Aftermath continues even after the end of the Kuroshio meander; changes in sea surface temperature [Ocean Summary October 19-25, 2025]

2025/10/29 14:10

The Japan Meteorological Agency and Japan Coast Guard have announced that the Kuroshio Current Meander will end in April 2025 (announced on August 29, 2025).

However, according to JAMSTEC's Kuroshio Watch, the aftermath of the Kuroshio Meander is continuing.



The Kuroshio Current approaches from Shikoku to the Kii Peninsula,
then flows south of Hachijo Island.

The distribution of sea surface temperatures is also low near the Izu Islands, where the Kuroshio current meanders south.

Below is the ocean summary (October 19-25, 2025).



#Pressure distribution and waves
Throughout the period, the front remained stationary from the southern coast of Honshu to the south of Japan, and from the 19th to the 24th, the high pressure system dominant over the continent remained stationary.

On the 20th, an anticyclone strengthened over the continent.
There were sea areas where wave heights were as high as 3 m in the Japan Sea and Yellow Sea, where northeast winds prevail around the edge of the anticyclone, and wave heights of 4 m in the East China Sea.

From the 21st to the 24th, the gradient in atmospheric pressure increased between the front on the southern coast of Honshu and the high pressure system on the continent, and the winds from the north and east became stronger.
The waves continued to be high in the Nansei Islands and the Pacific side of western and eastern Japan, with waves exceeding 4m in height on the 22nd, and waves of 6m in height off the coast of Shikoku on the 23rd.

On the 25th, the high pressure system that had been stationary over the continent became mobile, and
the high waves on the Pacific side gradually subsided.



#Sea surface temperature
In the Japanese sea area, areas where sea surface temperatures are much higher than normal are shrinking, and areas where sea surface temperatures are similar to normal are expanding.
On the continental side of the central Japan Sea, areas of lower-than-normal waters expanded.

In the East China Sea, areas above normal have shrunk, and areas above normal have expanded.

On the Pacific side, the area of higher-than-normal waters has shrunk, and
around the Izu Islands, the area of higher-than-normal waters has expanded.

Off the coast of Sanriku, conditions continued to be higher than normal.

On the other hand, the sea area south of the Kuril Islands continues to be slightly lower than normal.
The Sea of Okhotsk remained at normal levels.

Aftermath continues even after the end of the Kuroshio meander; changes in sea surface temperature [Ocean Summary October 19-25, 2025]

2025/10/29 14:10

The Japan Meteorological Agency and Japan Coast Guard have announced that the Kuroshio Current Meander will end in April 2025 (announced on August 29, 2025).

However, according to JAMSTEC's Kuroshio Watch, the aftermath of the Kuroshio Meander is continuing.



The Kuroshio Current approaches from Shikoku to the Kii Peninsula,
then flows south of Hachijo Island.

The distribution of sea surface temperatures is also low near the Izu Islands, where the Kuroshio current meanders south.

Below is the ocean summary (October 19-25, 2025).



#Pressure distribution and waves
Throughout the period, the front remained stationary from the southern coast of Honshu to the south of Japan, and from the 19th to the 24th, the high pressure system dominant over the continent remained stationary.

On the 20th, an anticyclone strengthened over the continent.
There were sea areas where wave heights were as high as 3 m in the Japan Sea and Yellow Sea, where northeast winds prevail around the edge of the anticyclone, and wave heights of 4 m in the East China Sea.

From the 21st to the 24th, the gradient in atmospheric pressure increased between the front on the southern coast of Honshu and the high pressure system on the continent, and the winds from the north and east became stronger.
The waves continued to be high in the Nansei Islands and the Pacific side of western and eastern Japan, with waves exceeding 4m in height on the 22nd, and waves of 6m in height off the coast of Shikoku on the 23rd.

On the 25th, the high pressure system that had been stationary over the continent became mobile, and
the high waves on the Pacific side gradually subsided.



#Sea surface temperature
In the Japanese sea area, areas where sea surface temperatures are much higher than normal are shrinking, and areas where sea surface temperatures are similar to normal are expanding.
On the continental side of the central Japan Sea, areas of lower-than-normal waters expanded.

In the East China Sea, areas above normal have shrunk, and areas above normal have expanded.

On the Pacific side, the area of higher-than-normal waters has shrunk, and
around the Izu Islands, the area of higher-than-normal waters has expanded.

