[Kanto Level 4 Heavy Rain Danger Warning Announced] Be careful of sudden changes in weather even during the holidays! (Commentary: Weather forecaster Atsuko Miyake)

2026/07/17 15:04

The atmospheric conditions in the Kanto region have been unstable since this morning, with thunderstorms occurring here and there.



Looking at the state of the rain clouds at 2:00 p.m., active rain clouds are scattered here and there in the Kanto region, and lightning strikes have also been observed.

In Hachioji City, Tokyo, extremely heavy rain of 58.5mm was observed in the hour until 2pm.



As of 2:00 p.m., a level 4 heavy rain danger warning has been issued for Hachioji City in Tokyo, Matsudo City, Chiba Prefecture, Ichikawa City, Yokohama City, and Kawasaki City in Kanagawa Prefecture.
If you are in a dangerous place, please assess your surroundings and immediately evacuate to a safe place.

As the atmosphere continues to be unstable, please be careful of sudden changes in the weather, even in places where it is not raining right now.
Be careful of lightning, tornadoes, strong wind gusts, and hail.



Now, let's take a look at the forecast for rain clouds.
After this, rain and thunderstorms are expected to occur over a wide area.
Also, the wind that carries the rain clouds is weak today, so even if rain clouds form, there is a possibility that extremely heavy rain will continue to fall in similar areas.


After this, there is a possibility that rain will continue in similar places in the northern Kanto region, such as around Utsunomiya,
through the night.

Also, the date has changed and rain clouds will continue to remain from early morning to early morning tomorrow (Friday), and
there is a risk that it will continue to rain heavily in similar areas.



In urban areas, if it continues to rain in the same area, drainage may not be able to catch up and rainwater may flow into
underpasses.

Today, please stay away from underground facilities and other places where rainwater can easily enter.

Also, lightning strikes are occurring, so please move to a sturdy building to protect yourself.

For information such as when the rain clouds will leave, please check the latest information on the rain cloud radar.



I think many people will have a three-day weekend starting tomorrow the 18th (Saturday), but it seems that there are few days in the Kanto region that are tightly covered by high pressure even during the holidays.

Moist air flows towards the front in the Sea of Japan.
The Kanto region continues to be prone to clouds and rain clouds.

There will still be rain and thunderstorms in the plains, especially tomorrow the 18th (Saturday), so please bring rain gear when you go out.

In the latter half of the holidays, there will be periods of sunshine, but thunderstorms are more likely to occur along the mountains.
Please be careful of sudden changes in weather when enjoying leisure activities in the mountains and rivers.



In the Kanto region, it is likely to rain during the first half of the holidays.
On the 18th (Saturday), there will be rain and thunderstorms even in areas marked cloudy, so
Please be aware of sudden changes in the weather.

The latter half of the holidays is likely to be sunny in the southern Kanto region, but the temperature will rise as the second half progresses.
Please be careful of heat stroke.



Weekly forecast.
The Kanto region will be marked as sunny from now on.
The rainy season has not yet ended in the Kanto-Koshin region, but I think there will be an announcement about the end of the rainy season soon.
However, once the rainy season ends, the heat will increase even more.
Inland areas are expected to continue experiencing extremely hot days with temperatures above 35c starting from the middle of next week.
The temperature will be quite high. Please be even more careful about heatstroke than ever before.

[3-day weekend weather] Atmospheric instability - Be careful of sudden changes in leisure weather in mountains and rivers! Warning heavy rain in Hokkaido (Commentary: Weather forecaster Atsuko Miyake)

2026/07/17 13:54

Atmospheric conditions have been unstable since the morning of today, the 17th (Friday).
Looking at the state of the rain clouds at noon, there are heavy rain clouds scattered here and there from the Kanto region to the Tohoku region.



Lightning has also been observed in the central Kanto area.
After this, in the afternoon, there is a high probability of lightning occurring not only in the Kanto and Tohoku regions, but also around the Kyushu region.

Please be careful of sudden changes in the weather from now on, even in areas where the weather is sunny now.
Please be careful of sudden strong rain, lightning strikes, strong gusts of wind such as tornadoes, and hail.



