[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.

[Atmospheric instability during the second half of the Obon holiday] Be careful of localized heavy rain and lightning strikes (commentary: weather forecaster Atsuko Miyake)

2026/08/13 14:17

Atmospheric conditions near Japan are currently extremely unstable.
The atmospheric conditions will continue to be unstable during this Obon period, so please be careful and be on guard against localized heavy rain.
Let's first take a look at the state of the rain clouds at noon today.



At this time, rain clouds are developing in places from Kyushu to the Tohoku region.
Especially in the Kanto region, you can see red signs, and there are places where it is raining more than 30mm per hour.

After the evening, it is likely that there will be some places where it will rain extremely heavily, exceeding 50mm per hour.



Let's take a look at the weather map to see what is causing this heavy rain.

There is a predominant high pressure system near the Kuril Islands.
Moist air circulating around the edge of this high pressure system is flowing into the Pacific side of the Kanto and Tohoku regions.

Also, there is a tropical cyclone in the Sea of Japan that was originally Typhoon No. 15.
Warm, humid air flows into this tropical cyclone from the south, and the area around Japan is a place where this humid air tends to flow.

Furthermore, cold air is flowing into the sky, making the atmosphere extremely unstable.

After this, rain clouds will develop locally and there will be warning-level heavy rain in some places.
Furthermore, this atmospheric instability will continue for some time.

The same pressure distribution will continue until the 15th (Saturday) the next day, so the unstable atmosphere will continue for a while.



Also, conditions where lightning is likely to occur are likely to continue.

Let's take a look at the probability of lightning occurring at 3pm today (Thursday) and 3pm tomorrow (Friday).

The probability of lightning is high in Kyushu and Tohoku,
particularly in the Kanto region, there is a high probability of lightning occurring into tomorrow.

Please be careful of lightning and gusts of wind.
If you see dark clouds approaching or hear thunder, move to a sturdy building.



Now, let's take a look at the rain forecast.
In the afternoon, active clouds will continue to form from Kyushu to the Pacific coast of Tohoku.

The rain clouds are not as thick as this forecast, and when it rains, the rain is expected to be locally strong.

At night, yellow and orange lights can be seen in the Kanto region.
There are likely to be some places where it will rain extremely heavily, exceeding 50mm per hour.

In addition, heavy rain of more than 30mm per hour is expected to fall locally in other areas.



It will continue to rain in similar places into tomorrow (Friday).
The expected amount of rain by tomorrow morning is expected to be as much as 100 mm in the Kanto, Tokai, and Kinki regions.
Also, in the Tohoku region it is 80 mm.
It is possible that this rain will fall all at once in just 1 to 2 hours.
Please be careful of landslides, rising water levels, and flooding of rivers.

Also, when it rains extremely heavily in urban areas, exceeding 50 mm per hour,
the drainage can't keep up and the roads sometimes turn into rivers. Please stay away from
underpasses.



Here is the weather for three days from today.
The Sea of Japan and Hokuriku areas in northern Japan will see periods of sunshine, and temperatures are likely to rise again.
In Niigata, the temperature is over 33c every day.
Also, there will be some sunny days in Fukuoka with temperatures reaching around 34 degrees Celsius.

In Tokyo and Sendai, the atmospheric conditions will continue to be unstable until around the 15th (Saturday), so
please be careful of sudden rain, lightning strikes, and gusts of wind.

There are days in Nagoya and Osaka where there is no rain symbol, but
there is also likely to be sudden rain, so it's best to bring rain gear when you go out.

Although it's not that intensely hot during this period, it looks like the intense heat will return next week.



Weekly forecast.

In Tokyo, the temperature will not be as intense until around 17th (Monday), at around 31c.
However, from the second half of next week, it looks like the extremely hot days with temperatures above 35 degrees Celsius will return.

Also, from the middle of next week, extremely hot days with temperatures above 35c will return in Nagoya and Osaka.
The heat is likely to take a break during the Obon period, but after the long holidays and after the Obon holiday, the heat is likely to return.
Please be careful not to get sick.

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.

Atmospheric instability continues in various places tomorrow, the 13th (Thursday); be careful of heavy rain accompanied by intermittent thunderstorms

2026/08/12 18:38

Tomorrow, the 13th (Thursday), rain will be more likely to fall from western Japan to the Kanto region and the Pacific side of the Tohoku region due to the influence of moist air blowing in from the tropical cyclone that replaced Typhoon No. 15 and the high pressure system near Chishima. Please be careful as there are places where it will rain heavily with thunder.





