Jump to content

Archived

This topic is now archived and is closed to further replies.

chionomaniac

Stratosphere Temperature Watch

Recommended Posts

The models are understandingly having difficulty translating this into a reliable prediction. However I can see what they are trying to resolve/ predict. Here is the lower stratosphere forecast at the level 100 hPa for T+240 (on its side on purpose).

post-4523-1232977040_thumb.pngpost-4523-1233085239_thumb.png

And here is the GFS 200 hPa jet profile for the same time:

post-4523-1232977084_thumb.png

There are certainly some similarities to be seen.

c

And tonight the ECM is picking up on that trend! But now we have moved on a day. So we have a split lower stratospheric vortex which is helping to influence the upper troposphere. Anyone spot any similarities (forgetting the fact that this is a dream chart)?

post-4523-1233085151_thumb.png

c

Share this post


Link to post
Share on other sites
That's an interesting observation and certainly quite often one major strqtospheric warming is followed by others! This happened for example late last winter. The difference this time, is that the stratospheric temperatures are not falling quickly after the main event but very slowly which is a good things for more long lasting effects (i.e. northern blocking).

I wonder what do the experts think about the possibility of further warming events occuring into February?

Edit: i've just read GPs and SMs posts in the model output thread - potential for further warming events to be trigerred.

Karyo

That’s interesting that they appear to come in clusters because it looks like each peak is higher than the last before tailing off.

Share this post


Link to post
Share on other sites
Guest North Sea Snow Convection
And tonight the ECM is picking up on that trend! But now we have moved on a day. So we have a split lower stratospheric vortex which is helping to influence the upper troposphere. Anyone spot any similarities (forgetting the fact that this is a dream chart)?

post-4523-1233085151_thumb.png

c

Very good observation.

That is another good thing about this thread: being able to map and compare relative model forecasts for the stratopshere and then check the downstream lags on the tropospheric models with the best case study that could be hoped for to do so :D . We know that other factors influence the final surface pattern besides the stratosphere movements, but in time we should be able to make an estimate of the sort of impact that this event has had on the surface. And this type of analysis, such as you are doing here, will be a very effective way of doing so :D .

But final analysis is some way off yet - this has got quite a bit of mileage left in it yet!

Share this post


Link to post
Share on other sites

Latest update.

Well the MMW is well underway with negative(easterly) zonal winds now at the 30 hPa level. These are forecast to drop below 10m/s which for any level of the middle stratosphere is not inconsiderable. These are forecast to remain easterly for the duration of the forecast period. In fact even at T+192 we still see negative mean zonal winds even at the 50 hPa level. Any easterly winds on the following charts are indicated in red as U= -1.1m/s.

http://strat-www.met.fu-berlin.de/cgi-bin/...p;forecast=f192

It would appear that the even though the fall of mean zonal winds is dramatic the recovery appear to be slow.

post-4523-1233139036_thumb.png

This recovery is normally slow looking at past events. However the number of days of easterly winds experienced has been far less with previous MMWs than we are forecast to experience. We are set to have mean negative zonal winds for a period of greater than 10 days (possibly 15 even). This must surely have an unprecedented knock on effect to the troposphere. I know that the models are suggesting an initial cold spell next week, but this I suspect may just be the hors-d'oeurves with starter and main course yet to come!

After an initial burst of negative anomaly winds in the last day or so a more concentrated burst will hit the troposphere and propagate right down to the surface at T+192 around 70-90ºN.

post-4523-1233139475_thumb.png

So maybe a period of stronger northern blocking will occur just after this time and hopefully we will be in the firing line!

As Tamara has suggested previously I feel I will reinforce. Not every MMW produces northern blocking and cold spells for us. However if there ever was an MMW that could produce extreme northern blocking and give us the chance of prolonged bitter weather then this is the one . Both the warming , negative zonal wind length and strength and propagation down to the troposphere have ensured this. Now it is time to sit back and see what the forecasting models can produce. Do your worst - that is what I say!

c

Share this post


Link to post
Share on other sites
Guest North Sea Snow Convection

The 10hPa and 30hPa polar easterlies keep on a rollin

fluxes.gif

The sustaining trend of the 30hPa, although not record breaking like the 10Hpa is quite astonishing IMO

Share this post


Link to post
Share on other sites
Guest North Sea Snow Convection
Latest update.

