The Australian Weather Forum

Found this great article on polar vortex displacements and polar vortex splits. This should help us with assessing the progress of our SH polar vortex anomalies.
Had a quick look at the 70 and 10hpa today and everything looks quite symetrical atm.
However still 2 months more of winter spring obs' to go

When Does A Displaced Polar Vortex Become A Split Vortex?
/ February 8, 2014

https://wattsupwiththat.com/2014/02/08/ ... it-vortex/

At 70mb, the polar vortex is slightly elongated. But what about at 10Mb!!

https://earth.nullschool.net/#current/w ... 87.78,1640
Looks like almost 2 elongated circulations at right angles to each other (if you zoom in)!

Thoughts anyone? I love learning about this large scale stuff

Polar vortex at both 70 & 10 hpa is elongated and twisted 30 deg clockwise from 70 up to 10:

https://earth.nullschool.net/#current/w ... -89.46,689
https://earth.nullschool.net/#current/w ... -89.46,689

At 10hpa, it looks like it is almost splitting

Didjman wrote: ↑Sun Aug 04, 2019 10:14 am Polar vortex at both 70 & 10 hpa is elongated and twisted 30 deg clockwise from 70 up to 10:

https://earth.nullschool.net/#current/w ... -89.46,689
https://earth.nullschool.net/#current/w ... -89.46,689

At 10hpa, it looks like it is almost splitting

yes, there seems to be a coupling zonal disturbance underway

Here is a link to some background definition on the AAO, ( Antartic Oscillation )
Also included from this link is some tabulated data of AAO index from 1948 to 2011

http://research.jisao.washington.edu/data/aao/slp/

I was looking for the record lowest AAO. But l have come to realize there are various ways of computing the AAO,and so l am not confident of making a valid comparison
However, it is evident that the AAO has been steadily trending positive since the data began in 1948 and is clearly evident from the time series below.
What is also interesting is that the trend is linear . The trend runs parallel to Southern Hemisphere surface warming during this same period.
Source

240hr forecast of the 10hPa temps' showing a displaced vortex and a developing warming patch.

2 funnels.,One descending, cold. One ascending , warm.
Will this be the start of a 10hPa warming event. from late August early september?

source
https://www.cpc.ncep.noaa.gov/products/ ... _f/#cpcz15

2 vortices now at 10Hpa:
https://earth.nullschool.net/#current/w ... 90.74,1950

Only one at 70 atm:
https://earth.nullschool.net/#current/w ... 63,-82.590

Animated gifs at 10 / 30 / 50 HPA:
https://www.cpc.ncep.noaa.gov/products/ ... 10anim.gif
https://www.cpc.ncep.noaa.gov/products/ ... 30anim.gif
https://www.cpc.ncep.noaa.gov/products/ ... 50anim.gif

Something interesting going on where current vic wx originated 2-3 weeks ago; Antarctica.
Current polar vortex at 10Hpa:
https://earth.nullschool.net/#current/w ... 77,-39.712

70hpa:
https://earth.nullschool.net/#current/w ... 77,-39.712

Current AAO tending more +ve to around -2

Check this out at 500hpa over Antarctica for Aug7.
https://www.cpc.ncep.noaa.gov/products/ ... d_anim.gif

Is this a precursor to another polar vortex split?? Or is 500 Hpa too low to cause zonal waves up into the Stratosphere(they have to start somewhere)?
Thoughts anyone? JS?? (I am also referring to a post on this thread by JS on July 31 at 0700 with reference to massive heating event mid August)

Meanwhile, at higher levels above the Antarctic:
https://earth.nullschool.net/#current/w ... -94.55,975 almost a split
https://earth.nullschool.net/#current/w ... -94.55,975 very elongated

So close to another Vortex split at 70Hpa!:
https://earth.nullschool.net/#current/w ... 87.44,1363

Just very elongated at 10Hpa:
https://earth.nullschool.net/#current/w ... 87.44,1363

We have a vortex split at 70hpa!

At 1600 AEST:
https://earth.nullschool.net/#current/w ... -86.62,975
https://earth.nullschool.net/#current/w ... -86.62,975

The weak vortex split at 70 Hpa didn't last 24hrs:
https://earth.nullschool.net/#current/w ... -89.14,689

At 50hpa, the heating anomaly appeared to be stretching and waning. Now the trend has reversed and it is contracting and strengthening in the old posi between Africa and Oz:
https://www.cpc.ncep.noaa.gov/products/ ... 50anim.gif

The Polar Vortex has "healed"for now, but IMHO, expect a split soon:
https://www.cpc.ncep.noaa.gov/products/ ... 10anim.gif
https://www.cpc.ncep.noaa.gov/products/ ... 30anim.gif
https://www.cpc.ncep.noaa.gov/products/ ... 50anim.gif
https://www.cpc.ncep.noaa.gov/products/ ... d_anim.gif

Precursor to a stratospheric disturbance is appearing in GFS. The eddies chiefly responsible for the transport are the planetary scale waves which when attaining amplitudes twice their monthly average, can be a signal of a large stratospheric disturbance in the near future.

First sign that mid to late September maybe quite feral in the mid latitudes for the Southern Hemisphere

JS, how do you read that chart??

Didjman wrote: ↑Thu Aug 15, 2019 2:08 pm JS, how do you read that chart??

Looking for large eddy anomalies propagating upwards into the stratosphere (above 70hPa). Seems like planetary scale waves from the lower troposphere are breaching into the stratosphere over the next 10 days. I look at eddies as a precursor to something bigger.

JasmineStorm wrote: ↑Thu Aug 15, 2019 2:20 pm

Didjman wrote: ↑Thu Aug 15, 2019 2:08 pm JS, how do you read that chart??

Looking for large eddy anomalies propagating upwards into the stratosphere (above 70hPa). Seems like planetary scale waves from the lower troposphere are breaching into the stratosphere over the next 10 days. I look at eddies as a precursor to something bigger.

Thx to Google, I found that chart and have bookmarked it! That eddie is heaps warmer than the air around it and is very deep altitude wise. I can now see how this can kick of a SSW event Will be watching things unfold with great interest!

How often is the chart updated??

SAM/AAO has been negative since 4th July 2019 . So been negative for 44 days today. A welcome change from the pos AAO which has dominated for so long
Forecast is for a hike toward positive later this week
Has contributed to snow storm in alps last week and another forecast this weekend.
A neg AAO sends the westerly belt and cold pools further north

source
https://www.cpc.ncep.noaa.gov/products/ ... ml#current

Hi Crikey,
Check the link below and select Eddy Heat Flux Anomaly's in the main drop down:
https://www.stratobserve.com/anom_ts_diags

This is the bigger picture stuff I have been looking for! This shows things happening BEFORE the vortex splits (and the cause of the split in the early stages).