Summer Rainstorm Survival Guide - How to Interpret Weather Alert Signals

The meteorological department of the meteorological department issued an early warning on the July 21 heavy rainstorm in Beijing. However, apart from the unsatisfactory distribution channels, the discussion on Weibo indicated that the warning signal itself also confused many friends. : The blue rainstorm signal was released at 9:30 in the morning on the 21st, and the yellow rainstorm signal was released at 2 pm. The yellow lightning signal was released at 2:20 pm and the orange rainstorm signal was released at 6:30 pm. Not paying much attention, and when the "yellow" that can be mentioned in the color of the warning came out, it was already dark and the city was raining, and netizens pointed out why such a serious disaster only caused orange rainstorms. Do not send the highest level of red. This shows that one major problem of this disaster is that the warning signal is sent out, but many netizens can call it “do not understand” and the effect of “warning” is greatly reduced.

How do these signals mean? Of course, the signal is indeed with explanatory text, but it is too much like our final exam questions for meteorology! The meteorological department has completed its established duties on the timing of the signal release. However, if only meteorological students and weather enthusiasts can accurately understand the significance of the warning signal, then this system is certainly not satisfactory. of. I hope that this article, in the most concise way, combined with my own experience of “chasing after rain” over the past few years, will clarify to readers the actual meaning of different signals, and that in the next extreme weather, we can have decisions for you. Little help. At the end of the article, I will also introduce the early warning signal mechanism in other regions. I hope that I can promote some thinking of the “humanization” and “popularization” of the early warning signal.

Weather warning signal

In general, the meteorological warning signals in various regions of the world can be roughly divided into two types: "alert" signals and "warning" signals. The former must convey that "the wolf is coming" and the latter to convey that "the wolf is coming". ". Judging from many years of experience, such a system is very effective: When the alert signal is issued, although the sky still looks calm, people should be aware that an hour or so may be an uphill battle! As a result, their travel arrangements are adjusted accordingly, and the disaster relief department should see such signals as being on standby; when warning signals are issued, people should stay in safe places as far as possible until the signal is discharged and do an accident. Preparedness occurs, and the disaster relief department must also operate at high speed to resolve the disaster in time.

In recent years, with reference to this experience, China has popularized a fairly comprehensive set of meteorological warning signals. In simple terms, it operates in this way: The direction of warning is divided into 11 categories: typhoon, rainstorm, high temperature, cold wave, etc. Each class uses different colors to indicate different levels. There are five types: white, blue, yellow, orange and red; but different The direction of the early warning direction is different. Many early warning directions are only two, three or four. In addition, the signal systems in different places are also slightly different. For example, there are no warning signs related to Blizzard in Guangdong, there are no typhoon warning signals in inland areas, etc., but they are generally similar.

We only focus on the signals in the two directions of “storm rain” and “thunderstorm” because they are two signals that are very common in summer rainstorms. According to the relevant literature, signals of different colors are issued under the following conditions:

Blue Rainstorm Warning Signal: Rainfall will be more than 50mm in 12 hours or more than 50mm and rainfall may continue (in some areas there is no such signal).

Yellow Rainstorm Warning Signal: Rainfall will be more than 50mm in 6 hours, or it will be over 50mm and rainfall may continue.

Orange Rainstorm Warning Signal: Rainfall will be more than 50mm in 3 hours, or it will be more than 50mm and rainfall may continue.

Red Rainstorm Warning Signal: Rainfall will reach more than 100mm in 3 hours, or it will reach 100mm or more and rainfall may continue.

Blue thunderstorm gale warning signal: During 6 hours, it may be affected by thunderstorms and strong winds. The average wind power can reach level 6 or above, or gusts above class 7 and accompanied by thunder and lightning; or already affected by thunderstorms and winds, the average wind power has reached 6-7. Or gusts 7-8 with lightning, and may continue.

Yellow thunderstorm gale warning signal: May be affected by thunderstorms and winds within 6 hours, average wind power can reach 8 or more, or gusts above 9 and accompanied by strong thunder and lightning; or have been affected by thunderstorms and winds, average wind power reaches 8-9, or Gusts of 9-10 are accompanied by strong lightning and may continue.

The orange thunderstorm gale warning signal: may be affected by thunderstorms and winds within 2 hours, and the average wind power may reach level 10 or above, or gusts above class 11 and accompanied by strong thunderbolts; or it may be affected by thunderstorms and winds, and the average wind power is 10-11. Or gusts 11-12 with strong lightning, and may continue.

Red Thunderstorm gale warning signal: It may be affected by thunderstorms and winds within 2 hours. The average wind power may reach 12 or more with strong thunder and lightning; or it may be affected by strong thunderstorms and winds. The average wind force is 12 or more and accompanied by strong thunder and lightning, and may continue. .

What do you mean? What should I do?

