Current & Forecast Climate Drivers

Michael Hauber

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Hi all and thanks for welcoming us over from weatherzone. Continuing on from discussions in weatherzone.

Borderline warm neutral/el nino status ongoing since last spring. Event is strong enough to be classified as el nino by US standards, but not according to somewhat stricter Australian BOM standards. The event is more of a modoki event than an east based event.The event has weakened somewhat early this year, which is typical of all ENSO events, and it is unclear whether the event will hold on, intensify or weaken further.

On the surface ocean temps have been cooling in the far east, however near the dateline the warm water seems to be holding on. A new westerly wind burst is starting which is likely to contribute to further warming.

surface.png


The subsurface is continuing to cool. Many ENSO watchers, and BOM believe that the cooling on the subsurface will have a cooling impact and move ENSO conditions towards a true neutral later in the year. However it is quite common in multi-year el nino/warm neutral events for the subsurface to cool to such levels. What is more unusual is the lack of subsurface warming following the last westerly wind burst in May.

subsurface.png
 
Hi Mike. Well done for kicking off an ENSO thread. It took me less than 5 min to register.
I will be reading your updates.
I can only add. There has been a low pressure anomaly at longitude 160-170e in the coral sea for much of autumn and now winter. The surface pressure isobars have been dipping as far south as NZ and their has even been cross equatorial flow info that region spawning multiple tropical lows.
regards.for a new beginning
 

Jellybeans

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Hi all and thanks for welcoming us over from weatherzone. Continuing on from discussions in weatherzone.

Borderline warm neutral/el nino status ongoing since last spring. Event is strong enough to be classified as el nino by US standards, but not according to somewhat stricter Australian BOM standards. The event is more of a modoki event than an east based event.The event has weakened somewhat early this year, which is typical of all ENSO events, and it is unclear whether the event will hold on, intensify or weaken further.

On the surface ocean temps have been cooling in the far east, however near the dateline the warm water seems to be holding on. A new westerly wind burst is starting which is likely to contribute to further warming.

surface.png


The subsurface is continuing to cool. Many ENSO watchers, and BOM believe that the cooling on the subsurface will have a cooling impact and move ENSO conditions towards a true neutral later in the year. However it is quite common in multi-year el nino/warm neutral events for the subsurface to cool to such levels. What is more unusual is the lack of subsurface warming following the last westerly wind burst in May.

subsurface.png
Nice job @Michael Hauber.
Glad to see some sort of reiteration of the WZ Climate Driver thread.

Looks like a WWB in the Western Pacific is coming our way.
2758A769-88DD-40E9-A64C-D49E798465FA.png


Interesting to see the atmospheric Nino conditions that have occurred over the past six months or so have finally weakened to neutral. Indicated by the AAM, looking at momentum.

9DD8A24A-CA2F-4831-8CCC-DAD00837E242.gif
 

Rush

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I find Mike Ventrice a good source of seasonal and sub-seasonal info.
 

Kino

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@Richard wondering if this thread can be re-named as there are multiple climate drivers for us (ENSO, IOD, AAO for e.g.) and it could be stickied?
 
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Sbooker

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For observers of this thread that are complete drongos like me could you dumb it down a lot every now and then to explain what this means from weather on the east coast of Oz in coming seasons (this spring and summer)?
Thanks.
 

Flowin

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I recognise what this thread is seeking to discuss from the similar theme on former WZ.
But I do struggle (and always have) with the concept of “climate driver”. We don’t fully know the full climate system response so we don’t fully know the driver. I would be more easily able to assimilate to the thread if it were titled with climate “signal” or “behaviour”.
 

Kino

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Signal or behaviour are even more subjective than driver...IMO. Clearly as the last 2 years has shown here in Aus, there’s more to our clime than ENSO, especially when we consider the multi ENSO stage drought that’s crippling inland areas. I read today that wool is at its lowest production levels for 100 years :(

Side note, that drop in 3.4 is impressive...is a Nina in the cards? If so, it better be a deep fully fledged system and none of the wishy washy rubbish of late.
 

bd7

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I would agree that there are more climate drivers expected Flowin than currently known, therefore they are all,currently known and future to be discovered, covered by the heading actually
 

bd7

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Issued 9 July 2019


The latest ENSO Wrap-Up and Climate Model Summary are now available on the Bureau's website.



