Thousands of disgruntled Hongkongers caught in heavy rain during their Tuesday morning commute have asked why the city’s weather forecaster did not issue its highest-level warning earlier, although meteorologists have said some deluges are hard to predict. Social media users took to the comments section of the Observatory’s posts to vent their frustration after the forecaster issued the first black rainstorm warning of the year on Tuesday morning as many were already well on their way to work or...