The longest ever: The Kuroshio Current meandering, which lasted for 7 years and 9 months, has ended. The current state of the seas around Japan [Marine Summary August 24th - 30th, 2025]

2025/09/03 11:48

As the Kuroshio snake no longer appeared in April this year (2025), the Japan Meteorological Agency announced that "signs of the Kuroshio snake could be seen on May 9th."


The Japan Meteorological Agency and the Japan Coast Guard have since monitored the situation of the Kuroshio Current, and
/Basically, the situation that does not have a large meandering situation has remained stable, owing to the progression of the southernmost latitude of the Kuroshio Current off Tokai and the docking situation of the Kuroshio Current off Shio Cape, and
/It has been determined that the Kuroshio Current's large meandering situation has ended in April 2025.

As a result, the longest period of the giant meandering that has continued since August 2017 has been seven years and nine months since 1965.


Even after the Kuroshio giant tortoise ends, the sea surface temperature continues to rise in the Sea of Japan and around Hokkaido, and the sea surface temperature continues to rise in the seas around Japan.

This is a summary of the oceans from August 24th to 30th.



#Pressure arrangement and waves


On the 24th to 25th, the area around Honshu was covered with a high pressure system centered on the south of Japan.
The waves in the waters around Japan are moving calmly.
From the 26th to the 27th, a low pressure system accompanied by a front developed from the Primco State to the Sakhalin area.
On the 27th, the wave height exceeded 4m in the west of Hokkaido and east of Sakhalin.
On the 28th, the low pressure system developed further in the Sea of Okhotsk, and the wave height in the Sea of Okhotsk was 6m high.

On the 29th, a low pressure system accompanied by a front traveled eastward around the Primco State.
Waves rose on the continental side of the central Japan Sea.
On the 30th, the low pressure system blocked and proceeded near Hokkaido, and the
front headed south through the Tohoku region.
The waves rose at around 2m off the coast of Akita.



#Sea surface temperature

The sea surface temperature in the Japanese Sea continued to be higher than normal.
In particular, on the continental side, it was much higher than normal, with a maximum of 5 C higher.


In the East China Sea and the Southwestern Islands, higher than normal waters have expanded.
On the Pacific side, the waters above normal have expanded, with a maximum of 3 C higher than normal.


The waters off Sanriku continue to be much higher than normal.

The waters around Hokkaido were higher than normal at the beginning of the period, but due to the passing of the
low pressure system, the seas gradually expanded to the east of the Sea of Okhotsk and Kuril Islands.

Rising linear precipitation zones in Kanto: flooding underground facilities and flooding of roads are also strictly wary of heavy rain disasters

2025/09/03 11:47

From the evening of the 3rd to the beginning of the evening, the 3rd, linear precipitation zones are likely to occur in Ibaraki, Tochigi, Gunma, Saitama, Chiba and Tokyo regions, leading to a sudden increase in the risk of heavy rain disasters.



A cyclone with the front travels eastward in Japan, with the front extending from the western Sea of Japan through eastern Japan and Tohoku, and extending eastward in Japan.
The front will travel south through eastern Japan tomorrow, the 4th (Thursday).


In Kanto, Koshin, today, the 3rd (Wednesday), the atmosphere is expected to be extremely unstable due to the warm, humid air flowing towards the front and rising daytime temperatures.



Today, Wednesday the 3rd, from the afternoon until late at night, there will be areas in Kanto, Koshin where very heavy rain, like waterfalls, accompanied by thunder.
Expected 1 hour precipitation for today, Wednesday the 3rd (at a high point)
North Kanto: 70mm
North Kanto: 60mm
Koshin: 50mm
Expected 24 hour precipitation until noon tomorrow, Thursday the 4th (at a high point)
North Kanto: 150mm
North Kanto: 150mm
Koshin: 80mm

In the event of a linear precipitation zone, there is a risk that the rainfall will increase locally even further.

Today, Wednesday the 3rd, from the afternoon until late at night, in Kanto, Koshin, be careful of flooding in lowlands, flooding of rivers, flooding, and landslides.
Rrain clouds may develop not only along the mountains but also in plains, and it is possible that underground facilities may be flooded or road flooded.