This is the forecast for rain clouds after this.
Towards the evening, rain clouds are expected to develop not only along the mountains in the Kanto, Tohoku, and Kyushu regions, but also
on the plains.

The wind that carries the rain clouds is quite weak today, so once the rain clouds develop,
it is expected to continue raining in the same places.

Rain clouds will clear up in the Tohoku and Kyushu regions at night, but in the Kanto region, rain is expected to continue in similar areas into the night.



There is a risk of heavy rain and thunderstorms in similar areas into the early hours of tomorrow.
Please be careful about flooding of roads and low-lying land.




Also, I think many people will have a three-day weekend starting tomorrow the 18th (Saturday), but it seems like it will be difficult to have clear skies even during the holidays because of the high pressure.

There are fronts and low pressure systems in the Sea of Japan, and the area around Honshu is a path for moist air.
Tomorrow, the 18th (Saturday), there will be a lot of clouds, and there are likely to be showers and thunderstorms here and there.
Please bring rain gear when going out.

There is a risk of warning-level heavy rain in Hokkaido from the 19th (Sunday) to the 20th (Monday/Holiday) as the low-pressure front approaches.
In Hokkaido, the ground has become loose due to past rains, so please be careful and be on guard against landslides.



This is the weather during the 3-day holiday.
It continues to rain in Hokkaido during the holidays.
Please be careful of heavy rain, especially from the 19th to the 20th.
Also, it tends to rain more in Tohoku and Hokuriku during the first half of the holidays.

Toward the latter half of the holidays, there will be some sunny days in western and eastern Japan, but
thunderstorms are also likely to occur along the mountains, so
please be careful of sudden changes in the weather when enjoying leisure activities in the mountains and rivers.



Weekly forecast. Next week. The sunny mark stands out.

In eastern Japan, such as the Kanto-Koshin region, and in the Tohoku region,
there is no announcement yet that the rainy season will end, but it looks like the end of the rainy season will increase in many places next week.



It looks like it will be quite hot from the middle of next week.
``Early weather information regarding high temperatures'' has also been announced, and from around the 22nd (Wednesday), it is likely to be ``very high temperatures'' nationwide.

For this time of year. There is a risk that the temperature will reach a level that occurs only once every 10 years.
Raise your precautions next week by one step higher than your previous precautions against heat stroke.

[Marine Summary] Severe drowning near the Nansei Islands due to Typhoon No. 9 (July 5th to 11th, 2026)

2026/07/17 13:39

Typhoon No. 9 was the most powerful and ferocious typhoon in the Mariana Islands.
After that, a large and strong force passed near the Sakishima Islands.
The sea near the Nansei Islands was severely flooded, with wave heights reaching a maximum of 13 meters when the typhoon passed.
Below is a summary of the ocean (July 5th to 11th, 2026)



#Pressure distribution and waves
On the 6th, a large and ferocious typhoon No. 9 moved westward near the Mariana Islands, and on the 7th and 8th it moved westward east of the Philippines with extremely strong force.
On the 9th, Typhoon No. 9, a large and very strong typhoon, changed its course to the northwest east of the Philippines, and reached the south of Okinawa on the 10th.
On the 11th, Typhoon No. 9 was large and powerful, passing near the Sakishima Islands and moving northwest.
As Typhoon No. 9 approached Japan, waves were rough in the south of Japan and near the Ogasawara Islands on the 7th and 8th, and waves were slightly higher in the east of Japan.
From the 8th to the 9th, there was a storm in the sea near the Nansei Islands, and in the south of Okinawa and the south of Japan, there was a severe storm around the typhoon.
From the 10th to the 11th, the sea near the Nansei Islands was hit by a typhoon, resulting in severe flooding, with wave heights reaching a maximum of 13 meters.



