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Stratosphere and Polar Vortex Watch


Paul

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Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl

ECM showing the reversal forecast of zonal winds above 70N out to day 10

ecmwfzm_u_f240.thumb.gif.5b499c68fe2ff622599aa45be7d45719.gif

Not an official reversal as this is not forecasted at 60N but it does underline the displacement of the vortex as shown on the GFS op. today and the ECM day 10 forecast with the core of the sv towards Siberia.

 Z_temp_10hpa_000.thumb.png.06d090e96bada0acadb7d8a86b8a02b7.pngecmwf10f240.thumb.gif.552a318a7168e0b1a738e1229b13244e.gif

Forecast from gefs also continue with a further decrease in mean zonal winds after a slight recovery also still decent wave 1 activity although falling off a little. 


epsmean10hPa60N.thumb.png.67ac37f54a54e45f1a9046af9f19ea56.pngwave_serie10.thumb.png.18fc7ae3d49a197f4fa095cb660c3ab4.png

so an ongoing weaker and displaced strat.vortex is the outlook, which is reflected in the 500 hPa outputs showing +ve height anomalies across the pole.

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
29 minutes ago, phil nw. said:


epsmean10hPa60N.thumb.png.67ac37f54a54e45f1a9046af9f19ea56.png

 

That is yesterdays 0z (the latest run on that chart), have you got todays please?

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Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl
37 minutes ago, feb1991blizzard said:

That is yesterdays 0z (the latest run on that chart), have you got todays please?

Yes that is the latest as Blue said feb. 

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Posted
  • Location: Weymouth, Dorset
  • Location: Weymouth, Dorset

If you look really really closely you may just be able to spot one very very small outlier... ?

u_60N_10hpa_gefs.thumb.png.8313fd43edd72f85413bdc1954cbb38a.png

Or maybe trendsetter...?

OK, that's a push but somewhere inbetween would of course be more than acceptable

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Posted
  • Location: Wyke regis overlooking Chesil beach.
  • Weather Preferences: Snowfall
  • Location: Wyke regis overlooking Chesil beach.
7 minutes ago, s4lancia said:

If you look really really closely you may just be able to spot one very very small outlier... ?

u_60N_10hpa_gefs.thumb.png.8313fd43edd72f85413bdc1954cbb38a.png

Or maybe trendsetter...?

OK, that's a push but somewhere inbetween would of course be more than acceptable

I always prefer the word trendsetter for that sort of run. S4L.

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.

Very very interesting, that temperature profile looks to me like it has all the hallmarks of a split a week down the line.

image.thumb.png.4b461843903aefd3ef418738fb252999.png

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Posted
  • Location: st albans
  • Location: st albans
2 hours ago, feb1991blizzard said:

Very very interesting, that temperature profile looks to me like it has all the hallmarks of a split a week down the line.

image.thumb.png.4b461843903aefd3ef418738fb252999.png

if it could be trusted ………..

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Posted
  • Location: Kirkcaldy, Fife, Scotland 20m ASL
  • Weather Preferences: Snow,Thunderstorms mix both for heaven THUNDERSNOW 😜😀🤤🥰
  • Location: Kirkcaldy, Fife, Scotland 20m ASL

 

Edited by Kirkcaldy Weather
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Posted
  • Location: Wantage, Oxon
  • Weather Preferences: Hot, cold!
  • Location: Wantage, Oxon
6 hours ago, s4lancia said:

If you look really really closely you may just be able to spot one very very small outlier... ?

u_60N_10hpa_gefs.thumb.png.8313fd43edd72f85413bdc1954cbb38a.png

Or maybe trendsetter...?

OK, that's a push but somewhere inbetween would of course be more than acceptable

Number 18 is that bad boy!

gefs-ens_nh-gphells_010hPa_20191129_f384.thumb.png.2b7c7cf3eb47ba968c063779d98e9ba0.png

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Posted
  • Location: Near King's Lynn 13.68m ASL
  • Weather Preferences: Hoar Frost, Snow, Misty Autumn mornings
  • Location: Near King's Lynn 13.68m ASL

So maybe the criticisms of the FV3 have been a bit premature. The FV3 on the 0z is actually weaker than the GEFS up to about 10 days before the now familiar extreme divergence:

EKi40iZWsAAIChy.jpg

 

Edited by Yarmy
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Posted
  • Location: Stroud, Gloucestershire
  • Weather Preferences: Extreme!
  • Location: Stroud, Gloucestershire

With the potential displacement looking favourable in terms of location the fact that we might not  see an official SSW is irrelevant.

At the end of the day the reason we look out for an official SSW is to get the Strat Vortex off it’s perch. That means either moving it into a favourable position- split it in two - or destroy it completely, with one of these outcomes ultimately bringing cold to the UK. An official reversal isn’t necessarily needed with a displacement if its displaced in the right place, and there is some connection between Strat and Troph. 

Looking at Matt Hugo’s twitter post deffo one to watch  

 

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Posted
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
  • Weather Preferences: severe storms,snow wind and ice
  • Location: Hoyland,barnsley,south yorkshire(134m asl)

Is the warming starting to punch the strat?

