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Stratosphere and Polar Vortex Watch


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1 hour ago, ArHu3 said:

Erring on the side of climatology seems like a wise thing to do for a professional forecaster and that climatology of course is mild

Fair enough ArHu3 although reciting climatology is not forecasting and means you don't see the Unusual or extreme when it's coming your way. Which surely is the whole point forecasting.  Your are of course correct that the climatology is mild, the weather on the other hand isn't always so.

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Some useful tropospheric developments upcoming which are likely to have stratospheric impacts towards the end of November and more particularly into December. A strong convectively coupled tropic

so after many days the GFS & FNMOC & canadian finally now follow the Euro with 44 out 64 Members with a split at day 9- The ECM is day 8. We will call it - SSW & Split for 1st Ja

For all that watch the zonal winds. Let me urge you to look at the geopotential heights more. At least as far as weakening/strengthening trends go. Because as the polar vortex cries for help, you migh

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3 hours ago, ArHu3 said:

Erring on the side of climatology seems like a wise thing to do for a professional forecaster and that climatology of course is mild

There is no point in erring on the side of climo when a SSW split has only occured 18 times ( in 18 months ) over about 50 odd years thats 18/150 

All wheels are back in motion & apart from one blip from the ECM every arrow points to a split now on 01st / 2nd Jan where ECM had it all along. GFS finally towing the line with a full house OP/ FV3 / Mean of a split.

 

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26 minutes ago, Steve Murr said:

There is no point in erring on the side of climo when a SSW split has only occured 18 times ( in 18 months ) over about 50 odd years thats 18/150 

All wheels are back in motion & apart from one blip from the ECM every arrow points to a split now on 01st / 2nd Jan where ECM had it all along. GFS finally towing the line with a full house OP/ FV3 / Mean of a split.

 

The models (we can see) keep postponing the split though, originally we were looking at a split 28th of December and now it's somewhere 3-5th of January 

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53 minutes ago, bluearmy said:

Anthony Massiello (Tony’s preferred strat expert) is of the belief that the resolution of the Atlantic sector was causing the modelling issue differences and the better trop model in the mid range and higher in the strat would prove to be a better guide .... ec ops 137 horizontal levels up through the atmosphere should give it a sig advantage. 

Im encouraged by the speed that the op seems to show the split across 10/50 hpa...... that should mean a decent downwelling and potentially a QTR rather than the 8/14 days that a standard initial downwelling wave would take. 

Yep I said that even before he did - It was well touted years ago ( I replied on here & to Ian F on twitter ) that the GFS isnt a high top model & will struggle to resolve the energy split...

6 days ago

518E65DA-2BB5-43AD-8500-C0F69B750853.thumb.png.80d4ba7d1e806b128b2c8b014199ef0d.png

Edited by Steve Murr
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22 minutes ago, Steve Murr said:

Yep I said that even before he did - It was well touted years ago ( I replied on here & to Ian F on twitter ) that the GFS isnt a high top model & will struggle to resolve the energy split...

6 days ago

518E65DA-2BB5-43AD-8500-C0F69B750853.thumb.png.80d4ba7d1e806b128b2c8b014199ef0d.png

It wasn’t that many years ago that NCEP modelling didn’t get above 5hpa !  Back then it really was a chocolate fire guard at times like this 

I wouldn’t dismiss its ideas completely - ecm can often be a little progressive higher up but in a fundemental strat disagreement scenario, ec is always the way to go 

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19 minutes ago, bluearmy said:

It wasn’t that many years ago that NCEP modelling didn’t get above 5hpa !  Back then it really was a chocolate fire guard at times like this 

I wouldn’t dismiss its ideas completely - ecm can often be a little progressive higher up but in a fundemental strat disagreement scenario, ec is always the way to go 

When ECM was upgraded 2-3 years ago its vertical resolution was far better than GFS ( so many years ago maybe not, but at least 2 or 3 )

8A9A35F1-B580-418A-99F5-2282F3BF96B4.jpeg

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51 minutes ago, Steve Murr said:

When ECM was upgraded 2-3 years ago its vertical resolution was far better than GFS ( so many years ago maybe not, but at least 2 or 3 )

8A9A35F1-B580-418A-99F5-2282F3BF96B4.jpeg

Ec has always been better upper strat

the eps used to stop at 5hpa up until a few years ago - I recall a reversal high up (could have been 2010?) when ec op was showing reversal above 5hpa downwelling and the eps were completely ignorant of it - suddenly the wave came below 5hpa and they flipped ! 

If the model cannot see it then it cannot be expected to respond to it ..... checking back to feb’s reversal, the gfs op runs seemed to get a handle on the reversal and the sudden amplification about five days before it arrived - if we see this again then tomorrow/Thursday could be interesting ! 

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13 hours ago, sebastiaan1973 said:

Thanks to Paul. This is the chart of 17 februar 2018. So a day of 5-6 after the dSSW. I really wonder if we get this 4-5 januar 2019. This is the chart of yesterday's output for 3 januar.

fu 10 hPa totaal azonaal.PNG

ecmwfzm_u_f240.gif

Unfortunately not, according to this morning’s...

