chart below (T+120) where the core of the stratospheric vortex is situated . The winds at the 1hPa level are fluctuating in intensity and position as the vortex grows in intensity but it is the mean zonal winds in the middle stratosphere (say 30 hPa) that are more important here.

By T+240 we can see that the increasing and dropping strengthening vortex is 'pulling' the jet stream towards it. Simplistic diagrams for a complex subject I know, but it helps explain these mean zonal mean wind charts.

[phil nw.]

Thanks again Chiono.

I think i get the idea now,something else to view as we go through Winter.

Edited October 26, 2011 by phil n.warks.

[summer blizzard]

One thing to note today is the positive zonal mean winds indicated on the following chart.

These wind anomalies are found around 100-200 hPa height and 40-50 Degrees north. This is the jet stream when averaged out across the northern hemisphere. Now look at the mean zonal wind chart forecast and watch the jet stream trend north. The further south we see this the better.

http://wekuw.met.fu-...l&var=u&lng=eng

On day 10 of the ECWMF chart we see light blue at 70N and above, would this indicate a -AO?

Am i to assume that we want to see blue right the way from the tropics to the pole for cold?

[chionomaniac]

On day 10 of the ECWMF chart we see light blue at 70N and above, would this indicate a -AO?

Am i to assume that we want to see blue right the way from the tropics to the pole for cold?

Not necessarily. It's gone now as well. Quite often negative anomalies will appear at the pole as the polar vortex shifts position around it.

[knocker]

Are we creeping in to a stronger vortex Chiono?

Edited October 29, 2011 by weather ship

[chionomaniac]

No changes seen in stratospheric conditions the last few days. Ozone forecasts are unremarkable leading to gradual cooling and a slow increase in the polar vortex strength. The only thing of note is a possibility that any Scandi Ridge will drop southwards at around the 10 days timeframe. If this occurs then I suspect that the jet will ride above. We have not seen that poorly angulated jet stream pattern for a while.

[SNOWPLOUGH]

Is the stratoshere not warming very slightly at the 30hpa level? (Still just below average though)

http://ds.data.jma.go.jp/tcc/tcc/products/clisys/STRAT/html_e/pole30_n.html

Dan

[summer blizzard]

Indeed we are seeing a warming of the stratosphere. We will need to keep it going for a few days although with the interquartile range still very close at this time of year it could indicate the potential for something good into December, we saw a similar event last year.

http://acdb-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra/t90n_30_2011_merra.pdf

This page is more detailed.

[phil nw.]

Indeed we are seeing a warming of the stratosphere. We will need to keep it going for a few days although with the interquartile range still very close at this time of year it could indicate the potential for something good into December, we saw a similar event last year.

http://acdb-ext.gsfc..._2011_merra.pdf

This page is more detailed.

I can only see one day of a slight upward curve on these graphs though.

We look about average at 30Hpa at present.

We need many more days before we can declare an upward trend.

[chionomaniac]

I tend to look at the average temperature between 60-90ºN. Cold pools can circle the pole at this time and so minor fluctuations at 90ºN can be picked up but the overall trend is still well below average.

http://acdb-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra/t60_90n_30_2011_merra.pdf

[phil nw.]

I tend to look at the average temperature between 60-90ºN. Cold pools can circle the pole at this time and so minor fluctuations at 90ºN can be picked up but the overall trend is still well below average.

http://acdb-ext.gsfc..._2011_merra.pdf

Thanks Chiono.

[cooling climate]

Ozone in the Arctic is looking better the past couple of days

plus there is an asian mountain torque event ongoing and a

uptick in 30 hpa stratosphere temperatures at the north pole.

Things are looking up.

[chionomaniac]

Ozone in the Arctic is looking better the past couple of days

plus there is an asian mountain torque event ongoing and a

uptick in 30 hpa stratosphere temperatures at the north pole.

Things are looking up.

I wouldn't say ozone levels are high but the forecast is certainly looking better. Now is the time to assess the BDC level.

Yesterday's ozone

T+120

No signs in the forecasts yet that the Asian MT is creating a wave breaking event in the stratosphere but I agree good to see nonetheless.

[summer blizzard]

No luck on the stratosphere front, the warming was small.