Stratosphere and Polar Vortex Watch

[BlueHedgehog074]

Weather Online still seem to be going for some kind of Mid-Latitude Blocking towards mid January with the possibility of this drifting far enough North as the month continues progressing:

UK Weather forecast for the upcoming month - Month ahead

WWW.WEATHERONLINE.CO.UK

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UK Weather report for the next month. Outlook over the next 30 days for England, Scotland, Wales and Northern Ireland.

It’s not necessarily worth putting all the oranges into one basket, as they could easily be wrong. Some clutching of straws, but I guess they do have some support from some of the ensembles of the GFS and ECMWF suites (Scandinavian/European blocking). Although I do admit, looking at the operational model runs currently, you would feel convinced that the M4 has relocated to the North of the UK!

Doesn’t off course rule out some, likely brief, Polar Maritime outbreaks behind Low Pressure systems passing through the UK. Could encourage the M4 and its snow shield to relocate further South again, even though it’s probably unlikely these cooler flows will be potent enough to dent many low level snow shields. Especially over Southern UK. But I wouldn’t rule out some more inviting runs appearing on the models within the next week or so showing some chillier scenarios. It just seems, though, that the blue and purple spirally thing wants to party about to the North and North-West of the UK. 

Not sure whether WeatherOnline expect some kind of split, weakening or displacement to the Troposphere/Stratosphere Polar Vortex’s later into the month to make their 30 day outlook possible. Northern blocking I don’t think is impossible without some kind of Stratospheric Warming and Vortex disruption events. Suppose these events (particularly the Sudden Stratospheric Warming ones) do help, and allow for any blocking to the North of the UK to sustain itself. 

[Interitus]

5 hours ago, Glacier Point said:

The way end of week 2 EPS and GFS look, wave 2 bottom up splits could be in play.

Maybe....maybe not -

 

2 hours ago, DiagonalRedLine said:

Not sure whether WeatherOnline expect some kind of split, weakening or displacement to the Troposphere/Stratosphere Polar Vortex’s later into the month to make their 30 day outlook possible. Northern blocking I don’t think is impossible without some kind of Stratospheric Warming and Vortex disruption events. Suppose these events (particularly the Sudden Stratospheric Warming ones) do help, and allow for any blocking to the North of the UK to sustain itself. 

As shown many times, northern blocking is as likely to lead to a SSW as be caused by one.

[feb1991blizzard]

5 minutes ago, Interitus said:

Maybe....maybe not -

 

 

As shown many times, northern blocking is as likely to lead to a SSW as be caused by one.

He means the GEFS suite.

 

EDIT : would imagine so anyway, that is how he usually utilises both products, i doubt he would use a single op run for back end of week 2 hemispheric wavelength pattern projections.

Edited January 2, 2020 by feb1991blizzard

[Interitus]

Just now, feb1991blizzard said:

He means the GEFS suite.

We know how good they are.

[feb1991blizzard]

Just now, Interitus said:

We know how good they are.

But he is saying the EPS are backing them, what else should we use then?

[Methuselah]

12 minutes ago, Interitus said:

Maybe....maybe not -

 

As shown many times, northern blocking is as likely to lead to a SSW as be caused by one.

That's only if they're connected at all, of course. And that's nae always certain?

[Interitus]

47 minutes ago, feb1991blizzard said:

But he is saying the EPS are backing them, what else should we use then?

With respect to him, how well have Michael Ventrice's composites performed based upon these in tweets posted on here? All the resources should be used, but the point is as said none of them are set in stone beyond the deterministic limit. It's relying on tentative long range trop predictions then supposing that the strat is merely passive in response (it's not, its state matters) so...maybe, maybe not. 

Edited January 2, 2020 by Interitus

[Cheshire Freeze]

This winter is done as far as anything tangible from the strat is concerned. However, if we happen to catch the break up of the sPV towards March/April we could be looking at a very potent late season cold spell IMO. 

Potential is there for a miserable spring/summer IMO as I think a predominant -NAO regime will be the feature.

[feb1991blizzard]

Just now, CreweCold said:

This winter is done as far as anything tangible from the strat is concerned. However, if we happen to catch the break up of the sPV towards March/April we could be looking at a very potent late season cold spell IMO. 

Potential is there for a miserable spring/summer IMO as I think a predominant -NAO regime will be the feature.

Really Aaron? already?

[Cheshire Freeze]

22 minutes ago, feb1991blizzard said:

Really Aaron? already?

Yes

Most of the long range modelling is pointing to vortex relaxation in April- which is late but can probably be expected with such a tightly wound vortex core. At this point, modelling suggests that HP will replace low at the higher latitudes sometime mid-spring.

Put it this way, most people should count themselves very very lucky if they even see one flake of snow before Feb is out.

Edited January 2, 2020 by CreweCold

[stodge]

25 minutes ago, CreweCold said:

Yes

Most of the long range modelling is pointing to vortex relaxation in April- which is late but can probably be expected with such a tightly wound vortex core. At this point, modelling suggests that HP will replace low at the higher latitudes sometime mid-spring.

Put it this way, most people should count themselves very very lucky if they even see one flake of snow before Feb is out.

I agree there's nothing much for the actual winter period on offer - the best we can hope for is a well-positioned MLB which could advect some colder air into southern areas.

I do think March and April will be much more interesting and exciting - I think from mid-March onwards we could be looking at some really interesting synoptics as the PV starts to break down.

[Cheshire Freeze]

Just now, stodge said:

I do think March and April will be much more interesting and exciting - I think from mid-March onwards we could be looking at some really interesting synoptics as the PV starts to break down.

