[Beware of sudden heavy rain] The trend of high temperatures and low rainfall continues in western Japan (commentary: weather forecaster Atsuko Miyake)

2026/08/14 14:58

Record-breaking heavy rain is occurring in Chiba Prefecture.



Looking at the precipitation for the 24 hours until 10 a.m. today, Chiba City had 367 mm, which is the highest in recorded history.
Also, the amount of rain that falls in Chiba City during this period is 115mm per month, which means that three times more rain than normal falls in just one day.

In Chiba Prefecture, record short-term heavy rain warnings were announced 25 times, which is also a record number.
Also, from last night until dawn today. Special warnings for heavy rain and landslides were also announced in Chiba Prefecture.



Let's take a look at the cause of why heavy rain was concentrated only in Chiba Prefecture.

Currently, there is a dominant high pressure system near the Chishima Islands, and the movement is slow.
Due to the northeast wind blowing from this high pressure system, humid air was flowing into Chiba Prefecture.
Also, warm, humid air from typhoons and tropical cyclones over the southern ocean was flowing in from the south.
Furthermore, cold air was flowing in from the inland areas of the Kanto region, riding on northwesterly winds.

It is thought that these winds collided in Chiba Prefecture, causing torrential rain.



And this pressure distribution is expected to continue from today to tomorrow.
The easterly wind around the edge of the high pressure system is likely to continue to flow humid air from the Kanto region to the Pacific side of the Tohoku region.

The cold air above is expected to gradually dissipate through tomorrow, but the
pressure distribution will not change much, so the atmosphere is likely to remain unstable into tomorrow.



Now, let's take a look at the rain clouds as the night progresses.
After this, heavy rain and thunderstorms are likely to occur here and there, not only in Kanto, but also from Kyushu to the Pacific side of Tohoku.

Also, in the Kanto region, there is a possibility of extremely heavy rain exceeding 50 mm per hour,
In some cases, heavy rain exceeding 80 mm per hour may fall.



In Chiba Prefecture, the rain will become stronger again after this, and there is a risk of secondary disasters occurring.
After this, there is a possibility of sudden heavy rain.
What should you do if you encounter such sudden heavy rain
When it rains extremely heavily in urban areas, exceeding 50mm per hour, the drainage cannot keep up and the roads become like rivers.

If you do so, rainwater will flow into the underpass and underground facilities.
When it rains heavily, please try to escape from these underground facilities.

And rainwater may flow into the first floor, so
when it is raining heavily, please protect yourself on the second floor or above in a sturdy building.

Please check the radar for the latest information, such as when the rain will stop.
Also, use Kikikuru to check areas that are prone to landslides and flooding.



Although there is heavy rain in Chiba Prefecture, the amount of rain in areas north of the Kanto region is higher than normal.

This is the total precipitation for the 20 days up to yesterday and compared to the normal year.
There are also green signs in areas north of Kanto, which is significantly above normal.

On the other hand, there are brown signs in western Japan, and the rainfall is much lower than normal.
Western Japan is expected to continue experiencing little rain for the next two weeks.



Also, the severe heat is likely to continue in western Japan.
This is the average temperature for 20 days up to yesterday and compared to normal.

In western Japan, temperatures are continuing to rise above normal, with red markings becoming more noticeable.

The high temperature trend is expected to continue for about a month.
Please be careful about heatstroke and managing your crops.



, we will look at the weather in various places.

The unstable atmosphere in the Kanto region will continue into tomorrow.
Please be careful of heavy rain with thunder, lightning strikes, and gusts of wind until dawn.
The heat will not be that intense until the first half of next week, but from the second half of next week the power of the summer Pacific high pressure system will become stronger.

It looks like the intense heat will return from the second half of next week. It also seems like we need to be careful about heatstroke.

[Localized heavy rain again in Kanto] Be wary of secondary damage in Chiba due to localized heavy rain! (Commentary: Weather forecaster Atsuko Miyake)

2026/08/14 14:04

Yesterday there was record heavy rain in Chiba Prefecture.



