Downpours overnight and today over most areas were triggered by a rapidly deepening mid-latitude cyclone in the Tasman. The low has gone from a barometric air pressure of 1004 hPa to 959 hPa in last 48 hours. This included a drop of 24 hPa in the last 24 hours which meets the criteria of what meteorologists define as explosive cyclogenesis or a ‘bomb cyclone. The cyclone will exit the Tasman tonight and be replaced by a new developing Tasman low tomorrow. More unstable weather on the way from Tuesday night with vigorous westerlies to follow late in the week.
Video: Today’s satellite imagery of the Tasman low rapidly deepening.