Sometimes the best weather features are invisible to the naked eye! This loop shows water vapour in the atmosphere during Monday, clearly outlining an upper trough which triggered lots of thunderstorms. If you ever hear us talk about an 'upper disturbance', this is what we mean. pic.twitter.com/GX8GyNGESU

— Bureau of Meteorology, Western Australia (@BOM_WA) April 3, 2018