Heavy rain over a wide area into the 28th (Friday); linear precipitation band possible in the Tokai region

2026/08/27 18:56

The front is extending from the Sea of Japan to the east of Japan, passing through northern and eastern Japan, and will gradually move south until tomorrow the 28th, reaching from the Sea of Japan coast of western Japan to the Pacific coast of eastern Japan.
In addition, through the 28th, a low-pressure system with cold air in the sky is expected to move from the Sea of Japan to the Sea of Okhotsk, and a trough of pressure is expected to pass from northern Japan to eastern Japan.



The warm, humid air flowing towards the front, the cold air in the upper atmosphere, and the trough in the atmospheric pressure will make the atmospheric condition extremely unstable until the 28th,
very heavy rain accompanied by thunder and heavy rain will occur over a wide area from northern Japan to western Japan, leading to heavy rain in some places.

[Rain Forecast]
Expected 24-hour precipitation from 6:00 p.m. on the 27th to 6:00 p.m. on the 28th is high in some places,
Hokkaido region 120mm
Tohoku region 120mm
Kanto-Koshin region 150mm
Hokuriku region 180mm
Tokai region 180mm Re
Kinki region 150mm
Chugoku region 100mm

Then, expected from 18:00 on the 28th to 18:00 on the 29th The 24-hour rainfall is high in some places, and if a linear precipitation band of 80mm
occurs in the Hokuriku region, there is a risk that the rainfall will increase locally.

Furthermore, the Japan Meteorological Agency is calling for caution in the Tokai region, where linear precipitation bands are forming and the risk of heavy rain disasters may rapidly increase.

[Forecast of meteorological phenomena]
The following are the regions and periods where linear precipitation bands may occur and the risk of heavy rain disasters may rapidly increase.



(Tokai region) Shizuoka Prefecture From dawn to noon on the 28th
(Tokai region) Aichi Prefecture From dawn to noon on the 28th
(Tokai region) Gifu Prefecture From dawn to noon on the 28th Kete
(Tokai Region) Mie Prefecture From dawn to noon on the 28th

Please further increase your preparedness for heavy rain and pay attention to disaster prevention weather information and information such as Kikikuru, which will be announced in stages.

Weather for tomorrow, the 28th (Friday): The area of rain will expand to the west

2026/08/27 18:15

Rain is expected over a wide area from Hokkaido to Chugoku and Shikoku due to the southward movement of the autumn rain front and the effects of low pressure. There is a risk of localized heavy rain, so vigilance is required in various areas.



Due to the influence of the autumn rain front, it will be easy to rain over a wide area from Kanto to Chugoku and Shikoku. Rain clouds are expected to develop, especially in the Hokuriku region, northern Kinki region, and the Sanin area near the front, and locally heavy rain is expected. There is also a possibility of heavy rain in the Tokai and Kanto regions.
Also, as a low pressure system accompanied by cold air passes through Hokkaido, there is a risk of heavy rain in various places from dawn to early morning.
The weather in Tohoku will gradually improve, and there will be times when the sun will reach us. Kyushu is less affected by the front and receives plenty of sunlight, but the lingering heat is expected to reach over 35 degrees Celsius, so please be careful of heatstroke.

Tomorrow is a full moon. A beautiful full moon is likely to be seen in the Tohoku Pacific side, Kyushu, and Okinawa. Let's look forward to other regions next month.

Finally, tomorrow the 28th is Weather Forecaster's Day. The name comes from the fact that the first national weather forecaster exam was held on this day in 1994. As weather forecasters, we work hard every day to improve our accuracy. I hope it will be of some use in your life...

The level 5 heavy rain special warning for Ishikawa and Toyama prefectures has been changed to a level 3 heavy rain warning, so please continue to be careful.

2026/08/27 17:29

The level 5 heavy rain special warning issued for Ishikawa and Toyama prefectures was changed to a level 3 heavy rain warning at 4:20 p.m.

Although the heavy rain alert level has been lowered, please continue to be cautious of flooding of low-lying land, rising water levels, and flooding of rivers into the morning of tomorrow, the 28th (Friday).
Also, there are some places where the ground has become loose due to heavy rain. Please be on high alert for landslides before noon on Friday the 28th.

