the weather
Written by: Hong Kong Observatory
2021-03-26 11:03
The last update date: 2021-03-26 11:03
(Editor’s note: The Observatory’s new "Probability of Significant Rainfall" forecast, the scientific director of the Observatory wrote a vivid way to deconstruct how to understand and use it.
The two leaned on a railing and looked out, the distant mountains looming in the drizzle.
He hesitated and said, "So, I can't give you a 100% sure answer, and I don't want to write a blank check." She sighed, "I didn't ask for anything. If everything in the future can be accurately predicted, wouldn't it be boring?"
Hearing this, he felt more courage to continue speaking, and moved a little closer to her: "But within the scope of my ability, I want you to know more about me, more my thoughts, and let you Plan your future well."
▼▼▼Click now to understand how to understand and use the "Significant Rain Probability" forecast? ▼▼▼
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She did not shy away, but in order to cool her hot cheeks, after thinking about it, she switched to a serious topic: "I remembered the weather forecast-the observatory has strengthened its nine-day weather forecast service and launched the "probability of significant rainfall" forecast. Five levels of expression: low, medium-low, medium, medium-high and high. The meanings are: the chance of occurrence is less than 30%, the chance is low but higher than 30%, the chance is about 50% (commonly known as "five-five waves"), and the chance is partial. Higher but lower than 70% and chances are as high as 70% or more."
He: "Does this mean the chance that it will rain? What does "significant" mean?"
She: "Not exactly. If you only provide opportunities for rain (rain probability), one or two drops of rain will be rain, and heavy downpour will also be rain. It does not reflect that the citizens are most concerned about the impact of the weather, so it should be marked as yes. How much rainfall. Taking into account the local rainfall characteristics in the past, the Observatory uses the average daily rainfall in Hong Kong during the rainy season (April to September), that is, the daily accumulated rainfall in a wide area of 10 mm as the threshold for "significant rainfall"."
He: "Oh, if a lower rainfall is used as a benchmark, there will often be a high probability of rainfall during the rainy season, and it is difficult to highlight the rainfall trend in the next nine days. What is the approximate concept of 10 millimeters of rainfall?"
She: "The amount of rain in a day reaches 10 millimeters. It's about like the continuous drizzle in front of you for a whole day, or a shower that will get wet in a short time. Both can influence people's outdoor plans."
He nodded if he knew it, "Yes. How heavy is the rain? When and where does it rain? Just like a girl’s heart, it’s difficult to predict accurately in the morning, but at least I probably know which days to watch for the weather and which day’s probability of significant rainfall. High, relatively speaking, we need to beware of heavy rain."
She: "Yes. When the "probability of significant rainfall" on a certain day in the "Nine-Day Weather Forecast" is "medium" to "high", it means that there is a greater chance of rain on that day. If I need to go out, I will bring rain gear. And will prepare for heavier rain. In addition, I will also pay special attention to the latest weather information related to the Observatory that day, such as rainstorm warning signals, heavy rain warnings in some areas, special flooding reports in the northern New Territories, special weather warnings, etc. After all, The only thing that can be determined is uncertainty. Even if there is a plan, it is difficult to defeat impermanence. The only way to master the existing information is to be fully prepared to deal with it."
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He: "It's going to rain, I can't stop it; I can't guarantee that the future will not make you sad and weeping. But if the probability of significant rainfall tomorrow is "medium" to "high", I will accompany you to prepare rain gear, and Re-examine the road to be taken tomorrow. As for how heavy the rain will be tomorrow, as for whether there is me in your future, you will only know the answer if you go down."
The rain stopped unconsciously, and the outline of the distant mountains gradually became clear.
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Original: future significant rainfall probabilities of u there I Author: Hong Kong Observatory Zhuang Sining
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