A typhoon is expected to occur within 24 hours, and we are approaching Honshu!

2025/09/03 08:52

To the south of Japan is a tropical cyclone that travels north-northwest at a speed of approximately 25 km/h per hour.
The tropical cyclone is expected to become a typhoon within the next 24 hours, with the possibility of approaching Okinawa and Amami regions on the 3rd and Kyushu on the 4th.
If a typhoon occurs, it is expected to become Typhoon No. 15.


The warm, humid air flowing into tropical cyclones and typhoons makes the atmosphere unstable, and heavy rain with lightning is expected to fall.
Please be careful and be careful of landslides, low-lying flooding of landslides, river flooding and flooding in the southern Kyushu region on the 4th, and be careful of lightning and gusts of wind in the southern Kyushu region on the 4th.
Also be careful of strong winds and high waves.



###Rain forecast
In the southern Kyushu region, extremely heavy or heavy rain falls locally from the afternoon of the 3rd to the late night of the 4th, leading to heavy rain.
If the rain clouds develop more than expected or if heavy rain continues in the same location, a heavy rain warning may be issued.


The expected one-hour precipitation on the 3rd is high, and
Kagoshima Prefecture (excluding Amami region) is 30mm.
30mm Amami region.


The expected one-hour precipitation on the 4th is high, and
Miyazaki Prefecture is 50mm.
Kagoshima Prefecture (excluding Amami region) 40mm.
30mm Amami region.

The 24-hour precipitation expected from 6am on the 3rd to 6am on the 4th is high, and
100mm in southern Kyushu and Amami regions.


After that, the 24-hour precipitation expected from 6am on the 4th to 6am on the 5th was high, with
120mm in southern Kyushu. It is expected to be

.


###Wind Prediction
Strong winds will blow in southern Kyushu and Amami regions on the 4th.

Maximum wind speed expected on the 3rd (maximum instantaneous wind speed)
Amami region 15 meters (23 meters).

Maximum wind speed expected on the 4th (maximum instantaneous wind speed)
Miyazaki Prefecture 15 meters (23 meters).
Kagoshima Prefecture (excluding Amami region) 18 meters (25 meters).
Amami region: 15 meters (23 meters).

###Wave prediction
There will be some areas in the coastal waters of southern Kyushu, Amami and Daitojima regions, with swells, and there will be some areas that will cause high waves along the 4th.
Wave height expected on the 3rd
Miyazaki Prefecture 2 meters with swells.
Kagoshima Prefecture (excluding the Amami region) 2 meters with swells.
Amami region: 3 meters, accompanied by swells.
Daitjima region: 3 meters, accompanied by swells.


Wave height expected on the 4th
Miyazaki Prefecture 3 meters with swells.
Kagoshima Prefecture (excluding the Amami region) 3 meters with swells.
Amami region: 3 meters, accompanied by swells.
Daitjima region: 3 meters, accompanied by swells.

Northern Japan to Eastern Japan experience low pressure and passing through front lines. He is strictly wary of heavy rain and landslides

2025/09/03 07:00

The front extends from the western Sea of Japan to northern Japan, and a cyclone on the front near Hokkaido is moving eastward.
This low pressure system will move east on the morning of the 3rd, and the front will move south around Honshu on the 4th.
As warm, humid air flows towards the low pressure and the front, the atmosphere is expected to be extremely unstable in northern and western Japan for the third day.

A low pressure system moves eastward around Hokkaido, and the front extending from the center passes through the Tohoku region and the Sea of Japan, reaching the Korean Peninsula.
Currently, there are areas in Tohoku to Hokuriku where heavy rain is falling with thunder, and there are areas where heavy rain, flood warnings, and landslide warning information has been issued.



Today, the front will pass through the north and eastern Japan.
In Tohoku and Hokuriku, linear precipitation zones can occur, causing the risk of heavy rain disasters to rise rapidly, so be careful of landslides, low-cost land flooding, river flooding and flooding.
Also, warm and humid air flows over a wide area of north to western Japan, making the atmosphere extremely unstable.
Please be careful of sudden heavy rain, lightning strikes, severe gusts of wind, and hail fall.




