AAO correlated with southern hemisphere synoptic 2019

Here l take snaps of the ACCESS g model southern hemisphere synoptic and also record the AAO/SAM parameter.

Looking for synoptic patterns and if they correlate with shifts in the AAO. I will make a few observation notes as warranted.

AAO link.

ACC g  southern hemisphere synoptic

The first entry is below and then scroll down to comments section for all further additions. Click on the heading to load if necessary

5th may 2019 _AAO

image below 8th may 2019  AAO  going strong positive  Here +0.7 and going up

8th may 2019 polar low displaces cold air _SH

11th may 2019 aao vs SH synoptic


19 comments on “AAO correlated with southern hemisphere synoptic 2019

  1. Testing theory that when AAO goes strongly positive. The timing between troughs in east Australia is longer , speed of high pressure belt slows and westerly belt contracted south.
    May 11th 2019.
    AAO highly pos +2.
    Trough on east coast of Oz has just left and highs have become west/east elongated. There are no troughs in the next 7days.High pressure persists.

  2. Crikey
    “I am currently doing some home based research on the topic of spatial synoptic patterns.Hasn’t been underway for long.
    I will post a few snippets over time on the theory l am currently testing.
    I am snapping pics of SH synoptic and matching with AAO trends currently.…-synoptic-2019/

    I have also come to realize that l need to possibly do the same with the jet stream pattern.

    The polar low pressure belt expands and contracts regularly.
    There is a sequence of steps or modes

    -contraction,.organized 5 or 6 nodes tightly condensed around antartic circle

    _expansion of polar low belt and subsequent expansion of westerly belt , northward. more chaotic and lacking symmetry.

    During the expansion stage the westerly belt is more meridonal or wavy and creates protrusions of low pressure in between the mid latitude highs called troughs or of strong enough cuts of a low into the mid latitude belt.

    The highs just respond to these contortions.
    The shape may be based on jetstream meanders or no meanders , westerly belt meanders and the speed of the high pressure belt.
    You can watch the symphony’ in play on this animation

    If the AAO is highly positive in winter , then the there is less cold excursions out of the polar region.
    If polar jetstream is zonal , less wavy.Then less troughing into mid latitudes from the westerly belt.…it=Refresh+View

  3. 14th May 2018
    AAO has just completed a big swing to +2.3 over the past week and has started downward trend a couple of days ago. The models are in agreement that the AAO will go negative strongly this week.
    Here l have taken todays SH synoptic and then 3days later when the AAO is expected to be + 0.8. That is a drop of 1.5

    Notice the weakening and expansion of the westerly belt in 3days and also the mid latitude highs are starting to expand and become more symetrical.
    The first sign of cold fronts arriving… in SW WA. The excursion of polar air peaking at SW WA. on 17th May 2019
    Report from weatherzone
    The Bureau of Meteorology (BOM) is forecasting a minimum of just 3 degrees Celsius on Friday and a maximum of 17C for both days.

    “We’re going to get a bit of a blast of winter, with some very cold temperatures overnight and also some low maximums as well,” BOM spokesman Neil Bennett said.
    “We haven’t had consecutive days of 17C or below since May 2013, when we had 14.6C on the 30th and 16.2C on the 31st.
    The 3C minimum is also fairly unusual, we haven’t had a May morning as cold as that since 2012 when in fact it got down to 1.3C ,so it’s been a long time since it’s been as cool as that in May.”

    16th may 2019 radar showing a sub polar excursion heading for SW WA

  4. 25th May 2019
    All ensemble members are in agreement that the AAO will continue down to – 2.8 in the coming days .

    There is clear evidence now of some strong meridonal flow of the sub polar belt at the surface layer.
    At the 200hpa stratosphere layer, the sub polar jet is wavy but the sub tropical jet is strongly zonal.