We posted at the same time! I have duplicated a small part of your overall analysis.

Must be increasing odds of an almost seamless move towards a FW (Final Warming). Be interesting to see where the +QBO is left in the midst of all this.

Share this post


Link to post
Share on other sites
We posted at the same time! I have duplicated a small part of your overall analysis.

Must be increasing odds of an almost seamless move towards a FW (Final warming). Be interesting to see where the +QBO is left in the midst of all this.

It's still there at around 10m/s. Look at the last chart I posted at the equator from 30-50 hPa.

I am at present looking to see if I can find trends from the lower stratosphere that may be translated to the upper troposphere.

Omega block anyone?

post-4523-1233142507_thumb.png

post-4523-1233142513_thumb.png

c

Edit - I just realised I didn't mention about the FW. Yes I agree this is a definite possibility now. It is taking an age just to get rid of the net easterly flow never mind cranking up a westerly vortex again. It will be the end of Feb before one could see any strength in the polar vortex, and I would say that is too late, as that is the time to be thinking about summertime hibernation. So cold start to spring a strong possibility as well.

Share this post


Link to post
Share on other sites
Guest North Sea Snow Convection
It's still there at around 10m/s. Look at the last chart I posted at the equator from 30-50 hPa.

I am at present looking to see if I can find trends from the lower stratosphere that may be translated to the upper troposphere.

Omega block anyone?

post-4523-1233142507_thumb.png

post-4523-1233142513_thumb.png

c

Yes, thanks, apologies - I am a bit chart drunk atm!

I think an Omega block is very likely. With the AO going to go very negative, surely, we do need to watch for where the very cold and warm anomalies go. Soemone is going to turn very cold as arctic air is strongly pushed away from the pole, but with every northerly there is a southerly. A strong gradient is going to set up down the line wherever this boundary meets - and obviously we want to be polar side of it.

Share this post


Link to post
Share on other sites
Yes, thanks, apologies - I am a bit chart drunk atm!

I think an Omega block is very likely. With the AO going to go very negative, surely, we do need to watch for where the very cold and warm anomalies go. Soemone is going to turn very cold as arctic air is strongly pushed away from the pole, but with every northerly there is a southerly. A strong gradient is going to set up down the line wherever this boundary meets - and obviously we want to be polar side of it.

Yes there is always the worry that we will be on the southerlies track. However with the nature of the vortex split (and subsequent tropospheric polar vortex split) and where the split daughter vortices subsequently are positioned, do you not feel that we would be more likely (for once) to be in the firing line for the northerly rather than the southerly? That's not wishful thinking - it makes sense, surely?

Share this post


Link to post
Share on other sites
Guest North Sea Snow Convection
Yes there is always the worry that we will be on the southerlies track. However with the nature of the vortex split (and subsequent tropospheric polar vortex split) and where the split daughter vortices subsequently are positioned, do you not feel that we would be more likely (for once) to be in the firing line for the northerly rather than the southerly? That's not wishful thinking - it makes sense, surely?

It does make sense, don't worry, I am just trying to balance my inclinations to want to ramp away this morning in truth! :lol:

I was thinking along the lines of the the deeper negative the AO goes, then towards the boundary of the polar front, then the risk/reward equation becomes greater. The blizzards of 1978 are an excellent example of that where the relatively narrow zone of southwestern counties were literally buried in snow and on the western edge of that zone there were temp differences between zero and below and +10C within a 30 mile radius or so. On a larger scale the winter of 1969 showed a very negative AO regime over both Jan and Feb - but the two months produced very different weather with southerlies for Jan and screaming northerlies and easterlies for the Feb.

I don't see a west based -NAO setting up at this time, which would risk southerly spoilers, and can see the PV slipping from Norway into europe associated with pressure rises for Greenland. Svalbard,Iceland. Later we may see some fun and games from the southwest as low pressure tries to undercut (like Feb 1978) but hey, I am just using my imagine here and lots of excting things might happen) :lol:

Share this post


Link to post
Share on other sites

Latest NCEP updates have just come through showing the propagation of the MMW through the Stratosphere towards the troposphere.

