Monsoon set to break
The last couple of months have seen a triple whammy of climate factors leading to widespread death and destruction right across the country.
The combined impacts from one of the strong positive Indian Ocean Dipole (IOD) events on record, a Sudden Stratospheric Warming (SSW) event and flow on strong negative Southern Annular Mode (SAM) events have resulted in 2019 being the hottest and driest year for Australia on record.
In short, the lack of moisture from the Indian Ocean and lift in the westerly storm track towards the country from the south has brought hot, dry weather - and devastating fire conditions.
One additional flow on effect of the strong positive IOD event was that it blocked the development of the monsoon trough across the north of the country, effectively holding it at bay until now. The onset of the monsoon usually occurs late October and into early November, bringing enhanced rainfall across northern Australia.
To categorise, the onset of the monsoon is confirmed when rainfall totals across the north of Australia reach 50mm from the 1st of September. While some locations were only slightly late this year, the majority of the north of the country has seen the monsoon delayed significantly with higher than normal temperatures in Darwin due to the lack of cloud and moisture. However, it's now breaking. This is also the reason for the record breaking heat into the last weeks of December, with the interior of the country being mostly cloudless allowing massive amounts of heat to build up.
With the IOD event steadily weakening and breaking down since its peak in late October, we're finally set to see an increase in tropical activity and rainfall across northern Australia.
The Madden Julien Oscillation (MJO) gives an indication of where this wave of tropical activity sits around the world, and also its strength. The MJO is monitored and forecast out to two weeks by various weather agencies around the world, and can be visualised on the charts shown below.
While it looks quite complicated, it's actually fairly simple. The globe is set up into eight rough sections, and if you imagine looking at the diagram from the south pole, you can see Australia falls in the middle of section 4/5 (Maritime Continent), 7/6 covers the Pacific Ocean, 8 America, 1 Africa and then back to the Indian Ocean 2/3.
The MJO was located in the Western Pacific at the end of December, leading to the formation of Tropical Cyclone Sarai late last week, but has since weakened and moved east.
The MJO is forecast to continue east and strengthen in sector 4/5, our continent. This will influence the north-west of the country, bringing with it enhanced tropical cyclone potential and increased rainfall.
Looking at the long-range model forecasts and there's plenty of activity on the cards for the Timor and Arafura Seas with a couple of cyclones possibly forming over the coming fortnight. The swell prospects for Australia will be limited to the north-west facing coasts off Western Australia, but eastern Indonesia looks to receive a large, close-range swell but with strong westerly winds.
The tropical activity won't influence the East Coast until the MJO moves further east, and only if it maintains its strength. We'll keep an eye on the outlook for WA and the Eastern states in the Forecaster Notes over the coming weeks.
Comments
hmmm.....there seems to be a breakdown in communication between the monsoon trough and wet season moisture incursion and the east coast.
we've seen this repeatedly in previous summers with high rainfall in the west and failed wet seasons in the east.
my theory is the Tasman sea heatwave is breaking down the teleconnection between MT instability and west pacific moisture sources.
that lack of vorticity from strong high pressure driven SE winds is/has been completely lacking in quite a few previous years, leading to what I call "toxic" summers.
Yeah, interesting. Would need to do a bit of research to confirm. So you're saying that the high's are weaker across the Tasman Sea as well from the heatwaves?
Question has the shift in the north and South Pole had any affect on sea water been hotter up or a shift in magnetic field causeing the sea bed to worm
No.
By "No" I think you meant to say that it's actually the shape shifting lizard elites that are to blame....?
Oh no Freeride, I heard the reason just the other day, from a very reliable friend of a friends friend. Apparently there has been multiple towers constructed along the west coast of Oz that breaks up the cloud and weather patterns as they hit the coast, this in turn prevents the weather from coming across to the east and raining on us - hahaha.
No word of a lie, that's the latest conspiracy theory designed to exacerbate the current fires and drought, send farmers broke and provide cheap land for the Chinese. We're all doomed.
I've seen this crap being shared as well. We're getting dumber and dumber by the day, it's so sad :(
hence my signature but
fair call...although, I'm not sure your spelling of "intelligent" is helping your case... ;-)
i seen what yor saying but its meent to be a pun but.
yeah, basically.
the temperature gradient between the Coral Sea and Tasman is all wrong and has been for a few years.
it should be warm in the Coral and cool in the Tasman , buts it the other way around.
which is leading to (or is a result of, not sure which) weak high pressure in the Tasman and fukall low pressure development in the CS.
this pattern of weak, mobile high pressure , often at more winter type latitudes regardless of the state of the SAM is becoming more and more a new normal.
