Thunderstorms and lightning across New South Wales could exacerbate dangerous fire conditions, as much of the east coast swelters. Sydney is expected to experience maximum temeepratures of 38C on Friday, the last time the mercury will rise above 30C before the start of 2025. After days of heat across Christmas, temperatures have dropped in Melbourne, with maximums forecast to remain below 30C over the next week. Sign up for Guardian Australia’s breaking news email The cooler conditions on Friday were helping firefighters battle an out-of-control blaze in Victoria’s Grampians national park that has scorched 74,000 hectares (183,000 acres) of bushland