Information on Significant Heavy Snowfall Fukui Prefecture Shiga Prefecture Japan 20240124

https://www.youtube.com/watch?v=PPiGj6schwE
"Forecaster Explanation" What is "Significant Heavy Snowfall"? Tomorrow brings heavy snow plus "typhoon-level" violent winds [Super J Channel] (January 24, 2024) - YouTube
Jan 24, 2024
On the 24th, "Information on Significant Heavy Snowfall" was issued four times for Fukui Prefecture and twice for Shiga Prefecture.
It is relatively easy to imagine what rain is like, but what kind of snowfall is "30 to 40 centimeters in 6 hours"? We ask weather forecaster Ryoko Imamura.
■ The situation changes suddenly... "30 to 40 centimeters of snow in 6 hours"
Imamura: A snowfall of 30 to 40 centimeters is an amount that usually falls over the course of an evening or a full day. Since this amount fell in just 6 hours this time, it means the snow fell in a concentrated, short period.
Imagine it like this: "There was no snow on the road during your morning commute and you were able to drive, but when you went to go out at noon, your tires were half-buried and you couldn't drive the car."
"30 to 40 centimeters of snow in 6 hours" is the kind of snowfall where the situation changes suddenly and easily leads to traffic troubles like getting stranded.
■ Tomorrow, in addition to snow... typhoon-level violent winds
In Sekigahara, Gifu Prefecture, vehicles have also become stranded. Will the snow continue to fall?
Imamura: The peak of the snowfall in Shiga Prefecture, Gifu Prefecture, and around the Meishin Expressway is beginning to pass. However, because snow clouds will continue to flow in throughout tonight, the situation where snow accumulation increases is likely to continue. Therefore, it is expected that snow removal will take time.
Furthermore, heavy snow will continue in other regions through the 25th. Regarding the wind, there is a risk that it will become even stronger than it was on the 24th.
This is the weather map for tomorrow, the 25th. There are many isobars near the Japanese archipelago, and it looks like a vertical striped pattern. It is a very strong winter pressure pattern, with more than 10 isobars covering the area near Japan.
When this happens, violent winds are likely to rage, mainly in northern Japan. The predicted maximum instantaneous wind speed is 35 meters in Hokkaido and 30 meters in Tohoku and Hokuriku, which are typhoon-level violent winds.
■ Explanation using a 3D model... Why do many isobars cause a storm?
On the 25th, in addition to snow, strong winds will blow, increasing the risk of disaster. Why does a large number of isobars lead to storm-like conditions?
Imamura: I will explain using a model. This is a weather map with a mid-winter pressure pattern similar to the 25th. As you can see, there are many isobars.
When you look at the model from a different angle, the isobars start to look three-dimensional rather than flat. This is what a strong winter pressure pattern looks like.
You can see that there is a considerable difference in altitude between the high-pressure and low-pressure systems.
Imamura: The high-pressure system over the continent is as high as a mountain, and the area around the Japanese archipelago near the low-pressure system is depressed. It forms a mortar shape from the top of the high-pressure system toward the center of the low-pressure system located east of Hokkaido. You can see that the center of the low-pressure system is where the isobars are most crowded and where it is most depressed.
Because wind has the property of blowing from areas of high pressure to areas of low pressure, it blows with more force where there are more isobars. That is why it becomes a violent wind.
This situation is also expected on the 25th.
There will be whiteouts, and snowdrifts will form. Therefore, there is a risk of traffic disruptions. Please consider the possibility of such events and ensure you have thorough equipment and preparations in place.