###Rain commentary
In the north of the Tohoku Sea of Japan side, there are some areas where precipitation has exceeded 200 mm since the start of falling, making the risk of landslides high.
Pressure from the start of rain (11am on the 1st) to 5am on the 3rd (preliminary figures from Amedas)
Akita Prefecture
247.5mm in Hitachi, Kitaakita City.
Wakigami, Kitaakita City: 237.0 mm.
Hachimantai, Kakunodate City 225.0 mm.
Odate 222.5mm.
Hitori Kiuchi, Senboku City 212.5mm.
Noshiro: 183.0mm.

/Please note that in Kitaakita City Hitachi, Kitaakita City, Wakigami, Kakunodate City, Hachimantai, Odate and Noshiro, 24-hour precipitation has been the highest in all-year history.

###Rain forecast
In the Tohoku region, heavy rain has increased the risk of landslides and flood disasters.
In Northern Japan, on the 3rd, there will be some areas where extremely heavy rain and heavy rain will fall with thunder from the 4th, and heavy rain will fall.


The expected hourly rainfall on the 3rd is high, and
30mm north of the Sea of Japan side of Hokkaido.
Hokkaido, southern part of the Sea of Japan side: 20mm.
Hokkaido, Northern part of the Sea of Okhotsk side 20mm.
Tohoku Sea of Japan Side 60mm.
Tohoku Pacific side: 30mm.

The 24-hour precipitation expected from 6am on the 3rd to 6am on the 4th is high, and
Hokkaido, northern part of the Sea of Japan side is 50mm.
Hokkaido, southern part of the Sea of Japan side: 40mm.
Hokkaido, Northern part of the Sea of Okhotsk side: 40mm.
Tohoku: Sea of Japan Side: 120mm.
Tohoku Pacific side 60mm.
Kanto-Koshin region: 120mm.
Hokuriku region: 100mm.


If a linear precipitation occurs, there is a risk that the rainfall will increase locally even further.

###Disaster Prevention Issues
In the Tohoku region, be careful of landslides, flooding of low land, flooding of rivers and flooding on the 3rd, and be careful of landslides, flooding of low landslides, and flooding of rivers from the 4th, in eastern Japan to western Japan, be careful of landslides, flooding of low land, and flooding of rivers.
Also, be careful of severe gusts of winds such as lightning strikes and tornadoes in northern and western Japan.
If there are signs of developing cumulonimbus clouds approaching, try to ensure safety by moving inside the building.
There is a risk of hail falling, so please be careful when managing agricultural crops and agricultural facilities.

Tomorrow's southbound front + typhoon egg (tropical cyclone) occurs; warning-level heavy rain range expands [Weekly Weather]

2025/09/02 12:32

Today, the 2nd (Tuesday), warm and humid air flows towards the low pressure system and fronts that move northeasterly through the Sea of Japan, causing record-breaking heavy rain, mainly in southern Hokkaido and northern Tohoku.



The 24-hour rainfall until 11am was 275.0 mm in Toi Tomari, Hakodate City, Hokkaido, and 149.0 mm in Noshiro, Akita Prefecture, and the highest value for September has been updated.


In Hakodate City and other cities, rainfall is 1.7 times higher than normal during this period in just one day, causing record-breaking heavy rain.




In Akita Prefecture, where active rain clouds continue to be exposed,
Rivers are rising, increasing the risk of flooding.

In the flood Kikikuru (hazard distribution map), there are many places with purple danger [equivalent to alert level 4].


Beware of flooding and flooding of rivers.


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In addition, landslide warning information has been issued within Akita Prefecture.

If you live in landslide warning areas such as near cliffs or exits in valleys, please be careful of information such as evacuation instructions issued by municipalities.



The front extending from the low pressure system is expected to travel south around Honshu through the next 3rd.


In northern and eastern Japan, heavy rain with thunder and extremely heavy rain is expected to fall tomorrow, the 3rd (Wednesday).


Please be very careful of landslides, flooding of low land, flooding of rivers and flooding.