  5. Here is a picture of the sub polar belt after a drop in the AAO of 5.3points
    from 10th May 2019 to 29th may = 19days
    Notice the large expansion of the sub polar belt and high amplitude of the intrusions into the mid latitudes.
    2 of the bigger nodes extend up to 25s
    AFTER a 5 point drop in the AAO

    BEFORE..19days earlier

  6. The AAO has been positive for one month on this picture of SH synoptic ,30th June 2019
    Here the sub polar belt is well contracted south as one would expect from a sustained positive AAO
    The low cells are organised and the westerly belt is zonal (non wavy)
    About half of the AAO ensemble forecast is tipping a big dip in the AAO in the coming weeks. ACCg might belong to that bunch as is forecasting an expansion of the sub polar belt and excursion of low pressure in between the big highs and protrusion into the mid latitudes in about 7days time. The low pressure bulge is forecast to peak in SW WA around the 5th July


  7. There was a decent drop in the AAO from
    16th June pos’ 2.5 to
    16th July 2019 minus 2.2

    There was no decent expansion of the westerly belt during this period and the sub polar jet was weak and even non existent during this time.
    There was a significant disturbance to the polar vortex at this time as well.
    See my post on ‘stratospheric warming/ polar vortex split’
    The degradation of the sub polar jet during this period may have contribute to the lack of northward migration into the mid latitudes.
    There was one good snow dump,at this time but was largely due to a well placed sub polar low .,Its moisture laden northern flank giving the alps about one metre of snow
    I believe both major dumps of snow this year were from neg AAO
    One back in MAY and the more recent July

  8. AAO is forecast by all ensemble members to drop to a massive minus 4 this week.
    I don’t believe this has happened before.?

    As expected the sub polar belt is seen to migrate north and on the 8th August 2019 a strong low is centred west of Tasmania and its northern flank protrudes well onto the SE corner of OZ.
    The low is jam packed with moisture.

    The cold pool sits on the lows SW flank and is down to a low snow level of 532 thickness. This is a 150hr forecast and the details of this event will be interesting as they unfold

  9. Continuing from above. The AAO is neutral today ,3rd August 2019and this event posted below is in 5days time.
    Massive long wave trough, reaching up to the NSW/QLD border
    150hr forecast

  10. Some background information about the AAO
    (This link also has tabulated data from 1948 to 2002)
    Antarctic Oscillation (AAO) time series, 1948 – 2002
    Definition and analyses | Data
    ‘The Antarctic Oscillation (AAO) is the dominant pattern of non-seasonal tropospheric circulation variations south of 20S, and it is characterized by pressure anomalies of one sign centered in the Antarctic and anomalies of the opposite sign centered about 40-50S. The AAO is also referred to as the Southern Annular Mode (SAM). There is a Northern Hemisphere analog to the AAO, and it is called the Arctic Oscillation (or Northern Annular Mode). More information is available on annular modes through this link.

    The AAO is defined as the leading principal component (PC) of 850 hPa geopotential height anomalies south of 20S (Thompson and Wallace 2000). (An AAO index calculated from SLP anomalies is available through this link.) ‘
    (Would l be right in saying the AAO has been trending positive for a long time.)

  11. 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 … ml#current

  12. 19th August 2019
    The AAO has been negative since July 2019. That’ 46 days in the negative range.
    We haven’t seen a long negative phase like this for awhile.
    The AAO is currently minus one and forecasts keep the AAO neg until the end of the month.
    The westerly belt is contracted north with a well defined meridonal wavy pattern.
    There are 4 large nodes today. All extending at least to 30s latitude.
    This bodes well for continued cold fronts and westerly belt troughing for the southern quadrant of Australia.
    Also continued chances of snow for the alps for the rest of August as cold pools get propelled northward

  13. A very strong anomaly in geopotential height in the upper stratosphere first week of spring. Sept 2019. ??? Have to watch to see how this translates ,(re: teleconnectons) ?

    An incredible correlation between vertical geopotential height and the phase of the AAO. Amazing l have never noted that before.,A light bulb moment.

    When geopotential height between surface to 100 hPa is positive . The AAO index is negative.
    When geopotential height between surface and 100 hPa is negative. The AAO index is positive.

    Some convincing proof that the condition of the polar vortex affects our weather.
    I will put this geopotential height anomaly in the polar vortex on my weekly obs ‘ round.

    and link to my research on stratosphere and the Polar vortex PV

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