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Today (19th), the atmosphere was unstable, and it rained everywhere. Yesterday evening, in some areas in the metropolitan area, only lightning flashed in the dry sky, but the temperature is getting higher and the steamy heat is expected to rise to 36 degrees this week.
Correspondent Seo Dong-gyun.
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Lights flash in the night sky as if a flare was fired.
The zig-zag lightning is clear, not a drop of rain, and no thunder.
[Eyewitness: I can't hear any thunder and how can it flash like that?]
Last night, these dry lightning sightings continued around the metropolitan area.
[Jo Seong-kwon / Dongjak-gu, Seoul: Something twinkling in the sky kept appearing about once every 10 seconds. I think it's the first time I've seen such a thing.]
These lightning bolts came from the 'cumulonimbus cloud', a shower cloud.
Cumulonimbus clouds are formed when heated air from the surface of the earth rises high in summer, and sometimes extends straight up to a height of 10 km above the ground.
When lightning strikes in the upper part of the cumulonimbus cloud so far away, it becomes 'dry lightning' that is visible to the naked eye, but there is no rain or thunder.
The dry lightning seen last night in southern Seoul was analyzed as lightning that fell along with a shower at the same time and 50 km away from Pyeongtaek, Gyeonggi Province.
This week's sweltering heat will get worse.
The day after day, the overlapping days, and Gulpy, the Daeseo, and the mercury levels in Seoul are expected to soar to a high of 36 degrees this year.
The hot and humid North Pacific high pressure gradually expands to Korea, and the 6th typhoon 'Popa', which passes southeast of Okinawa, Japan, also blows hot steam into Korea.
(Video coverage: Kim Yong-woo, video editing: Yoon Tae-ho)