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Stratosphere and Polar Vortex Watch


Paul

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Posted
  • Location: Wyke regis overlooking Chesil beach.
  • Weather Preferences: Snowfall
  • Location: Wyke regis overlooking Chesil beach.
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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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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Posted
  • Location: Carryduff, County Down 420ft ASL
  • Location: Carryduff, County Down 420ft ASL
23 minutes ago, Summer Sun said:

 

With the strat warming now REAL and not predicted it will be interesting whether we see a big change to cold in the ensembles.

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Posted
  • Location: Netherlands close to the coast
  • Location: Netherlands close to the coast
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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Posted
  • Location: st albans
  • Location: st albans
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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Posted
  • Location: st albans
  • Location: st albans
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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Posted
  • Location: Netherlands
  • Location: Netherlands

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

Edited by sebastiaan1973
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Posted
  • Location: Weymouth, Dorset
  • Location: Weymouth, Dorset
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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Posted
  • Location: Purley, Surrey - 246 Ft ASL
  • Weather Preferences: January 1987 / July 2006
  • Location: Purley, Surrey - 246 Ft ASL
8 minutes ago, s4lancia said:

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

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

Is this showing the Vortex regaining strength at the 1 - 5 hpa level and a slow trop response as the negative wind anomalies are not moving closer to the surface?

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Posted
  • Location: Netherlands
  • Location: Netherlands

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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Posted
  • Location: Scouthead Oldham 295mASL
  • Location: Scouthead Oldham 295mASL
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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Posted
  • Location: Carryduff, County Down 420ft ASL
  • Location: Carryduff, County Down 420ft ASL
9 minutes ago, northwestsnow said:

So no QTR then..

I think Sebastian is saying no response in the trop at all, never mind a quick response.

Edited by mountain shadow
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Posted
  • Location: Weymouth, Dorset
  • Location: Weymouth, Dorset

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.

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Posted
  • Location: Netherlands
  • Location: Netherlands
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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Posted
  • Location: South Ockendon, Thurrock, SW Essex
  • Weather Preferences: Severe frosts, Heavy snowfall, Thunder and lightning, Stormy weather
  • Location: South Ockendon, Thurrock, SW Essex
Posted
  • Location: Slovenia (Maribor)
  • Location: Slovenia (Maribor)

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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Posted
  • Location: Weymouth, Dorset
  • Location: Weymouth, Dorset
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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Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet

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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Posted
  • Location: Scouthead Oldham 295mASL
  • Location: Scouthead Oldham 295mASL
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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