20 19 Guangdong Dragon Boat Water Time+Defense Guide Where is it easy to flood in the southern rainstorm?

After the Dragon Boat Festival, the rainstorm in Guangdong affected everyone's travel, and it was common for flights to be cancelled and roads to accumulate water. The following small series will talk about the relevant defense strategies of this dragon boat water. Everyone should pay more attention to related matters.

There is a period of relatively concentrated precipitation in the first flood season in Guangdong, and there are often days of heavy rain, heavy rain and even heavy rain and torrential rain. Because it is the time of dragon boat race, people call it "dragon boat water", which is the "last madness" in the first flood season in South China.

For the convenience of statistics, "dragon boat water" generally refers to the precipitation from May 2 1 day to June 20.

It is understood that the cause of "Dragon Boat Water" is related to summer monsoon and cold air, and the weather change in South China is the most complicated period before and after the Dragon Boat Festival. The cause of dragon boat water is closely related to the alternating changes of winter and summer monsoon in the South China Sea. The South China Sea summer monsoon usually breaks out in May. After the monsoon broke out, it pushed to South China, producing monsoon convective precipitation. At the same time, the cold air in the north is reluctant to part with South China.

Although after May every year, the influence of warm and humid air from the tropical ocean has been continuously strengthened, and the temperature in the area south of Nanling Mountains has gradually increased, and the weather has turned hot, but the cold air has always refused to "retreat northward", and the convergence of cold and warm air has caused frontal precipitation. Therefore, under the combined influence of monsoon precipitation and frontal precipitation, large-scale concentrated precipitation often occurs in Guangdong from late May to mid-June, that is, "Dragon Boat Water".

The formation mechanism of rainstorm is quite complicated, but there are two important macro conditions:

First, there must be a rich source of water vapor; Second, there must be a strong updraft and a favorable atmospheric circulation situation to make the intensity of precipitation large enough and last long enough.

Coincidentally, before and after the Dragon Boat Festival every year, when South China is affected by the low trough of the front, these two conditions are easy to meet, so heavy rain and "dragon boat water" are in an outbreak state.

According to the waterlogging risk warning issued by the Central Meteorological Observatory today (12), due to the rainy weather in southern China recently, the waterlogging risk level in many places is high. Which places are prone to waterlogging under heavy rain in the south? There are waterlogging risks in western Fujian, south-central Jiangxi, southern Hunan, northern Guangdong and Shenzhen.

The Central Meteorological Observatory issued the meteorological forecast of waterlogging risk on June 2 18:

Affected by rainfall, it is estimated that from 20: 00 on June 12 to 20: 00 on June 13, the risk of waterlogging in western Fujian, south-central Jiangxi, southern Hunan, northern Guangdong, Shenzhen, northeastern Guangxi and eastern Yunnan is high, among which the risk of waterlogging in western Fujian, eastern Jiangxi and northern Guangdong is high, and it is easy to form urban waterlogging.