Impacted by the easterly wave, Guangdong will see a severe convective weather with substantial rainfall from August 3 to 5, easing the hot weather significantly, Guangdong Meteorological Observatory says.

From Tuesday night to Wednesday, east Guangdong will see heavy rains to rainstorms with localized torrential downpours. Most of the Pearl River Delta will experience thundershowers and localized torrential rain.

The rest of the province will have scattered thundershowers with localized heavy rains or rainstorms. The highs of west Guangdong and cities in the west of Pearl River Delta will be 34 ℃ to 36 ℃.

Photo: Nanfang Daily

The coming rainfall will be good news for Guangdong people after being baked for a long period. However, some people may be still confused: why didn't Guangdong carry out artificial precipitation to lower the temperature during scorching days?

The principle of artificial precipitation is that rockets or aircraft or other tools are used to spread condensation nuclei or artificial ice nuclei into clouds, to promote the rapid increase of small cloud droplets into raindrops or make small ice crystals grow bigger as soon as possible to fall and melt into raindrops.

According to Gao Jianqiu, senior engineer of the Guangdong Weather Modification Center, to carry out artificial precipitation, clouds must meet four conditions: the cloud thickness should be at least 2-3 km; the height of the cloud base is below 2 km; the area of the cloud reaches dozens of square kilometers; and there are updrafts within the cloud. The clouds in Guangdong over the past hot days didn't satisfy these requirements.

The reason behind is that too thin and small clouds can hardly provide enough cloud droplets to form raindrops. Also, if the cloud base is too high, the raindrops will evaporate in the air before landing on the ground. Besides, the updraft is a natural pusher for rainfall.

Author | Lily (intern)

Editor | Wing, Keane, Will, Abby, Jerry