I believe the anomalously warm water pooled moreorless permanently in the Tasman is the main contributor to that and is being caused by climate change.
does that makes sense?
Yep totally, researched a few marine heatwave articles and studies but haven't found anything substantial as of yet.
Fuelled as well by the East Australian Current making its way further and further south instead of steering off east around Seal Rocks - owing to climate change.
Also a good marine heatwave tracker site here.. Marine Heatwave Tracker
Makes sense......
Interesting stuff Craig/FR.
I saw an article about a large pool of water east of NZ which was up to 6 deg warmer than its surrounds and no one had any idea how/why it got there.
Everything's heating up.
yeah, that heat blob east of the South Island was/is a real beast.
I haven't really been tracking Tasman sea SST anomalies in a rigourous way but I can't remember the last time they weren't higher than the climatological average.
One thing I can't understand is why all that warm water doesn't erupt in ECL's every autumn/winter.
There's been a real dearth of ECL's in the last few years.
I count the June 2016 Black nor-easter as the last big winter swell, but even bog standard cut-off Tasman lows (the classic onion ring) have been notable by their scarcity over the last couple winters.
the biggest S swell we've had here since the black nor-easter came during Jan 2018.
Fucking January!
other than that it's been refracted S swells from frontal progressions tied to higher latitude parent lows.
Why are they called cut off lows ?
Blowin, when the flow aloft (e.g. 500hPa to 200hPa - middle atmosphere to jet level) forms a low and not a trough, it is essentially cut off from the general flow, and the surface low doesn't move (much), but just slowly fills up. That's a cut off low.
Normally a low sits under a 500hPa trough and moves eastwards.
Shitty explanation, and I'm letting myself down here, but on our way out the door with the hound. Hope it made sense.
Also, marked by concentric circles - the aforementioned 'onion rings' - rather than, say, a low embedded in an elongated westerly wind field.
Yeah as explained above, cut-off from the general flow and a solitary system in its own rights.
Thanks for the insight gentleman.
Another great article Craig.
FR, curious about your theory.
if the Tasman is warm then there is more evaporation and possible rainfall. The weather models do show rain systems over the Tasman developing, however, they keep moving east, away from the coast, so isn’t this a result of the weather being controlled by the strong continental high pressure from the SAM that doesn’t allow the Tasman moisture to push back onto the coast, rather than the Tasman being the controlling feature?
Great breakdown guys . I have been an avid "met nerd" for years but I'm not as educated on the topic as you are.
Apart from the lack of classic onion ring lows' year round , there are other missing parts to what I consider regular seasonal weather .
The lows , when I was a grommie , would sit off the east coast and hang for days , sometimes weeks ! These lows would fan rain bands up and down the coast , penetating far inland . Surely everyone would remember flooding of areas on a regular basis.
My dad had a Waterski shack at Ebeneezer on the Hawkesbury and roughly every 3 or so years I would get the call to drive up and everyone in the village would have to
dig in , moving fridges,washing machines and even the ski boats to higher ground .
Inside the cabin were marks on the walls dated , with the event named , Cyclone Tracey being the highest . The cabin was 10 or more meters above the river .
I have been planting trees sweltering in Broome. And it seems my preying relentlessly for some wave action is starting to take effect.
I've also wondered that as well Steve re lack of ECL's with the warmer waters in the Tasman.
Also the active monsoon has led to deadly flooding in Jakarta.. Jakarta floods: 'Not ordinary rain', say officials
another feature of summers gone has been "stalled" monsoonal systems.
ie instead of systems steadily tracking west to east and bringing monsoonal rains to the whole Indo/NAM area they get stuck .
which means Indo or the NWWA gets massive rainfall and QLD gets nothing.
or a system like we saw over Townsville just sits there and doesn't move.
Anyhow you can clearly see the moisture incursions now in the infrared greyscale, but it's all focussed on WA and the interior.
lack of E'ly inflow into the NW/SE continental trough ( due to weak, mobile high pressure) means mostly dry for eastern states.
This seems to be the one feature of our changing climate that climate change predictions have got wrong.
They said with the expansion of the tropics we would see a reduction in cool season rainfall in the sub-tropics.
In fact we are seeing very much a reduction in summer rainfall.