Positive Indian Ocean Dipole likely to be dominant Australian climate influence


ENSO Outlook

Our ENSO Outlook provides
up-to-date information on the likelihood of an El Niño or La Niña developing.

zzzz4e8bdaced1b44315zzzz5955ce303eb3b929


Current status: INACTIVE

The El Niño–Southern Oscillation (ENSO) is currently neutral—neither El Niño nor La Niña. While the possibility of El Niño can't be completely ruled out for 2019, the tropical Pacific Ocean is expected to remain in an ENSO-neutral phase over the coming months, meaning the ENSO Outlook remains at INACTIVE. Model outlooks indicate a positive Indian Ocean Dipole is likely to be the dominant climate driver for Australia's weather for much of the rest of 2019, meaning an increased likelihood of a drier than average winter–spring.

Most indicators of ENSO are neutral. Tropical Pacific sea surface and sub-surface temperatures remain slightly warmer than average, but in the neutral range. Atmospheric indicators, such as cloudiness near the Date Line and trade winds, have been close to average, while the Southern Oscillation Index (SOI) is the only ENSO indicator that has continued to hover close to El Niño thresholds.

Climate models indicate the tropical Pacific will maintain an ENSO-neutral state through the austral winter and spring.

While the Indian Ocean Dipole (IOD) index has been neutral in recent weeks, the broader Indian Ocean sea surface temperature and atmospheric patterns remain generally consistent with a positive IOD. This means the influence upon Australia is likely to remain.

Climate models forecast positive IOD conditions for the remainder of the austral winter and spring. Typically, a positive IOD brings below average winter–spring rainfall, above average temperatures, and an earlier start to the fire season for southern and central Australia.
 
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Michael Hauber

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Modoki el nino conditions continue with a further WWB, and the warm waters near the dateline showing little signs of weakening.

surface.png


The subsurface, while still on the cooler side is showing signs of responding. Early indications are of a stronger warm Kelvin wave than for the previous WWB, even though the current WWB seems overall weaker.
subsurface.png


The MJO is about to enter the La Nina friendly Indian Ocean zones, but is generally looking very weak. The current WWB should likely wind down, however short term forecasts suggest weak westerly anomalies for the forecast period.

mjo.gif


Sea level patterns show a strong high pressure throughout the South Pacific. This would be trying to boost the trade winds, but it seems that lower pressure in the north Pacific is winning out. Substantial high pressure anomalies over Australia reflect a substantial el nino atmospheric influence.

SLP Pressure.gif


Model forecasts continue to suggest cooling in the east, including nino 3.4, but tend to forecast little or no cooling over nino 4 regions. With a substantial warm pool in place on the dateline I would normally be expecting the warmth to amplify through this time of year, but no models are currently forecasting this.
 

bd7

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The colder than normal water over the north Australian and Indonesian Area and into the east Indian Ocean are dominating
the ocean SST and pressure patterns...interesting how we have a warm area SW to NE from the equator to Alaska, and a contrasting NW to SE from the equator to the Australian Bight Area. Can't say that that looks particularly promising for inland Australian areas for any break to the drought in the near future.
coldwater2.png
 
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Michael Hauber

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Its a combination of the cool waters to the north of Australia and the warm waters in the Pacific which move tropical convection away from Australia into the Central Pacific.
 
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Kino

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There is no Modoki or Modoki like conditions. The ENSO state is warm-neutral at best. The drivers for Aus at present are the +IOD and the -AAO.
 

bd7

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Yes, while the warm water out in the Pacific does not help much, the dominant feature is the cold water over and to the W and NW of Australia and near Indonesia that is dominating inland Australian weather with little or no NW Cloud-bands
 
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Kino

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Yes, while the warm water out in the Pacific does not help much, the dominant feature is the cold water over and to the W and NW of Australia and near Indonesia that is dominating inland Australian weather with little or no NW Cloud-bands

Can just imagine what a -IOD + a -AAO could mean for us right now - bet it would be wild, wintry and wet.
 
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snowbarbie

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There is no Modoki or Modoki like conditions. The ENSO state is warm-neutral at best. The drivers for Aus at present are the +IOD and the -AAO.
....the drivers behind the drivers then....sam is forecast to swing back tother way
 

bd7

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JB I was meaning an answer to Kino on what the situation would be like with a -Dipole and -SAM...ie that it would be like 1992, not that this year was anything like 1992, but I maybe did not make myself clear enough.
The real drivers behind the SAM, Dipole, ENSO are not found in any publication at present but are likely to be solar, magnetic, , gas, volcanic and ocean current induced imo anyway
 
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Kino

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The drivers behind the drivers....an interesting topic indeed. Side bar - note that Townsville & Mackay recorded 3 nights sub 8c which is a first in 12 years and Mackay in 17 years or so I saw from WeatherWatch.

Also western Europe is staggering through record cold in Summer, with Slovakia recording it's coldest ever min & max temps.
 