#Sea surface temperature
Sea surface temperatures in the Japanese waters continued to be higher than normal.
The temperature gradually rose significantly above normal, mainly in the central part of the country, reaching a maximum of 3 C above normal.
The East China Sea, the waters near the Nansei Islands, and the south of Japan remained at normal levels, while the waters off the southeastern coast of Kanto continued to be slightly lower than normal.
Off the coast of Sanriku, conditions continued to be at normal levels.
Off the southeastern coast of Hokkaido, sea areas continued to be significantly higher than normal, with temperatures up to 4 C higher than normal.
In the waters near the Kuril Islands, the area slightly below normal has shrunk.
The Sea of Okhotsk was slightly higher than normal.

Today's weather (Friday 17th): The atmosphere is unstable nationwide. Be careful of sudden heavy rain and thunderstorms. The Tokai Kinki region is experiencing intense heat.

2026/07/17 07:58

Atmospheric conditions will be unstable over a wide area today, the 17th (Friday). Please be aware of sudden and severe thunderstorms in places, especially in the afternoon.
It will be hot and humid in many places, so please continue to take precautions against heat stroke.



Today, the weather is likely to be cloudy in many places, and rain clouds are likely to form in some parts of the Kanto region during the morning commuting hours. In the afternoon, rain clouds will appear here and there, mainly in Kyushu, Kanto-Koshin, and Tohoku, and there will be places where it will rain heavily, accompanied by thunder. In eastern Japan, rain will continue into the night.



The probability of lightning strikes is high in Kyushu and eastern Japan from late afternoon to evening, and in Kanto and Koshin areas even into the night. In some places in eastern Japan, it's more than 50%. If the sky suddenly becomes dark or you hear the sound of thunder nearby, please move to a safe place.


There are some places where the sun shines, and the temperature rises during the day, making it extremely hot. Temperatures are expected to rise to 34c in Asahikawa, Hokkaido, where it is sunny, and 32c in Sapporo.
It will be extremely hot in the Tokai and Kinki regions, with Kyoto at 37 degrees Celsius, and places like Osaka and Gifu at 36 degrees Celsius, which is likely to be as hot as body temperature. The humidity will be high and the heat will be uncomfortable, so please take care of your health.

From around July 22nd, dangerous heat of "once in 10 years" will be felt all over the country, so be on guard against heat stroke!

2026/07/17 06:48

Yesterday, the 16th, the Japan Meteorological Agency announced "early weather information regarding high temperatures" for Hokkaido, Kyushu, Amami, and Okinawa.



"Early weather information regarding high temperatures" is announced when the region is expected to experience high temperatures that are at a once-in-a-decade level for this time of year.
The Japanese archipelago will be more likely to be covered in warm air from now on, so it is expected that there will be many days with ``fairly high temperatures'' over the next two weeks.
Extremely high temperatures are expected from Hokkaido to Kyushu and Amami from around the 22nd (Wednesday), and in Okinawa from around the 25th (Saturday). In addition to taking care of your health, please also be careful about managing your crops.



Next week, temperatures inland are expected to be just one step away from being extremely hot, with maximum temperatures reaching 40c. It looks like the rainy season will end next week in the Kanto-Koshin and Tokai regions.
The risk of heat stroke also increases. In particular, when a heatstroke warning alert is announced, please take proactive measures to prevent heatstroke, such as drinking plenty of water and salt, and avoiding prolonged outdoor activities and using an air conditioner indoors.

[Breaking news] New tropical cyclone develops and becomes typhoon No. 12

2026/07/16 17:45

According to information released by the Japan Meteorological Agency at 16:15 on the 16th, a new tropical cyclone has formed near the Truk Islands.
If this tropical cyclone develops, it is expected to become Typhoon No. 12.



The central pressure is 1006 hPa and it is moving east-northeast at 15 km/h. The maximum wind speed near the
center is 15 m/s, and the maximum instantaneous wind speed is 23 m/s.

At 3pm on the 17th, it is expected to proceed northeast at 15km/h near the Truk Islands, and at 3pm on the 18th, it will change course to the north and proceed at 10km/h.

Please check the latest information regarding your future career path.