12z gfs op and control.

gfsnh-10-384.thumb.png.813d2bd604deb084dd1cc26966ad75cb.pnggensnh-0-7-384.thumb.png.5332fdb94459b3eda0997f6eb35b1008.png

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Posted
  • Location: Kirkcaldy, Fife, Scotland 20m ASL
  • Weather Preferences: Snow,Thunderstorms mix both for heaven THUNDERSNOW 😜😀🤤🥰
  • Location: Kirkcaldy, Fife, Scotland 20m ASL

first split of the PV I have seen from the GEFS gensnh-8-7-384.thumb.png.be55c474a03adddedc55c59de35c6b11.png things still very interesting as we edge ever closer to the first days of winter, although exact details still far from being resolved but the signal for consistent pressure and a weaker than normal PV continue.

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Posted
  • Location: chellaston, derby
  • Weather Preferences: The Actual Weather ..... not fantasy.
  • Location: chellaston, derby
40 minutes ago, s4lancia said:

I’m very much liking the latest update. Much more agreement...

2DA343D7-AD83-4ED1-A96F-53B1CD9338AF.thumb.png.f79aa4bf1b5ea7fe53374a9380eccc09.png

 

As you’d expect, even prettier at 65N

8842DF7B-ECBF-4664-9E4F-5CA9423DCC68.thumb.png.cfe74bd7949557e631cf467188ea9a06.png

We’ve been here before but things seem set better this time for it to occur. Whether ‘it’ becomes a full blown SSW, that’s yet to be seen of course.

 

so assuming these predictions are correct, and in around 3 days time (out to about the 19th) and a reversal looks likely - how long would that take to propgate downwards to the surface and give us a cold spell?... and what are the chances of a reversal getting down to the surface to give us a cold spell ....... sorry for my ignorance..

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Posted
  • Location: Near King's Lynn 13.68m ASL
  • Weather Preferences: Hoar Frost, Snow, Misty Autumn mornings
  • Location: Near King's Lynn 13.68m ASL
19 minutes ago, mushymanrob said:

so assuming these predictions are correct, and in around 3 days time (out to about the 19th) and a reversal looks likely - how long would that take to propgate downwards to the surface and give us a cold spell?... and what are the chances of a reversal getting down to the surface to give us a cold spell ....... sorry for my ignorance..

According to the paper I read above, about 66% of all major SSWs (i.e. reversal at 60N 10hPa) propagate down to the Trop in a way that generates a -NAO response. However, the timing can be anything from a few days to a few weeks. 

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Posted
  • Location: chellaston, derby
  • Weather Preferences: The Actual Weather ..... not fantasy.
  • Location: chellaston, derby
10 minutes ago, Yarmy said:

According to the paper I read above, about 66% of all major SSWs (i.e. reversal at 60N 10hPa) propagate down to the Trop in a way that generates a -NAO response. However, the timing can be anything from a few days to a few weeks. 

thank you.

so in essence, its still just possible to get a strat induced  white christmas , but it more likely afterwards, assuming these predictions go accordingly and with only a 66% chance anyway...

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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
2 hours ago, mushymanrob said:

thank you.

so in essence, its still just possible to get a strat induced  white christmas , but it more likely afterwards, assuming these predictions go accordingly and with only a 66% chance anyway...

There's no real pattern to the timing of it all and there's not always an easy way to tell if we already have a 'kind trop'. 

In my anecdotal experience there is usually a fairly quick atmospheric 'jolt' which can produce but in many cases we have had to wait a month before a sustained spell followed. 

In 2018 we had to wait around 2 weeks for the cold spell to arrive and the cool/cold conditions largely sustained until mid-april. In 2016 we had the strange warming/final warming and saw a similar timeframe (March and April remaining cooler than average) while in 2013 we saw an easterly about 2 weeks after but most of February was high pressure dominated and non-descript before another attack from the troposphere finally kicked the trop vortex. But in 2005 and 2012 for example it was the better part of a month before a pattern change occurred, indeed we did not get a massive kick last year albeit it changed the pattern.

I guess what it highlights is that you need a quick downwelling to the troposphere to recieve a quick impact and then you need probably a second bout of wave activity to finally kill it. In cases like 05, 12 and 19 the downwelling took a long time and was patchy and thus while there was a response it was not sustained for long. 

You also have the danger of years like 09 where we were already quids in and the stratospheric warming changed the pattern in a negative way for us.  

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Posted
  • Location: Gillingham, Kent
  • Weather Preferences: Snow, Thunderstorms,
  • Location: Gillingham, Kent
5 hours ago, s4lancia said:

I’m very much liking the latest update. Much more agreement...

2DA343D7-AD83-4ED1-A96F-53B1CD9338AF.thumb.png.f79aa4bf1b5ea7fe53374a9380eccc09.png

 

As you’d expect, even prettier at 65N

8842DF7B-ECBF-4664-9E4F-5CA9423DCC68.thumb.png.cfe74bd7949557e631cf467188ea9a06.png

We’ve been here before but things seem set better this time for it to occur. Whether ‘it’ becomes a full blown SSW, that’s yet to be seen of course.

 

Worth noting the -VE bias on the GEFS though, this isn’t the first time they’ve shown this only to revert to less extreme of a deceleration as the time approaches. 

GFS/ECM are a much better guide & have been far more accurate so far this season.

 618C6B1D-3A1B-4949-9E1F-8042F31B9582.thumb.png.d6bd40fa7be1cae231e36cc5d46756cd.png
Wouldn’t get excited until we see some notable weakening showing from the GFS

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