Firstly the temperature chart

post-4523-1233184612_thumb.png

Pretty spectacular propagation there reaching the troposphere.

Next the zonal mean wind anomaly (showing how far away the winds are from average which would be a strong westerly at present)

post-4523-1233184807_thumb.png

Next the mean zonal winds which we can work out how much of the stratosphere is under the influence of easterly winds. And from this we can see that from around 40 hPa upto the top layers of the stratosphere there are net easterly winds. You will struggle to find a previous profile in January that has easterly winds as strong!

post-4523-1233185064_thumb.png

It's hard to fathom how winds can change from +70m/s to -40m/s at the top of the strat in just over a week!

c

Share this post


Link to post
Share on other sites
Guest North Sea Snow Convection
Latest NCEP updates have just come through showing the propagation of the MMW through the Stratosphere towards the troposphere.

Firstly the temperature chart

Pretty spectacular propagation there reaching the troposphere.

Next the zonal mean wind anomaly (showing how far away the winds are from average which would be a strong westerly at present)

Next the mean zonal winds which we can work out how much of the stratosphere is under the influence of easterly winds. And from this we can see that from around 40 hPa upto the top layers of the stratosphere there are net easterly winds. You will struggle to find a previous profile in January that has easterly winds as strong!

c

Yes I tried to say as much just now on the model thread. Not the best place really in the circumstances :lol: Sounds OTT I know, but the mind boggles at the synoptics possible when this does kick off into model output. When you look at where we are just for the next week.

Share this post


Link to post
Share on other sites
Yes I tried to say as much just now on the model thread. Not the best place really in the circumstances :lol: Sounds OTT I know, but the mind boggles at the synoptics possible when this does kick off into model output. When you look at where we are just for the next week.

Hi Tamara/CH.

I know this may sound like asking how long is a piece of string but when would you expect the full effects of the MMW to present itself on the model output?

Share this post


Link to post
Share on other sites
Guest North Sea Snow Convection
Hi Tamara/CH.

I know this may sound like asking how long is a piece of string but when would you expect the full effects of the MMW to present itself on the model output?

You know Dave, I started off thinking that this would all kick off about the second week of February. And the likes of the actual experts like GP have suggested i think from about 10 to 14 Feb. However, the whole thing looks such a strongly dynamic process that I do wonder at just how quick it may be. For eg, the jan 85 event had a very fast effect within that month - with a bitter easterly hard on the heels of cold winds and snow during the first week of the month which you could argue was almost in tandem with the actual MMW itself (a bit like next weeks cold spell is in line with current MMW)

So it could very well be that we have a cold spell in advance which leads straight onto the effects of the MMW proper :lol: Who knows!?

But as CH says at the end of his post above,the abrupt change in zonal winds from raging polar westerly to potent polar easterly in the space of a week is the measure in terms of how one might try and measure the anticipated changes in the models. As I say, who knows on that basis - because this is a real biggie to try and make judgements on!

Lag times may go out of the window here!

Share this post


Link to post
Share on other sites

Thanks Tamara for the speedy reply.

Looking again at the model output the +168 period (Feb 4th) is starting to show a particular trend towards blocking over Iceland/Greenland. Now the problem seems to be how influencial the Arctic HP could be around this period. Furthermore LP systems taking a S,ly track is a prospect but whether we remain on the S side of the PFJ is another matter.

So based on what you say we could see the model output trend towards blocking in a more significant way than currently modelled for the medium term. If this is the case I shudder to think what model output we may see over the next few days although I do expect it to be volatile.

Share this post


Link to post
Share on other sites
Guest North Sea Snow Convection
Thanks Tamara for the speedy reply.

Looking again at the model output the +168 period (Feb 4th) is starting to show a particular trend towards blocking over Iceland/Greenland. Now the problem seems to be how influencial the Arctic HP could be around this period. Furthermore LP systems taking a S,ly track is a prospect but whether we remain on the S side of the PFJ is another matter.

So based on what you say we could see the model output trend towards blocking in a more significant way than currently modelled for the medium term. If this is the case I shudder to think what model output we may see over the next few days although I do expect it to be volatile.

