Oh, I agree with you. According to the HKO, plus somewhat of my guess, the rainstorm occurs between 4/19 and 4/21. So, if someone are interested to think so, one is not hard to show that there is very large thunderstorm occurs between 4/19 and 4/21.
However, the sun does not shine until 4/23 which is guessed by HKO.
As I have discussed, HKO may be KO the later sunny periods even it may come true in the future.
Summary of the typhoon: the strong wind is one of the element, but thunderstorms are the first priority element that influences HK. This is true because the typhoon is expected come near to HK if possible!