The 24-hour rainfall up to 10 a.m. today, Friday, the 14th, was 367.0 mm in
Chiba City, which is the highest in recorded history.
This 367 millimeters of rain was more than three times the amount of rain that falls in a month at this time of year.

Yesterday, the 13th (Thursday), record-breaking short-term heavy rain warnings were announced 25 times in Chiba Prefecture,
this is also a record number of times.

Also, from last night until dawn today,
special warnings for heavy rain and landslides were also announced in Chiba Prefecture.

The rain has temporarily stopped, but there is a possibility that heavy rain and thunderstorms will return after this.



Now, let's take a look back at the causes of the torrential rains in Chiba Prefecture.

There is a predominant anticyclone near the Kuril Islands, and the movement is slow.
Moist air around the edge of this high pressure system was flowing into Chiba Prefecture on the northeast wind.

Also, warm, humid air around typhoons and tropical cyclones was flowing in from the south,
making it easy for humid air to flow into Chiba Prefecture.

Furthermore, cold air was flowing in from the inland areas of the Kanto region on northwesterly winds, and
the winds were converging just within Chiba Prefecture.

As a result, the rain clouds did not move much, and heavy rain continued for a long time in similar places.

The same pressure distribution will continue into tomorrow, the 15th (Saturday), and the unstable atmosphere is expected to continue for a long time.



Now, let's take a look at the rain forecast.
After this, linear rain clouds are expected to form again along the coasts of Chiba and Ibaraki prefectures.

We do not know whether a linear precipitation band will form like yesterday, but
the Kanto region will continue to be prone to active rain clouds.

Also, this rain cloud is expected to gradually move westward through the night, but the position of this developed rain cloud is expected to change depending on the wind direction.

Please check the latest status on radar etc.


The date has changed, and even into the early hours of tomorrow (Saturday), active rain clouds are likely to continue in the Kanto region.
In some cases, heavy rain can exceed 80mm per hour.
Please be careful about how it rains after this.




Also, even a small amount of rain increases the risk of landslides in Chiba Prefecture, so even after the rain has stopped, please do not approach cliffs or slopes that are likely to collapse.

The water may rise downstream of the river after the rain has stopped, so please do not go to see the
river or rice fields.

And tonight, some places, such as Tokyo and Kanagawa Prefecture, will see a peak of rain overnight.
It is actually dangerous to evacuate during heavy rain during dark hours.
Please move to a safe place while it is daylight.



, we will take a look at the detailed weather of each place.
The unstable atmosphere will continue in the Kanto region into tomorrow (Saturday).
Especially into the early hours of tomorrow (Saturday), please be careful of heavy rain, thunderstorms, and gusts of wind such as tornadoes.

The cloudy weather will continue into the beginning of next week.
In the second half of next week, the summer Pacific anticyclone will become stronger again.

It looks like we will have another extremely hot day with temperatures exceeding 35 degrees Celsius.
We need to be careful about heat stroke again in the second half of next week.

Weather for today, the 14th (Friday): The Pacific side of the Kanto and Tohoku regions are warned of heavy rain and thunderstorms. Atmospheric instability continues

2026/08/14 08:11

Today, the 14th (Friday), it will likely rain on the Pacific side of the Kanto and Tohoku regions, and in some places it will rain very heavily, accompanied by thunder. It is necessary to be wary of flooding and landslides in low-lying areas. Hokkaido, Hokuriku, Kinki, Kyushu, and Okinawa will experience periods of sunshine.



Today, rain is likely to fall mainly on the Pacific side of the Kanto and Tohoku regions, and there is a risk of thunderstorms and heavy rain on the east coast of the Kanto region, especially in the afternoon.