It is also expected that a typhoon egg (tropical cyclone) will occur in the evening of the 3rd (Wednesday) in the evening of the night of Kyushu.

I don't know yet whether tropical cyclones will develop into typhoons, but
FlA humid air around tropical cyclones will flow from the Nansei Islands to the Pacific Ocean side of western Japan, and there are likely to be heavy rain in the Nansei Islands as well.



On tomorrow, the 3rd (Wednesday), there is a risk of heavy warning-level rainfall in the eastern Japan, Tohoku, where the front moves south, and in the Nansei Islands, where typhoon eggs approach.


Please be careful and vigilant about the rain on the Nansei Islands and the Pacific side of western Japan through Thursday the 4th.

The rainy season begins in 2025, and the rainy season is confirmed to end, much earlier than usual

2025/09/02 08:10

On September 1st, the Japan Meteorological Agency announced the final price for the start of this year and the end of the rainy season.


There has been a significant review of the rainy season beginning and the end of the rainy season, and in many cases the rainy season has begun earlier than the preliminary estimate. Many regions have been the earliest ever since the rainy season ended.


The rainy season began in May from Okinawa to Hokuriku, and the early days in Kinki and Hokuriku have hit a new record. The rainy season in Tohoku began about a week later than usual, but as a result, the rainy season has arrived earlier than usual for areas outside of Tohoku.


Regarding the end of the rainy season, preliminary prices remained the same for Kyushu, Shikoku, Chugoku, Kinki, and southern Tohoku, but the preliminary prices for Tokai, Kanto, Koshin, Hokuriku, and northern Tohoku were earlier than the preliminary prices. The rainy season ended in June in all regions except north and south of Tohoku, making it unusually fast. The rainy season ended in Okinawa, Amami, northern Kyushu, Chugoku, Kinki, Kanto, Koshin, and Hokuriku, the earliest rainy season has ended since statistics began.



The rainy season this year in 2025 was characterized by the fact that the season progressed quite quickly, the unusual rainy season began and the rainy season ended early, and the activity on the rainy season front was weaker than normal. The average average precipitation rate during the rainy season was almost normal in Okinawa, but the rest of the area was below normal. In particular, precipitation was about half the average in the Hokuriku and northern Tohoku, while precipitation was about 37% of the average in the southern Tohoku region, significantly lower than normal.

Due to the effects of a cyclone accompanied by a front, heavy rain disasters are being wary of the Northern Japan and Hokuriku side, centering on the Sea of Japan side.

2025/09/02 06:59

A cyclone with a front moves northeasterly through the Sea of Okhotsk, and another cyclone on the front extending into the East China Sea is moving northeasterly through the Sea of Japan.
Warm and humid air flows towards the cyclone and the front, and very developed rain clouds are hanging around northern Japan. In addition, due to the influence of the front, rain clouds that have developed have also been passing through the Sea of Japan side of northern Kyushu.

As of 6am today, the 2nd, a heavy rain warning (landslide) has been issued in Fukaura Town, Aomori Prefecture.



The low pressure in the Sea of Okhotsk will continue east of the Kuril Islands until tonight, and the low pressure in the Sea of Japan is expected to pass through near Hokkaido. A cold front will move south along with the low pressures in the Sea of Japan, and warm, humid air around the edge of the Pacific high will flow towards the front and low pressure. Very developed rain clouds are expected to flow, mainly in northern Japan.

On the 1st, yesterday, at Toi-dora, Hakodate City, Hokkaido, a record-breaking rain was observed with an AMEDAS rain gauge of 102mm per hour, and information on heavy rain for a short period of time was announced. The 24-hour rainfall per day at Toi Tomari reached 270mm, which was about 1.8 times the rainfall amounted to the average month of September (155.8mm).



On the Sea of Japan side from northern Japan to Hokuriku today, the 2nd, there will be some areas where extremely heavy rain accompanied by lightning due to the effects of fronts and low pressures. On the Sea of Japan side of the northeastern Tohoku region, rain continues in similar areas, causing heavy rain to exceed the average month of September. In Hokuriku, as the front moves south, there will likely be some heavy rain late tonight with thunder.


