Front stagnates south of Honshu; linear rain belt may form in Izu Islands

2025/10/21 08:11

Today, the 21st (Tuesday), the autumn rain front is stationary in southern Honshu. A tropical cyclone formed near the Sakishima Islands around 3 a.m. and is slowly moving southwest.

Warm, humid air from around the tropical cyclone will flow toward the front, and with the added influence of a pressure trough in the upper atmosphere, atmospheric conditions are expected to become extremely unstable in Okinawa, Amami, and the Izu Islands, which are close to the front.
Also, the Pacific side of western and eastern Japan will experience cloudy and unrefreshing weather, with some places experiencing showers and thunderstorms.

In Okinawa and Amami, there will be heavy rain accompanied by thunder from before noon to early afternoon, and in the Izu Islands, localized areas are expected to see more than 80 mm of rain per hour from evening to early night. There is little movement of the front into tomorrow, the 22nd (Wednesday), so there is a risk that heavy rain will continue in similar areas.

Especially in the Izu Islands, from the evening of today, the 21st, to late at night, there is a possibility that a linear rain band will develop, and the risk of heavy rain disasters will increase rapidly. If a linear precipitation band occurs, the total rainfall may be much higher than expected.
Please be extremely cautious of landslides, flooding of low-lying areas, rising water levels and flooding of rivers, etc.



#Rain forecast (Izu Islands)

The predicted hourly precipitation on the 21st is high in places,
Izu Islands 80 mm

The predicted hourly precipitation on the 22nd is high in places,
Izu Islands 40 mm

The 24-hour precipitation expected from 6 o'clock on the 21st to 6 o'clock on the 22nd is high in places
Izu Islands 200 mm

Then, the 24-hour precipitation expected from 6 o'clock on the 22nd to 6 o'clock on the 23rd is high in places
Izu Islands 80 mm

Winter news continues to arrive in Hokkaido: First snow observed in Wakkanai, Asahikawa, and Abashiri

2025/10/20 20:17

Today, the 20th (Monday), we observed the first snow in Wakkanai, Hokkaido. This was the first snowfall of the season observed at weather observatories across the country. On the same day, it was announced that the first snow had been observed in Asahikawa and Abashiri.

Also, the first snowfall was observed at Mt. Yokotsu in Hakodate, Mt. Washibetsu in Muroran, and Mt. Teine in Sapporo.

Today, on the 20th, the area around Honshu had a wintry-type atmospheric pressure pattern of high in the west and low in the east, and in Hokkaido, cold air flowed in with temperatures below -6c at around 1500m, which is a guideline for snow to fall even on flatlands. Streak clouds that are seen in winter have formed over the Sea of Japan, and some of these clouds have also covered the land of Hokkaido, and it is thought that the rain has turned to snow due to the drop in temperature.

#First snow
Asahikawa 1 day later than average, 1 day later than last year
Wakkanai 1 day later than average, 1 day later than last year
Abashiri 10 days earlier than average, 1 day later than last year

#First snow
Hakodate Yokotsudake 9 days earlier than average, 18 days earlier than last year
Muroran Mt. Washibetsu: 11 days earlier than normal, same as last year
Sapporo Teineyama: 2 days later than normal, same as last year



In Hokkaido, there will be places in Hokkaido tomorrow morning when cold air with temperatures below -6 C will flow in at around 1500m above the ground, and there will likely be places where it will snow even in the flatlands of the inland areas, especially in the mornings and evenings. There is a possibility of snow accumulation in high altitude areas, so please be careful of road conditions when driving.

Autumn rain front stagnates. Warning-level heavy rain until the 24th in Okinawa and Izu Islands. Cloudy and rainy on the Pacific side of Honshu. 16c expected in the city. Snowy days in inland Hokkaido. [Weekly weather forecast]

2025/10/20 12:58

#Autumn rain front stagnates, warning level of heavy rain expected until 24th in Okinawa and Izu Islands
#Western and eastern Japan also suffers from sluggish weather on the Pacific side, quickly turning into autumn air
#Hokkaido cold, with snow days inland



#Autumn rain front stagnant There is a risk of warning-level heavy rain in Okinawa and Izu Islands until the 24th
The autumn rain front will remain stationary from the East China Sea to the south of Japan until around the 24th (Friday).
Okinawa/Amami and the Izu Islands will be affected by the front on many days, and intermittent rain is expected.
On Miyakejima, there are places where the ground has become loose due to the rain that has fallen so far, so the risk of landslides may increase even with low rainfall.
Also, the atmospheric conditions will be unstable due to the influence of humid air, and heavy rain may occur.
Depending on the level of activity of the front, there is a risk of warning-level heavy rain, so please pay attention to the latest information.





