The thunderstorm area will affect the Hong Kong Observatory in the next two to three hours: early warning of uncertainty in the rain area

It continued to rain in Hong Kong, and the Observatory issued a special weather warning this morning (12th), pointing out that the thunderstorm area to the west of the Pearl River Estuary may affect Hong Kong in the next two to three hours, calling on the public to be vigilant.

However, some citizens have questioned in the past few days that the Observatory has not warned of heavy rain in advance and announced the suspension of classes as in Macau and Zhuhai.

Li Zixiang, Senior Scientific Officer of the Observatory, said that the rain in Sai Kung, Hong Kong Island, Lantau Island, etc. was more severe yesterday, but he described the rainfall as scattered and did not reach the level of torrential rain. He also said that this time, the cold air from the north and the warm air from the south are "fighting", which will seriously affect Due to the behavior of the trough of low pressure, it is difficult to warn in advance in the case of great uncertainty. It is emphasized that the Observatory has updated the weather conditions and reminded the public of the arrival of heavy rain through weather forecasts and essays in the past few days.

▼Hong Kong under heavy rain on May 11▼

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The Observatory said that an active trough of low pressure is bringing unstable weather to the coast of Guangdong.

More than 30 millimetres of rainfall were recorded in many parts of Hong Kong this morning, with more than 70 millimetres of rainfall in the northern and eastern New Territories. The weather is expected to continue today with dense clouds, showers and squally thunderstorms, with heavy rain at times.

Moderate to strong south to southwest winds.

(screenshot of the observatory)

No warning needed for Hong Kong's rain yesterday

Macau and Zhuhai warned of heavy rain yesterday (10th) and announced that classes would be suspended for the whole day yesterday.

The Observatory's senior scientific officer, Li Zixiang, explained in the RTHK program "Millennium" in the morning that Hong Kong continued to be affected by showers and thunderstorms yesterday, so all districts recorded more than 50 mm of rainfall, and the situation in Sai Kung, Hong Kong Island and parts of Lantau Island was More serious, the rainfall exceeded 100 mm throughout the day, "The rain spreads out at the same time, and the rainfall in each hour is not too heavy, and it is not at the level of heavy rain, so I am looking for a rainy day to talk about, although the rainfall is relatively high, But it did not reach the conditions that warranted a rainstorm warning."

Li Zixiang, senior scientific director of the Observatory, said.

(File photo/Photo by Luo Junhao)

Observatory: Early warning must balance uncertainty

He continued that the unstable weather this time was affected by an active low-pressure trough, and described the development of the low-pressure trough as having a lot of "randomness". The moving speed and direction of the relevant rain area, and the uncertainty and error of timing and fixed-point forecasting of heavy rain are extremely large: "A low-pressure trough will not rain everywhere, and it is like boiling water near the low-pressure trough, and it affects randomly. We're in the area," he said, describing the rain area as being relatively scattered, and the obvious changes in the east and west of the Pearl River Estuary, emphasizing that early warning must be balanced against uncertainty.

He continued to point out that he understands that the public wants to know the weather changes as soon as possible. Therefore, the nine-day weather forecast has taken the lead in stating that the weather may be unstable in the near future, and there is a chance of thunderstorms, heavy showers and even heavy rain. He described this as the first step. By Monday (9th) ) and Tuesday (10th), after further confirming the relevant forecast, the latest forecast will be issued through "Weather Essays" and press conferences to remind the public that the weather will be unstable in the future.

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