Even if the rain eases during the day, it is expected to pick up again in the evening. In areas such as southern Kanto and Tohoku, it is necessary to be careful as the rain becomes heavier in a short period of time. Even in Chiba Prefecture, which experienced record heavy rain, there will be places where thunderstorms will occur again.

In other areas, there are many places where the sun will shine, but there will be places where there will be sudden rain or thunderstorms in the afternoon.

Today again, we need to be on high alert for disasters caused by heavy or very heavy rain. Be careful of landslides, flooding, and sudden rises in river water in low-lying areas such as slopes, near cliffs, along rivers, and underpasses. If you feel that things are even slightly different than usual, move to safe higher ground or a designated evacuation center before dark, and frequently check evacuation information from local governments.

Level 5 special alert is in effect in northwestern Chiba prefecture and northeastern Chiba prefecture; Kanto-Koshin area is on high alert for heavy rain through Friday the 14th!

2026/08/14 00:18

In the Kanto-Koshin region, warm, humid air circulating around the high-pressure system east of the Chishima Islands flows in, combined with the influence of cold air in the upper atmosphere, resulting in extremely unstable atmospheric conditions, with some places experiencing extremely heavy or torrential rain accompanied by intermittent thunderstorms. In particular, in Chiba Prefecture, heavy rain has continued since the evening due to linear precipitation bands, and level 5 special warnings have been announced in various areas.



As of midnight on the 14th, the special warnings announced for Chiba Prefecture are as follows.

#Level 5 Heavy Rain Special Warning
Chiba City, Ichikawa City, Funabashi City, Matsudo City, Mobara City, Sakura City, Togane City, Narashino City, Kashiwa City, Ichihara City, Yachiyo City, Abiko City, Kamagaya City, Yotsukaido City, Yachimata City, Inzai City, Shirai City, Oami Shirasato City, Nagara Town, Shirako Town

#Level 5 Landslide Special Warning
Chiba City, Ichihara City, Oami Shirasato City, Mobara City

Level 5 heavy rain special warning is information that serves as a guideline for local governments to issue "emergency safety measures." It is extremely likely that a disaster has already occurred. Please check your surroundings and take extreme precautions against flooding of low-lying land and rising and flooding rivers. Please check the evacuation information from your local government and take the best action to protect your life.



Also, the main rainfall observed to date is as follows.

24-hour precipitation as of 22:00 on the 13th (preliminary figures from AMeDAS)
Chiba Prefecture
Chuo-ku, Chiba City 279.0mm
Sakura 233.5mm
Ushiku, Ichihara City 196.5 mm

Many locations are observing the highest value in observation history, making it a record-breaking heavy rain that has never been experienced before.

In the Kanto-Koshin region, heavy to very heavy rain with thunder is expected to fall late into the night of the 14th, with localized torrential rain expected. If rain clouds develop more than expected or if developed rain clouds continue to cover the area, the area and period of warning-level heavy rain may expand.

The expected hourly precipitation on the 13th is:
Northern Kanto region 50mm
Southern Kanto region 80mm
Koshin region 40mm
Izu Islands 50mm
The predicted hourly precipitation on the 14th is high in the following areas: Northern Kanto region 50mm
Southern Kanto region 80mm
Koshin region 40 mm
Izu Islands 30 mm
24-hour precipitation expected from 0:00 on the 14th to 0:00 on the 15th is high in places,
Northern Kanto region 100 mm
Kanto region Southern area: 200 mm
Koshin region: 80 mm
Izu Islands: 80 mm
If a linear precipitation band occurs, there is a risk that the amount of rainfall will increase locally.

In Chiba Prefecture, please exercise extreme caution for flooding of low-lying areas, rising and overflowing rivers, and landslides through the early hours of the 14th. In the Kanto-Koshin region, please be extremely cautious of landslides, flooding of low-lying land and underground facilities, and rising and flooding rivers until noon on the 14th. Also, please be careful of flooding of low-lying land, rising river water, and landslides late into the night of the 14th. Also be careful of strong wind gusts such as lightning and tornadoes. If there are signs that a cumulonimbus cloud is approaching, please take precautions such as moving inside a building. There is also a risk of hail, so please be careful when managing crops and agricultural facilities.

