Australian Weather Calendar: February 2015

February photograph by Chris McFerran

Explosive convection east of Warwick, Queensland

Chris McFerran drove east from Warwick, Queensland, to watch a storm brewing on the other side of the Great Dividing Range in December 2013. From his viewpoint, says Chris, 'we see the top two thirds of the thunderstorm; we don't actually see the base'. East of the mountains, in the path of the storm, 4.5 cm sized hail was reported near Boonah around the time Chris took his photo.

Thunderstorms are often triggered when surface heating causes rising air in a moist, unstable atmosphere. If the atmosphere is particularly unstable, or the surrounding winds are favourable, a thunderstorm can become severe.