Hong Kong was soaked by heavy rain early on Monday morning with the Observatory issuing an amber rainstorm warning signal for more than 2½ hours. The signal was raised at 5.10am and cancelled at 7.45am. However, the Observatory warned the public to stay alert to flooding. Weather officials said there might be serious flooding in Wan Chai, Central, Western and Eastern districts of Hong Kong Island, where more than 70mm of rainfall was recorded in the hour ending at 6.35am. The thunderstorm warning signal was raised at 1.35am and will remain in effect until 9am. An amber rainstorm warning signal means that heavy rain has fallen or is expected to fall generally over the city, exceeding 30mm in an hour, and is likely to continue.