Australian Weather Calendar: August 2020

August photograph by David Macdonald

Call of the storm

For David Macdonald it’s not so much the art of photography that he finds captivating, rather its subject. 'I’m definitely more of a weather enthusiast than a photographer,' says David, explaining that his interest in weather stems from his career as a pilot. 'Anything meteorological I find fascinating—I guess you’d say I have a "weather eye"'. In fact, David used a humble mobile phone to capture this amazing scene at Lake Macquarie. 'It’s the weather that stirs me and makes me think "I’ve got to get a photo of that!"' he says. 'The mobile phone generation has put a camera in everyone’s pocket—the quality you get out of a phone these days is just fantastic.' David says he relies on the Bureau’s aviation weather forecasts and warnings in his professional life and is immersed in meteorology every day. 'I have a deep respect and awe for thunderstorms in particular, because that’s something that we take great pains to avoid, to understand, and appreciate in a careful sense.' Now, if only he could get Mother Nature on speed dial…

The science

Mammatus cloud is an example of cloud formed in sinking air. As air descends the water in the air evaporates. Under certain atmospheric conditions this evaporation results in an increased downward movement of air, which drags the cloud down. The result of this is the sagging protrusions from the underside of a cloud known as mammatus. Mammatus is most commonly formed in the sinking air, or downdrafts, which form in the anvil at the trailing edge of a large cumulonimbus cloud (thunderstorm)—meaning they're often accompanied by showers, lightning, and sometimes hail.