On the morning of the 19th, it was confirmed that long and thin dark clouds lined up horizontally over Kinki, and it became a hot topic on the Internet.
The Japan Meteorological Agency warns that when cold air and warm air collide with each other, a gust of wind blows when the cloud is seen, and there is a risk of a heavy thunderstorm due to the developed cumulonimbus cloud. I need it.
On the morning of the 19th, posts of arcus clouds were posted one after another on Twitter etc. and became a hot topic.
In the video taken in Taisho-ku, Osaka around 9:30 am on the 19th, you can see a row of clouds floating low and parallel in the sky above the residential area.
Similar clouds were witnessed in Hyogo Prefecture, and posts such as "I'm scared of ghostly clouds" and "It started to rain when this passed" were posted on Twitter.
According to the Japan Meteorological Agency's weather counseling office, cold air blows out under the developed cumulonimbus clouds, and when they collide with warm air near the ground, a "small front" called "gust front" is generated, and the clouds look like an arcus cloud. Therefore, it is called "Arcus cloud" or "Arc cloud".
The gust front is one of the turbulent air currents created by the activity of developed cumulonimbus clouds, which spreads more horizontally than a tornado and can reach tens of kilometers in length.
On the morning of the 19th, the weather conditions around Osaka were extremely unstable due to the effects of the cold air and warm and moist air in the sky, and gust fronts were likely to occur.
Be aware that under the arcus cloud, the temperature will drop in a short period of time, the weather will change suddenly and gusts will blow, and there is a risk of heavy thunderstorms due to the developed cumulonimbus clouds.
At the AMeDAS observation point in Osaka City, the temperature dropped by 1.1 degrees between 10 am and 10:30 am, which is close to the time when the video was shot, and at other observation points in the surrounding area, the temperature dropped. In some places, it dropped by 2 to 3 degrees.
The Japan Meteorological Agency says that arcus clouds, which are usually found at sea, are rarely seen on land so clearly.