This story has been made freely available as a public service to our readers. Please consider supporting SCMP’s journalism by subscribing. Hong Kong is expected to experience thunderstorms on Sunday, as a cold front sweeps across the coast of Guangdong and brings temperatures down to as low as about 21 degrees Celsius (69.8 Fahrenheit) a day later. The Hong Kong Observatory said on Saturday that the weather would turn bad late on Sunday, with a trough of low pressure over central China...