Stratosphere temperature watch - 2016/17

[Singularity]

I think there's a muddle of forcing from tropical factors, the unusually well-entrenched cold across much of Europe, and minor stratospheric influences (as in, not the dramatic SSW kind, just an encouragement of the trop. pattern in certain directions) which is proving difficult to disentangle. With such complexity, its little wonder the models are having a 'mare.

[Nick F]

1 hour ago, Nouska said:

We go from this ...

to this ....                

The models will be playing around with what the effects are at the surface but the current move to a southerly jet stream looks like a fairly quick response to the strat picture or am I missing something?

It's hard to find a great deal of literature on the downwelling effects on the trop of a displaced sPV on particular geographical domains in relation to where the PV core is displaced. Plenty of literature over troposphere upward mechanics. Though there are appears to be some consistency from recent NWP output that, like you say, points toward the PFJ being pushed further south as the zonal winds increase southward in the upper troposphere/lower stratosphere as the PV pushes over towards our side of the N Hemisphere.

[joggs]

Is this coming into effect now,showing on the model forums? 

Or is it too early?

Still to come?

Edited January 24, 2017 by joggs

[bluearmy]

17 minutes ago, joggs said:

Is this coming into effect now,showing on the model forums? 

Or is it too early?

Still to come?

I assume you are asking if the consequences of the SSW/near SSW are showing on the models.

the models include the stratosphere in their  atmospheric simulation. so they are modelling the events at the strat in the same model at the same time as the z500 charts we look at most of the time in the same model run. just as you look at the z500 height chart and the temps at 850hpa, further up all the way to 1hpa (and even higher in ecm I believe) at the same timeframe the algorithms are working away to resolve what is happening in the specific run. there is no disconnect. its all part of the same single model.

so what happens after the initial warming next week can be viewed on the strat charts fro each gfs run on instantweathermaps.com (and at 30hpa specifically on NW). the z500 charts after the initial warming are there for your perusal too.

the gfs goes out another 8/10 days past the first warming. judge for yourself what the consequences appear to be. there are no secrets here.

there are expectations of how long a downwelling wave takes to affect the trop but it isn't cast in stone and this winter there seems to be  discussion as to how closely the upper strat pattern is affecting the trop anyway.

the best advise is to watch the output. that's what everyone else is doing!

[Summer Sun]

 

[swebby]

31 minutes ago, Nick F said:

It's hard to find a great deal of literature on the downwelling effects on the trop of a displaced sPV on particular geographical domains in relation to where the PV core is displaced. Plenty of literature over troposphere upward mechanics. Though there are appears to be some consistency from recent NWP output that, like you say, points toward the PFJ being pushed further south as the zonal winds increase southward in the upper troposphere/lower stratosphere as the PV pushes over towards our side of the N Hemisphere.

Literature wise, would the effects be reliant on far too many variables to produce a simplistic composite for a hemispheric pressure pattern like those made for the MJO? E.g. How strong was the spv prior to displacement, the exact location/shape of the spv prior to displacement, the trop pattern at the time of displacement, etc.... 

I would guess that any associated displacement of the PFJ would be a short term forecast to be made only as the spv actually relocates? 

[Don]

8 hours ago, Ladyofthestorm said:

Are you being sarcastic or is this good news for cold weather fans?

Sarcastic I'm afraid.

[Nouska]

Hmm... see references to SSW January 2013 similarity in model thread. Yes, immediate response to initial warming might be similar but a split vortex followed very rapidly. Nothing like this currently showing in stratospheric levels but that's not to say it will not occur, should there be a technical reversal of zonal winds as was the case back then.

Edit for @Allseasons-si to show projected day 12 forecast.

No signs of a split on GFS and not on ECM at day 10 either.

The problem with the displacement is there is still the tail going back to NE Canada - not allowing the separation for heights to build in the gap. It's a strange year of disconnects - could still allow for something different to evolve from tropospheric up rather than strat down.

 

 

 

Edited January 24, 2017 by Nouska

[Allseasons-Si]

26 minutes ago, Nouska said:

Hmm... see references to SSW January 2013 similarity in model thread. Yes, immediate response to initial warming might be similar but a split vortex followed very rapidly. Nothing like this currently showing in stratospheric levels but that's not to say it will not occur, should there be a technical reversal of zonal winds as was the case back then.

 

I don't usually post in here as it's a little over the top for me sorry but i do have some knowledge on the subject

when i first saw the pics you posted,i thought that it was a comparison for 2017 to 2013 lol

do you have the latest 2017 one for comparison or does the event have to happen first?...if at all.

we do nead the line at 10 hpa to get above the av to be noteworthy though,lets see in the coming days if it will happen.

