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Stratosphere and Polar Vortex Watch


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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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On 16/11/2019 at 11:47, Northern Sky said:

Apologies for what may be some obvious questions but just trying to learn a bit - 

1. At the moment we have a very unorganised trop vortex that is not coupled to a strong strat vortex? 

2. The strat vortex is forecast to become weaker so does that mean it is likely to become more or less coupled to the trop vortex?

3. What would cause the trop vortex to gain strength as we move into Winter, would that be from forcing's in the trop, strat or both?

4. In very basic terms I think I understand that a weak strat vortex induced by a warming can downwell to help to make a weak trop vortex which makes high latitude blocking in the trop more likely - although where that sets up may or may not be conducive for cold in the UK?

5. Finally, given the current state of the trop vortex is there an optimum time for the potential influence of a warming to strike - ie would it be more effective if the trop vortex reorganises and following on from that would a strat warming be wasted on an unorganised trop vortex (if you see what I mean)?

Thanks in advance.

NS

I suggest you watch the 3d vortex animations on https://www.stratobserve.com/misc_vort3d to sort of understands what happens, too bad you can't see last year's vortex split being modeled 

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A strat conundrum on the GFS 0z, here at T384:

image.jpg.6af367ff596813c6f3d8cd54837b78da.jpg

It was a bit toastier too on the 6z, but the following plot from stratobserve, which I believe is based on the same 0z run, doesn't seem to add up:

image.thumb.jpg.a9a96170a29e445866bb3362a61bfbcf.jpg

It puts the op run well behind most of the others including ensembles here.  Any ideas, anyone? 

Looking at the GEFS at T384, it does seem that if any event is to happen, at the moment it looks like a displacement rather than a dismemberment...

image.thumb.jpg.da5746f0b6fa2d1e8a37e3ded7a6b7de.jpg

Edited by Mike Poole
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@Mike Poole not sure about your question regarding the differences with the GFS op compared to the ensembles but that may still suggest that it will be similar to last year with perhaps having more back and forth runs whilst the ensembles remain fairly steady, will certainly be an interesting watch as we progress. 

And here is the solo ensemble member showing the reversal again from the CMC / GEM image.thumb.png.dbb4dcdac688d2f8ed37670a31a0e04a.pngimage.thumb.png.04d0e72f77099ab77b239b581e93253c.pngimage.thumb.png.361dc95f0e38bc56a18a0304f10dab93.png 

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And just like that were back to Weakened zonal winds except for one stray ensemble slightly above average come late January, February 

20191117_212957.jpg

Edited by Kentspur
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14 minutes ago, Summer Sun said:

 

The back end of the gfs op at 10hpa looks very suppressed at the very top of the strat - could be worth watching if it repeats as perhaps the start of a slowdown which could possibly stall the zonal flow at 10hpa 

 

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19 minutes ago, IDO said:

 

So November continues with the wedges of heights to our north that are not conducive in UK cold. The UK remains at the end of the stalling Atlantic train as it slams into the Euro/Russian high and ATM signs that by the end of the month the Atlantic will slowly ease that Euro/Russia high east:

 

 

I am sure i read somewhere that that is standard just prior to an SSW.

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Just now, Sceptical said:

?

Seriously though, there are a lot of times when a very zonal pattern suddenly becomes very blocked due to an SSW, more so than times where a blocked pattern becomes even more blocked, its a well known fact that the zonal flow increases just before an SSW although i cannot remember which layer of the atmosphere that most applies to.

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4 minutes ago, feb1991blizzard said:

Seriously though, there are a lot of times when a very zonal pattern suddenly becomes very blocked due to an SSW, more so than times where a blocked pattern becomes even more blocked, its a well known fact that the zonal flow increases just before an SSW although i cannot remember which layer of the atmosphere that most applies to.

I also think this is true - as one start area warms up intensely, the opposite side can actually go much colder. It's not until everything reaches tipping point and collapses at the top and hopefully trickles down that we get all the fun and games. It's certainly exciting to watch, and if it happens around the turn of the month, a certain date towards the end of December could be the best for years. Let's hope so!

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