Read any textbook about the climate here and it will say humid, sub-tropical marked by high rainfall summers.
I now have to hand water Mediterranean herbs to keep them alive through summer.
We had close to a hundred mills during December but that didn't even touch the sides of soil moisture profiles due to the incredible deficit and high evapo-transpiration rates.
FR what was the rainfall total this year? If you normally get 1.8 metres a year, which is 3x Melbourne on a good year, were you down to 500mm? If the rainfall is low, the humidity is low (less than 50% and as low as 10%) and temps would be much higher for months more, it is way beyond mediterranean plants, more like desert.
My folks, who live up in the hills near Nimbin, say they had the driest year on record at their place - they got about 50% of the mean, which I think is around 1200-1500mm. Fuck all, by their standards. dry enough to make the rainforests burn when the fires hit nearby.
yep, add that moisture deficit to increased temps and hot dry winds and boooosh, up she goes.
Tell me about it. I'm looking out the window from the kitchen table and all I can see is ash.
2019 was all time record low rainfall at Murwillumbah (139 years of data).
Most of coastal Northern NSW recorded its lowest ever rainfall in 2019.
I'm catching fish that aren't meant to be here and not seeing fish that i expect.
Wholesale change in breeding patterns and movements.
Water temps have changed here...SA.
Which exotic species you catching ?
rainfall was about 600-700mm in deficit from av.
Thanks Craig and others. Have been watching the monsoon season not start, wondering if that needs to happen just to kick things over.
A WA cyclone quickly tracking to central parts of Oz and dumping shitloads of rain is a system disruptor that can change the weather patterns, for the better.
FR, have noted the lack of winter ECLs and the other effect, which is beaches full of sand with deep gutters and crap sand banks. It's been up and down the coast too, not just the local.
Can barely remember the last good sand set up that survived more than a week or two.
I agree with the lack of rain and ecl over the last few years but due to climate change and the heating of the Tasman?. I’m not sure.
Possibly the lack of cold pools of air pushing over the warm autumn/early winter waters of the Tasman is possibly the case. It’s only been the last few years. Merely a blip in the earths climate....
Hopefully the return of the monsoon and lack of positive IOD will now help moisture getting to the east. I’ve heard the IOD has the most influence on Australian climate, more than the pacific....
Bring on the rain
IOD is primarily responsible for winter/spring rainfall.
Because it has been so extreme this year it has been associated with the delay in the monsoon.
IOD has little effect on summer rainfall east of the great divide.
That rainfall is primarily Pacific derived.
Yep, IOD and Pacific influences are different times of the year as Steve has stated.
What’s the transition from positive to negative IOD? Year, Years?
Yearly oscillation.
Cheers, bout due for a negative IOD then
Was one in 2016, brought lots of rain to the central and south-east of the country.
was that the last time the Indian Ocean dipole was negative Craig?
Yeah strong negative.
Can I say a big thanks to all you meteorological learned crew - I have learnt so much over the years from ‘eves dropping’ in all your discussions.
Now can I just ask a question from a naive layman’s point of view, does anyone get the ‘sense’ that this formidable and unrelenting pattern could end soon, and in a big way? (i.e: onset of rain, swell, CS lows, ECL’s, etc)
there's an intuitive sense that something has to break soon and there's the atmospheric sense that all this heat energy being stored in the continent and near-shore SST's has to manifest in some serious weather systems somewhere, at some time.
so yes, there's a position there thats logical.
I'd still like to see the temperature gradient between the CS and Tasman reverse though, because it seems like a lot of that latent energy is being stored in the lower Tasman and thus discharged in low pressure development more centred in NZ longtitudes and aimed into the South Pac, as we've seen this last 6-12months.
fingers crossed.
Fingers certainly crossed mate. Thanks for the reply.
I’m not even worried about the surf. I just hope things change for those living In drought stricken communities and those suffering from or at threat of fire.
Looks like that ‘sense’ that things would break was correct Freeride
looks like good chances for NWWA into Victoria from the current moisture from the monsoon trough ....possibly a bit for southern NSW.
continuing dry with "toxic" summer pattern for sub-tropical NSW and into SEQLD.
For Port Macquarie in 2019 there was only 515mm annual rainfall, about 850mm below the average and lowest since records started in 1842.
There are desalination plants going in at Nabiac and a temporary one is proposed at Bellingen while in Gloucester they are trucking water in. Poor buggers west of the ranges are even drier. Could see climate change “economic refugees” in Australia shortly as farms become unsustainable out west and people head to the coast.