Even in an ordinary situation (ie a non or lesser MMW situation) arctic high pressure is poorly modelled as we know. But we do know that the vortex is splitting almost as we speak, and the splintered chards of the vortex as mapped by for eg the NCEP updated charts suggest in turn very favourable Omega cold blocking for our our neck of the woods in terms of tapping into CAA - long term deep upper cold at that. Is that a ramp? -I don't know!? :lol:

It might be a 'battle' playing out in the snow against watching ever colourful model charts coming out in the next week or so. We hope - better not over hype. Too late. already done! :D:D

Share this post


Link to post
Share on other sites

ECMWF forecast keeping the zonal winds negative for another day;

post-4523-1233219492_thumb.png

With good forecast propagation to the troposphere throughout the period.

http://strat-www.met.fu-berlin.de/cgi-bin/...t=all&var=u

Regarding the time frame wrt to tropospheric effects I am convinced that these can occur quicker than previously thought. Traditionally it is thought that the soonest effcts are felt at around two weeks from the beginning of the event. The start of the first warming of this MMW was around the 18th Jan. Having looked at other MMWs and the propagative properties of this current one added to the fact that we are experiencing a vortex split MMW and adding two weeks, then the first few days of Feb are bang on time for the initial early effects. Add to this favourable GWO effects as the excellent GP says then the combined effects may be enhanced.

Now the real question is how long can it last?

c

Share this post


Link to post
Share on other sites
Hi T

I am scratching my head big time on this. I actually think we will have rapid development like '87 and a waning ie not prolonged 86 as I expect the blocking to shift around [Feb 86 seemed to be ever so static and my favourite winter month of my lifetime].

BFTP

WRT the lag effect it seems that we hve a rapid development of intense cold heading our way...like '87. Now the point is will it wane like then or will this 'extra' powerful event prolong the cold. I think for sure we have 2 weeks out of this.

BFTP

Share this post


Link to post
Share on other sites
ECMWF forecast keeping the zonal winds negative for another day;

post-4523-1233219492_thumb.png

With good forecast propagation to the troposphere throughout the period.

http://strat-www.met.fu-berlin.de/cgi-bin/...t=all&var=u

Regarding the time frame wrt to tropospheric effects I am convinced that these can occur quicker than previously thought. Traditionally it is thought that the soonest effcts are felt at around two weeks from the beginning of the event. The start of the first warming of this MMW was around the 18th Jan. Having looked at other MMWs and the propagative properties of this current one added to the fact that we are experiencing a vortex split MMW and adding two weeks, then the first few days of Feb are bang on time for the initial early effects. Add to this favourable GWO effects as the excellent GP says then the combined effects may be enhanced.

Now the real question is how long can it last?

c

These events tend to start at around the 5hPa layer and then propagate down. This normally takes two to three weeks to reach the 100hPa (the tropopause) which it has done now. There is then a period when the 100hPa layer slowly begins to affect the tropospher depending on the QBO and certain other factors. It is not entirely unknown for a stratospheric event to have absolutely no affect on our weather depending on the QBO and the strength of the tropospheric patterns, so we need to be careful assuming it will have a lasting affect. Typically we start to see affects from a stratospheric event 1 month to 6 weeks after its initiation ,but in my view this tends to be quicker if the event is stronger. Currently at the 5hPa layer the event is over although the weather pattern now setting up is likely to trigger further stratospheric activity in the near future. Perhaps an early final warming is on the cards this year as a result leading to a stormy spring and warmer summer.

Share this post


Link to post
Share on other sites
Guest North Sea Snow Convection
ECMWF forecast keeping the zonal winds negative for another day;

post-4523-1233219492_thumb.png

With good forecast propagation to the troposphere throughout the period.

http://strat-www.met.fu-berlin.de/cgi-bin/...t=all&var=u

Regarding the time frame wrt to tropospheric effects I am convinced that these can occur quicker than previously thought. Traditionally it is thought that the soonest effcts are felt at around two weeks from the beginning of the event. The start of the first warming of this MMW was around the 18th Jan. Having looked at other MMWs and the propagative properties of this current one added to the fact that we are experiencing a vortex split MMW and adding two weeks, then the first few days of Feb are bang on time for the initial early effects. Add to this favourable GWO effects as the excellent GP says then the combined effects may be enhanced.