Off the coast of Sanriku, conditions continued to be higher than normal.

On the other hand, the sea area south of the Kuril Islands continues to be slightly lower than normal.
The Sea of Okhotsk remained at normal levels.

November started with stormy weather; during the first half of the three-day weekend, there was warning-level heavy rain in the Kanto region and other areas, and strong winds affected transportation [Weekly Weather]

2025/10/29 12:00

Today, October 29th (Wednesday), there is a high pressure system centered over the Sea of Japan, and many places in western and eastern Japan are sunny.

Meanwhile, strong cold air is flowing into the sky over Hokkaido,
raining and snowing in some places.

Snowfall in Hokkaido has been decreasing since last night, but as of 11am, 20cm of snow remains in Sounkyo, Kamikawa Town, 4cm in Asahikawa City, and 9cm in Yubari City.




The center of the high pressure system will move towards the Tohoku region tonight, and the snow in Hokkaido is expected to gradually weaken in the afternoon.

Throughout the day on the 30th (Thursday), it will be sunny in many places within the high-pressure area, but
tomorrow night, moist air will flow in around the edge of the high-pressure system,
and it will start raining in places like Kyushu.


A front will extend from the continent tomorrow, the 31st (Friday),
it will rain in western Japan in the morning,
it will rain in many places in eastern Japan in the afternoon.



From the 31st (Friday) to the 1st (Saturday), a low-pressure system on the
front is expected to develop and pass near eastern Japan, and the start of November is likely to be rough with strong rain and wind in eastern and northern Japan.




As of today, the 29th (Wednesday), ``alarm-level heavy rain'' is expected to occur widely from the Kanto region to Hokkaido on November 1st (Saturday), and a storm warning may be issued in
northern Japan.

I think many people will be traveling to distant places during the three-day holiday,
especially in northern and eastern Japan,
heavy rain and strong winds may affect traffic.

Please check the latest weather and traffic information when you go out.




Finally, here is the weekly weather.

Western and eastern Japan will be covered by a mobile high pressure system from the 2nd (Sunday) to the 3rd (Monday), and many places will be sunny.

During the day, the temperature will rise to around 20c,
The second half of the holidays will be pleasant and sunny.

Although there are many places in northern Japan and Hokuriku where it rains during the holidays, the sunshine will return on the 4th (Tuesday).

However, on the 5th (Wednesday), the weather is expected to start to go downhill from the west, and
it is expected to rain again in many places from western Japan.

From here on out, the weather is likely to change periodically, like late autumn.

Today's weather on the 29th (Wednesday): Broad skies and sunshine. The weather is also improving on the Sea of ??Japan side.

2025/10/29 06:07

Today, the 29th (Wednesday), the area around Japan is expected to be covered in high pressure. The atmospheric pressure pattern of high in the west and low in the east will be resolved, and the weather will gradually improve in northern Japan as well.



In northern Japan and Hokuriku, clouds tend to spread mainly in the morning, and there will be places where rain or snow will remain until around noon. By the afternoon, the area of rain and snow will gradually shrink, and the sun will likely return in some places. During the day, the temperature will be higher than yesterday, and the cold weather will likely be gone.

The area from Kanto to Kyushu will be covered by high pressure and will be sunny over a wide area. During the day, the temperature in many places is around 20c, making it a pleasant experience. It can get cold in the mornings and evenings, so please be careful when choosing what to wear when going out.

Okinawa is gradually experiencing sunshine, but please be careful of sudden changes in the sky as there is a possibility of showers mainly in the morning.

Hokkaido is on high alert for strong winds, and on the Sea of Japan side, be careful of traffic disruption until dawn tomorrow.

2025/10/28 18:59

A well-developed low pressure system is moving through the Sea of Okhotsk, and the atmospheric pressure around Japan is high in the west and low in the east.
Around Hokkaido, the gradient of atmospheric pressure is increasing, and westerly winds are increasing mainly in the coastal areas.
As of 17:00, there are areas in Hokkaido's Ishikari and Hiyama regions where a storm warning has been issued.

In Hokkaido, the atmospheric pressure is expected to remain high in the west and low in the east until tomorrow the 29th. In addition, atmospheric conditions will be unstable due to the influence of cold air in the upper atmosphere.