Be careful of strong gusts of wind, including lightning and tornadoes, from the evening of Friday the 28th. There is also a risk of hail, so please be careful when managing crops and agricultural facilities.



Currently, there is a lull in the rain, but there is a possibility that active rain clouds will form again into the morning of tomorrow, the 28th (Friday). Please pay attention to the latest disaster prevention information and evacuation information, and frequently check the level of risk in your area on the Japan Meteorological Agency's website Kikikuru.



[Rain forecast (Hokuriku region)]
The predicted 1-hour rainfall today, the 27th (Thursday), is high in some places
Niigata Prefecture 40mm
Toyama Prefecture 60 mm
Ishikawa Prefecture 40 mm
Fukui Prefecture 40 mm

The predicted hourly precipitation for tomorrow, the 28th (Friday) is high in the following areas:
Niigata Prefecture 50 mm
Toyama Prefecture 60 mm
Ishikawa Prefecture 50 mm
Fukui Prefecture 50mm

The expected 24-hour precipitation from 6pm today, Thursday, the 27th to 6pm, Friday, the 28th, is expected to be high in the following areas: Niigata Prefecture 150mm
Toyama Prefecture 180mm
Ishikawa Prefecture 150mm
Fukui Prefecture 120mm

Then, the predicted 24-hour precipitation from 6pm on Friday the 28th to 6pm on Saturday the 29th will be:
Toyama Prefecture 60mm
Ishikawa Prefecture 80mm
Fukui Prefecture 60mm

[Special heavy rain warning in Hokuriku] Take action to protect your life; the area of heavy rain will further expand tomorrow (commentary: weather forecaster Atsuko Miyake)

2026/08/27 14:06

Ishikawa and Toyama prefectures are experiencing heavy rain like they have never experienced before.



There are areas in Ishikawa Prefecture and Toyama Prefecture where a Level 5 heavy rain special warning has been announced.
There is a high possibility that some kind of disaster has already occurred.
Please take actions that are likely to save lives, even if just a little.



This is what the rain clouds look like.
From early morning until dawn today, linear rain clouds continued to cover Ishikawa and Toyama prefectures.
In Ishikawa and Toyama prefectures, information on the occurrence of linear precipitation bands has been announced one after another.
In addition, heavy rain is observed in Ishikawa Prefecture in the morning.

From morning until noon, the rain clouds are gradually moving southward.

Looking at the precipitation for the 12 hours up to 11 a.m.,
Hakui City, Ishikawa Prefecture, recorded 317.5mm of rain, and Himi City, Toyama Prefecture, recorded 317mm of rain.
Both values have updated the highest values in observation history.



Although the rain has temporarily stopped,
Please continue to exercise the highest level of vigilance in Ishikawa and Toyama prefectures until the evening.

Vehicle evacuation is dangerous.
During the heavy rains in Chiba the other day, some people were forced to drive into flooded areas, became stuck, and died in their cars.
Also, please avoid driving near flooded rivers.
In past heavy rain disasters, there have been cases where people were driving near a swollen river and were swept away by the swollen river.

If the flooding is progressing, evacuating may actually be dangerous.
Make sure to enter the river in a safe place, away from cliffs that are higher than the second floor of your house.



The cause of this heavy rain is the front.
Warm, moist air continues to flow toward this front from the south.
There is also a low pressure system with cold air in the upper atmosphere, and the atmosphere is expected to remain unstable, especially near the front.

Also in areas far from the front lines. Due to the damp air and cold air, very heavy rain is expected to occur in some places.



Rain cloud forecast.
Currently, the rain is temporarily weakening in some parts of the Hokuriku region, but
active rain clouds are expected to start covering the Hokuriku region again tonight.
It looks like it's going to rain heavily again.

Also, looking at northern Japan, heavy rain is likely to peak in Hokkaido during dark hours due to the passing of a low pressure system accompanied by cold air.

Tomorrow, linear rain clouds are expected to roll over from the Sea of Japan, across Hokuriku,
to the Kanto-Koshin region.

