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chionomaniac

Stratosphere Temperature Watch

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current conditions not looking too favourable then! :)

It's early days yet and at least the stratosphere temps aren't below average!

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It's early days yet and at least the stratosphere temps aren't below average!

fair enough, suppose theres plenty of opportunity for cold snaps, but snap is the key word as northerlies are so weak nowadays, and if the continent continues the way it is at present we shall be basking in the sun from an easterly!

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fair enough, suppose theres plenty of opportunity for cold snaps, but snap is the key word as northerlies are so weak nowadays, and if the continent continues the way it is at present we shall be basking in the sun from an easterly!

Ah but the recent northerly was indeed a very potent one considering the time of year, a similiar potent northerly in mid winter would deliver notable cold air, the late october event gives us a bit of hope for future northerlies and there potency.

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Latest data:

post-4523-1226256708_thumb.png

Stratospheric polar temp back to average for this time of year after last weeks slight warming.

Polar winds are about where they should be with no great anomalies:

Future forecast for average temps in the stratosphere:

So nothing to get too excited about at present.

c

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http://www.cpc.noaa.gov/products/precip/CW...hgt.ao.cdas.gif

There is actually a decent stratospheric warming event occuring at the moment, though i have no clue how long it will last, or whether its amplitude will increase (just as important as the event itself).

At the moment we essentially have a neautral AO pattern, and that is what i expect to dominate the rest of November as well, however the good news is that we should see the AO be on the negative side during early December.

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http://www.cpc.noaa.gov/products/precip/CW...hgt.ao.cdas.gif

There is actually a decent stratospheric warming event occuring at the moment, though i have no clue how long it will last, or whether its amplitude will increase (just as important as the event itself).

At the moment we essentially have a neautral AO pattern, and that is what i expect to dominate the rest of November as well, however the good news is that we should see the AO be on the negative side during early December.

Hi SB, from looking at the CPC chart, the stratospheric temperature is currently fairly neutral. If anything it is just emerging from a cool phase between 2 - 10 hpa.

Stratospheric Temp Anomaly

What we need to see is intense warming from the upper level which then propogates down to the lower layers thus displacing the cold arctic air southward and possibly in our direction. With a six week lag for this effect to be realised at the surface, we need to see this before the end of December IMO. Here is the chart from 1987..

1987 Chart

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its not really a 'full' warming though, a sight of it no more at the moment, the lag time, depending on various factors is usually 21-30 days, WHEN a sudden warming occurs.

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http://www.cpc.noaa.gov/products/precip/CW...hgt.ao.cdas.gif

This chart shows warming now occuring, and the lag time is around twenty days.

SB, I think the chart on that link shows the strength of the polar vortex from July to present day in the troposphere, not the stratosphere.

To quote the NOAA :

"The daily geopotential height anomalies at 17 pressure levels are shown for the previous 120 days as indicated, and they are normalized by standard deviation using 1979-2000 base period. The anomalies are calculated by subtracting 1979-2000 daily climatology, and then averaged over the polar cap poleward of 65°N.

The blue (red) colors represent a strong (weak) polar vortex. The black solid lines show the zero anomalies."

So what we have is a below average polar vortex which is translated into the negative AO presently seen in the blue bars.

The stratosphere temps and wind anomalies haven't changed much since yesterday.

Regards

c

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After a period of normal to slightly above normal temperatures

http://ds.data.jma.go.jp/tcc/tcc/products/...e/pole30_n.html

the stratosphere is expected to become colder in the coming days...

http://strat-www.met.fu-berlin.de/cgi-bin/...mps&alert=1

Let's hope it doesn't last long because if it does it's bad news for December!

Karyo

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the record of this type of forecasting is rather less than the 'score' we see posted about GFS by NOAA so don't worry too much.

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Latest update:

The stratosphere is cooling down as one would expect as we head through November. Both the temperature and wind anomaly at the 30hpa level are around average for this time of the year:

The drop in temperature has not been linear, but I think this is to be expected:

The prediction over the next 5 days is that the temps are going to drop further dipping below average:

Both the ECM and NOAA have similar predictions for 5 days out:

So nothing to get to excited about at present. If we follow the six week rule then it would appear that is a chance that the tropospheric vortex will be strong around the New Year With no major northern blocking. One of the reasons I am monitoring the stratosphere is so that I can make retrospective analysis later on in the winter, and see how much the stratosphere may have influenced the weather patterns we experience.

Regards

c

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good idea C

as to the forecasts, as with ANY issued they too should carry a Government Health Warning!

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good idea C

as to the forecasts, as with ANY issued they too should carry a Government Health Warning!

I will try and update weekly so I can see how the forecasts compare with what actually occurs. I certainly won't get too excited if a warming event is predicted at T+384!

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be good to watch how it pans out whatever the prediction is, there obviously is a link, just how good, we may see as winter unfolds

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I am surprised to see another slight warming event occuring! http://ds.data.jma.go.jp/tcc/tcc/products/...e/pole30_n.html

This goes against the forecast for a cooling event. http://strat-www.met.fu-berlin.de/cgi-bin/...mps&alert=1

In fact stratospheric temperatures have been generally above normal since the beginning of November. Could this be enough for Northern blocking to occur in the second half of November?

Karyo

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If it reaches the peak of the previous high and is sustained for the week then I think we may be on the cusp of something special for the end of the year. But until then I'm not going to let myself get too excited.

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This goes against the forecast for a cooling event.

Karyo

I do try to warn against taking ANY forecast too much for granted, NONE are infallible.

anone else type things the wrong way round before the spell check?

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I do try to wanr against taking ANY forecast too much for granted, NONE are infallible.

You certainly do John but I remember last winter the forecasts were a lot more reliable!

Karyo

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They don't give their base period's to work out the anomaly. My guess is that they are 10 years out between the two, looks like remaining neutral all things considered.

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..and this is where I get lost. This link appears to be showing a warming event. What am I missing? http://ds.data.jma.go.jp/tcc/tcc/products/...e/pole30_n.html

I reckon that link is just for over the North Pole whereas the NOAA one is the mean average anomaly from 60N to 90N. So it may be slightly warmer over the North Pole but cooler in the latitudes north of 60N.

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..and this is where I get lost. This link appears to be showing a warming event. What am I missing? http://ds.data.jma.go.jp/tcc/tcc/products/...e/pole30_n.html

maybe i'm missing something - the line into 2009 shows the normal expected curve of temps with the black line overlaid showing current temps (which looks bang on to the norm to me). no sign of anything away from average at present

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..and this is where I get lost. This link appears to be showing a warming event. What am I missing? http://ds.data.jma.go.jp/tcc/tcc/products/...e/pole30_n.html

From chionomaniac

I reckon that link is just for over the North Pole whereas the NOAA one is the mean average anomaly from 60N to 90N. So it may be slightly warmer over the North Pole but cooler in the latitudes north of 60N.

In that case, could the brief warming event at the beginning of November be reflected in the height rises over tepole now?

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