Weather for tomorrow 17th (Friday): There is a risk of thunderstorms in Kanto and Tohoku

2026/07/16 17:35

Moist air is expected to flow around the edge of the high pressure system over the east coast of Japan. A front is expected to extend from the continent to the vicinity of the Korean Peninsula.



Clouds tend to spread in the Kanto, Hokuriku, and southern Tohoku regions due to the influence of humid air, and the weather is likely to be unrefreshing. There is a chance of rain and thunderstorms in places.
There is a risk of thunderstorms in Kyushu and western China due to the front, so please bring an umbrella when going out.
In eastern China, Shikoku, Kinki, Tokai, northern Tohoku, and Hokkaido, there are places where the sun can reach, and the intense heat continues. Please take all possible precautions against heatstroke, such as frequently drinking water and salt, taking adequate breaks, and using a parasol or hat when engaging in outdoor activities.

[Sudden weather change] Possibility of heavy rain in the Kanto region by the time you get home. There is a risk of warning-level heavy rain in northern Japan during the three-day weekend (Commentary: Weather forecaster Atsuko Miyake)

2026/07/16 14:26

From today (Thursday) afternoon until tomorrow, the 17th (Friday), the atmospheric conditions will be unstable due to the extremely warm and humid air brought in by the
typhoon.
Please be careful of sudden changes in weather even if it is sunny.



This is the state of the rain clouds at noon today (Thursday).
At this time, rain clouds are beginning to develop in parts of the mountains from the Kanto-Koshin region to the Tohoku region.
Not many rain clouds have flown into the plains yet, but after this, due to the humid air and rising temperatures, rain clouds are likely to form here and there.



Rain clouds are forecast from the evening.
In the Kanto-Koshin and Tohoku regions, rain clouds flow not only along the mountains but also into the plains.
There is also a red sign, indicating that there will be heavy rain locally.
There are likely to be thunderstorms in some places.



At 6pm, rain clouds are expected to gradually disappear in the Tohoku region, but
in the Kanto region, active rain clouds are expected to gradually move southward.

Especially around 7pm to 8pm, when it's time to go home, red signs are noticeable in places like Saitama Prefecture,
There are likely to be places where it will rain heavily.
It seems like it will hit central Tokyo as well.

Please be careful of flooding of roads and low-lying areas.

It seems that there are some areas that will remain active until the date changes.



This heavy rain refers to rain that falls between 30 and 50 mm per hour.
When it rains heavily, you may get wet even if you have an umbrella, and
the rain can turn the road into a river.

Also, the sound of rain becomes so loud that about half of the people who are sleeping notice it.
If you drive too fast, the brakes may become ineffective, so be careful.



The unstable atmosphere will continue tomorrow (Friday) as well.
Looking at the probability of lightning strikes tomorrow afternoon, the probability of lightning strikes is high not only in the Kanto region, but also in the Kyushu, Chugoku, and Shikoku regions.

Please be careful of lightning, gusts of wind, and hail tomorrow.



Rain clouds are already expected to spread over the Kanto region tomorrow (Friday) morning.
There is a risk of heavy rain even in central Tokyo.

Also, in the afternoon, rain clouds begin to form along the mountains in Kyushu, the Chugoku region, and the Shikoku region.
It is likely that rain and thunderstorms will continue to occur here and there in the Kanto region.

In the Kanto region, heavy rain from evening to night may turn into thunderstorms.
The rain is expected to continue in similar parts of the Kanto region until late at night.

Please be careful of localized heavy rain. The
river may rise or flood, rainwater may flow into low-lying areas, and the
underpass may overflow.
Please stay away from flooded rivers and underpasses.



Starting from the weekend, there will be a three-day holiday, but during the holidays, low pressure systems and fronts will pass through northern Japan.
For this reason, it rains more frequently in northern Japan.
There is a risk of heavy rain in Hokkaido, especially on the 19th (Sunday), so please be careful about how the rain falls.



Let's take a look at the weather in various places.

We need to be careful about the severe heat and sudden changes in the weather tomorrow (Friday) as well.

Osaka and Nagoya are expected to have a very hot day with temperatures reaching 35 degrees Celsius.