[Breaking news] [Level 5 landslide special warning] announced for Chiba and Ichihara cities. Immediately evacuate to a safe place!

2026/08/13 22:23

Due to the heavy rain that occurred in Chiba Prefecture on the afternoon of the 13th, a special level 5 landslide warning was announced at 9:55 pm, following a special level 5 heavy rain warning for the northwestern part of the prefecture.



The following municipalities have been issued with a level 5 landslide special warning.

Chiba City, Ichihara City



This is the first time that a level 5 landslide special warning has been issued since the start of operation in May.

There is an extremely high possibility that landslides have already occurred in Chiba City and Ichihara City, and lives are in danger. The utmost vigilance is required.

If you are near a cliff, etc., please check your surroundings and if it is dangerous to go outside, please ensure your safety immediately by moving to the upper floor of a sturdy building or to a room as far away from the cliff as possible.

Please take action to protect lives.

[Breaking News] "Level 5 heavy rain special warning" announced in Chiba Prefecture. Take immediate action to protect your life!

2026/08/13 20:06

A Level 5 heavy rain special warning was recently announced for northwestern Chiba Prefecture. Please take immediate action to save lives.




#The municipalities where a Level 5 heavy rain special warning has been announced are as follows.

Chiba City, Ichihara City, Ichikawa City, Funabashi City, Matsudo City, Narashino City, Kashiwa City, Yachiyo City, Kamagaya City, Sakura City, Yotsukaido City, Shirai City, Abiko City, Inzai City




In the northwestern and southern parts of Chiba Prefecture, extremely heavy rain continues in a linear precipitation belt. The risk of life-threatening disasters occurring is rapidly increasing. Please ensure your safety immediately.

Continuing, "Weather Disaster Prevention Alert (Stranded Rain Band Occurrence)" has been issued for the northwestern and southern parts of Chiba Prefecture. In the northwestern and southern parts of Chiba Prefecture, extremely heavy rain continues to fall in the same places due to the linear precipitation belt. The risk of life-threatening disasters occurring is rapidly increasing. Please ensure your safety immediately.

In Chiba Prefecture, there are places where heavy rain is occurring, mainly in the northwest and south.

19:00
+About 120mm per hour near Yachiyo City.
+About 100 mm per hour near Yotsukaido City.
+About 110 mm per hour near Funabashi City.
+About 110 mm per hour near Shirai City.

18:50
+About 110mm per hour near Sakura City.
+About 100 mm per hour near Yachiyo City.
+About 100 mm per hour near Inzai City.

18:40
+About 110mm per hour near Chiba City.
+110mm per hour in Chuo Ward, Chiba City.

18:20
+Record heavy rain is expected to continue in the northwestern and southern parts of the country into the early hours of tomorrow, the 14th (Monday), at a rate of approximately 10mm per hour near Ichihara City. We are in a situation where a major disaster is imminent.
Please take action to protect your life.

Weather for tomorrow the 14th (Friday): Be careful of heavy rain in the Kanto region

2026/08/13 18:01

Tomorrow, the atmospheric conditions will be unstable and it will rain in places. The weather may change suddenly in the afternoon.



Eastern Japan and the Pacific side of Tohoku are likely to have a rainy day due to high pressure over the sea east of Hokkaido and moist easterly winds flowing in from Typhoon No. 17. Please be careful of heavy rain accompanied by thunder mainly in the Kanto region. Don't forget to bring an umbrella when you go out. There are many places where the temperature does not reach 30c during the day, so it will feel cool.
In Hokkaido, the Sea of Japan side of Tohoku, and Hokuriku, there are times when the sun can reach you, and the summer sky will be wide open.
Atmospheric conditions are unstable from the Tokai region to the west, and even if the sun shines, there is a possibility of sudden thunderstorms in the afternoon. Please take a folding umbrella with you when you go out. It's predicted to be a midsummer day with high humidity, so it's going to be hot and humid.
The weather in Okinawa is expected to be cloudy and cloudy.

