A low pressure system is rapidly developing, and tomorrow will be rough in northern Japan and Hokuriku. Beware of blizzards.

2025/12/13 07:50

Today, the 13th, a low pressure system is expected to develop and advance over the Sea of Japan and the Nansei Islands. There will be periods of sunshine in the morning, but rain will spread throughout eastern and western Japan into the evening. If you will be returning late, please prepare rain gear.

Then, from tomorrow the 14th (Sunday) to the 15th (Monday), a low pressure system will rapidly develop along the Pacific coast of Honshu and move toward Hokkaido, while a low pressure system moving along the Sea of Japan will also rapidly develop and move from the central Japan Sea to the Tohoku region. Due to the effects of these low pressure systems, northern Japan and the Hokuriku region are expected to experience heavy rain from tomorrow the 14th (Sunday) to the 15th (Monday).

In northern Japan and the Hokuriku region, be careful of strong winds, snowstorms, and high waves.In northern Japan, be careful of traffic disruptions due to heavy snow, high tides, and be careful of avalanches and snow accumulation.




[Wind Forecast]
In northern Japan and the Hokuriku region, extremely strong winds will blow tomorrow the 14th (Sunday), and in northern Japan from the 14th (Sunday) tomorrow to the 15th (Monday) the following day, extremely strong winds will blow accompanied by snow, resulting in heavy blizzards in some places.
#Expected wind strength
+Maximum wind speed (maximum instantaneous wind speed) expected from tomorrow the 14th (Sunday) to the 15th (Monday) the day after tomorrow
Hokkaido region 25m/s 25m/s (35m/s)
Tohoku region 2 5m/s (35m/s)
Hokuriku Region 25m/s (35m/s)

[Wave Forecast]
In northern Japan and the Hokuriku region, there will be heavy waves from tomorrow the 14th (Sunday) to the 15th (Monday).
#Expected wave height
+Expected wave height from tomorrow 14th (Sunday) to the following day 15th (Monday)
Hokkaido region 6m
Tohoku area Direction: 6m
Hokuriku region: 6m

[Snow forecast]
In northern Japan, there will be heavy snow in some places from tomorrow the 14th (Sunday) to the 15th (Monday).
#Forecasted amount of snow (in areas with the most)
+24-hour snowfall expected by dawn on the 15th (Monday) the next day
Hokkaido region 70cm
+24-hour snowfall expected by dawn on the 16th (Tuesday)
Hokkaido region 40cm

Weather for today, the 13th (Saturday): The winter-like atmospheric pressure pattern is gradually dissolving; the weather is going downhill from the west.

2025/12/13 06:25

Today, the 13th (Saturday), we will be covered by high pressure and the winter-like pressure pattern will gradually disappear. On the other hand, the weather is expected to go downhill in western and eastern Japan due to the influence of a low pressure system approaching from the west.



It will snow in Hokkaido until around noon. Please be careful as there are strong winds and blizzards.
Clouds tend to spread in the Tohoku region, and there are likely to be some places where snow will remain until the morning. It is expected to gradually stop in many places in the afternoon.

From eastern to western Japan, there will be many places where the sun will reach in the morning, especially on the Pacific side. However, the weather is expected to turn downhill from the west in the afternoon. It will start raining in Kyushu in the evening, and in the evening it will start raining in Chugoku, Shikoku, Kinki, and Tokai. In the Kanto region, it is more likely to rain late at night, and the further inland it is, the more likely it will be sleet. Don't forget to bring rain gear when you go out.

It's cold all over the country, and it looks like it's going to be as cold as mid-winter. The temperature in central Tokyo is expected to be 9 degrees Celsius, the coldest of the season. When going out, please take all possible measures to protect yourself from the cold.

"High temperature trend once in 10 years" This Christmas will be warm [Early weather information regarding high temperatures]

2025/12/12 15:00

On the 11th (Thursday), the Japan Meteorological Agency announced
``Early Weather Information Regarding High Temperatures'' for a wide area of Japan.