Today (Thursday) is already the third consecutive day of extremely hot weather in Nagoya, so if the temperature exceeds 35c tomorrow, it will be the fourth consecutive day of extreme heat. Please be careful of heat stroke.

Also, even in areas marked as sunny, be careful of sudden changes in the weather in the afternoon.



Weekly forecast.
During the three-day weekend starting on the 18th (Saturday), it will be rainy especially in northern Japan and Hokuriku.

The weather in western and eastern Japan is also likely to be cloudy and less clear than in the first half of the holidays.

Although the rainy season has not yet ended in eastern Japan and the Tohoku region,
it is expected to be sunny next week.
I think there will be an announcement of the end of the rainy season in eastern Japan next week.

Tomorrow, the 17th (Friday) Lightning warning area expanded; be careful of heavy rain, gusts of wind, and hail

2026/07/16 12:59

A low pressure system accompanied by a front is passing near Sakhalin. Low pressure On the other hand, there is a high pressure system south of Okinawa, which is stationary near the Nansei Islands.
The Tohoku region is currently covered in rain clouds, and the weather is expected to gradually improve after this.
The heat continues today, with temperatures nationwide being higher than normal,
predicted to be even hotter than midsummer.
Sapporo is expected to be at 31c, Tokyo is expected to be at 35c, and Nagoya is expected to be at 37c, so it looks like the temperature will be unbearable. Please take care of your health.



In addition to the rise in temperature near the ground, the influence of warm, humid tropical air brought in by the low pressure system that was Typhoon No. 9 will make the atmosphere unstable in the afternoon of today (Thursday) the 16th,
and there is a risk of heavy rain accompanied by thunder mainly along the mountains of the Kanto region.



Tomorrow, the 17th (Friday), there will be some sunshine in western Japan, but the atmospheric conditions are unstable mainly in the Kanto, Hokuriku, and Kyushu regions, and there is a risk that rain clouds may form locally in the morning.





It is expected that areas with a higher probability of lightning than today will expand, such as along the mountains of the Kanto and Hokuriku regions and the Kyushu, Chugoku, and Shikoku regions.Please pay close attention to the latest information and be wary of the sudden development of rain clouds.
In the target areas, please be careful of flooding of low-lying land, rising river water, flooding, and landslides.

The end of the rainy season is announced earlier than normal in northern Kyushu, Shikoku, and Kinki. Large typhoon No. 9 approaches the Sakishima Islands on the 11th (weather summary from July 5th to July 11th, 2026)

2026/07/16 07:42

This is a summary of the weather for this period (July 5th to July 11th, 2026).

#Summary of the weather for this period (July 5th to July 11th)
During this period, warm air tends to enter, and after the rainy season front became unclear, some places in western Japan recorded extremely hot days. Particularly in western and northern Japan on the Sea of Japan side, there were some places where the air currents over the mountains caused high temperatures, and the average temperature was above normal, mainly on the Sea of Japan side. Temperatures on the Pacific side of eastern Japan were below normal in some places due to the influence of cool air north of the seasonal rain front.

Although heavy rain was recorded in some places in Kyushu and Shikoku in the first half of the period, the seasonal rain front gradually became unclear and high pressure became dominant, so the total amount of precipitation was below normal in many places. In the second half of the period, Hokkaido recorded much higher-than-normal precipitation due to the effects of a trough in atmospheric pressure and lower-level warm and humid air, and the Sakishima Islands due to the effects of Typhoon No. 9.

Sunshine hours tended to exceed normal levels, mainly from Tohoku to Kyushu on the Sea of Japan side, as the seasonal rain front became unclear near Honshu and there were many sunny days covered by high pressure. In Hokkaido, the number of cloudy and rainy days increased in the latter half of the period due to the effects of a trough in atmospheric pressure and warm, humid air in the lower levels, and there were some places where temperatures were below normal.