Desal for nabiac? Where are they pulling the water from?
Have to be upper reaches of Wallis Lake/Wallamba River.
Coastal swamp thus why it's salty. Sounds better if they call it Nabiac aquifer than Tuncurry aquifer (only 4km straight line from Tuncurry)
Its crazy how it all works. Looking at Mt Seaview (Yes we know it is a rain mecca) has an average of 1760mm/yr, 2019 was 1532mm, but over the long term it has had above average rainfall the past 6 years (2018-2013) sometimes up to 1478mm above the average. Yet the surrounds and road over the top Oxley highway was burning even with above average rainfall in previous years? Some things don't make sense.
Leroy, there is something weird about that rainfall data for Mt Seaview. The Mountain is literally on fire at the moment so as you said it is hard to believe that the rainfall was only slightly below average for 2019 which is about 1000mm (!) above the rainfall at Port Macquarie.
After you mentioned it last time, I also had a look at the river levels and there wasn’t a kick when there was about 90mm which is strange. Couldn’t find historical river level plots to see if there were similar events.
I don’t think it is a conspiracy but wonder if there is a data collection issue at that site.
The Indonesian government are dropping salt into incoming storm clouds to reduce the intensity and totals.
Not sure this is proven science or an experiment.., the word 'tries' points to the later.
Indonesia tries cloud seeding as flood death toll rises to 46
I think the Australian government would like to do what ever the opposite is at the moment.
As you said craig, triple whammy of negative rain fall climate drivers for Australia in 2019 is causing this shocker, near feels like Armageddon...... Here’s hoping the monsoon trough delivers some good rain for the country this summer and early autumn.
Plant a shade tree people
Models still confident in a strong MJO phase developing throughout northern Australia over the next fortnight.
I went looking for what used to be our wonderfully benign summer sub-tropical maritime climate and found it.
About 900K's due east on Norfolk Island.
Forecast for Monday
Mostly sunny. S/SE winds to 5 knots.
Seas: Below 1 metre.
Swell: Southwesterly 1 to 1.5 metres.
Precis: Mostly sunny. Min: 18 Max: 25
Forecast for Tuesday
Partly cloudy. Medium (40%) chance of showers during the evening. Light winds
tending SE 10 to 15 knots during the evening.
Precis: Possible late shower. Min: 19 Max: 25
Forecast for Wednesday
Mostly sunny. E winds 10 to 15 knots.
Precis: Mostly sunny. Min: 19 Max: 24
Thats what our summers used to be like. Lows in the high teens, highs in the mid-high 20's.
Now we have a much hotter continental influenced summer climate.
Ballina: 32 °C 30 °C 29 °C 30 °C 30 °C 31 °C 30 °C
Appreciate all the commentary here, many thanks.
Ben, could you, in particular with recent events across Australia in mind, give us an update of what we can expect weather-wise for the next few weeks/months, perhaps, for Australia?
I'm sure many of us would value your expertise over Tim Bailey's weather wall...
Not sure how desal plants will go in estuarine systems with variable salinity but shows how desperate the Councils are. Only 60 days of water left for Taree.
Details of the two systems proposed on the NSW North Coast below.
Nabiac
https://www.midcoast.nsw.gov.au/files/assets/public/document-resources/w...
Bellingen.
https://www.bellingencourier.com.au/story/6539638/desalination-plant-get...
Thanks FR, Craig, Thermal B for the very interesting data/info!!!
Feels like these fires are going to create their own weather system
I'm imagining TC Blake may get sucked into the vortex of heat build up over the south east, thus creating a fairly large sized depression with lots of rain.
Only because forecasts of predominantly easterly winds for the south east of the country.
Why no mention of ENSO in this? Cool sea surface temps in the CS due to ENSO?
Yeah, it's neutral though as Steve pointed out, much like a weak El Nino. Not much influence.
ENSO is officially neutral, although some will say it's been in a Modoki-like state.
Just had to google this..so the central pacific has warmed? Yet both the eastern and western pacific are still cool...benefits no continent but a few islands..
One problem with water supply for those councils that pump out of the rivers will be all the ash and sediment run off with the next significant rains. Sediment loads will be too high to pump out into storage dams. A real life of water water everywhere but not a drop to drink situation.
Looks like TC Blake, soon to be ex Tc Blake will give Pilbara, Gascoyne and Goldfields a big drink.
not much rain for the eastern seaboard though.