In the southern part of the Japan Sea side, please be on alert for strong winds until early evening today, the 28th. Additionally, people in the Hokkaido region need to be careful of strong winds and high waves through tomorrow, the 29th.
In the northern part of the Sea of Japan coast, please continue to be careful of traffic disruptions due to heavy snow until dawn on the 29th.
Depending on the degree of development of the low pressure system, there is a possibility that the area and duration of the storm may expand, or there may be warning-level heavy snow.
In the Hokkaido region, please continue to be careful of snow deposits on power lines due to lightning, gusts of wind, hail, and wet snow until dawn on the 29th.


[Wind report]
Maximum wind speed and maximum instantaneous wind speed from 00:00 on the 27th to 15:00 today on the 28th (preliminary report by AMeDAS, unit: meter) )
Cape Soya, Wakkanai City
Maximum wind speed 22.3 meters West (Today 28th 07:54)
Maximum moment Wind speed 31.4 meters West (Today 28th 04:20)
Inaho, Okushiri Town
Maximum wind speed 21.8 meters West-northwest (Today 28th 09:27)
Maximum instantaneous wind speed 28.5 meters West (Today 28th 08:44)
Esashi
Maximum wind speed 20.2 meters West-northwest (21:03 on the 27th)
Maximum instantaneous wind speed 27.6 meters West-northwest (27th 21:00)
Ishikari City Hamamasu
Maximum wind speed 19.9 meters West-northwest (Today 28th 04:23)
Maximum High instantaneous wind speed 27.2 meters West (Today 28th 03:32)
Hatsuyamabetsu
Maximum wind speed 18.9 meters West (Today 28th 03:42)
Maximum instantaneous wind speed 30.1 meters West-southwest (Today 28th 05:36)




#Expected wind strength
+Maximum wind speed (maximum instantaneous wind speed) expected for today, the 28th
Northern land on the Sea of Japan side 15 meters (30 meters)
Northern sea on the Sea of Japan side 18 meters (30 meters)
Southern land on the Sea of Japan side 20 meters (35 meters)
Southern sea on the Sea of Japan side 20 meters (30 meters)
Pacific coast western land 15 meters (30 meters)
Pacific coast western sea 20 meters (30 meters) )
Eastern Pacific Ocean Land 15 meters (30 meters)
Eastern Pacific Ocean Sea 18 meters (30 meters)
Okhots Northern land on the Sea of Okhotsk side 12 meters (25 meters)
Northern sea on the Sea of Okhotsk side 15 meters (25 meters)
Southern land on the Sea of Okhotsk side 12 meters Tor (25 meters)
Southern Sea of Okhotsk Sea 18 meters (30 meters)
+Maximum wind speed (maximum instantaneous wind speed) expected on tomorrow 29th
Day Northern land on the Honkai side 13 meters (25 meters)
Northern sea on the Sea of Japan side 15 meters (25 meters)
Southern land on the Sea of Japan side 1 5 meters (30 meters)
Southern sea on the Sea of Japan side 15 meters (25 meters)
Western land on the Pacific side 13 meters (25 meters) )
Western Pacific Ocean Sea 18 meters (30 meters)
Eastern Pacific Ocean Land 12 meters (25 meters)
East Pacific Side Sea area 15 meters (25 meters)
Northern land area on the Sea of Okhotsk side 12 meters (25 meters)
Northern sea area on the Sea of Okhotsk side 15 meters (25 meters)
Southern land on the Sea of Okhotsk side 12 meters (25 meters)
Southern sea on the Sea of Okhotsk side 15 meters (25 meters)

#Expected wave height
+Expected wave height for today 28th
Northern Sea of Japan side 5 meters
Southern Sea of Japan side 5 meters
Western Pacific Ocean 5 meters
Eastern Pacific Ocean 5 meters
Northern Sea of Okhotsk 4 meters
Southern Sea of Okhotsk 5 meters Tor
+Height of waves expected on tomorrow 29th
Northern Sea of Japan side 4 meters with swell
Southern Sea of Japan side 4 meters
Pacific Ocean Western side 4 meters
Eastern Pacific side 4 meters with swells
Northern Sea of Okhotsk side 3 meters with swells
Okhotsk Southern sea side 4 meters with swells

#Expected amount of snow
+Expected 24-hour snowfall amount by 6:00 PM on the 29th tomorrow
Northern Sea of Japan side 40 cm

Stormy weather in Hokkaido, maximum instantaneous wind speed exceeds 30 m/s, warning of strong winds, winter chill in the sky, new snowfall

2025/10/28 11:55

Today, the 28th (Tuesday), a low-pressure system in the Sea of Okhotsk is developing and moving northeast, creating a winter-like pressure pattern with high pressure in the west and low pressure in the east, centered on northern Japan.
There is a large gradient in the atmospheric pressure, resulting in rough weather in Hokkaido, and storm warnings have been issued in some places, mainly on the Sea of Japan side.
Also, near 5,500m above Hokkaido, cold air with temperatures below -36c, which is strong for this time of year, is flowing into the air, making the atmospheric condition unstable.