Please be on alert for heavy rain disasters from the Kanto region to the Hokuriku region,
and even northern Japan into tomorrow.



The predicted 24-hour precipitation by noon tomorrow (Friday) is
200mm in the Hokuriku region, 150mm in the Tohoku, Kanto-Koshin, and Tokai regions, 120mm in the Hokkaido and Kinki regions, and
100mm in the Chugoku region.

Furthermore, rainy conditions will continue after that, with 80mm of rain expected to fall in the Hokuriku, Tokai, and Kinki regions until noon the next day (Saturday).

However, if a linear precipitation band occurs,
there is a risk that the amount of rainfall will be even higher than this predicted amount.
Please continue to pay attention to the latest heavy rain information.



Rain and thunderstorms are expected to continue over a wide area into tomorrow.
Be careful of sudden rain or thunderstorms even in areas without an umbrella mark.
It looks like there will be some places with very heavy rain with thunder tomorrow.
If you hear thunder, try to get into a sturdy building.

In addition, Kyushu is expected to experience extremely hot days with temperatures exceeding 35 degrees Celsius into tomorrow.
Please continue to be careful of heat stroke.



Weekly forecast.
The weather is expected to improve in northern Japan on Saturday the 29th, but
the atmosphere will continue to be unstable from Hokuriku to the Tokai, Kanto-Koshin, and Kinki regions.

Also, the rain is likely to continue mainly in northern Japan and Hokuriku after the 30th (Sunday).
We need to be careful about the heavy rain that continues for a long time.

And from Kanto-Koshin to western Japan, it looks like there will be places that will experience another extremely hot day next week.
Please continue to be careful about the heat.

Sea surface temperatures near Japan continue to be higher than normal in the northern part [Ocean summary (August 16 to August 22, 2026)]

2026/08/27 11:17

Sea surface temperatures near Japan continued to be higher than normal in the northern part of the country, and areas with significantly higher than normal sea temperatures expanded in the northern and central Japan Sea, off the southeastern coast of Hokkaido, near the Kuril Islands, and in the Sea of Okhotsk. In the waters around the Kuril Islands and the Sea of Okhotsk, temperatures were up to 6 C higher than normal.

In the latter half of the period, a tropical cyclone remained in the sea near the Nansei Islands, and waves rose from the waters near the Nansei Islands to the East China Sea. On the 22nd, wave height reached 3.5m in the south of Okinawa.

Below is a summary of the ocean (August 16 to August 22, 2026)



#Pressure distribution and waves
From August 16th to 18th, the area around Japan was gently covered by an anticyclone centered east of the Kuril Islands. There was a tropical cyclone near Ogasawara, and it was slowly moving northeast. On the 16th, the waves near Ogasawara increased slightly. From the 17th to the 18th, waves near Japan remained calm.
On the 19th, a low pressure system moved northeast near Primorye. On the 20th, a front extending from a low pressure system moving northeast over the Sea of Okhotsk passed near northern Japan. Waves were rising in the northern Sea of Japan, and on the 20th, wave heights reached around 3 meters in the Mamiya Strait.
From the 19th to the 22nd, a tropical cyclone stalled near the Nansei Islands. Waves were rising from the waters near the Nansei Islands to the East China Sea, reaching a wave height of 3.5 meters south of Okinawa on the 22nd.



#Sea surface temperature
In the Japanese sea area, the sea surface temperature was near normal in the western part of Japan, and areas in the northern and central regions where the sea surface temperature was much higher than normal had expanded. The maximum temperature was 4c higher than normal.
The East China Sea and the waters near the Nansei Islands continued to be slightly lower than normal.
Off the coast of Shikoku and Tokai, sea conditions were at normal levels.
The eastern part of the Kanto region was slightly higher than normal, and off the coast of Sanriku there were areas that were significantly higher than normal.
In the waters off the southeastern coast of Hokkaido, near the Kuril Islands, and in the Sea of Okhotsk, areas with significantly higher than normal waters expanded. In the waters around the Kuril Islands and the Sea of Okhotsk, temperatures were up to 6 C higher than normal.