Getting a bit of rain tonight through storms on the central coast nsw.. Best rain I’ve had at my house in 2 months. A little slither of storms on the radar.
Finally shaping up nicely for the Coral Sea with this swinging in.
GFS 00z looking very nice.
925mm of rain for 2019 at barkers vale just nw of nimbin- 200 mm of that was in december , which was totally awesome. Last year 1172 mm. 2017 the cyclone debbie year we got 2333 mm. Lots of the eucalypt forests around here are turning brown -dunno if they will bounce back.
Great video here of north-west moisture feeding in off ex-TC Blake..
You would think they would get it right, BOM that is.
Carnegie is not #Goldfields, it's categorised as 'Interior' even on their own website, closer to the Pilbara than it is to Kalgoorlie.
Nice rain though
Haha, Climate change?! Might be a new rainforest in The wa interior in 100 years? Joking of course... that said nw wa is supposed to get wetter with climate change. Deserts might turn into savanna.....
I was working out in the WA desert one year when an ex-Cyclone came though. Landscape was flooded in every direction and within a couple weeks it went from red rocks and salt lakes to a sea of daisies with blue lakes. Just amazing.
my mates are stressing , they work exploration out there and don't want the rain.
anyhow, not sure it is legit to equate IOD with a TC incursion in summer.
it's winter/spring NW cloud bands that were stymied by the mega IOD+
Did it come across that way in one of my posts? Didn't mean to if it did.
Yeah true but it was that strong it stemmed the early summer rains and moisture too which didn’t help.
no, not really Craig. not having a go mate.
No worries.
Now we've got Severe Tropical Cyclone Claudia..
And this is also great news..
Such good news. Good to see the arse end of the positive IOD and Johnny monsoon back
A great image showing all the climate influencers across Australia and what we've been discussing on Swellnet for years..
IOD, SAM, SOI, Monsoon trough..
So good to finally see the rains arrive.... but so devastating to see what it has now lead to in the Macleay River, North Coast NSW and what was a premier bass river.
Upper catchment destroyed by drought then bushfires and now the rains have washed the topsoil, ash, cow shit and whatever else into the river. So the water is now dirty and has no dissolved oxygen .... and no fish.
https://www.theguardian.com/world/2020/jan/17/hundreds-of-thousands-of-f...
Just contemplatie the implications if this scenario continues down the east coast as rain hits bushfire destroyed catchments. Devastating for the wildlife, the environment but these rivers are also the source of drinking water for many large towns.
nervous moments now........fair bit falling in the Richmond/Wilsons river catchments....hopefully the run-off and potential deoxygenation doesn't cause a fish kill.
Still had less than a millimeter here.
looks like that rain band is heading for Coffs coast. you might get lucky.
Yep 175mm since Friday, always returns.
That was glorious.
Eric Olthwaite here.
94mm in my rain gauge.
Inland Northern Rivers.
The water table got to the lowest it has been in 50 years.
This will bring it up a bit.
I was on the Tweed over the weekend and I haven’t seen or heard rain like that for a long time. Was great to see and be amongst!
Looks like more tropical moisture coming to se qld/ nth nsw this coming weekend.... I hope it keeps on giving. Weather channel said something about a landsoon which is a tropical low over land for the nt
Freeride, reports on ABC on fish kill in the Upper Richmond River.
got a link D, I went looking but couldn't find anything.
Was on the abc country hour today, talking to the Council GM I think it was, upriver near Casino apparently .
[Record Breaking News]
18 Jan 2020 tbb's city Gold Coast copped 1 in 100 downpour (Real Hard'n'Fast)
https://7news.com.au/news/weather/qld-braces-for-more-rain-after-deluge-...
Current 'Late Onset Monsoon' now pre dates 1973 to start record keeping 1957/8
http://www.bom.gov.au/climate/tropical-note/
https://www.abc.net.au/news/2020-01-28/darwins-latest-monsoon-onset-on-r...
[Monsoon Breaking News]
https://www.news.com.au/technology/environment/warning-of-life-threateni...
1973 Late onset Monsoon Cyclones
Same as 2020 - Cyclones danced around N/W however just one broke free to Qld.
https://en.wikipedia.org/wiki/1972%E2%80%9373_Australian_region_cyclone_...
Feb/March Cyclone Kirsty Formed off Qld top end skirts GC/Byron across ditch to NZ.
http://www.australiasevereweather.com/tropical_cyclones/1972_1973/jtwc/t...