Australian Bureau of Meteorology Sydney temperature forecast 12 Jan 2013 – another amazing failure

Sydney was forecast to have 39 degrees but enjoyed a day around 31 degrees. HT Tim Blair. A huge 8 degrees forecast error. Several other centres had unusual large errors too which are on this map.

Last month I noticed the BoM tended to over-egg forecast warmth.
On 27 Nov the BoM warned of a widespread, severe heatwave – turned out a short heatwave
BoM exaggerated Brisbane heatwave – and it was only a “one day wonder”
and from early December
Massive failure in BoM forecast temperatures Sydney and SE regions
Just to repeat what I have said earlier – I do not expect exact forecast accuracy – we know that is not possible – but if the BoM was not biased then errors would fall equally warm and cool.

10 thoughts on “Australian Bureau of Meteorology Sydney temperature forecast 12 Jan 2013 – another amazing failure”

  1. The observatory did have a Stevenson screen but not sure when it was installed. There’s a book isbn “9781142650841” History and Description of Mr Tebbutt’s Observatory, Windsor, New South Wales. That might have some answers. Given the paucity of early Sydney records observations from Tebbutts would e interesting to look over. Don’t suppose anyone knows what as happened to these.

  2. Re [1] I have monthly mean max and min of Tebbutt’s 1863-1897 – these date from 1993. Will try and find out if the BoM has digitised the dailies.
    That 122F or 50C was on Wednesday 11 Jan 1939 – and the article mentions it was recorded by a Mr Keith Tebbutt, no doubt a relative of John Tebbutt. I wonder if records survive of 20th Century weather obs at the Tebbutt Observatory. Could any readers near Windsor try and find out ? Here is an 1880’s photo showing Tebbutt with a Glaisher Stand on his right. There is a slatted box on left of photo ?

    Re [2] – The map shows temperatures from 11 Jan.

    Re [3] – This link is the same as 2 Marc – did you have some other link in mind ?
    Re [4] Will try and hunt down Tebbutt’s publications.
    Re [5] & [6] there are newspaper reports of Stevenson screen in use in WA in 1898 – and a photo of Stevenson screen in use at Perth 1899.

  3. I heard that the official definition for a heatwave is 5 consecutive days or more days when each day is 5.0C or more above the average temp for that month.
    I have also heard that it is 3 consecutive days or more above 40.0C.
    Does anyone have an official definition (or do they make it up as they go along)?

  4. Same story here in Adelaide.. unless the temps start rising again here today, this will mark 3 days in a row where the forecast (issued in the morning) has been 3 degrees higher than actual.

    Monday – 26 vs 21.7
    Tuesday – 28 vs 24.7
    Wednesday – 36 vs 32.7 (unlikely to go higher later this afternoon)

    It’s pretty rare for the forecast to be below actual.

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