 

Edited January 24, 2017 by Allseasons-si

[feb1991blizzard]

3 hours ago, Allseasons-si said:

I don't usually post in here as it's a little over the top for me sorry but i do have some knowledge on the subject

when i first saw the pics you posted,i thought that it was a comparison for 2017 to 2013 lol

do you have the latest 2017 one for comparison or does the event have to happen first?...if at all.

we do nead the line at 10 hpa to get above the av to be noteworthy though,lets see in the coming days if it will happen.

 

That will definitely happen, we need it shooting right up the page and then staying above average, looks like we will need a second peak to do the necessary damage to the vortex though.

[Duane S.]

A clear SSW now showing on this morning's Berlin charts. Better zonal profile below as well with that troublesome pocket of +20m/s speeds more dissipated.

However, whilst the vortex at SSW level is clearly well under attack, it is holding firm (no doubt as a result of a strong W-QBO). Further up though it is a different story, it is in complete disarray

There is little doubt in my mind this wont pass without consequence (in terms of further blocking and a cold feed out of the Arctic) felt on ground level come February. As per usual though, when where and in what form yet to be decided!

I say 'further' blocking because in this winter of frustration and searching for snow events, it is easy to forget how blocked it has actually been. It has been a while since we've had so many frosts down here in a winter.

Does make you wonder though what would have been if we'd have had the E-QBO that by rights should have been with us this winter...

 

Edited January 25, 2017 by s4lancia

[chris55]

An official SSW on the Berlin charts this morning -2.8ms

Only a displacement and not a split though. 

It may help to push the jet south but can't be sure how the connect between the strat and troph may pan out.

Beyond the initial warming warm air keeps being pumped into the strat by the displaced vortex hopefully resulting in a complete collapse of the strat PV

 

[Summer Sun]

 

[bluearmy]

Need to seee the Berlin charts  consistent with pushing those neg flows further down. Today's output from yesterday's op better than previous runs. reversal at 10hpa/60N or not?  It's  just semantics now. The zonal flow profile 50/70N below 10hpa is what is important. Granted we need to see the environment higher up stay slack to avoid the vortex reforming.

we just about have a window of opportunity with standard type downwelling timescales to see some HLB second half Feb which could bring sustained snowfall to our latitudes (on an island remember  - read some stuff on forums yesterday about latitude and snowfall which was almost hilarious). 

[Summer Sun]

 

[Interitus]

7 hours ago, chris55 said:

 

 

The Berlin charts at 1hPa show a fascinating sequence of wavebreaking peeling off daughter vortices - there are 3 vortices in the chart above and in the next there are 4 -

The GEOS-5 forecast goes for an SSW at about the same time as ECM -

But the GFS still not really interested, with notably only a few of the ensembles showing a reversal on today's 00z -

And in long range the 1mb level puts the throttle down and is like, SSW? what SSW?

As this SSW is wave 1 from essentially Atlantic side blocking, is the tendency of the GFS to steamroller this away resulting in reduced or shortened forcing compared to the other models?

[joggs]

So is there definitely going to be a major warming?

Sometimes it's just as up n down in here as the model thread lol.

[mountain shadow]

21 minutes ago, joggs said:

So is there definitely going to be a major warming?

Sometimes it's just as up n down in here as the model thread lol.

From what im reading there will be a major warming but it will only displace the PV not split it and that is not great fot the UK.

[Seasonality]

5 minutes ago, mountain shadow said:

From what im reading there will be a major warming but it will only displace the PV not split it and that is not great fot the UK.

Where is a displacement good for?

Edited January 25, 2017 by Seasonality

[mountain shadow]

3 minutes ago, Seasonality said:

Where is a displacement good for?

Central Asia/Siberia

[Frostbite1980]

2 minutes ago, mountain shadow said:

Central Asia/Siberia

Surely it depends where the displacement ends up?

Edited January 25, 2017 by Frostbite1980

[Seasonality]

Just now, mountain shadow said:

Central Asia/Siberia

So by 'good for' I take it that means more cold. Central Asia and Siberia hardly need help with cold  Ironic isn't it

[mountain shadow]

1 minute ago, Frostbite1980 said:

Surely it depends where the displacement ends up?

Well yes, but with a displaced PV the deep cold is more likely to end up in Asia. With a split, North West Europe favoured.

[Frostbite1980]

2 minutes ago, mountain shadow said:

Well yes, but with a displaced PV the deep cold is more likely to end up in Asia. With a split, North West Europe favoured.

But if the PV was displaced to Scandinavia for example could this not potentially promote HLB over Greenland drawing in N/NE winds over the UK. Not trying to be funny just trying to get to grips with all possibilities.

[karyo]

19 minutes ago, mountain shadow said:

Well yes, but with a displaced PV the deep cold is more likely to end up in Asia. With a split, North West Europe favoured.

No, even with a split it can be unfavourable for the UK. Similar to the displacement it depends where the split occurs. For example you can have a split but with some residual low remaining in the Atlantic side and the UK in a southerly flow. Nothing is guaranteed.