#Weather is sluggish on the Pacific side of western and eastern Japan as well. Autumn air changes all at once.
The autumn rain front is stationary in the south of Honshu, and there will be many days of sluggish weather with cloudy weather and rain in western and eastern Japan, especially on the Pacific side.
From the 24th (Friday) to the 25th (Saturday), high pressure is expected to move from the Sea of Japan to the east of Japan, and more areas near Honshu will be exposed to sunlight.
However, from the 26th (Sunday) to the 27th (Monday), the front in the south of Japan will move northward and a low pressure system will form above the front, moving from the south of Japan to the east of Japan and moving north.
It is expected to rain again in more places.
Western Japan will experience midsummer days over the weekend, and there will be many days suddenly enveloped in the autumn air.
Eastern Japan, including the Kanto-Koshin region, will have many days with temperatures at or below normal, and the Tohoku region is expected to have many days with temperatures lower than normal.
In central Tokyo, the 22nd (Wednesday) will be as sunny as mid-November, with a maximum temperature of 16c due to rain and cold northeast winds.
Please be careful not to catch a cold due to the sudden cold.



#Hokkaido Cold air with snow days inland
Cold air is expected to move southward near Hokkaido into the second half of the week.
There will be days when cold air with temperatures below -6 C will cover Hokkaido at around 1500m above the ground, and if it rains, it will snow even in flat areas inland.
In particular, from tonight until the beginning of tomorrow, the 21st (Tuesday), cold air with temperatures below -6 degrees Celsius is expected to move southward to the Pacific side of Hokkaido at an altitude of around 1,500 meters.
In the inland areas of northern and central Hokkaido, there is a risk of snow even on flat areas.
Please wear winter tires when traveling along mountains or through mountain passes.

Warning-level heavy rain is likely to occur in Okinawa until around the 24th (Friday). Be careful of heavy rain disasters.

2025/10/20 07:17

The front is stationary from the East China Sea to the south of Honshu, and Typhoon No. 24 is moving northwest in the South China Sea. Humid air is flowing into the Okinawa region from the east, and 35.0 mm of heavy rain was observed in Hateruma, Taketomi Town, Okinawa Prefecture in the hour up to 5:29 a.m.



Today, the 20th, the front is expected to gradually move south. Atmospheric conditions in the Okinawa region will be extremely unstable due to the influence of moist air flowing around the edge of the Pacific high pressure system. As a result, rain clouds are likely to develop, leading to heavy rain and thunderstorms. There is a risk of heavy rain in a short period of time, so please be careful about flooding of the underpass.



The Okinawa region will be affected by fronts and humid air from now until the end of this week, so it will rain easily and for a long time. Depending on the degree of rain cloud development, there is a risk of warning-level heavy rain until around the 24th (Friday), so please be careful of landslides, flooding of low-lying areas, and rising river waters.

Weather for today, the 20th (Monday): The weather is gradually improving on the Pacific side; snow is possible even in flat areas in Hokkaido

2025/10/20 06:35

Today, the 20th (Monday), the front is expected to move south of Honshu. The weather will gradually improve on the Pacific Ocean side, but there will be many places on the Sea of Japan side where it will gradually start to rain. It seems that there are places in Hokkaido where it will fall as snow.



Cold air of -6c or below is expected to flow into Hokkaido, mainly in northern Hokkaido, which is a guideline for snow on the flatlands at an altitude of about 1500m. In some areas, such as inland areas and along the mountains, snow may fall mainly in the morning and evening. In northern Hokkaido, there are places where it snows even on flatlands, so be careful of frozen roads and snow accumulation on mountain passes, and if you plan to drive on mountain passes, please change to winter tires.
Temperatures will be low throughout the day, with maximum daytime temperatures around 10c in many places. Please stay warm.

There are some places on the Pacific side of eastern and western Japan where it will rain until morning, but it is expected to gradually stop in many places. On the other hand, the weather on the Sea of Japan side between Tohoku and San'in area is gradually becoming more prone to rain, so please bring rain gear even if it's not raining when you go out. In the Kanto region, there is a possibility of rain even at night, so it would be a good idea to have a folding umbrella.

The sky in Kyushu is cloudy at first, but it looks like there will be some places where the sunshine will gradually return.

Okinawa is prone to rain due to the influence of fronts, and there is a risk of heavy rain and thunderstorms. Please be careful of landslides, flooding of low-lying areas, and rising river waters.

Heavy rain warning mainly in the Okinawa region and the Sakishima Islands. Indirect effects of the typhoon!

2025/10/19 17:45

There is a low pressure system east of the Kuril Islands, and a front from the center passes through the eastern coast of Japan and the southern coast of Honshu, extending into the East China Sea.
Also, there is Typhoon No. 24 in the Philippines and it is moving north-northwest.
On the other hand, an anticyclone is protruding from the continent near the Sea of Japan.