#Hokkaido storm warning announced In Hokkaido, where the maximum instantaneous wind speed exceeds 30 m/s, the winter pressure distribution is high in the west and low in the east, and the pressure gradient is increasing in Hokkaido, where stormy winds are raging.
The maximum instantaneous wind speed until 10 a.m. today, the 28th (Tuesday), was 31.4 m/s at Cape Soya in Wakkanai City, 31.3 m/s at Cape Erimo in Erimo Town, and 30.1 m/s at Hatsuyamabetsu in Hatsuyamabetsu Village, with some locations exceeding 30 m/s.
More than 25m/s was observed in urban areas such as Rumoi City and Muroran City.
As of 10:30 a.m., a storm warning has been issued for the Rumoi, Ishikari, and Hiyama regions of Hokkaido.
Towards the evening, the wind will be very strong from the west, mainly on the Sea of Japan side.
Beware of strong winds.



#Sky over Hokkaido Strong winter cold air for this time of year
A strong winter cold air for this time of year is flowing into the vicinity of 5500m above Hokkaido, with temperatures below -36c, making the atmospheric condition unstable.



Snow and rain are falling over a wide area from the Sea of Japan side of northern Japan to Hokuriku.
There is snow in the inland areas of Hokkaido and the mountainous areas of Tohoku.
Up to 10 a.m. today, the 28th (Tuesday), the snow depth was 13 cm at Sukayu in Aomori City, Aomori Prefecture, 8 cm at Sounkyo in Kamikawa Town, Hokkaido, and 6 cm at Kamikawa in Kamikawa Town, Hokkaido.
In Hokkaido, new snow is expected to accumulate, mainly in the northern part of the Sea of Japan.
Until dawn on Wednesday the 29th, please be careful of traffic disruptions due to heavy snow and snow buildup on power lines due to wet snow.

Northern Japan/Eastern Japan Atmospheric instability

2025/10/28 08:43

There is a low pressure system in the Sea of Okhotsk that is moving northeast. There is a high pressure system over the Yellow Sea that is moving eastward. Near Japan, the atmospheric pressure is high in the west and low in the east.



Today, strong cold air will flow over northern and eastern Japan, making the atmospheric conditions extremely unstable.
In northern and eastern Japan, please be careful of severe gusts such as lightning and tornadoes on the 28th.
There is also a risk of hail, so please be careful when managing crops and agricultural facilities.

[Go home early] Hokkaido: Rain turns to snow at night. Snow falls on flat areas tomorrow. Beware of strong winds. Low pressure system is rapidly developing.

2025/10/27 13:03

Today, the 27th (Monday), a low pressure system accompanied by a front is moving northeast in the sea near Chishima Island, and will rapidly develop into the Sea of Okhotsk through tonight.



An anticyclone is protruding from the continent, and the area around Japan is expected to have high pressure in the west and low pressure in the east until tomorrow, the 28th (Tuesday).
The gradient of atmospheric pressure will increase near Japan, and around 1500 meters above Hokkaido, strong cold air will move south for this time of year with temperatures below -6c.



Today, the 27th (Monday), atmospheric conditions will be unstable in Hokkaido due to the influence of cold air in the upper atmosphere, and caution should be taken against sudden strong rain, lightning, gusts of wind, and hail.
In addition, temperatures will drop in the afternoon, and rain will turn to snow in the mountains at night.
Not only in northern Hokkaido, but also in the Oshima and Hiyama regions in southern Hokkaido and the Iburi and Hidaka regions in central Hokkaido, it is expected that snow will fall intermittently in high mountain passes and mountainous areas from tonight until tomorrow 28th (Tuesday), resulting in snow accumulation in some places.
There is a risk of snowfall even in flat areas.
Please be careful of traffic obstructions due to snowfall and frozen roads.