Heavy rain special warning announced in Toyama and Ishikawa prefectures - Be on high alert for heavy rain disasters!

2026/08/27 07:15

At around 6:20 a.m. today, the 27th (Thursday), a Level 5 heavy rain special warning was announced for Toyama and Ishikawa prefectures. There is a high possibility that heavy rain disasters such as serious flooding and river flooding have already occurred, so please take strict precautions against heavy rain disasters.



The areas where a special heavy rain warning was announced at 6:20 a.m. are as follows.

#Toyama Prefecture
Himi City

#Ishikawa Prefecture
Hodatsushimizu Town, Hakui City, Nakanoto Town, Shiga Town

The front has stalled near Honshu, and warm, humid air is flowing towards the front, combined with the influence of cold air in the upper atmosphere, making the atmospheric condition extremely unstable.
In Toyama Prefecture and Ishikawa Prefecture, extremely heavy and torrential rain has been falling since early morning on the 27th (Thursday), with heavy rain exceeding 150 mm in 3 hours.
A linear precipitation band occurred again in western Toyama Prefecture and the Noto region of Ishikawa Prefecture just after 6 a.m. today, the 27th (Thursday).

In the Hokuriku region, it will continue to rain intermittently, with localized extremely heavy rain or torrential rain accompanied by thunderstorms. The front will remain stationary near the Hokuriku region tomorrow, the 28th (Friday), and heavy rain is expected to continue, causing the total rainfall to increase further.





Please be extremely cautious of landslides, flooding of low-lying areas, and rising and flooding rivers. Also, please be careful of lightning strikes, tornadoes, and other strong gusts of wind, and carefully check evacuation information from local governments and take safe actions.
If it is dangerous to evacuate to an evacuation site, take emergency measures to ensure your safety, such as moving to a building far enough away from cliffs or rivers, or to a place that is less likely to flood.

Linear rain belt occurs in Toyama and Ishikawa prefectures - strict warning against heavy rain disaster

2026/08/27 04:13

Around 3:00 a.m. today, the 27th (Thursday), the Japan Meteorological Agency announced a ``Meteorological Disaster Prevention Bulletin (Occurrence of Linear Precipitation Bands)'' stating that extremely heavy rain continues to fall in western Toyama Prefecture and Ishikawa Prefecture (Kaga/Noto) due to linear precipitation bands.

The front is stationary near Honshu, and warm, humid air from Typhoon No. 18 is flowing toward the front. In the Hokuriku area, rain clouds that have developed intermittently have passed through the area since late on the night of the 26th, and extremely heavy rain continues to fall in similar locations.
As of 3 a.m. today, the 27th, the maximum 3-hour precipitation was 121.5 mm in Himi City, Toyama Prefecture, and 115.5 mm in Hodatsushimizu Town, Ishikawa Prefecture, which are the highest values in recorded history.

In the Hokuriku region, intermittent rain will continue into the afternoon today, with localized heavy rain accompanied by thunder. As of 3:30 a.m., there are areas in Toyama and Ishikawa prefectures where Level 4 heavy rain warnings and landslide warnings have been issued, and the risk of life-threatening heavy rain disasters is increasing.

Please be extremely cautious of landslides, flooding of low-lying areas, rising water levels and flooding of rivers. Also, please be careful of lightning strikes, tornadoes, and other strong gusts of wind, and carefully check evacuation information from local governments and take safe actions.
If it is dangerous to evacuate to an evacuation site, take emergency measures to ensure your safety, such as moving to a building far enough away from cliffs or rivers, or to a place that is less likely to flood.

Although some areas experienced record-breaking heavy rain, there is a trend towards less rainfall nationwide, with the lingering heat continuing in western Japan (weather summary from August 16, 2026 to August 22, 2026)

2026/08/26 20:27

During this period (August 16th to August 22nd), some areas experienced record heavy rainfall, including Saitama and Tokyo, where atmospheric conditions became unstable and rain clouds developed locally, and the Sakishima Islands, which were affected by a tropical cyclone. However, the area around Honshu is mostly covered by high pressure and has few rainy days, and nationwide there has been a trend towards less rain.
Below is a summary of the weather for this period (August 16th to August 22nd).