The Kanto and Tohoku Pacific sides continue to experience rainy weather due to the influence of warm, humid air blowing toward the tropical cyclone and humid air blowing in from the high pressure near the Chishima Islands. The atmospheric conditions are likely to be extremely unstable due to the influence of cold air in the upper atmosphere. There is a risk of heavy or extremely heavy rain in localized areas, so please be on guard against flooding of roads, flooding of low-lying land, and landslides.
Please be sure to prepare rain gear such as a folding umbrella when going out.

Also, in western Japan, the atmospheric conditions will be unstable due to the influence of moist air blowing in from tropical cyclones, and the weather will be changeable. Rain is expected to start to fall suddenly in some places, and it may be heavy for a while.




The predicted 24-hour precipitation from 18:00 on the 12th to 18:00 on the 13th is expected to be 120 mm in the Tohoku region.
Kanto-Koshin region 100mm
Tokai region 180mm
Kinki region 150mm

Expected.


On the other hand, with the timing of sunlight reaching mainly western Japan, the temperature is likely to rise. It will be a midsummer day with temperatures exceeding 30 degrees Celsius in many places.
As the heat and humidity increases, please take precautions against heat stroke if you are going to be outdoors for a long time.

Weather and temperature summary (August 2nd to August 8th) Typhoon No. 13 hits the main island of Okinawa. Record-breaking heat continues in western Japan

2026/08/12 14:53

This is a summary of the weather and temperature from August 2nd to August 8th, 2026.

[About this period's weather]

#Characteristics of pressure distribution
On the 2nd, the Sea of Okhotsk anticyclone moved eastward, and the Pacific anticyclone centered near the East China Sea almost stagnated. Additionally, a front extends from the Tohoku region to the east of Japan, and a low pressure system moves eastward above the front. In addition, Typhoon No. 13 was moving west-northwest near Minamitorishima with extremely strong force. On the 3rd, the high pressure system centered over the East China Sea was almost stagnant. Typhoon No. 13 remained large and extremely powerful as it moved westward through the waters near Ogasawara. On the 4th, a large and extremely strong typhoon No. 13 continued to move westward near Ogasawara. On the 5th, the area around Japan was gently covered by high pressure systems centered far east of Japan and near the Yellow Sea, and a large and extremely strong typhoon moved westward south of Japan. On the 6th, a large and strong typhoon No. 13 moved westward northeast of Minami Daito Island, engulfing the Daito Island region in a stormy area. On the 7th, a large and extremely strong typhoon No. 13 continued to advance westward near the main island of Okinawa. The Daito Island region, Okinawa main island, and Amami were all within the typhoon's storm range. On the 8th, a large and extremely strong typhoon passed near the main island of Okinawa. It moved westward through the East China Sea.

#Precipitation
On the 2nd, rain continued in Tohoku due to a front. On the other hand, the atmospheric conditions in the Kanto and Tokai regions were extremely unstable, with extremely heavy rain falling at 61.5 mm/h in Ena, Gifu Prefecture, and 60.0 mm/h in Kanuma City, Tochigi Prefecture. Atmospheric conditions remained unstable in the Kinki and Kanto regions on the 3rd. A heavy rain warning has been announced in Osaka Prefecture. On the 4th, there was unstable precipitation in Kyushu and the Chugoku region. Due to the approach of Typhoon No. 13, it rained on the Ogasawara Islands, and 102.0 mm/day was observed on Hahajima. On the 5th, it rained mainly in the Daitojima region due to Typhoon No. 13. There were also places on the Pacific side of eastern Japan and western Japan with rain. On the 6th, due to Typhoon No. 13, it rained in places from the Sea of Japan side of western Japan to Okinawa. Locally, the rain became stronger, with heavy rain falling in southern Kyushu. On the 7th, heavy rain was observed in Okinawa and Amami due to rain clouds from the typhoon itself. Heavy rain occurred in Naze, Amami City, Kagoshima Prefecture, with daily maximum rainfall exceeding 300 mm, including 335.5 mm. On the 8th, Typhoon No. 13 brought strong winds and rain to a wide area of the Nansei Islands. In northern and eastern Japan, there were places in Ishikawa Town, Fukushima Prefecture, where there was heavy rainfall of 92.0 mm/h due to the influence of humid air.

