Stratosphere and Polar Vortex Watch

[Spah1]

 

[Spah1]

 

[bluearmy]

Ecm now showing quite a displaced upper vortex again by day ten - nw scandi.  There is a split before this but the wave one then takes over and it's a 'big wave'. The zonal flow retreating back towards where it was (latitude) prior to the big uptick and dropping back to levels where it won't influence the trop. Associated warming also showing on the temp graph. The latest 00z run seems as displaced. 

[Singularity]

So today, the atmosphere is well into the process of springing back and GEFS for example is adjusting accordingly, but the more interesting responses in our part of the world remain at 10 days and beyond, including the stratospheric events by and large, although the models still generally show the new, very strong warming from the Himalayas simply taking over proceedings rather than joining forces with the warming on the other side of the vortex, which either remains weak or fades away.

I'm not sure how effective a repeat of the displacements seen in Dec, but with stronger warming, would be at encouraging HLB in the right places for us to develop?

 

Oh and I can't get my head around GloSea5 retaining a strong vortex for the rest of this month. How is that possible given that we're seeing signals from other models rooted in developments that take place over the next 4-5 days?

Edited January 10, 2018 by Singularity

[bluearmy]

12 minutes ago, Singularity said:

So today, the atmosphere is well into the process of springing back and GEFS for example is adjusting accordingly, but the more interesting responses in our part of the world remain at 10 days and beyond, including the stratospheric events by and large, although the models still generally show the new, very strong warming from the Himalayas simply taking over proceedings rather than joining forces with the warming on the other side of the vortex, which either remains weak or fades away.

I'm not sure how effective a repeat of the displacements seen in Dec, but with stronger warming, would be at encouraging HLB in the right places for us to develop?

 

Oh and I can't get my head around GloSea5 retaining a strong vortex for the rest of this month. How is that possible given that we're seeing signals from other models rooted in developments that take place over the next 4-5 days?

It could be a strongish displaced vortex rather than a split one which some are seeing .......,,

[feb1991blizzard]

1 hour ago, bluearmy said:

It could be a strongish displaced vortex rather than a split one which some are seeing .......,,

And given the Met Office forcast and the 1mb GFS charts - looks like to the 'wrong' place as well.

EDIT : but lets hope chiono's wave 2 will follow up and the GLOSEA will pick it up suddenly as well.

Edited January 10, 2018 by feb1991blizzard

[bradymk]

6 hours ago, feb1991blizzard said:

And given the Met Office forcast and the 1mb GFS charts - looks like to the 'wrong' place as well.

EDIT : but lets hope chiono's wave 2 will follow up and the GLOSEA will pick it up suddenly as well.

His latest update sounds more promising though..... “emergent signs of SPV weakening late Jan rather than (as previously signalled) early Feb, but NB: that's *not* code for definite SSW. Let's see what unfolds.”

[Snowy L]

 

 

8 hours ago, Singularity said:

So today, the atmosphere is well into the process of springing back and GEFS for example is adjusting accordingly, but the more interesting responses in our part of the world remain at 10 days and beyond, including the stratospheric events by and large, although the models still generally show the new, very strong warming from the Himalayas simply taking over proceedings rather than joining forces with the warming on the other side of the vortex, which either remains weak or fades away.

I'm not sure how effective a repeat of the displacements seen in Dec, but with stronger warming, would be at encouraging HLB in the right places for us to develop?

 

Oh and I can't get my head around GloSea5 retaining a strong vortex for the rest of this month. How is that possible given that we're seeing signals from other models rooted in developments that take place over the next 4-5 days?

Is it saying strong vortex in general or in our part of the world? I can get the 2nd part because the displacement pushes it into the Baffin Bay area which is terrible for us.

Edited January 10, 2018 by Snowy L

[Spah1]

 

[comet]

Regardless of what the Glosea5 model is showing  (probably just late to the party) if the strength of warming remains the outcome at this early stage is impossible to forecast. Perhaps in 5 to 10 days we may well see a strong wave 2 response being forecast which could make things very interesting going forward end of Jan into February.

[bluearmy]

1 hour ago, Snowy L said:

 

 

Is it saying strong vortex in general or in our part of the world? I can get the 2nd part because the displacement pushes it into the Baffin Bay area which is terrible for us.

Spv looks more likely to displace to Scandi/Greenland than Baffin - where that leaves the tpv.........

[mb018538]

 
 

 

[Day 10]

The 10hpa warming is still moving closer.

Edited January 11, 2018 by Day 10

[bluearmy]

Still waiting for consistency on this warming on gfs ops. it’s there every run but it is varying still. Once the modelling gets to day 10 on it we should have a handle on how it will play out at 10hpa and above 

[ghoneym]

2 hours ago, mb018538 said:

 
 

 

Somebody help me out here please, I'm maybe just being thick (as usual), but looking at this chart 

50 mb temps at their coldest look to be -60 deg C. The cold part of the vortex on his 50mb chart shows -80 is the vortex at that height just exceptionally cold this year in the NH or is the chart I post just out of date / wrong? Also does anyone have a similair chart that just shows the trop and strat with the same parameters and variables? I find the chart usefully to visualise what some of these posts show.

Cheers

[Blessed Weather]

 

[ghoneym]

5 minutes ago, Blessed Weather said:

 

Again using this daft chart I have 

The "normal" temp for 10mb is -20 deg C so if the anomaly chart above is showing the warming to be +60 deg C then surely the "normal" temp at 10mb would be -80? Confused.com 

[Singularity]

6 minutes ago, ghoneym said:

Again using this daft chart I have 

The "normal" temp for 10mb is -20 deg C so if the anomaly chart above is showing the warming to be +60 deg C then surely the "normal" temp at 10mb would be -80? Confused.com 

That vertical cross-section looks to be for a typical location outside of the Arctic circle where the polar vortex tends to reside. The coldest air is within the vortex circulation, so a vertical cross-section for somewhere like Greenland on a 'typical day' would look much colder up at 10 hPa.