Now the real question is how long can it last?

c

My own humble little view would continue to be that the intensity of the event will mean a surface effect, I still expect that the true blocking pattern in relation to this will appear before mid Feb.

The question, does the PV regroup in any way, or do we go straight to a Final Warming is all a long way off really - when there is so much compulsive model watching both on here with the strat/zonal wind forecasts and on the other thread before we get to that. However it will ensure that this excellent thread is still alive and kicking for some time after winter is officially completed :lol: .

Ho-hum, I will have to confess to my friends that I have become a stratospheric anorak girl! :lol:

Share this post


Link to post
Share on other sites
These events tend to start at around the 5hPa layer and then propagate down. This normally takes two to three weeks to reach the 100hPa (the tropopause) which it has done now. There is then a period when the 100hPa layer slowly begins to affect the tropospher depending on the QBO and certain other factors. It is not entirely unknown for a stratospheric event to have absolutely no affect on our weather depending on the QBO and the strength of the tropospheric patterns, so we need to be careful assuming it will have a lasting affect. Typically we start to see affects from a stratospheric event 1 month to 6 weeks after its initiation ,but in my view this tends to be quicker if the event is stronger. Currently at the 5hPa layer the event is over although the weather pattern now setting up is likely to trigger further stratospheric activity in the near future. Perhaps an early final warming is on the cards this year as a result leading to a stormy spring and warmer summer.

And we can certainly say that this event is just that.

Looking at the propagation again we can see a couple of things looking at the mean zonal anomaly winds. Firstly the initial propagation of slowing winds (the first lightest green) is shooting down to the troposphere and will arrive by Feb. These could give some immediate affect on the short term modeling.

post-4523-1233250897_thumb.png

Secondly there is a more pronounced second phase increase in negative zonal winds around the 10 hPa level just coming into view now. It is the propagation of these winds which I feel will give the real blocking scenarios in a couple of weeks.

post-4523-1233250171_thumb.png

My own humble little view would continue to be that the intensity of the event will mean a surface effect, I still expect that the true blocking pattern in relation to this will appear around mid Feb .

The question, does the PV regroup in any way, or do we go straight to a Final Warming is all a long way off really - when there is so much compulsive model watching both on here with the strat/zonal wind forecasts and on the other thread before we get to that. However it will ensure that this excellent thread is still alive and kicking for some time after winter is officially completed :) .

Ho-hum, I will have to confess to my friends that I have become a stratospheric anorak girl! :)

Here is another strat chart for Tamara and any other strat anoraks out there!

post-4523-1233250445_thumb.png

I think that is a record January warming at the 30hPa level.

c

Oh and extent of temp propagation.

post-4523-1233250000_thumb.png

post-4523-1233250626_thumb.png

Share this post


Link to post
Share on other sites
Here is another strat chart for Tamara and any other strat anoraks out there!

[

c,

As a warming this is really quite incredible, as it has almost reached the highest stratospheric temperatures for any time of the year since 1979. This has to be a quite extraordinary event.

As to the effects, well looking at the ECWMF NH charts it seems to be influencing projected NH heights now with a 1045 mb high over the pole. Is this it - or is this just the start and as the effects become more "modellable" the true influence will become clearer?

Given this is such a large event and that it is still in development, my view is that there is much more to come in terms of a negative AO and all that entails.

We shall see.

MM

Share this post


Link to post
Share on other sites

Classic propagation node showing up. Negative zonal wind anomalies are now established at all levels and mean negative zonal winds have made it to around 50 hPa with some slowing of the rate of downwelling. Still looks like an impact with the upper troposphere somewhere between 10-20 February although we should note that blocking is already becoming established c/o those -ve anomalies.

Share this post


Link to post
Share on other sites

I would not be surprised if this has something to do with the intense heatwave in Australia, with the effects also being felt in the southern hemisphere as well.

I may be wrong of course.

Share this post


Link to post
Share on other sites

×
×
  • Create New...