Weather for tomorrow the 14th (Friday): Be careful of heavy rain in the Kanto region

2026/08/13 18:00

Tomorrow, the atmospheric conditions will be unstable and it will rain in places. The weather may change suddenly in the afternoon.



Eastern Japan and the Pacific side of Tohoku are likely to have a rainy day due to high pressure over the sea east of Hokkaido and moist easterly winds flowing in from Typhoon No. 17. Please be careful of heavy rain accompanied by thunder mainly in the Kanto region. Don't forget to bring an umbrella when you go out. There are many places where the temperature does not reach 30c during the day, so it will feel cool.
In Hokkaido, the Sea of Japan side of Tohoku, and Hokuriku, there are times when the sun can reach you, and the summer sky will be wide open.
Atmospheric conditions are unstable from the Tokai region to the west, and even if the sun shines, there is a possibility of sudden thunderstorms in the afternoon. Please take a folding umbrella with you when you go out. It's predicted to be a midsummer day with high humidity, so it's going to be hot and humid.
The weather in Okinawa is expected to be cloudy and cloudy.

Latest 1-month forecast: It's expected to get hotter nationwide, with the lingering heat expected to be severe through the first half of September

2026/08/13 17:20

On the 13th (Thursday), the Japan Meteorological Agency announced the latest one-month forecast, which shows the weather outlook for the next month.



Forecasts for the average sea level pressure for the next month indicate that there will be a high-pressure area from North China to the sea near the Chishima Islands, and the Sea of Japan side will likely be covered by high pressure.
Temperatures around 1500m above the sky are expected to be higher than normal, mainly in northern Japan. For this reason, it is expected that the whole country will be easily covered in warm air.



Recently, the power of the Pacific high pressure system has weakened and the heat has calmed down a bit in some places, but it looks like the heat will return to the extreme. Depending on the location, it can become dangerously hot, with some places recording extremely hot days of over 40 degrees Celsius. The average temperature for the month is higher than normal nationwide, and is expected to remain high until the first half of September, with the lingering heat expected to be severe.
Please continue to take measures to prevent heatstroke.

From now on, the Sea of Japan side is likely to be covered by high pressure, and it is expected that there will be many sunny days from northern Japan to the Sea of Japan side of western Japan. Precipitation for the month is expected to be around normal or below normal in areas from northern Japan to the Sea of Japan side of eastern Japan, and on the Pacific side of western Japan, and below normal in areas on the Sea of Japan side of western Japan.
In areas such as the Pacific side of northern Japan, the Kanto region, and the Tokai region, the weather is expected to change over several days, and the amount of precipitation will be around normal.

[Typhoon No. 17] Possibility of approaching Kanto, so be careful of course (Commentary: Weather forecaster Atsuko Miyake)

2026/08/13 14:35

As of noon today, August 13th (Thursday), Typhoon No. 17 (Nankar) is located near Minamitorishima and is moving northeast at 35 km/h.



The central pressure is 994 hPa, and it is expected to continue moving north without developing much.

However, the forecast circle for next week and beyond is quite large, and the course is uncertain.



Looking at one forecast model, active swirling rain clouds are expected to be just east of the Kanto region as of 9:00 a.m. on the 17th (Monday).

The typhoon may move northward to just east of the Kanto region at the beginning of next week.



If you compare it with the predicted course of the typhoon currently announced by the Japan Meteorological Agency, you will see that the center position of the typhoon has shifted considerably as of 9:00 a.m. on the
17th (Monday).

I still don't know where I will go next week.

As there is great uncertainty regarding the path of the typhoon, please continue to pay close attention to the latest typhoon information.