[About this period's weather]
#Characteristics of pressure distribution
On the 5th, the seasonal rain front stalled from northern Kyushu to near Shikoku, and the front extended as far east as Japan. The seasonal rain front remained stationary in western Japan until the 6th, but on the 7th the front near western Japan gradually became unclear, and the area around Honshu was widely covered by high pressure near Okinawa and high pressure east of the Chishima Islands. From the 8th onwards, the seasonal rain front was almost invisible around Honshu, and was covered by a high-pressure system extending far to the east of Japan.However, from the 9th to the 11th, the area around Hokkaido was susceptible to the effects of a trough in pressure and lower-level warm, humid air. Meanwhile, Typhoon No. 9, a large and powerful typhoon, moved westward near the Mariana Islands on the 5th, and passed through the Mariana Islands at its peak on the 6th. After that, it became a large and very strong force as it moved westward over the sea east of the Philippines, and around the 10th, it gradually changed its course to the northwest and headed north over the sea south of Okinawa. On the 11th, Typhoon No. 9 became large and powerful and passed near the Sakishima Islands. On this day, a daily maximum instantaneous wind speed of 45.3 m/s was observed in Kitahara, Kumejima Town, Okinawa Prefecture.

#Precipitation
On the 5th, heavy rain occurred mainly in western Japan due to the influence of the seasonal rain front. Extremely heavy rain of 76.0 mm/h occurred in Soeda Town, Fukuoka Prefecture, linear rain bands formed in Kumamoto Prefecture, and extremely heavy rain was observed in Uwajima City, Ehime Prefecture on Shikoku. On the 6th, the rainy season front brought rain over a wide area of western and eastern Japan, with particularly heavy rain observed in western Japan, especially in Kyushu. On the 7th, the rainy season front moved south of Honshu, with somewhat heavy rain near the Izu Islands. In western Japan, the seasonal rain front became unclear, but there was localized rain and thunderstorms along the mountains and inland. On the 8th, the area around Honshu was in a high-pressure zone, with almost no precipitation. The end of the rainy season was announced in northern Kyushu, Chugoku, and Kinki (all 11 days earlier than normal). On the 9th, there was a trough in the atmospheric pressure near Hokkaido, and the inflow of lower-level warm and humid air made the atmosphere unstable, resulting in heavy rain. On the 10th, heavy rain of 43.5 mm/h was observed in Nakatonbetsu, Hokkaido, and on the 11th, extremely heavy rain of 54.0 mm/h was observed in Fukagawa City, Hokkaido. On the 10th and 11th in the Nansei Islands, heavy rain was observed in Kunigami Village and Miyakojima City, Okinawa Prefecture due to Typhoon No.9.

#Temperature
On the 5th, there were some places in northern Japan that were covered in high pressure and the sunlight reached midsummer, and the temperature was recorded at 32.4c in Takasu, Kitaakita City, Akita Prefecture. On the 6th, western Japan experienced cloudy and rainy weather due to the seasonal rain front, but temperatures were high; in Miyazaki Prefecture, a temperature of 34.2 degrees Celsius was recorded in Akae, Miyazaki City, where southerly winds caused a ferohn phenomenon. On the 7th, midsummer air flowed over Kyushu and the temperature rose, with Dazaifu City, Fukuoka Prefecture experiencing an extremely hot day of 35.7c. On the other hand, in Tokyo, there was little sunshine due to easterly winds, and the maximum temperature remained at 24.7 degrees Celsius. On the 8th, the temperature rose due to sunshine and warm air brought in by Typhoon No.9. Extremely hot days were recorded in 10 locations, including Maebaru, Itoshima City, Fukuoka Prefecture, and Hita City, Oita Prefecture. On the 9th, the area around Honshu became an area of high pressure, with clear skies and rising temperatures. An extremely hot day of 35.3c was recorded in Kyoto. On the 10th and 11th, the area around Honshu continued to be in a high-pressure zone, and areas with clear sunshine recorded extremely hot days. On the 10th, Yatsushiro City, Kumamoto Prefecture experienced a heatwave of 37.2c, and on the 11th, Dazaifu City, Fukuoka Prefecture recorded a temperature of 39.2c, the highest in recorded history. The number of observation points on the extremely hot day on the 11th reached 43.