#Summary of the weather for this period (August 16th to August 22nd)
Average temperatures were above normal in areas from western Japan to northern Japan on the Sea of Japan side, which were susceptible to the effects of high pressure, and in northern Japan, where warm air easily entered due to the effects of low pressure, the average temperature was well above normal. In Hokkaido, areas on the Sea of Okhotsk experienced remarkable high temperatures of more than 4 degrees Celsius above normal.

Precipitation amounts were heavier than normal in some areas, such as Tokyo, where localized thunderstorms occurred, but the area around Honshu was dominated by high pressure, making it difficult for heavy rainfall to occur, resulting in many areas seeing much less rainfall than normal. On the other hand, the Sakishima Islands experienced heavy rainfall that was significantly higher than normal due to the effects of a tropical cyclone (which developed into Typhoon No. 20 on the 22nd).

Sunshine hours were above normal in many locations due to the high pressure and many sunny days, with some places in Hokkaido far exceeding normal. In the Nansei Islands, there were many cloudy and rainy days due to the effects of a tropical cyclone (which developed into Typhoon No. 20 on the 22nd) and humid air, and temperatures tended to be below normal.



[About the weather during this period]
#Characteristics of pressure distribution
On the 16th, the center of the high pressure system was almost stationary over the sea east of the Kuril Islands. To the west of Japan, a low pressure system is moving eastward near the Yellow Sea. On the 17th, the center of high pressure moved far east of Japan, and a low pressure system moved northeast near the Korean Peninsula. On the 18th, another low pressure system formed and moved northeast over northeastern China. A tropical cyclone has formed in the south of Japan and is slowly moving northwest. On the 19th, a low pressure system moving over the continent developed and formed a front. The center of high pressure remained stationary over the sea east of Japan, and on the 20th, a new center of high pressure formed over the sea east of Kanto. A tropical cyclone is stationary near the Sakishima Islands. Typhoon No. 18 occurred near the Truk Islands. A front extending from a low-pressure center approached near northern Japan, and on the 21st, the front stalled from Tohoku to Hokuriku. A new center of high pressure was formed near the Sea of Japan and the Sea of Okhotsk, and the high pressure over the Sea of Okhotsk passed near Hokkaido on the 22nd. The front is stationary in the east of Japan, and the lower-level warm and humid air heading toward the front converges near the Kanto region. A tropical cyclone developed into Typhoon No. 20 near the Sakishima Islands.

#Precipitation
On the 16th, it rained in western Japan due to the shear line associated with the low pressure near the Yellow Sea and the moist air behind the high pressure. Heavy rain of 47.0mm/h was observed in Susaki City, Kochi Prefecture. From the 17th to the 18th, warm, humid air circulating around the edge of a high-pressure system far east of Japan caused rain from Tohoku to eastern Japan and the Pacific side of western Japan. On the 17th, heavy rain of 46.0 mm/h was observed in Mihama Town, Mie Prefecture, and on the 18th, heavy rain of 27.0 mm/h was observed at Shionomisaki, Wakayama Prefecture, as the rain continued to intensify on the Kii Peninsula. On the 19th, it rained in Hokkaido due to a low pressure system and a trough of pressure. In the Sakishima Islands of Okinawa, locally heavy rain was observed due to the effects of a tropical cyclone. On the 20th, warm and humid air moving toward the front caused localized thunderstorms in inland and mountainous areas of northern and western Japan, with warning-level heavy rain occurring in parts of Tohoku, Hokuriku, and the San'in region. On the 21st, warm and humid air flowed toward a stationary front near Tohoku, causing heavy rain of approximately 110 mm/h near Saitama City. On the 22nd, in the evening around the Kanto region, warning-level heavy rain occurred in Tokyo and Saitama due to the influence of a local front. Heavy rain also occurred in the Sakishima Islands of Okinawa due to Typhoon No. 20.