The high pressure system is expected to protrude near Japan until tomorrow the 20th, and the front is expected to slowly move south and become stationary near Amami and Okinawa.
The Okinawa region will experience extremely unstable atmospheric conditions due to the influence of moist air surrounding the typhoon and around the edge of the high pressure system.
In the main island of Okinawa and the Sakishima Islands, please be careful of strong gusts such as lightning and tornadoes through the 20th.



Depending on the degree of rain cloud development, there is a risk of warning-level heavy rain from around the 19th to the 24th.
Please be careful of landslides, flooding of low-lying areas, and rising river waters.




### Rain forecast
The expected hourly precipitation on the 19th is high in some places,
Okinawa main island region 30mm
Yaeyama region 30mm

The hourly precipitation expected on the 20th is high. In some places,
Okinawa main island region 30mm
Miyakojima region 30mm
Yaeyama region 30mm

24-hour precipitation expected from 18:00 on the 19th to 18:00 on the 20th is high
Offshore. Nawa Main Island region: 60 mm
Miyakojima region: 60 mm
Yaeyama region: 80 mm

After that, the predicted 24-hour precipitation from 18:00 on the 20th to 18:00 on the 21st will be high in the Okinawa Main Island region. 80mm
Miyakojima region 80mm
Yaeyama region 80mm

### Disaster prevention matters
In the Okinawa main island region and Sakishima Islands, please be careful of strong gusts such as lightning and tornadoes through the 20th.
If there are signs of a developing cumulonimbus cloud approaching, please take every precaution to ensure your safety, such as moving inside a building.
In the Daitojima region, please be careful of lightning strikes, gusts of wind, and sudden heavy rain under the cumulonimbus clouds that developed over the 20th.
In the main island of Okinawa and the Sakishima Islands, heavy rain is expected to occur in some places through the 20th.
Depending on the degree of rain cloud development, there is a risk of warning-level heavy rain from around the 19th to the 24th.
Please be careful of landslides, flooding of low-lying areas, and rising river waters.

New typhoons are forming as the season advances from the north; tomorrow night there is a risk of snowfall even in the flatlands of Hokkaido [Typhoon information/Weekly weather]

2025/10/18 11:59

Typhoon No. 24 (Funshen) occurred in the east of the Philippines at 3 a.m. today, October 18th (Saturday).

The typhoon is expected to advance westward as it continues to develop, and is expected to move westward around the 21st (Tuesday), accompanied by stormy winds, in the South China Sea.



Although there is no direct impact on Japan,
the autumn rain front is expected to stay near the Nansei Islands next week, and
please be aware that the front may become more active due to the influence of moist air flowing in from the typhoon.

A low pressure system accompanied by a front is passing near Honshu, and
active rain clouds are approaching from the Sea of Japan.



Looking at the state of the rain clouds as of 11 a.m. today,
band-shaped rain clouds are spreading over the Sea of Japan due to the front,
and the rain is starting to get stronger in Hokkaido and other areas.

Rain clouds will cover a wide area this afternoon
There are likely to be heavy rain and thunderstorms in western and eastern Japan.

Be careful of sudden heavy rain, lightning strikes, and strong gusts of wind such as those caused by tornadoes.



After this rain, strong cold air is expected to flow into the sky.

Looking at the forecast for cold air for three days from today, the 18th (Saturday),
today, warm air similar to September will flow towards low pressure systems and fronts, but
tomorrow, the 19th (Sunday), cold air that will bring snow in the mountains
will flow into the northern Tohoku region.

Additionally, by Monday the 20th,
cold air that brings snow on the flatlands will move south to southern Hokkaido,
on the northern Sea of Japan side of Hokkaido and the Sea of Okhotsk side,
even on the flatlands are expected to experience snowfall in some places.

Please use winter tires and be careful of
traffic hazards caused by snow and frozen roads.



An anticyclone is expected to protrude from the continent next week, and the
autumn rain front is expected to stay on the southern coast of Honshu.

As a result, rain will continue to fall near the Nansei Islands and Izu Islands, with the possibility of
warning-level heavy rain.

It is necessary to be careful and vigilant against heavy rain disasters caused by long rains.



The season will take a big step forward this weekend.
The maximum temperature in Sapporo on the 20th (Monday) is expected to be 9c, and on the 21st (Tuesday), Tokyo is expected to reach 19c and 20c.

Even in Western Japan, which has been experiencing high temperatures until now, there will be fewer days where temperatures reach 25c next week.

There will be many days when it will be cold in the mornings and evenings, so
Please be careful not to get sick due to the temperature difference between morning and evening and daytime, as well as the daily temperature difference.