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Jellybeans

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but are likely to be solar, magnetic, , gas, volcanic and ocean current induced imo anyway
Volcanoes can have a large impact, but it needs to pump lots of gas into the stratosphere and upper troposphere to have that impact.
Gas (eg. Ozone, etc) has an impact too.
Solar also plays its part.
As does the ocean currents, that are often factored into Atlantic SSTA forecasts, and to a lesser extent ENSO.

I think of them as separate drivers though, interlinked with all the others.
 
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Kletterer

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Understanding the extent of non linear interactions still has a fair way to go imo. Statistical significance of all Teleconnections remains ellusive. The SOM approach exhibits how much we were clutching at straws.
 
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Kletterer

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Im not convinced with a strong correlation between IOD to Australian snowfalls . Biggest recent IOD swings were 97,98,99. Spencers Creek snow measurements were similar in all 3 seasons. 1989 through to 92 also lacks correlation.
 

bd7

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Yes, true, jw, however, the anomalies still upset the normal atmospheric balance in pressure, wind, humidity, cloudiness, rainfall, etc. when they vary from the mean and cause significant changes to Australian weather and rainfall in particular.
And re snow seems to depend more on the SAM and colder southern sources so IOD would be less of a snow driver I would suspect, more of a rain driver for Australia.
 

Kino

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I really detest the colours assigned in anomaly charts - take above for eg - 1c warmer is red while cooler is light green. Baloney
 

Michael Hauber

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Im not convinced with a strong correlation between IOD to Australian snowfalls . Biggest recent IOD swings were 97,98,99. Spencers Creek snow measurements were similar in all 3 seasons. 1989 through to 92 also lacks correlation.

ENSO dominates rainfall patterns for NSW and QLD, and IOD dominates South Australia. Rainfall in Victoria is a bit more mixed with a IOD maybe being more important than ENSO, depending on which research paper you read. However for SE Australia a blocking index seems to beat both ENSO and IOD. Blocking is the tendency of the long wave trough's to peak/park in various sectors of the Southern Ocean.

https://journals.ametsoc.org/doi/full/10.1175/2009MWR2861.1[URL]https://journals.ametsoc.org/doi/full/10.1175/2009MWR2861.1][/URL]reference[/url]
driver comparison.gif
 
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Michael Hauber

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Latest weekly readings of nino 4 are still over 0.7. If this continues for the rest of July that could make it the second or third highest July reading for nino 4 on record, with 97/98 reaching 0.76 and 15/16 at 1.05. The nino 4 index is not a perfect reflection of modoki, but with the modoki index published at Jamstec discontinued in November its the best index available (In November Jamstec modoki index showed the current event comfotably over el nino modoki threshold). Nino 4 during 2004 peaked at 0.82 and had only reached 0.49 in July.

The current event is not only a modoki el nino, but a strong one.
nino4.png
 

Kletterer

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ENSO dominates rainfall patterns for NSW and QLD, and IOD dominates South Australia. Rainfall in Victoria is a bit more mixed with a IOD maybe being more important than ENSO, depending on which research paper you read. However for SE Australia a blocking index seems to beat both ENSO and IOD. Blocking is the tendency of the long wave trough's to peak/park in various sectors of the Southern Ocean.

https://journals.ametsoc.org/doi/full/10.1175/2009MWR2861.1https://journals.ametsoc.org/doi/full/10.1175/2009MWR2861.1]reference[/url]
driver comparison.gif
Note that techniques used for partial correlation are still from 1980- 1989.
 
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bd7

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Dr Ummenhofer discovered the IOD was an even bigger factor than El Nino in driving long-term Australian droughts.

"When you're looking at prolonged drought periods, particularly the millennium drought or the earlier droughts that Australia has experienced, it's actually more the Indian Ocean that is in an unusual state, particularly Indian Ocean Dipole events occurring in unusual numbers."

Dr Ummenhofer's work on the IOD changed the way drought in Australia is understood and helped propel the climatologist to the top of her field.
 
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Jellybeans

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Latest weekly readings of nino 4 are still over 0.7. If this continues for the rest of July that could make it the second or third highest July reading for nino 4 on record, with 97/98 reaching 0.76 and 15/16 at 1.05. The nino 4 index is not a perfect reflection of modoki, but with the modoki index published at Jamstec discontinued in November its the best index available (In November Jamstec modoki index showed the current event comfotably over el nino modoki threshold). Nino 4 during 2004 peaked at 0.82 and had only reached 0.49 in July.

The current event is not only a modoki el nino, but a strong one.
nino4.png
I wouldn’t call it very warm or strong.
I think you are looking at the wrong place.
 
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