Please be very careful of landslides, flooding in lowlands, flooding of rivers, and flooding.

Fronts and low pressures approach, risk of warning-level heavy rain in northern Japan; strict caution against landslides

2025/09/01 06:43

The front extends from China through the Yellow Sea and into the Sea of Japan. By the morning of the 1st, a low pressure system is expected to occur near the Primcoes on the front. This low pressure system will continue tomorrow, on the 2nd, through the Sea of Japan and the Soya Strait to the coast of the Kuril Islands, and the front will travel south through northern Japan.


As warm, humid air flows towards the front and low pressure lines, the atmosphere is expected to become extremely unstable in northern Japan by the next day, the two days.




[Rain Prediction]
In Northern Japan, heavy rain will fall over 30mm per hour with lightning and very heavy rain over 50mm per hour, over the next day, over the next day.
#Expected amount of rain (in places)
+24-hour precipitation expected by the dawn tomorrow, br+Hokkaido region: 120mm
Tohoku region: 100mm
24-hour precipitation expected by the dawn tomorrow, br+Tohoku region: 120mm

[Disaster Prevention Items]
In Northern Japan, be very careful of landslides and be careful of low-lying land flooding, rising rivers and flooding. Also, be careful of severe gusts of wind, such as lightning strikes and tornadoes, and hail fall. If there are signs of developing cumulonimbus clouds approaching, try to ensure your safety by moving inside the building. As there is a risk of hail falling, care must be taken when managing agricultural crops and agricultural facilities.

Fronts and low pressures approach, risk of warning-level heavy rain in northern Japan; strict caution against landslides

2025/09/01 06:43

The front extends from China through the Yellow Sea and into the Sea of Japan. By the morning of the 1st, a low pressure system is expected to occur near the Primcoes on the front. This low pressure system will continue tomorrow, on the 2nd, through the Sea of Japan and the Soya Strait to the coast of the Kuril Islands, and the front will travel south through northern Japan.


As warm, humid air flows towards the front and low pressure lines, the atmosphere is expected to become extremely unstable in northern Japan by the next day, the two days.




[Rain Prediction]
In Northern Japan, heavy rain will fall over 30mm per hour with lightning and very heavy rain over 50mm per hour, over the next day, over the next day.
#Expected amount of rain (in places)
+24-hour precipitation expected by the dawn tomorrow, br+Hokkaido region: 120mm
Tohoku region: 100mm
24-hour precipitation expected by the dawn tomorrow, br+Tohoku region: 120mm

[Disaster Prevention Items]
In Northern Japan, be very careful of landslides and be careful of low-lying land flooding, rising rivers and flooding. Also, be careful of severe gusts of wind, such as lightning strikes and tornadoes, and hail fall. If there are signs of developing cumulonimbus clouds approaching, try to ensure your safety by moving inside the building. As there is a risk of hail falling, care must be taken when managing agricultural crops and agricultural facilities.

Weather today, Monday, September 1st: The rainy area will spread in northern Japan. Warning: Eastern Japan to western Japan is extremely hot

2025/09/01 06:10

Today, the 1st (Monday), the start of September, is expected to approach Hokkaido, with a front. While the weather is downhill in northern Japan, it is likely that eastern to western Japan will continue to be covered by high pressure, and the weather will continue to be sunny and extremely hot.



Due to the effects of low pressure and fronts approaching, rain will likely expand in Hokkaido and northern Tohoku from around noon. The falling gradually increases, mainly on the Sea of Japan side, and there is a risk of heavy rain or thunderstorms. It would be a good idea to have a large umbrella when going out.


Sunset will reach and temperatures will rise from southern Tohoku to southern Kyushu, where high pressure is covered. In Nagoya and Kumagaya, there are likely some places where the temperature is exceeding the expected 38 C. It's September, but please continue to be cautious about the extreme heat and take full precautions against heat stroke.
In the afternoon, rain clouds develop locally, mainly along the mountains, so be careful of sudden thunderstorms.


In northern Kyushu, moist air is likely to flow into, and there are areas where showers are likely. It's safe to have a folding umbrella.