After reading the definition of the circumstance above, readers may have noticed a detail: For a long time, what kind of signal is "Wolf coming?" Which one belongs to the signal "The wolf is coming?" Literally, it seems that any kind of signal can be interpreted as either "the wolf is coming" or "the wolf is coming!" If it is unclear which kind of signals “Wolf Will Come”, until the wolf has come and let the people hurry to deal with it, then what effect of “early warning” is there?

According to my observation of the release of early warning signals over the past few years and the observation of actual weather conditions, the rules for the issuance of these signals are as follows:

"White" and "blue" belong to the warning signal that "The wolf is coming." Unfortunately, because the colors are too bright, many citizens may not have enough attention when they see it. When there is no warning signal for these two colors (for example, Guangdong, the lowest level of heavy rain signal is yellow), the "yellow" is the signal that "the wolf is coming".

More advanced signals, such as "yellow" (for areas where the lowest level is "blue"), "orange", and "red," are generally when bad weather has affected the local area and may persist or even become worse release.

To sum up, it is very, very simple: to see the lowest level signal (for example, for Beijing, the lowest level of heavy rain signal is “blue”). When releasing, it is necessary to keep in mind the bad weather in the next 12 hours (or 6 hours) , depending on the definition of the lowest level signal) may affect the local. Since rainstorm clouds can generally be observed on local radars with a maximum of 2-3 hours in advance, (if more than 3 hours, the clouds may be weakened or redirected, and meteorological departments generally will not issue warning signals for this purpose. ), so we must not have the idea that "there's a lot of time," and be careful to plan as if you have only 1-2 hours of spare time. Careful consideration should be given to plans for excursions, outings or trips to low-lying areas. Attention should be paid to the changes in the sky. It must not be taken lightly because of the fine weather at that time, unless the meteorological department cancelled the warning signal later. In bad weather, if you see a higher-level warning signal issued, you should respond according to the instructions of the corresponding signal.

The atmosphere is a complex chaotic system. The weather forecast has its own objective technical difficulties. With the current technology, the country's input power is even greater, and it is impossible to be 100% accurate. Errors in early warning signals are not uncommon, but many times are still accurate. . Therefore, when the meteorologists jokingly do not have any problem at ordinary times, you can see that when the warning signal is released, you should not boast about it. For yourself and your family, do a good job of defense. When nature loses its temper, the power is terrible.

There is truth in the data: Post observation data for Beijing Meteorological Station (54511) for the exchange of international meteorological data from the evening of the 21st to the early morning of the 22nd. This is the most primitive SYNOP code. I believe that any graduates of meteorology graduates will have a profound memory of transcoding. Readers who are interested or have doubts about the data can also search for relevant materials of the weather code and learn to read it.

AAXX//=

AAXX//

AAXX=

Finally, I will explain one question: Is the July 21 rainstorm in Beijing an orange rainstorm warning signal appropriate? This involves the issue of the applicability of an early warning signal. China’s early warning signal system is used throughout the country. In the south, it is possible to basically reach the standard for red storm warning signals in an entire region. However, in the north, due to the obvious locality of strong rainfall, it is extremely rare for an entire region to meet such standards. . Take the observation data of the Beijing Meteorological Station on July 21, the 6-hour precipitation reported at 2:00 pm on July 21 and July 22 at July 7 were 76.0 mm and 80.0 mm, respectively, far below the red rainstorm warning signal. The standard (three-hour rainfall reaches 100 mm), and at 8 o'clock on the 22nd on the 22nd report that the precipitation in the past 24 hours is 160.2 mm, which is close to the average of the whole city, so we can see that the respective regions may meet the standard of the red rain warning signal. However, for the data currently disclosed, orange rainstorm warning signals are appropriate. Moreover, it was reported that this was even the first orange rainstorm warning signal in Beijing since the implementation of this system in 2005.

However, this does have its unreasonable side. Arranging a “red rain warning signal” for Beijing in a rare year is just like scheduling a road ice warning signal in Guangzhou. The probability is too low, which is not conducive to fully mobilizing emergency resources. I think that localities should consider appropriately adjusting the conditions for issuing early warning signals at different levels according to the local conditions. At the same time, at least the regions that may be far beyond the geographical averages should be repeatedly emphasized in the warning explanatory texts. For example, the most severely affected area in the Fangshan area is It is quite possible to meet or even exceed the issuance conditions of the red rainstorm warning signal.

Example: Guangzhou Heavy Rain on May 22, 2011

In fact, for a long time, the key is to focus on the weather. Here we take the heavy rain in Guangzhou University City on the afternoon of May 22, 2011 as an example to see how we can use weather warnings to adjust our travel arrangements in a timely manner.

