Australian Weather

[Styx]

Summer didn't live up to the expectations of an El Nino sizzler. The most famous drought and heatwave summers have occurred during El Nino events. There was a lot of anticipation of a dangerous summer because of the high El Nino index and because many recent summers have produced some remarkable heat events. The global situation may have also ramped up the caution.

Australia monthly temperature anomalies compared to 1961-90 period:

December: +1.0

January: +0.5

February: +0.9

^Summer rainfall: 2% down ( 61-90 comp )...........^Spring and Summer rainfall

[Styx]

Quote

Tasmania sweltered through warmest summer on record

Tasmania has had its warmest summer since records began with the mean temperature almost two degrees hotter than average.

There was also little rain over summer after the state's driest ever spring season.

The state suffered from unprecedented bushfires in summer which started in the middle of January and continue to burn.

Bureau of Meteorology climatologist Ian Barnes-Keoghan said it was a record-breaking season in a number of ways.

 

http://www.abc.net.au/news/2016-03-01/tasmania-swelters-through-warmest-summer-on-record/7211264

[Styx]

This just out. Record sea surface temperature in Australia over summer. Southern Ocean region exceeded previous record by a very big margin.

http://www.bom.gov.au/climate/change/#tabs=Tracker&tracker=timeseries&tQ[graph]=sst&tQ[area]=trop&tQ[season]=1202&tQ[ave_yr]=0

[Styx]

This is very likely to be Australia's warmest start to March on record. About 70% of Australia's 700 weather sites are currently  above their previous March mean maximum temperature record, with big anomalies of 3-6C. No doubt it's going to cool down but there will need to be a dramatic drop in temperature in the second half of the month to prevent this finishing up as Australia's hottest March. I think that would be really significant as it would be the fifth calendar month to break a national record since 2013 if it comes off.

In Tasmania we don't just have autumn heat to contend with but an emerging crisis due to the lack of rain in catchment areas which feed the hydro electricity dams. As of last Monday dam levels were at an historic low of 15.5%, declining by 0.5-1% a week. This now exceeds the 1966-8 drought which happened to break shortly after this critical threshold was reached. It becomes a high risk strategy to draw down dams below 10% as silt can interfere with the operation of the turbines.  There is now concern for one of Tasmania's largest lakes, Great Lake ( 68square miles about 10 times bigger than Lake Windermere ). It is a Hydro feed lake in central Tasmania that is ecologically significant and home to rare species. After a string of drier than average seasons, spring rainfall in western and central Tasmania was 50% lower than the previous record. Summer followed with drier than average conditions.

Edited March 12, 2016 by Styx

[knocker]

I read a little about this in an article in the Times yesterday. Not looking too clever in your neck of the woods Styx.

[Styx]

1 hour ago, knocker said:

I read a little about this in an article in the Times yesterday. Not looking too clever in your neck of the woods Styx.

The Times? That's something. Yes there will have to be an independent inquiry into energy policy and whether the situation may have been avoidable, and whether the trend of declining rainfall means more future risk. The manmade component of this is starting to get some traction, there may have been too much exporting of energy to the mainland via the underwater cable, which might now be fried. I think the Ireland-Scotland one was out for 6 months. On the other hand it was also an importer of energy ( capable of bringing in 40% of the islands needs ), and the dry weather has been unprecedented in a century of records. Like governments everywhere there is a real problem in transparency and confidence they have their eyes on the future, best description to describe the response is a calm panic. Situation will get worse before it gets better but it will eventually rain soon. Hope all is well knocker.

[knocker]

BoM has written a report explaining the unusual weather all around Australia.

http://www.bom.gov.au/climate/current/statements/scs55.pdf

[Styx]

'Catastrophic' environmental event forecast for Tasmania, as Hydro dams forecast to become inoperable by winter as lakes which feed into them go close to drying up. It needs to rain big to prevent this from happening. No hydro electricity and an unrepairable electricity cable which connects to the mainland grid will leave the island close to 50% short of winter demand. A gas power station, wind and diesel generators make up the other half. Huge environmental and economic cost if hundreds more diesel generators are brought in from overseas. That might be the only option. Burning dirty diesel to keep the lights on.

Some dramatic pictures here of Tasmania's drying up lakes from different sources. Old tree trunks are making an appearance for the first time in decades.