 

. . . . . . .

Still waiting to see if when the observed eastward tropical signal comes in, this will re-introduce k2 warming in the longer-term. Failing that, we'll need a very strong displacement I expect.

[chionomaniac]

The temperature at 10hPa differs depending on the time of year. The mean temp between 90N and 65N in January at 10hPa is around -60C.

[Yarmy]

8 minutes ago, ghoneym said:

Again using this daft chart I have 

The "normal" temp for 10mb is -20 deg C so if the anomaly chart above is showing the warming to be +60 deg C then surely the "normal" temp at 10mb would be -80? Confused.com 

The diagram is the average over a whole year, over the entire planet. Apples and oranges.

[Glacier Point]

This isn't new, but reanalysis of 10hPa temps after passage of strong Indian Ocean MJO events underlines the potential relationship between tropical forcing and the stratosphere.

I reckon we peaked tropical signal in phase 2 around the 8th or 9th Jan.

For years with strong MJO signal centred in phase 2, 10 hPa temps:

Rolled forward, by day 15, displacement starting to occur:

By day 39/40, we get peak warming signal:

The surprising thing is the duration of the warming signal (days 20-40+) but this is more likely a result of the large number of dates used smoothing out the warming signal.

Now, current during the same peak in MJO phase 2:

Much more perturbed with wave 2 already in evidence from previous forcing. Different location of warming being forecast, much more aligned through 260 - 180 W rather than Asia to the Atlantic.

Suggestion: warming and substantive weakening of the vortex likely to occur given the scale of the MJO wave passage, timings probably more advance given the state of the vortex at onset. Whether a trigger for a SSW or MMW are sufficient will be worth monitoring but not guaranteed.

[Blessed Weather]

 

[sebastiaan1973]

Abstract We investigate the connection between the equatorial Madden-Julian Oscillation (MJO) and different types of the Northern Hemisphere mid-winter major stratospheric sudden warmings (SSWs), i.e., vortex-displacement and vortex-split SSWs. The MJO-SSW relationship for vortex-split SSWs is stronger than that for vortex-displacement SSWs, as a result of the stronger and more coherent eastward propagating MJOs before vortex-split SSWs than those before vortex-displacement SSWs. Composite analysis indicates that both the intensity and propagation features of MJO may influence the MJO-related circulation pattern at high latitudes and the type of SSWs. A pronounced Quasi-Biennial Oscillation (QBO) dependence is found for vortex-displacement and vortex-split SSWs, with vortex-displacement (-split) SSWs occurring preferentially in easterly (westerly) QBO phases. The lagged composites suggest that theMJO-related anomalies in the Arctic are very likely initiated when the MJO-related convection is active over the equatorial Indian Ocean (around the MJO phase 3). Further analysis suggests that the QBO may modulate the MJO-related wave disturbances via its influence on the upper tropospheric subtropical jet. As a result, the MJO-related circulation pattern in the Arctic tends to be wave number-one/wave number-two ~25–30 days following phase 3 (i.e., approximately phases 7–8, when the MJO-related convection is active over the western Pacific) during easterly/westerly QBO phases, which resembles the circulation pattern associated with vortex-displacement/vortex-split SSWs.  http://web.gps.caltech.edu/~kfl/paper/Liu2014.pdf

Edited January 11, 2018 by sebastiaan1973

[lorenzo]

Given a few reanalysis posts and also the examination of precursors and processes - thought it would be a useful addition to delineate the thread with some 'state of play' charts.

Few oldies from the JMA site 10hPa variable, the VI phase evident on the 30hPa plot.

Also wrt the VI phase I liked looking at this plot from JMA showing the aggregate wave activity.

Red line roughly where the the Wave 1 influence of late Autumn is overtaken as the Vortex goes into ramp up mode, then as this intensification period wanes, replaced by W2 EP Flux.. Wondering if we have anywhere as a dataset that shows the canonical time frames involved for classic VI phases. I know a few papers have reanalysed vortex from development > growth > maturation> waning. The point being, has this time period changed in response to Arctic Sea ice variability, and have the notable reductions of recent years ( vortex fuel) altered the base state of the classic Vortex Intensification phase.

Part two of that question and maybe or maybe not related is around the prevalence for strong W1 activity with echoes of early 80s CW infractions on the vortex and why given such an absence, they are prevalent now?

U and Heat Flux forecasts go to the edge of what could be the noted 'potential period' for decent strat event, as per above this is where the question of classification comes in. Previously it was MMW or SSW, now things are certainly more nuanced in terms of how the community views the impacts. What is certain is - we are on the cusp with the precursors mentioned and things already showing their hand. It's a watch and learn, and watch and see...

Edited January 11, 2018 by lorenzo

[Singularity]

I'm sure I've seen somewhere or other, perhaps on this forum or maybe the ASI forum, a proposition that greenhouse gases, by reflecting back down a significant proportion of the longwave radiation from the surface, are leading to stratospheric cooling. The past few winters sure seem to support that theory but 'a few cases does not a warehouse make' (or whatever the phrase is...).

In fact with the warmed troposphere I wonder if we may be locked into having a generally more variable vortex than in times past that often tends toward one extreme or the other, as a weaker lower vortex either interacts or remains disconnected from a stronger upper vortex?