Agree 100%

[mb018538]

1 hour ago, stodge said:

I agree there's nothing much for the actual winter period on offer - the best we can hope for is a well-positioned MLB which could advect some colder air into southern areas.

I do think March and April will be much more interesting and exciting - I think from mid-March onwards we could be looking at some really interesting synoptics as the PV starts to break down.

But they often are with the PV breaking down. There’s nothing unusual with that - more likely to snow at Easter than Xmas etc. Trouble is they are about as good as an ashtray on a motorbike that late in the season. We want it now while it’s still dark and not going to melt away in an hour. Sadly this winter is just shaping up like most of the last 20-30 years.

[Kirkcaldy Weather]

 

[Cheshire Freeze]

1 hour ago, Kirkcaldy Weather said:

 

 

That EC monthly chart doesn't hint at high pressure to the NE at all, I read that as more of a Sceuro block.

Edited January 2, 2020 by CreweCold

[Cheshire Freeze]

Just now, markw2680 said:

I’m sorry I’m obviously not in the know like some on here but how on earth can you say this winter is as good as over? It’s the start of January for crying out loud, things change at the flick of a switch and yes background signals can be good or bad but even when good they don’t work out in our favour so I’m gobsmacked that you can say that we would be very lucky to see a snow flake lol. And then to start saying summer will be crap.......think I’ll leave it there unless you wana make a prediction for next winter too.

if I’m completely honest I think things will look an awful lot better than they do right now in a week or too, can’t look much worse 

Easy- what is there to stop the W-E flow in the upper strat which is connected to the trop? Nothing is the answer. The seasonal models had this winter nailed months ago and so far it's running exactly to script.

[summer blizzard]

3 hours ago, stodge said:

I agree there's nothing much for the actual winter period on offer - the best we can hope for is a well-positioned MLB which could advect some colder air into southern areas.

I do think March and April will be much more interesting and exciting - I think from mid-March onwards we could be looking at some really interesting synoptics as the PV starts to break down.

Would agree with that, it’s rare you get a full period without some disruption so I suspect a March SSW attempt and then a final warming shortly afterwards in April.

We are probably due a Nina attempt too with the -QBO so I agree with those who think summer might be found wanting.

[Blessed Weather]

Several overnight posts have been moved to the Moans/Ramps/Chat thread. Please ensure posts in this thread are relevant to stratosphere and polar vortex discussions. Many thanks.

[Kirkcaldy Weather]

On 02/01/2020 at 13:20, Glacier Point said:

The way end of week 2 EPS and GFS look, wave 2 bottom up splits could be in play.

like this? 

[Kirkcaldy Weather]

 

[mountain shadow]

5 minutes ago, Kirkcaldy Weather said:

 

That makes no sense. How can a ridge over Europe push North into the North Atlantic? 

[Catacol]

20 hours ago, Interitus said:

With respect to him, how well have Michael Ventrice's composites performed based upon these in tweets posted on here? All the resources should be used, but the point is as said none of them are set in stone beyond the deterministic limit. It's relying on tentative long range trop predictions then supposing that the strat is merely passive in response (it's not, its state matters) so...maybe, maybe not. 

Indeed - but those willing to put their neck on the block by coming forward with their thoughts on the future are due a modicum of respect for being willing to take a punt. Your decision to use a single op run at 16 days range to counter the arguments of another speaks (or probably shouts) volumes. Most I suspect appreciate the glass half full approach.

[Catacol]

16 hours ago, CreweCold said:

Easy- what is there to stop the W-E flow in the upper strat which is connected to the trop? Nothing is the answer. The seasonal models had this winter nailed months ago and so far it's running exactly to script.

Hmmm - your gloom over this winter is colouring your judgement. I suspect you are correct when implying that the current winter will end up underwhelming and probably mild overall, but it is also the case that we have a changing Pacific context underway (probably) and another round of convection set to arrive in the next few weeks. While the background context is currently unfavourable it is incorrect to state that “nothing” can break the coupling. In addition there is currently a downwards propagation of reducing wind speeds underway from 1hpa probably the result of a long running significant wave 1 warming at the top of the vortex

and when one considers the current spike in AAM that is helping deposit decent momentum into the sub tropical jet and thereby raising the possibility of a late Jan/ early Feb North Atlantic wave break I think to write things off is premature.

None of the above disguises the disappointment of the current season, and the post facto analysis may hone in on an interpretation that sees the + IOD as the driver that has brought heat to Australia, floods to parts of Africa and a fixed forcing across the NH that has assisted in vortex domination, and perhaps we were over optimistic with regards to the switching of the QBO ( I’ve done a monthly analysis earlier in this thread demonstrating the significance of the December QBO signature) but I still think a nihilistic approach to up to 10 weeks of winter season future synoptics is off beam. 1 week with cold and snow in February would be enough to spread some honey on stale bread!

[Catacol]

41 minutes ago, mountain shadow said:

That makes no sense. How can a ridge over Europe push North into the North Atlantic? 

North West. This is the wave 2 hope flagged by GP and hinging on a combination of momentum transfer from the current spike and expected renewed convection before month’s end. It assumes the maintenance of the North Pacific ridge which seems to be a near permanent feature these days.

It has some legs. But gloom from multiple failures in recent years tends to lead to an assumption of failure and this forum is very glum today. Personally I will never forget Feb 18 and for that matter Feb 96....both events that came from pretty tame initial origins. There is always hope. Thank goodness for Skywalker...

[Catacol]

I seem to be on a posting roll. 2 images. Hope springs eternal.  ‘nuff said.

 

 

Edited January 3, 2020 by Catacol