#Temperature
The heat was particularly severe on the 2nd in western Japan, which was covered with hot air in the upper atmosphere, with extremely hot days of 40.8 degrees Celsius observed at multiple locations in Ekawasaki, Shimanto City, Kochi Prefecture. It was record-breaking heat, breaking the record for August at 59 locations nationwide, and breaking the record for record-setting heat at 45 locations. On the 3rd, temperatures were extremely high in western Japan, with temperatures exceeding body temperature in many places, including Kumamoto City at 40.3 degrees Celsius and Saga City at 40.2 degrees Celsius. On the other hand, temperatures in the Kanto region, where easterly winds blow from the sea, were slow to rise. On the 4th, it was extremely hot mainly in western Japan due to the effects of high pressure. In the Pacific side of northern and eastern Japan, the rise in temperature was suppressed by the northeast airflow of the Sea of Okhotsk High. On the 5th, temperatures rose in the Sea of Japan and western Kyushu due to airflow over the mountains. On the 6th, sunlight reached western Japan and eastern Japan on the Sea of Japan side. In addition, due to the southerly winds of the typhoon, a feng occurred on the Sea of Japan side. Temperature rises are particularly noticeable from southern Kyushu to the Chugoku region. 39.0c in Yatsushiro City, Kumamoto Prefecture, 38.9c in Tottori, etc. From the 7th to the 8th, temperatures continued to be strong mainly on the Sea of Japan side, with temperatures of 39.6 C observed in Ota City, Shimane Prefecture on the 7th, and 38.9 C in Fukuchiyama City, Kyoto Prefecture on the 8th.




#Summary of the weather for this period (August 2nd to August 8th)
The average temperature was extremely hot in western Japan, which was covered by an anticyclone, and reached record high temperatures mainly in the Chugoku region, northern Kyushu, and the East China Sea side, and extremely hot days were recorded in Kyushu. On the other hand, in the Tohoku Pacific side and the Kanto region, where cool easterly winds from the Sea of Okhotsk high pressure system blew, temperatures were at or below normal in many locations.
Precipitation was higher than normal in Hokuriku, which was susceptible to the effects of the seasonal rain front, Kinki, where atmospheric conditions were prone to instability, and the Nansei Islands, which was affected by Typhoon No. 13, with some places experiencing heavy rain. On the other hand, other regions were covered in high pressure for many days throughout the period, so the total precipitation for the period was lower than normal or significantly lower, with many locations reaching 0 mm.
Sunshine hours tended to exceed normal years, with many sunny days covered by high pressure throughout the country. On the other hand, in the Nansei Islands and southern Kyushu, which were susceptible to the effects of Typhoon No. 13 and humid air, temperatures tended to be below normal with many cloudy and rainy days.

Typhoon No. 15 turns into a tropical cyclone; watch out for sudden, short-term heavy rain from Tohoku to the Chugoku region from the afternoon onwards

2026/08/12 12:43

Typhoon No. 15 turned into a tropical cyclone in the Sea of Japan around 9 a.m. today, Wednesday, the 12th.

However, the warm, humid air brought in by Typhoon No. 15 remains in the vicinity of Japan, and the combination of the effects of cold air in the upper atmosphere has made the atmospheric conditions unstable. Dense rain clouds can be seen in places from Tohoku to the Chugoku region, with intermittent rain falling, and in some places the rain is becoming heavier.



Looking at the probability of lightning striking at 6:00 pm today, the 12th (Wednesday), the probability of lightning striking is expected to be high in areas such as the Tohoku Pacific side, Kanto, and Kinki. Even though there may be a break in the rain, rain clouds and thunderclouds will continue to form easily, and there is a risk that heavy rain of 30mm or more per hour may fall in localized areas.

Today, the 12th (Wednesday), please be careful of sudden changes in the weather from the afternoon. Sufficient attention should be paid to landslides, flooding of low-lying areas, flooding of roads, and sudden rises and flooding of rivers. Also, please be careful of thunderstorms, tornadoes, and other strong gusts of wind.



In coastal areas, waves will continue to be high with swells, so please be careful of high waves. It is also the spring tide season, and storm surge is expected to occur in some places. Currently, there are places in Kagawa Prefecture where a Level 3 storm surge warning has been issued, including Takamatsu City. Please be wary of rising tide levels due to storm surge.

[Typhoon information] New typhoon No. 17 (Nanka) occurs near Ogasawara

2026/08/12 11:26

At around 9 a.m. today, the 12th (Wednesday), a tropical cyclone that was developing near the Ogasawara Islands became Typhoon No. 17.
Typhoon No. 17 is moving east-northeast at a slow speed, with a central pressure of 994 hPa, maximum wind speed near the center of 18 m/s, and maximum instantaneous wind speed of 25 m/s.

#Typhoon No.17 12th (Wed) As of 9:00 am
===================
Size Ogasawara vicinity
Traveling speed East-northeast Slowly
Central pressure 994hPa
Maximum wind speed 18m/s (near the center)
Maximum instantaneous wind speed 25m/s
===================

Typhoon No. 17 is expected to continue heading northeast while increasing its speed, reaching the sea east of Ogasawara around 9am tomorrow. There is a possibility that the Ogasawara Islands will enter the strong wind region of a typhoon in the future, so please be careful of strong winds and high waves accompanied by swells.