This day happens to be Sunday. The little X who studied in the university city decided to write homework in the morning and ride in the university city in the afternoon. On this morning, a heavy rain fell in the urban area and an orange rainstorm warning signal was issued (Guangzhou Daily reported). However, the Panyu District where the University City was located had only a light rain. Xiao X had finished his homework and had a nap after lunch. He even saw some sunshine. Although the weather forecast pointed out that there will be heavy rain, but small X believes that the risk is not large, decided to travel with confidence, but that the road should be properly brushed on the District Weather Bureau website.

Usually go out to play always feel that time goes fast, unknowingly more than five in the afternoon, but small X found himself playing only half. When he stopped to rest, he discovered that the Regional Bureau of Meteorology issued a series of yellow storm warning signs and blue thunderstorm warning signals nearly one hour before (16:28). Although the weather seemed calm at the time, he still decided to go home immediately. Less than six o'clock, he arrived at the dormitory, and the sky still did not change much. He began to confess: Did he leave it to the meteorological bureau? However, soon, the sky darkened quickly. A dark cloud came slowly from the west. Lightning and thunder broke in an instant. Visibility dropped to a minimum of 90 meters. Within a half hour, 30.3 millimeters of rain fell (equivalent to heavy rain). Gusts reached level 6.

The travel plan was upset by the heavy rain. Xiao X hopes to eat some supper. Although the rain stopped temporarily, the high-hanging early warning signals let him honestly stay in the dormitory and pick up the potato chips until the weather bureau released two warning signals at 20:07. He was relieved to go out. After a slight rain, Xiao X finally managed to eat a satisfying night snack.

We can see that as long as we pay attention to the weather and understand the significance behind the warning signal, we must not "undermined the enemy" at the crucial moment. The result can be completely different; it is really a bad thing to be trapped outside in the stormy days of heavy rain. . Of course, if you can proficiently interpret the radar data (the following image shows the radar data before and after the torrential rains on May 22, and the place marked “East” is the University City), then you can also act according to your own judgment. But remember that if you make a mistake, the consequences can be serious.

No matter how professional the content of any weather warning system is written, the public must be able to obtain early warning information and understand its meaning. This system can be regarded as a good system. Let’s take a look at how other countries and regions operate their weather warning system. Here are two examples I am more familiar with, Canada and Hong Kong. The systems of other countries are basically similar.

There are more than a dozen directions for weather warnings in Canada, but the main warning terminology is divided into two types: “watch” and “warning” when the atmosphere is suitable for the development of a bad weather system. Issued a "warning" that issued a "warning" when the system affected the area. Or, the former is to warn you that "the environment is suitable for wolf infestation," and the latter is to warn you that "the wolf is now haunted." All signals are unified on the website of the Ministry of Environment (the Ministry of the Environment is responsible for the weather service in Canada). When the “warning” comes into effect, the Ministry of Environment will update the “warning” content every dozen minutes and inform the public about the movement of the severe weather system. The warning or warning content is very refined, and the old one can involve meteorological terminology, so that anyone at any level can easily understand it. For example, this is a strong thunderstorm warning signal issued today in central Manitoba:

There may be strong thunderstorms tonight. Strong thunderstorms with hail and destructive winds may develop.

Observe the weather and pay attention to the updated weather report. If you find that bad weather is approaching, take immediate safety precautions.

A strong thunderstorm system is near western Manitoba. Some areas of thunderstorms may not be weakened tonight. The threat from these thunderstorm areas is extremely strong rainfall and gusts of up to 90 km/h.

Hong Kong’s early-warning signal systems to a large extent take into account complex and ever-changing climates at low latitudes. In addition to the “alertness” nature, “warnings” are also divided into several levels, and different levels correspond to different disaster response strategies, and the mainland’s current The use is closer. For the heavy rain in summer, the yellow, red, and black storm warnings are used mainly, as well as special "thunderstorm warnings." The Yellow Rainstorm Warning, which sometimes also assumes the function of warning "The Wolf is Coming", has also had many unsuccessful forecasts. However, in the summer when heavy rain and lightning often appear together, the more flexible “thunderstorm warning” plays a very good “early warning” effect. As the convective rains in summer have a large or small area, the Hong Kong Observatory has often issued a thunderstorm warning and written explanations of areas that may be affected. If the convection area develops strongly and the rainfall reaches the standard, a rainstorm warning will be issued. In addition, Hong Kong has already established a fixed and effective model for the wording, release and transmission of warning signals. Once key early warning signals such as rainstorms and typhoons are issued, there will be relevant notices in malls, ports, stations and other densely populated locations, and the Observatory's website will There is a concise response guide to ensure that citizens understand the release of signals in the first instance and are familiar with the response strategies under different early warning signals.

In short, whether it is Canada or Hong Kong, its weather warning system aims to achieve a goal: to ensure that the public can understand the contents of the warning message in a timely and accurate manner.

to sum up

It seems like I have written quite a lot. Say nothing more, or use the simplest chart to summarize the most important point of view of this article.