Hongkongers woke up to more rain and thunderstorms in the city on Sunday, with an amber rainstorm warning in force since about 6am.After a week of rain, the Hong Kong Observatory warned that there would be more squally thunderstorms accompanied by frequent lightning on Sunday morning.More than 30mm of rain was recorded in most parts of the city, meeting the threshold of an amber signal, the lowest level in the three-tier rainstorm warning system, the forecaster said.Rainfall in some areas of Lantau and Sai Kung exceeded 50mm, which is the threshold of a red rainstorm warning.The Observatory said there were moderate southerly winds were prevailing and would be stronger on higher ground.Temperatures were expected to range between 24 and 28 degrees Celsius (75 to 82 Fahrenheit) on Sunday.