From around December 17th to around 25th,
Hokkaido, Tohoku, Kanto-Koshin, Hokuriku, Tokai, Kinki, Chugoku,
Shikoku, northern Kyushu, and southern Kyushu regions may experience ``remarkably high temperatures'' that only occur once every 10 years at this time of year.

#Period of extremely high temperatures/5-day average temperature difference#

Hokkaido From around December 18th +2.5c or more
Tohoku From around December 18th +2.3c or more
Kanto-Koshin From around December 19th +2.3c or more
Hokuriku From around December 19th +2.6c or more
Tokai December 19th From around +2.4c or more
Kinki From around December 18th +2.5c or more
Shikoku From around December 18th +2.7c or more
China December 1 From around the 8th +2.5c or higher
Northern Kyushu From around December 18th +2.9c or higher
Southern Kyushu From around December 18th +3.2c or higher



Towards tomorrow the 13th (Saturday), there will be many places where the temperature will be 2c or more lower than normal due to strong cold air.

From around the 14th (Sunday) to the 15th (Monday), heavy rain is expected to occur mainly in
northern Japan due to the developing low pressure system and the strengthening of winter-like pressure patterns.

It will be cold in many places, typical of this time of year, but
after that, from around the 16th (Tuesday), it will be easily covered by high pressure,
warm air will flow in.

After the 17th (Wednesday), there will be many places where the temperature will be more than 2 degrees Celsius higher than normal.
During the daytime, it will be hard to believe that it is December.
There will be many days when the sun will feel so warm.

On the other hand, the Pacific side of northern and western Japan has many sunny days, and the air continues to be dry.

Please be careful when handling sources of fire, such as cigarettes and oil stoves.

Weekend: Highest temperature in the city expected to be 8 degrees Celsius; snow may fall in some places in the southern Kanto region at night

2025/12/12 12:22

It looks like it will snow in some places in the southern Kanto region this weekend.
Tomorrow, the 13th (Saturday), the weather is going downhill in the Kanto region.



The area around Japan is covered in high pressure, and the winter-like pressure distribution is expected to gradually dissipate.
The Kanto region will also be covered in high pressure during the day, and many places will be sunny.
Although it will be sunny, the effects of cold air will remain, and the maximum temperature in central Tokyo will be 8c, which is likely to be the first time this season that the maximum temperature will be in the single digits.
Then, a low pressure system accompanied by a front moved south of Japan, another low pressure system moved over the Sea of Japan, and the weather started to descend from the west.
In addition to low pressure and fronts, clouds will spread from the southern Kanto coast due to the convergence line that forms offshore where the winds collide.
It is expected that there will be some places where it will start to rain at night.
As cold air remains in the sky, by the time the date changes, there will be some places inland and along the mountains in the southern Kanto region where it will snow.
There are some places in Tokyo where it will snow, and there is a possibility that we will see the first snowfall. However, as the low-pressure system approaches, the cold air will move northward, so the time it will take for it to fall as snow will be short.
The day after tomorrow, the 14th (Sunday), the rain will change again in the morning in many places, so there doesn't seem to be any worry about snow accumulating.

Strong cold air and winter-like atmospheric pressure distribution. Be careful of stormy weather in Hokkaido, Tohoku, and Hokuriku

2025/12/12 11:09

There is a developed low pressure system east of Kuril Islands, which is moving east-northeast.
There is also a low pressure system south of Okinawa that is moving southeast.
On the other hand, there is a high pressure system over northeastern China that extends to the east, and strong cold air enters the upper atmosphere near Japan, creating a winter-like atmospheric pressure pattern of high in the west and low in the east.

Currently, snow is falling mainly on the Sea of Japan side from Hokkaido to the Hokuriku region, and rain and snow are falling on the Sea of Japan side of the Kinki region and in the shadow of the mountains, and blizzard warnings have been issued in Miyagi Prefecture and wave warnings in Ishikawa Prefecture.



Today, heavy snow is expected in some places in Hokkaido, Tohoku, and Hokuriku. In addition, the northwest monsoon winds are strong, and there are expected to be some swampy areas.
If winter-like atmospheric pressure patterns strengthen, there is a risk of warning-level heavy snow and blizzards.