This old mining town which was flooded under a manmade lake several decades ago comes back from the dead

Parts of Great Lake in central Tasmania are now mud flats as far as the eye can see

Story: http://www.abc.net.au/news/2016-03-16/tasmania-facing-worst-case-scenario-as-dam-levels-drop/7252196?WT.ac=statenews_tas

Edited March 16, 2016 by Styx

[Styx]

Unprecedented drought in Tasmania's west shows no sign of breaking. Something disturbing is afoot, the most prominent weather driver - the westerly wind belt with its associated fronts, which supplies the west with regular rainfall across all seasons - has pretty much vanished since the end of last winter.

Tasmania has never seen anything like this:

 

[knocker]

Things not looking very clever. I remember reading a lengthy report on the pros and cons of the Basslink and if I remember correctly one reason for going ahead was that it would save having a backup power station in the case of drought. Of course they weren't considering a failure of the link.

[Styx]

17 hours ago, knocker said:

Things not looking very clever. I remember reading a lengthy report on the pros and cons of the Basslink and if I remember correctly one reason for going ahead was that it would save having a backup power station in the case of drought. Of course they weren't considering a failure of the link.

Spot on knocker. Basslink was laid in 2006 when lake storages were rapidly in decline during the Millenium drought . Storages bottomed out at 18% of full capacity a year or two later, before recovering. Thing is, the cable is only capable of bringing in 40% of Tasmania's demand. If it hadn't ceased functioning just before Christmas dam reservoirs would be at about 18%, compared to 14% today ( the average of the dam network ).  Some, like King William, are at the bottom end of that average, looks like a scene from a desert really. This is King William's fast decline, this chart from Hydro Tasmania.         If you go to that website ignore the media releases that everything is fine, no one is actually believing it.

 

Edited March 28, 2016 by Styx

[Styx]

Confirmation of Australia's warmest March on record ( since 1910 ). March is the fifth calendar month this decade to set a heat record, but like everywhere else the temperature has been trending up for quite a while longer. Every region, state and populated district in Australia has a story to tell about disruption and changes to their local ecosystems over recent years.

Australia's warmest months on record for mean temperature

Summer.....................Dec 1972

................................ Jan 2013

................................ Feb 1983

Autumn..................... Mar 2016

.................................Apr 2005

............................... .May 1958

Winter.......................Jun 1996

................................Jul 1973

................................Aug 2009

Spring......................Sep 2013

...............................Oct 2015

...............................Nov 2014

 

 

Edited April 1, 2016 by Styx

[knocker]

The latest survey on the bleaching of the Great Barrier Reef makes pretty grim reading.

Edited April 1, 2016 by knocker

[Styx]

It's been a while since one of Australia's eight capital cities broke a monthly heat record for daily maximum, but Sydney did that today with a new April high of 34.2C, surpassing the previous record of 33.9C in 1986 ( records since 1858 ). The April average is 23C.

Sydney's highest recorded temperature per month

Summer...............................Dec 42.2C in 1957

............................................Jan 45.8C in 2013

............................................Feb 42.1 in 1926

Autumn................................Mar 39.8C in 1983

............................................Apr 34.2C in 2016

............................................May 30.0C in 1919

Winter..................................Jun 26.9C in 1931

............................................Jul 25.9C in 1990

...........................................Aug 31.3C in 1995

Spring.................................Sep 34.6C in 1965

...........................................Oct 38.2C in 2004

...........................................Nov 41.8C in 1982

Edited April 6, 2016 by Styx

[Styx]

April is following the pattern of the first half of March with massive temperature anomalies compared to normal April values across the whole country. A very large section of inland eastern Australia is up by 5-6C for mean maximum, really quite amazing, with the next seven days showing only a slight easing.  I think we've got the making of another record heat month.

[Styx]

The northern tropics have been very dry and hot this year. This is the final month of the six month wet season, but the turnover into 'the dry' is probably already underway with low convective activity. The Australian inland is still very warm, and dry desert air is flowing up into the tropics on a high pressure ridge to the south. For the next four days Darwin has an expected maximum of 36C from the BOM, the April record is 36.7C. Seems to be a pretty good chance it might get there. It will be the second state/territory capital city to break the April record this month, after Sydney got a new high at the start of the month.

Despite record warm seas in Australia - and the records have been very big - Australia is likely to have it's weakest cyclone season on record, with only three cyclones in Australian waters ( the average is about 14 ) and only one land crossing. The season officially ends at the end of April but sometimes something springs up in May.