Additionally, as the low pressure system rapidly develops and moves towards the Sea of Okhotsk, winds are expected to gradually increase in northern Hokkaido.
From the evening of today, the 27th (Monday) to tomorrow, the 28th (Tuesday), westerly winds will become stronger, blowing very strongly at sea, and causing sea barges.



Maximum instantaneous wind speeds of 35 m/s are expected on land, mainly along the coast of northern Hokkaido.
Please be on guard for strong winds from late evening today, the 27th (Monday) until noon on the 28th (Tuesday) tomorrow.
Depending on the course of the low pressure system and the extent of its development, the period of stormy winds may expand.
It will also snow, so be careful of poor visibility due to blizzards.

Today, the 27th (Monday), it is safe to go home early before the snow turns to snow and the wind picks up.

Weekly weather: Very strong cold air moving south in Hokkaido. Will the next three-day weekend start with rain over a wide area

2025/10/27 07:49

From now on, at the beginning of the season, Hokkaido will experience snow even in flat areas, especially in northern Hokkaido, due to the influence of strong cold air. In the latter half of the
period and the beginning of the next three-day holiday (November 1st to 3rd), it is likely to rain in many places due to the effects of low pressure.



A low pressure system will develop in the Sea of Okhotsk into tomorrow, the 28th (Tuesday), and northern Japan will experience a strong winter-like pressure pattern. In addition, extremely cold air with temperatures below -36 C will flow into Hokkaido approximately 5,000 meters above the ground, resulting in snow even on flat areas, especially in northern Hokkaido, and strong winds that will cause blizzards in some places.
Please be aware of road conditions due to snow accumulation, poor visibility due to blizzard, and traffic obstructions.
Tomorrow, the 28th, due to the influence of cold air moving south from Tohoku to eastern Japan, it will snow in the high mountains, and it is likely that some places will receive news of the first snowfall.



On the 29th and 30th, the area around Honshu will be covered by high pressure, and many places will be sunny. However, Okinawa is susceptible to fronts and will likely be cloudy and rainy.

From around the 31st (Friday) in the latter half of the week to the 1st (Saturday), the beginning of the next three-day weekend, a low pressure system is expected to develop and pass near Honshu. As a result, the weather will turn downward from the west, causing rain over wide areas of western and eastern Japan. Be careful of heavy rain with localized thunderstorms. In northern Japan, the wind is likely to pick up again and the weather will be rough.
Around the 2nd (Sunday), another new low pressure system is expected to form behind the low pressure system accompanying the front and move through the Sea of Japan. Western and eastern Japan will be covered in high pressure around the middle of the three-day weekend, and the weather is likely to improve mainly on the Pacific side, but in northern Japan, the atmospheric conditions will become unstable mainly on the Sea of Japan side, and there is a possibility that the weather will continue to be rough.

Although the current forecast is uncertain, such as the path of the low pressure system, predicted degree of development, and extent of rain, if you have plans for the next three-day weekend, please be sure to check the latest weather information that will be updated in the future.

Strong cold air is expected to flow over Hokkaido on the 28th, indicating heavy snow. Possibility of a blizzard in northern Hokkaido.

2025/10/26 21:19

From tomorrow the 27th (Monday) to the 28th (Tuesday), the area around Japan is expected to experience a strong winter-like atmospheric pressure pattern.
On the 28th (Tuesday), extremely cold air with temperatures below -36c at an altitude of approximately 5000m is expected to flow into the sky over Hokkaido.



In Hokkaido, there will be places where the snow will change from the night of the 27th tomorrow. Tomorrow, on the 28th, snow is expected to fall on flat areas in inland Hokkaido, especially in northern Hokkaido, and snow is expected to spread to areas in central and southern Hokkaido.
There is a risk of heavy snowfall and increased snowfall along the mountains, as well as strong winds and rough weather, leading to poor visibility and traffic problems due to the blizzard.



There is an increasing possibility that a strong wind and blizzard warning will be issued from the 27th to the 28th, especially in the Soya region, Kamikawa, and Rumoi regions. Pay attention not only to the latest weather information, but also to traffic information.

Also, the cold air that causes snow to fall along the mountains will move south from southern Tohoku to the Hokuriku region, so there is a possibility of snow falling along the high mountains from Tohoku to eastern Japan on the 27th and 28th. When driving on mountain passes, you need to pay attention to the condition of the road surface. Be sure to prepare for winter tires as early as possible.