0A40FCEA-874E-4F3E-897D-AD5C65D2E673.thumb.gif.fdc5cc644fe33d03e9ed494dea685e6b.gif

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Well the SSW is on 31/12/2018 on this run, So another delay. And I see barely a downwelling. Lot's of talk about displacement or split. But in my opinion it's more important if it downwells or not. I think what we miss is enough heatflux at 100 - 300 hPa as I showed by the article on an earlier page.

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21 minutes ago, sebastiaan1973 said:

Well the SSW is on 31/12/2018 on this run, So another delay. And I see barely a downwelling. Lot's of talk about displacement or split. But in my opinion it's more important if it downwells or not. I think what we miss is enough heatflux at 100 - 300 hPa as I showed by the article on an earlier page.

So no QTR then..

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28 minutes ago, s4lancia said:

From how I see it, this is where a decending W-QBO phase does not help us. I’m not sure it necessarily inhibits downwelling but will likely reinstate zonal winds quicker higher up.

This is a list of SSWs (with QBO-phawse) and nSSWs dSSWs . The latter is a downwelling. On this list since 1979 there are 13 dSSWs. Of them (and then you use the other list) 11 of them are with an eQBO. Seems to me that a wQBO is a big disadvantage. Just 1979 and 2009 are an exception.

List-of-the-Major-SSW-Events-Recorded-Between-1958-and-2013-Peak-lunar-tidal-Peak-ZMZW.png

lijst avn ssws.PNG

Edited by sebastiaan1973
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In my humble opinion the weather models are still very good, and most of them are showing us split vortex in the beginning of january. One center of vortex goes on the Canadian side and one on European. If we combine that with the favourite MJO phase 7,8 we are getting a very positive results. The big question is with the downvelling or propagation from high-parts of stratosfere to the troposfere. But after comparing other years with the SSW events, I found out that it might be the case that when the zonal winds in troposfere are weak before this event it might be easier. And I am seeing pretty much weak to normal zonal winds from 100 hPa to 1000 hPa which lasted for entire december. The problem was with the strong zonal winds in the upper parts of stratosfere. Because of strong strat. warming (wave1,2,3) near the pole this zonal winds have weakened a lot in last few day. So we are now seeing weaker zonal winds in the troposfere and in the stratosfere. This is why I am still confident that even if the the "main" part of propagation doesnt reach the lower parts of troposfere that we can still see good effect of it for Europe. The weakening of zonal flow is always welcomed, and this early in the winter we can still see some extra warming in the stratosfere in january, so the vortex can get that final "blow". It will be also very important how strong the Sibirian high will be with the very cold continental flow from the east. Its gonna be intriguing to watch how the entire situation will develop in the next few weeks.

1413964426_DvRPvdzXQAAywhd.jpglarge.thumb.jpg.6f813ff884c9956d40758dbe53acba7d.jpg

epsmean10hPa60N.png

stratosfera-6.png

Edited by Redbull165
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2 minutes ago, Redbull165 said:

In my humble opinion the weather models are still very good, and most of them are showing us split vortex in the beginning of january. One center of vortex goes on the Canadian site and one on European. If we combine that with the favourite MJO phase 7,8 we are getting very positive results. The big question is with the downvelling or propagation from high-parts of stratosfere to the troposfere. But after comparing other years with the SSW events, I found out that it might be the case that when the zonal winds in troposfere are weak before this event it might be easier. And I am seeing pretty much weak to normal zonal winds from 100 hPa to 1000 hPa which lasted for entire december. The problem was with the strong zonal winds in the upper parts of stratosfere. Because of strong strat. warming (wave1,2,3) near the pole this zonal winds have weakened a lot in last few day. So we are now seeing weaker zonal winds in the troposfere and in the stratosfere. This is why I am still confident that even if the the "main" part of propagation doesnt reach the lower parts of troposfere that we can still see good effect of it for Europe. The weakening of zonal flow is always welcomed, and this early in the winter we can still see some extra warming in the stratosfere in january, so the vortex can get that final "blow". It will be also very important how strong the Sibirian high will be with the very cold continental flow from the east. Its gonna be intriguing to watch how the entire think will develop in the next few weeks.

epsmean10h-Pa60-N.png

stratosfera-6.png

 

Yep, completely agree. A base state of weaker than average u winds makes a huge difference, as you say.

For a last week of December, we are in a really good position for some fun and games down the line. 

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One must remember that the vortex is a bit like a tornado spinning so although we'd prefer a large downwelling to completely remove it, the upper to mid layers stopping will significantly harm the thing as a whole. If we go with the proviso of a friendly trop (bar weeks 1 and 3 of December we have seen strong mid-latitude blocking) as default then i'm optimistic that it will do the job.

The interesting question is how well the vortex recovers when we get to the next bout of strong pressure on it in early to mid Feb.

This does all remind me of 2013 in timing and potential impact. Possibly cold second half of Jan and then potentially a cold later half to feb into March.

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12 minutes ago, bluearmy said:

Exeter continue to cover the standard two week downwelling wave on their 30 dayer so they consider it feasible 

Hope so Blue..

Dont think i am alone in getting jittery..

If mid Jan doesnt happen the clock will be ticking for 'winter'..

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