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.

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.

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.

Intermittent rain in the Kanto region; localized extremely heavy rain possible; strict warning against landslides

2026/08/13 06:44

Warm, humid air circulating around the high-pressure system east of the Chishima Islands is flowing into the Kanto-Koshin region, and with the added influence of cold air in the upper atmosphere, the atmospheric conditions continue to be unstable. Rain clouds developed in
Kesa mainly in Chiba Prefecture, and heavy rain of 25.5 mm/h was observed in Ushiku, Ichihara City, Chiba Prefecture, and 23.5 mm/h in Kisarazu City.



Atmospheric conditions are expected to become extremely unstable in the Kanto-Koshin region late into the evening of today, the 13th. It's likely to rain intermittently on and off, so it's likely to be a day when rain gear is essential.
In the Kanto-Koshin region, it is expected that there will be localized heavy rain with thunder and very heavy rain of over 50 mm per hour until late at night on the 13th. If rain clouds develop more than expected or if developed rain clouds continue to cover the area, there is a risk that the area and period of warning-level heavy rain may expand.
Also, there are places where the ground has become loose due to the rain that has fallen so far, and even with a small amount of rainfall, the risk of landslides may increase.

In the Kanto-Koshin region, please be on high alert for landslides from the afternoon of the 13th to late at night, and be careful of flooding in low-lying areas and rising river waters from late at night on the 13th. Also, be careful of lightning, tornadoes, strong wind gusts, and hail. Please also pay attention to the management of crops and agricultural facilities.

#Expected rainfall (in areas where there is a lot)
+Expected hourly precipitation for today, the 13th
Northern Kanto region 50 mm
Southern Kanto region 50 mm
Koshin region 30mm
+Precipitation expected for 24 hours by 6:00 tomorrow 14th (Friday)
Northern Kanto region 100mm
Southern Kanto region 100mm
Koshin region 60mm

Intermittent rain in the Kanto region; localized extremely heavy rain possible; strict warning against landslides

2026/08/13 06:44

Warm, humid air circulating around the high-pressure system east of the Chishima Islands is flowing into the Kanto-Koshin region, and with the added influence of cold air in the upper atmosphere, the atmospheric conditions continue to be unstable. Rain clouds developed in
Kesa mainly in Chiba Prefecture, and heavy rain of 25.5 mm/h was observed in Ushiku, Ichihara City, Chiba Prefecture, and 23.5 mm/h in Kisarazu City.



Atmospheric conditions are expected to become extremely unstable in the Kanto-Koshin region late into the evening of today, the 13th. It's likely to rain intermittently on and off, so it's likely to be a day when rain gear is essential.
In the Kanto-Koshin region, it is expected that there will be localized heavy rain with thunder and very heavy rain of over 50 mm per hour until late at night on the 13th. If rain clouds develop more than expected or if developed rain clouds continue to cover the area, there is a risk that the area and period of warning-level heavy rain may expand.
Also, there are places where the ground has become loose due to the rain that has fallen so far, and even with a small amount of rainfall, the risk of landslides may increase.

In the Kanto-Koshin region, please be on high alert for landslides from the afternoon of the 13th to late at night, and be careful of flooding in low-lying areas and rising river waters from late at night on the 13th. Also, be careful of lightning, tornadoes, strong wind gusts, and hail. Please also pay attention to the management of crops and agricultural facilities.

#Expected rainfall (in areas where there is a lot)
+Expected hourly precipitation for today, the 13th
Northern Kanto region 50 mm
Southern Kanto region 50 mm
Koshin region 30mm
+Precipitation expected for 24 hours by 6:00 tomorrow 14th (Friday)
Northern Kanto region 100mm
Southern Kanto region 100mm
Koshin region 60mm

Today's weather on the 13th (Thursday): Widespread atmospheric instability. Pay attention to changes in the sky pattern.

2026/08/13 06:11

Today, the 13th (Thursday), a tropical cyclone that has changed from Typhoon No. 15 is expected to move eastward off the San'in coast. Atmospheric conditions are expected to become unstable from Tohoku to western Japan due to the effects of warm, humid air heading toward a tropical cyclone and cold air in the upper atmosphere. Please be careful of sudden thunderstorms.



In Hokkaido, there are areas where the sunlight reaches, mainly on the Sea of Japan side. On the other hand, on the Pacific side, clouds tend to spread and there is a possibility of showers, so it is a good idea to bring a foldable umbrella when going out.

Atmospheric instability continues from Tohoku to western Japan. Rain clouds are likely to develop in various places, and there will be localized areas with heavy rain and thunderstorms, resulting in heavy rain. Please pay attention to changes in the sky, as conditions can change in a short period of time, and be careful of landslides, flooding of low-lying areas, and rising river waters during heavy rain.

Since the weather will be cloudy and rainy in many places, the maximum temperature is expected to be around 30c in many places, and there are few places where extremely hot days are expected. However, it can feel hot and humid during the day, so please take precautions against the heat by staying hydrated frequently and choosing breathable clothing.