Typhoon No. 24 (Funshen) occurs. Although there is no impact on Honshu, there is a possibility of heavy rain in Okinawa

2025/10/18 06:11

At around 3:00 a.m. on the 18th (Saturday), Typhoon No. 24 "Funshen" formed off the eastern coast of the Philippines. This will be the fourth typhoon since October.

#Typhoon No. 24 Saturday, 18th as of 3:00 a.m.
==================
Center location East of the Philippines
Movement speed West 25km/h
Central pressure 1000h Pa
Maximum wind speed 18m/s (near the center)
Maximum instantaneous wind speed 25m/s
==================

Typhoon No. 24 is expected to pass through the Philippines and reach the South China Sea. There is no direct impact on areas near Japan.



However, Okinawa and the Sakishima Islands may be affected by the warm and humid air from the typhoon. From now on, the front is likely to remain stationary near Okinawa, and warm, humid air from the typhoon may flow in, causing heavier rain. Please pay attention to the latest weather information that will be updated in the future.

Latest 1-month forecast: The season is rapidly advancing in northern Japan. The season is progressing slowly in eastern and western Japan.

2025/10/17 20:43

On the 16th, the Japan Meteorological Agency announced the latest one-month forecast, which provides the weather outlook for the next month.



According to the numerical forecast, the Siberian High is expected to protrude from the continent, while the average pressure is expected to be low near Okinawa.
The average temperature at around 1,500 meters above sea level is expected to be lower than normal in northern Japan, and higher than normal in western Japan and near Okinawa/Amami. Near Japan, the temperature difference between the north and south sides is expected to be large.



For this reason, northern Japan will be more susceptible to the effects of cold air in the upper atmosphere. During this period, strong cold air will flow into the sky, and there is a possibility that snow will fall not only along the high mountains in Hokkaido, but also on the flatlands. When driving on mountain passes, you need to be careful about the road surface conditions, so it's a good idea to consider changing to winter tires as soon as possible.
There will be more autumn-like days in the Tohoku region, and the trees will start to change color.

Eastern Japan, the Pacific side of western Japan, Okinawa and Amami will be more susceptible to the effects of low pressure systems and fronts, and will have many cloudy and rainy days. Precipitation in Okinawa and Amami is likely to be around or above normal.
From next Tuesday, the 21st, there will be days in eastern and western Japan where the maximum daytime temperature will not reach 20c and it will feel like autumn. However, looking at the total period, it seems likely that temperatures will continue to be higher than normal, and the season will progress slowly.
However, the temperature difference between morning and evening and daytime tends to be large, so please be careful about your physical condition.

[Typhoon No. 24 to occur] A typhoon egg is developing in the east of the Philippines. Be careful of typhoons in October as well. Tropical cyclone information

2025/10/17 11:40

At 3 a.m. today, the 17th (Friday), the Japan Meteorological Agency announced that the tropical cyclone that was developing in the east of the Philippines was ``expected to develop into a typhoon within 24 hours.''
If it develops into a typhoon as expected, it will be called "Typhoon No. 24."



#Tropical cyclone October 17th (Friday) 9:00 am
Area of existence East of the Philippines
Center location 13 30'N latitude 131 20'E
Movement West 20 km/h
Central pressure 1006 hPa
Maximum wind speed: 15 m/s (near the center)
Maximum instantaneous wind speed: 23 m/s

The tropical cyclone east of the Philippines is developing and moving westward, and is expected to become a typhoon east of the Philippines tomorrow, the 18th (Saturday).
Then, it will move west-northwest and pass the Luzon Island the next day, on the 19th (Sunday).
It is expected to reach the South China Sea on the 20th (Monday) and continue westward through the South China Sea until the 22nd (Wednesday).

#The impact on Okinawa will have no direct impact on Japan.
However, depending on the course of the typhoon and the extent of its development, there is a risk that waves may become high with swells, especially in the Sakishima Islands of Okinawa.
In addition, from the afternoon of the 18th (Saturday) tomorrow, the moist air around the typhoon will flow around the edge of the high pressure system and flow into the vicinity of Okinawa, and the rain may become heavier from the day after tomorrow until the 19th (Sunday).
The autumn rain front will remain stationary near Okinawa from the 20th (Monday) to the 23rd (Thursday), and there is a risk of heavy rain due to the front mainly from the 21st (Tuesday) to the 22nd (Wednesday).
As the rainy days continue, please be careful of the latest information.

#Typhoon could make landfall in October
If the tropical cyclone east of the Philippines becomes "Typhoon No. 24," it will be the fourth typhoon to occur this month.
The average number of typhoons in October is 3.4, and it is still a time when typhoons are likely to occur.
Also, the average number of landfalls is 0.3, and landfalls may occur in October.
It's a good idea to stay alert in October and take precautions against typhoons and heavy rain.