Australian Weather Calendar: February 2017

February photograph by David Jaensch

David Jaensch was driving back from a camping trip on South Australia's Eyre Peninsula when he spotted this thunderstorm cloud, or cumulonimbus, with the characteristic 'anvil' top spreading out above the core.

The ingredients for a thunderstorm are moisture in the air, atmospheric instability and something to cause the air to move upwards–such as updrafts from hot ground or airflow over mountains. In this case, an approaching low-pressure trough created enough lift to trigger a thunderstorm in what was already an unstable atmospheric environment.

Diagram