Friday, January 10, 2014

A sign of the (hot) times...Heat wave forecasts from the Australian Bureau of Meteorology

Australia's Bureau of Meteorology is piloting a new product - a heat wave forecast.  It's a new product that is based on a specific definition of heatwave conditions for Australia.  This is: three days or more of high maximum and minimum temperatures that is unusual for that location, plus it takes into account conditions preceding the hot weather, allowing for whether people have acclimatised to the heat or not.

As I understand it, the same temperature over consecutive days in September might rate as a heat wave that wouldn't rate as one in February, because people would have been acclimatised to summer conditions in February.  Not that we won't have heat waves in February.  That's when we can get the worst of them.  Just that the temperature would probably have to be consistently higher than it would have been in September, to be classed as a heat wave.

In the same way, what is considered a heat wave in Cairns might not be considered one in Melbourne, because Melbourne, despite being much further south of the equator, can get quite a bit hotter than Cairns.

We're heading for a heatwave over the next few days.  I've animated the BoM charts below.

Source: BoM

The heat wave maps will help service providers such as power companies, ambulance, hospitals etc, as well as ordinary people.

You can read more about the new product and its purpose here.  And here is a 2013 technical report from CSIRO on heat waves, written by John Nairn and Robert Fawcett.


  1. I could wish they had been a bit more specific about what "unusual" means, and what the thresholds for various levels are (presumably excursions above a certain number of +SDs), but this looks an interesting and useful addition to the forecasting kit.

    The FAQ page says:
    Severe and extreme heatwaves have taken more lives than any other natural hazard in Australia's 200 year history. For example, during the 2009 Victorian bushfires, 173 people perished as a direct result of the bushfires, however 374 people lost their lives to extreme heat in Victoria in the heatwave before the bushfires.

    Unfortunately there is little to no data available on those who survive but who suffer permanent impacts on their quality of life as a result of such heatwaves (for example severe heatstroke leading to permanent cognitive impairment)

    1. good question and you can ask on the link, suspect it will refer to % above average but yes well worth finding out, your job frank

    2. here

  2. This one looks real bad again.
    Special hit for the SE, highest bush fire alert.
    Adelaide usually has a see-saw temp graph so the expected 5 consecutive days of 40° C or over is very special too.

  3. Elders Weather forecast for Adelaide as I type: 33, 34, 40, 41, 41, 43, 40 - at least the forecast minima are still back in the 20s!

  4. Adelaide happened a 45.1° C yesterday. Today again, tomorrow expected 46° C. Neat.

    Looking at the city I lived three years in during a time it averaged three days of 40+ a year (what a laugh, isn't it) becoming uninhabitable fast - they don't have the water Las Vegas got under ground. They do have salt there. They got energy for the world but I guess Abbott bans solar paneling?

    Is there a superlative for 'Angry Summer'?

  5. Ceduna last hour, which is around midnight, rose the temp from 30° C tot 38.3° C at 00:49.
    Your new Aussie ways are scary.

    1. I remember that happening one night when I was down at Anglesea (Australia). The wind changed to a northerly and the temperature must have jumped quite a few degrees. That was back when a typical heat wave was shorter and not as hot as we get these days.

      More recently, we had some very odd hot weather in mid Autumn last year, with an overnight minimum close to 30 degrees as I recall. Very strange.

      What's more "scary" is imagining what the next El Nino will bring when we can get temperatures like last summer and this summer without it.

    2. Something like that appears to have happened at Ceduna. The rise came out as a spike, temps dropped some 6, 7 degrees again.

      CAGW is scary and much of Australia is on the desert's edges. There is not a lot of margin. Am afraid for contraction of Antarctic influence, causing the Dead Heart to go stretch down over Adelaide.


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