Edited April 22, 2016 by Styx

[jamesay]

Sure has been a warm autumn so far. April   2016 was as warm as March 2015 and around 3 degrees above average . 

[Chris W]

Same here in NZ, a really warm Trans-Tasman autumn with very high SSTs, strong highs keeping the westerlies south or only far enough north so to draw a warm airmass over here.  Same again next week though a wet-looking low for Victoria midweek.

Edited May 1, 2016 by Chris W
correcting grammar

[Chris W]

On 26/03/2016 at 10:35 AM, Styx said:

Unprecedented drought in Tasmania's west shows no sign of breaking. Something disturbing is afoot, the most prominent weather driver - the westerly wind belt with its associated fronts, which supplies the west with regular rainfall across all seasons - has pretty much vanished since the end of last winter.

Tasmania has never seen anything like this:

 

That's astonishing Styx, really would have expected a pattern change as we cross months but no sign as yet.  Let's hope the Antarctic really lets rip sometime soon!

[Styx]

Australia had its second warmest April with an anomaly of +2.0C  ( 1961-90 comparison ). It was always going to be tough to outdo April 2005 which had an anomaly of 2.66C - one of the bigger  anomalies for any month. Hobart was one place that had a runaway heat record ( in 135 years of records ) with a mean maximum outdoing the previous peak by +0.8C (!) and for overall mean temperature by +0.5C - huuuuge record to record margins with so many years of data behind us. Nature doesn't know where it's at. Weather related impacts due to the heat, dry, high sea temperatures have been consistently in the news for several months now. Never seen anything like it.

Rainfall deficiency has been significant in Tasmania's west, the phenomenal dry spring did most of the damage, then the hottest summer on record added to the problem with high evaporation rates. There could be a change in pattern underway with the zonal westerly wind pattern back - good rain forecast for the west on successive fronts and troughs, maybe a month - month and half worth's of  rain in the coming week. This will be good news for the hydroelectricity dams and the lakes and tributaries.

[Chris W]

Something large looming for WA/SA/Vic at least later this week on the latest BOM run, aided by the NZ block.

[knocker]

Not looking bad this morning Styx

 

Edited May 3, 2016 by knocker

[Styx]

Even prettier this morning. The mountain range behind the city had its first snow of the season overnight, settling near 600m. The first snow is always a big talking point. By the way that view of the docks is from a hotel room and is looking due south with the mouth of the river in the distance. The mountain would be 90° to the right.  I wish i could say the cold weather has set in but this was only a brief sweep of cold air from the south behind a front, back to a mild and fairly windy westerly regime for something like 7-10 days. The last picture is from the ABC and the others are from a gallery of 27 pictures from Hobart Heart radio  http://www.heart1073.com.au/photo/pufferon/

[Styx]

I think it's safe to assume Tasmania's energy crisis is over. For the first time since September the hydro electricity dams and lakes are filling up and the rivers are starting to flow again. The dam levels hit a low of 12.8% two weeks ago but they will be near  20% at the next reading on Monday. Most of Tasmania has already exceeded it's average rainfall for May. The western and central district which is home to the hydro electricity network has copped the most in a persistent moist windy westerly stream with embedded fronts. BOM describes the uninterrupted westerly pattern as slightly unusual for May, but no one is complaining about the weather this time. On the eastern side of the island the rain tapers off as it crosses the leeward side of the western mountain range but Hobart has 66mm in the gauge so far this month, the first wet month since August. Mount Read in Tasmania's west is up over 500mm. It may be wet but it stays very very mild in this pre winter month.

 

Edited May 13, 2016 by Styx

[Styx]

905mm this month at Mount Read on Tasmania's west coast up to 4pm today ( 225% of the May average ). This will be the second wettest month ever recorded for any location in Tasmania for any month. A few more millimetres to add before the end of the month, but the record - 984mm at Mount Mawson in October 1980 - 90km to the west of Hobart won't be superceded. Mount Read overlooks the small mining town of Rosebery. It is a very isolated area not much traveled by anyone.

 

The end of May has turned a lot colder and drier as winter approaches - but nothing dramatic, and the high sea surface temperature anomalies have abated. Nothing will stop this autumn from being Hobart's warmest in 135 years of records ( by about +0.3C ). This follows on from the third warmest summer in the city ( Tasmania's warmest ) and the equal warmest spring ( Tasmania's second warmest ).