Typhoon No. 17 is expected to continue moving northward over the eastern seaboard of Japan. There is a wide range of forecasts at this point, so there is some uncertainty, but there is a possibility that it will affect the area around Japan again from next week onwards. Please pay attention to the typhoon information that will be updated in the future.

[Typhoon information] Typhoon No. 15 moves west toward the Sea of Japan. Beware of heavy rain, strong winds, and high waves

2026/08/12 08:06

As of 6 a.m. today, the 12th (Wednesday), Typhoon No. 15 is located approximately 40 km east-northeast of Tsuruga City and is moving westward at a speed of approximately 35 km per hour.
After this, Typhoon No. 15 is expected to move further west and become a tropical cyclone off the coast of San'in by early afternoon today.

#Typhoon No. 15 12th (Wednesday) 6:00 a.m.
==================
Center location: Approximately 40km east-northeast of Tsuruga City
Direction of movement, speed: West 35km/ h
Central pressure 996hPa
Maximum wind speed 18m/s (near the center)
Maximum instantaneous wind speed 25m/s
==================



Typhoon No. 15 made landfall in southern Ibaraki Prefecture at around 8 pm yesterday, Tuesday, the 11th. The typhoon then passed through the Kanto-Koshin region, and as of 6 a.m. today, Wednesday, the 12th, the typhoon's center was moving west near Tsuruga City, Fukui Prefecture.

Rain fell across a wide area of northern and western Japan, and in Miura, Miura City, Kanagawa Prefecture, heavy rain of 40.5 mm was observed in the hour up to 3:20 a.m.

Typhoon No. 15 is expected to continue moving westward and become a tropical cyclone off the coast of San'in by early afternoon today, but people from Tohoku to western Japan should continue to be careful of strong winds, high waves, and heavy rain. In particular, rain is expected to continue in the Tohoku and Kanto regions even after the typhoon has left the region, as moist air flows in from easterly winds.

Strong winds will blow from eastern Japan to western Japan today, the 12th (Wednesday), causing heavy swells.
In addition, the atmospheric conditions will be unstable due to the effects of warm, humid air flowing into the typhoon and cold air in the upper atmosphere, so heavy or very heavy rain with thunder is expected to occur in a wide area from the Tohoku region to western Japan today, the 12th (Wednesday), resulting in heavy rain in some places.

In addition, as the effects of spring tides and typhoons overlap, the tide level will rise in eastern Japan today, the 12th (Wednesday), and in western Japan, tomorrow the 13th (Thursday), resulting in high tides and storm surges in some places.





[Rain Forecast]
Tohoku region 150 mm
Tohoku region 150mm
Kanto-Koshin region 120 mm
Tokai region 150 mm
Kinki region 150 mm
[Disaster prevention matters]
Today, the 12th (Wednesday), please be extremely cautious of landslides in the Tohoku region. In addition, in the Tohoku region and the Kanto-Koshin region, please be wary of flooding of low-lying land, rising water levels and flooding of rivers.
In western Japan, please be on high alert for high tides until tomorrow the 13th (Thursday).
From the Tohoku region to western Japan today, the 12th (Wednesday), please be careful of strong gusts of wind that could cause 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.

[Typhoon Information] Typhoon No. 15 makes landfall in southern Ibaraki Prefecture

2026/08/11 20:53

Typhoon No. 15 made landfall in the southern part of Ibaraki Prefecture around 8 pm today, Tuesday, the 11th.



Typhoon No. 15 is currently moving westward at a speed of 20km per hour, and is expected to pass through the Kanto-Koshin region and near Gifu City tomorrow morning.



Currently, it is raining over a wide area from Tohoku to eastern Japan.
In the future, there is a risk that strong rain clouds will form over a wide area of eastern Japan, including the Kanto-Koshin region, which is close to the path of the typhoon, and on the Pacific coast of Tohoku, where warm, humid air flows in from the sea.There is a risk that heavy or very heavy rain accompanied by thunder may result in heavy rain.
Tomorrow, the 12th (Wednesday), it will start raining in the morning on the Sea of Japan side of western Japan, and in the afternoon it will rain over a wide area of western Japan.

In addition, strong winds are widespread across Tohoku and eastern Japan, and as of 8:30 p.m. today, a storm warning has been issued for Fukushima, Ibaraki, and Chiba prefectures. Waves are high at sea, and a wave warning has been issued for coastal areas from Aomori to Chiba prefectures.

Please pay attention to upcoming weather information.