Category Archives: BoM Australia

Weather Bureau for Australia

Update Perth dams catchment rainfall and water waste

My Catchment Rain Index updated. Large vers.

Plus my chart of catchment efficiency 1980-2017 – large vers.

And BTW calcs show from 2001-2017 1646GL of water could have been saved if catchments had been managed so that efficiency could have been maintained at ~5.6%. That = 96.8GL PA wasted. A whisker more than inflows this year. What would that waste be worth? A lazy $Bn ?

50°C in Sydney region 1939 – perspective on recent heat

Last Sunday 7 Jan 2018 Our ABC reports the BoM – Sydney hits its highest temperature recorded since 1939 with Penrith reaching 47.3C. The BoM had just belatedly found that RICHMOND RAAF 067033 hit 47.8 on 14 Jan 1939. But there is much more to the history of hottest days in Sydney. There was another site recording at Richmond in 1939; John Tebbutt’s historic Observatory which recorded 122°F or 50°C on 11 Jan 1939 as reported in the Windsor and Richmond Gazette Fri 13 Jan 1939 Page 3 Sweltering Week Sets New Hawkesbury District Record.
In Jan 1896 there are a multitude of reports of a stunning and deadly NSW heatwave summarized by Lance Pidgeon at JoNova and picked up by the UK Daily Mail – How a 24-DAY heatwave on Australia’s east coast in January 1896 saw temperatures climb to 49 degrees and killed 437 people. The Windsor and Richmond Gazette for Sat 18 Jan 1896 Page 6 Hawkesbury Heat – On Monday 13 Jan 1896 John Tebbutt’s Observatory recorded 118.8°F or 48.2°C – also well clear of the 47.3 at Penrith last Sunday. There is a report in The Daily Telegraph Sydney,
for Tue 14 Jan 1896 Page 5 123 IN THE SHADE AT CAMDEN. But we have no information re the thermometer exposure. I wonder what readers can find. The upshot seems to be that the 47.3 at Penrith last Sunday was only a run of the mill very hot day for the Sydney region. And even less notable when you take into account the ever growing urban heat island and the fact that Penrith records one second intervals in a modern electric AWS which must produce hotter spikes than a slower acting mercury in glass thermometer.

BoM summer Outlook axed in a fortnight now “lives at risk” due Vic floods

Summer rain Outlook 16 Nov foretold near average for SE Aust. Summer rain Outlook 30 Nov better but already wrong if the ‘Lives at risk’ scare is half correct. OK so anybody can make mistakes – lets check what they forecast for November rain on Oct 12th and then on Oct 26th. Here is map of November rain percentages so the later Outlook on 26th Oct was worse than the one on the 12th. Taxpayers could save $millions slashing BoM budget – we could get forecasting from www. Let BoM do core job of running our weather observations network properly.

Cape Bruny AWS reads warmer than Stevenson screen 18m away

There are two temperature series for Cape Bruny on the southern tip of Tasmania. CAPE BRUNY LIGHTHOUSE 94010 and it seems that an AWS was commenced in 2002 CAPE BRUNY 94198. The BoM site map shows the screen and AWS are ~18m apart.

I downloaded the max and min monthly data from CDO online and for the years of overlap 2002 to 2016 the CAPE BRUNY 94198 annual max is 0.45° warmer on average than CAPE BRUNY LIGHTHOUSE 94010. Furthermore the AWS was warmer than Lighthouse in every year.
For the same period the CAPE BRUNY 94198 annual min is 0.16° cooler on average than CAPE BRUNY LIGHTHOUSE 94010. Furthermore the AWS was cooler than Lighthouse in 15 of the 19 years, the readings were the same for 2008 and 2012, 2013, 2014. An interesting case of BoM AWS reading on an annual mean temperature basis (how global warming is measured), consistently 0.29° C higher than Stevenson screen readings only 18 metres away. Yet the BoM maintain their AWS are calibrated to be equivalent to liquid in glass thermometers.

BoM says Hobart October 2017 was the warmest ever

But the BoM fails to say that outside the Hobart urban heat island (UHI) record warmth is harder to find.
I checked the following stations around the Hobart region – first the mean monthly max – only Tasman Island agreed with Hobart but the site has only operated from 2002.

then the mean monthly min gives a similar result.

So the BoM should have told the ABC that although central Hobart had a record warm October – few other sites in the district confirmed that so on balance you would assume that the UHI effect has been quietly ramping up warmth in Hobart data for a ~century.

Australian BoM October rain Outlook disaster

Could have done better – miniscule areas with above average rain predicted but it looks as if about half of the misgoverned nation enjoyed over average rain. And they get Tasmania exactly wrong.
October max(daytime) temperatures were forecast to be high in most of the coastal rim and cool in the centre extending to the SW. Reality was that pattern was nothing like that with a fail along the coastal half of Qld and many central failed areas. I wonder who benefits from these Outlooks – anybody out there hangs out for them?
October min(night) temperatures were forecast to be a bit cooler than the days with a similar shape. Reality was the peak hot nights were nowhere near where they were predicted but there were some small wins in the cool areas. Again I wonder who benefits from these Outlooks.

Lets check the BoM 3 Month Outlooks – first rain – OK I think it shows not one square centimetre of Australia was due for above average rain. But reality was that vast areas of Australia had above average rain. Monster fail.
Now Max (daytime) temperature – I think it shows not one square centimetre of Australia was due for average or below average temperatures. But reality was that large areas of Australia from Carnarvon-Southern Vic- Tasmania and FNQ coast experienced near average or very mildly warm temperatures . And nowhere in the rest of Australia did the scale of temperature anomalies reach the extreme level of the predictions. Fail.

Now Min (night) temperatures. Not one square centimetre of Australia was due for average or below average night temperatures. Yet in the real world large areas were either anomalously cool or only very mildy warm. Big fail here.