#Temperature
On the 16th, temperatures rose in sunny areas west of the Tokai Sea. In Kumamoto Prefecture, more than half of the observation points experienced extremely hot days due to the effects of the Fohn phenomenon. On the 17th, southerly winds around the edge of the high pressure system caused high temperatures in Fukui, Oita, Kumamoto, and other areas, with Bungotakada City, Oita Prefecture recording an extremely hot day of 37.2c. On the 18th, there were many hot days in western Japan, mainly on the Sea of Japan side, where southerly winds heading toward a low pressure system caused the phenomenon, and severe lingering heat continued from Hokuriku to Kyushu. A similar pressure pattern prevailed on the 19th, with severe heat in western Japan caused by southerly winds, with the highest temperature in Kumamoto reaching 38.7 C. On the 20th, temperatures rose not only in western Japan covered by high pressure, but also on the Sea of Okhotsk side due to the southerly Fohn, with temperatures reaching 34.3 degrees Celsius in Shari Town, Hokkaido. On the 21st, a severe lingering heat wave continued mainly in western Japan, which was covered in high pressure, and the number of observation points on extremely hot days was 126. In Asakura City, Fukuoka Prefecture, the temperature was 38.8c, the highest in recorded history. On the 22nd, it was extremely hot in western Japan, where tall high-pressure systems continue to prevail, with Minamata City, Kumamoto Prefecture recording a temperature of 38.6c, the highest temperature ever recorded.

Today, the 26th - tomorrow morning: Warning of sudden thunderstorms from northern Japan to western Japan

2026/08/26 14:06

Today, the 26th (Wednesday), a front extending from a low pressure system centered east of Kamchatka has passed through the east of Japan and reached the Tohoku region.
This front is expected to pass from the Sea of Japan to northern and eastern Japan until tomorrow, the 27th (Thursday), and after that, it is expected to stay mostly stationary in the east of Japan.



In addition, as cold air flows into the upper atmosphere, the atmospheric conditions are expected to become extremely unstable over a wide area from northern Japan to western Japan due to the effects of warm, humid air flowing toward the front, cold air above, and rising temperatures during the day.



Please be careful of thunderstorms, tornadoes, strong gusts, and sudden heavy rain.
If there are signs that a developed cumulonimbus cloud is approaching, please take precautions such as moving inside a building. There is also a risk of hail, so care must be taken when managing crops and agricultural facilities.

If the developed cumulonimbus clouds continue to form, heavy rain may occur in a short period of time, which may lead to flooding of low-lying areas and flooding of small and medium-sized rivers.
Please pay attention to the latest information.

Today's 26th (Wednesday) weather: Okinawa and Amami continue to experience stormy weather due to Typhoon No. 18; western and eastern Japan are on alert for intense heat

2026/08/26 07:47

Today, the 26th (Wednesday), strict vigilance is required in areas near the main island of Okinawa and Amami Oshima near Typhoon No. 18 (Soudel), due to strong winds, heavy rain, high waves, and high tides until around noon. The intense heat continues across a wide area west of the Kanto region. Northern Japan needs to be careful of heavy rain and thunderstorms, especially in the southern Tohoku region.



Typhoon No. 18 (Soudel) passed between the main island of Okinawa and Amami Oshima in the early hours of today, the 26th (Wednesday), and continues to enter the storm area. Strict vigilance is required in the area until around noon due to strong winds, heavy rain, high waves with swells, and high tides.
Please refrain from going out and stay indoors in a safe place away from windows. The typhoon will gradually move away in the afternoon, but we still need to be on guard against strong winds, high waves, and heavy rain.





From the Kanto region to western Japan, many places will be covered in high pressure and will be sunny, and the harsh lingering heat will continue. Please continue to take precautions against heatstroke.

On the Pacific side of Kyushu, where moist southeasterly winds from typhoons tend to flow in, clouds will spread, and there will be some places where it will rain temporarily. In other areas, the atmospheric conditions will be unstable in the afternoon as temperatures rise, and people should be careful of showers and thunderstorms.

Meanwhile, the front will remain stationary from the Sea of Japan to the Tohoku region. In the southern Tohoku region and around Niigata Prefecture, clouds are spreading and rain is likely to fall, so be careful of heavy rain and thunderstorms.