News Tokyo is less likely to cause heavy snow on a low -pressure course, so be careful of the road surface freezing for a while

Christmas cold and New Year's cold waves

　In the second half of November, the day of the west high -east low -type winter pressure distribution increased in the second half of November (2021), and a little strong cold weather has fallen south.

　The winter days when the lowest temperature is below freezing, and from the end of November to the beginning of December, more than 460 (half) of the 920 points nationwide are observing the temperature (Figure 1).

　In mid -December, strong chills began to go south, and the number of places to observe the midwinter day below freezing at the maximum temperature has begun to increase, and the Christmas cold wave has been observed on midwinter than 40 % nationwide.

　After the Christmas cold wave, the winter -type pressure distribution temporarily weakened, but at the end of the year the New Year's cold waves went south, and the spots that observed midwinter were over 40 % nationwide.

　In 2022, it began with a winter -specific weather distribution, which was almost cold nationwide due to the invasion of the New Year's cold wave, sunny on the Sea of Japan side, sunny on the Pacific Ocean side, and cloudy in Okinawa.

　On January 6, when the cold waves retreated a little north, the low pressure went east on the south shore of Honshu, and heavy snow warnings were announced for the first time in four years, and heavy snowfall became heavy snow.

　The title image is a satellite image of the Kanto region the morning after heavy snow, but it is not cloudy, but snow.

　From this image, the heavy snowfall indicates that there was a lot of snow in the southern Kanto region except along the coast.

Course of low pressure that does not cause heavy snow in Tokyo

　When a strong cold from Siberia comes south, it becomes heavy snow on the Sea of Japan side and clears on the Pacific Ocean side.

　In the south of the strong cold, the low pressure does not pass on the south coast of Honshu, as large high pressure, which is centered on the continent, covers Japan.

　When the south of the chills from Siberia crosses the pass, the low pressure called the southern coastal low pressure passes through the south coast of Honshu.

　From 3rd to 4th years (2021 to 22 years), when Christmas cold and New Year's cold waves are south, the southern shore low pressure does not pass, and on January 6, when these cold waves weakened.The south coast low pressure passed a little south of Hachijojima (Figure 2).

　For a long time, it has been said that the possibility of heavy snow in the Kanto region increases when the south coast low pressure passes directly above Hachijojima.

　When the south coast low pressure passes north from Hachijojima, the possibility of rain is high because warm air is easier to enter from the south.

　Conversely, when the south coastal cyclone passes south from Hachijojima, coldness is likely to enter from the north, so the possibility of snow is high, but the amount of snow is small due to the low pressure, and in some cases.Because it does not fall.

　On January 6, the south shore low pressure passed a little south of Hachijojima, so it is cold, but it is hard to become heavy snow, although it is cold.

　One of the reasons why it became cold in Tokyo and became heavy snowfall was that a small swirl was occurring on January 6, when the snow became stronger, on the northeast side of the south coast low -pressure swirls, near the land of the Kanto region.It will be given (Fig. 3).

　This small swirl sent a snow cloud on the sea to the sky, such as Tokyo, etc., but it is difficult to predict a small swirl trend that does not appear in this weather map, which is difficult with the current forecast, and "small swirls and winds.The possibility of heavy snow can be made by being able to converge. "

　One of the characteristics of heavy snow when the temperature is low is that it is difficult to snow on electric wires and trees, and that the solid road surface is frozen immediately and has an ice burn.

　The heavy snow on January 6 was a heavy snowfall with a low temperature, and Iceburn was formed immediately, causing a series of car slip accidents and pedestrians fall.

　And on the morning of January 7, the Iceburn, which has been strengthened by the cold at night, has continued to slip on cars and fallen pedestrians.

　In the Tokyo metropolitan area, more than 1,300 people were injured by heavy snow, and there were many cars that were unable to drive with normal tires.

　Even though the same heavy snowfall, compared to the heavy snow on the Sea of Japan side, what is called heavy snow on the Pacific side is small, but it has a significant impact because it is not prepared for snow.

　This time, the south coastal cyclone is also characterized by the fact that the temperature rises quite well, as it does not bring warm air, as it does not bring in warm air as the southern coastal cyclone of many years.

　During the day of January 7, the snowfall is reduced by the sunlight, but there are some places that have disappeared in the shade, and the ground is not completely dry.

　Even in the morning of January 8, the cold at night has continued to cause car slip accidents and pedestrians fall.

　It is very dangerous and out of the question to drive on the snow and frozen road with summer tires during the three consecutive holidays.

　I think that the road surface is frozen, ride a studless tire car, drive as much as possible, avoid "sudden acceleration", "sudden acceleration", "steep handle", and drive with "drip that does not slip". please.

　In order to prevent falls, it is important to walk with a small stride, with the entire shoe.

Nanforce low pressure on adult days

　A low pressure approaches the southern Kanto region on January 10 (Monday) on the last day of the three -day holiday.

　For this reason, it may rain or snow in the southern Kanto region (Figure 4).

　Depending on the course of this low pressure and the degree of development, the Pacific Ocean may be wider again, but it may be raining instead of snow because it is expected to be higher than the heavy snow on January 6th.。

　Check the latest forecasts frequently and be prepared early in the case of snow.

Title Image, Fig. 3, Fig. 4 Source: Weathermap is provided.

Source of Fig. 1: Created based on the materials provided by the Weather Map.

Source of Fig. 2: Japan Meteorological Agency website.