A blast of cold from the Antarctic is set to hit several states this week, bringing wintry and dangerous conditions. In NSW, the Bureau of Meteorology is warning of heavy rains and snow down to 900 metres, while in Victoria, forecasters are warning of destructive winds and rainfall of up to 250 millimetres. NSW bureau forecaster Hugh McDowell said the “cold air outbreak” would mean difficult weather conditions. “It’s coming up from Antarctica, it is changing on the way, but it is quite unusual for it to be this cold,” he told AAP. A cold front crossing South Australia and Victoria on Monday has already brought gusty winds. In NSW snow is likely down to 1000m on Monday night, while on Tuesday a developing low-pressure system will bring the risk of flash flooding in parts of the state, as well as potentially damaging winds in the tablelands and the alps, …