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

  • Marc h

    Thought this one might interest…. 122 degrees in Sydney region. Jan 13 1939. Can’t find this in bom records.

    trove.nla.gov.au/ndp/del/article/85811924

  • Marc h

    trove.nla.gov.au/ndp/del/article/17557773

    Good map showing heat wave conditions over nsw. Black friday bush fires in Vic. Reported on the following day.

  • Marc h

    The informal 122 at Windsor recorded at Tebbutt’s observatory. Link to smh article …

    trove.nla.gov.au/ndp/del/article/17557773

  • Marc h

    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.

  • Marc h

    Off topic but this mention of Stevenson screen in WA in 1900 caught my eye…not sure when BOM indicate it was being used here.

    adsabs.harvard.edu/full/1901MNRAS..61..376.

  • Marc h

    Stevenson screen Installed in 1901. Comparative records made with Greenwich screen.

  • WSH

    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.

  • Ian George

    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)?

  • Marc h

    I’ll endeavour to chase down the 20c Tebbutt records over the next month or so.

  • Dave N

    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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