In Hokkaido, please continue to be careful of traffic disruptions due to heavy snow, snowdrifts, and snowdrifts until late on the 12th, mainly in the southern part of the Sea of Japan.

Please be on guard for heavy snowstorms on the Pacific coast of Tohoku until the morning of the 12th.
In addition, in the northern Tohoku region, please be careful of traffic disruptions due to heavy snow, snow falling from roofs, damage to buildings and agricultural facilities, and be careful of snow accretion on power lines and trees and avalanches until the evening of the 12th.

In the Hokuriku region, please be careful of high waves until the evening of the 12th.



[Snow Forecast]
The expected 24-hour snowfall from 6:00 on the 12th to 6:00 on the 13th is expected to be 40 cm in the northern part of Hokkaido on the Sea of Japan side.
Hokkaido Southern Sea of Japan side 40cm.
Tohoku Sea of Japan side along the mountain 50cm.
Tohoku Sea of Japan side flat land 20cm.
Tohoku, Pacific Ocean side, along the mountain, 50 cm.
Tohoku Pacific side flat land 15cm.

[Wind Forecast]
Maximum wind speed (maximum instantaneous wind speed) expected on the 12th
Hokkaido Northern Sea of Japan side Land 13m/s (25m/s).
Hokkaido Northern Japan Sea side Ocean 18m/s (30m/s).
Hokkaido Southern Sea of Japan side Land 18m/s (30m/s).
Hokkaido Southern Japan Sea side Ocean 18m/s (30m/s).
Tohoku Sea of Japan side Sea 18m/s (30m/s).
Tohoku Sea of Japan side land 15m/s (30m/s).
Tohoku Pacific Ocean Sea 20m/s (30m/s).
Tohoku Pacific side land 15m/s (30m/s).

[Wave forecast]
Wave height expected on the 12th
Niigata Prefecture 5 meters, with swells.
Toyama Prefecture 3 meters with swells.
Ishikawa Prefecture 5 meters with swells.
Fukui Prefecture 4 meters with swells.

It's warm around Christmas and suddenly cold during the New Year holidays! More precipitation on the Kanto and other Pacific sides, less snow on the Sea of ??Japan side [1 month forecast]

2025/12/11 16:35

Today, the 11th (Thursday), the Japan Meteorological Agency announced the forecast for the month from December 13th to January 12th next year.

#Winter-type atmospheric pressure pattern does not last long, low pressure is rising one after another on the Pacific side
#It is warm around Christmas, suddenly cold during the year-end and New Year holidays
#Snowfall: Less on the Sea of Japan side Precipitation: Most on the Pacific side of eastern and northern Japan
#Air dryness on the Sea of Japan side of eastern and northern Japan Be careful when handling fire and infectious diseases



#Winter-type pressure distribution does not last long On the Pacific side, one low pressure after another
The monthly average sea level pressure is predicted to be weaker than normal for the Aleutian Low, and weaker Siberian High pressure toward the East China Sea, so the winter-like pressure pattern near Japan will not last long.
The Pacific side of eastern and northern Japan is expected to have periods when it is susceptible to the effects of low pressure.
Temperatures at an altitude of approximately 1,500 meters are predicted to be higher than normal in western and northern Japan, mainly around eastern Siberia.
On the other hand, temperatures in southern Japan will be lower than normal, and temperatures in Okinawa and Amami will be near normal.



#It will be warm around Christmas, but it will suddenly get cold during the New Year holidays
As we are less likely to be affected by cold air, temperatures in the coming month are expected to be higher than normal in western and northern Japan.
Especially around Christmas, from December 20th to December 26th, temperatures are likely to be quite high across western and northern Japan.
However, during the year-end and New Year holidays, temperatures across the country will be around normal, and it will feel like it has suddenly gotten colder.



#Snowfall Less precipitation on the Sea of Japan side Since the Pacific side of eastern and northern Japan is less susceptible to the effects of cold air, the amount of snowfall over the next month is expected to be low on the Sea of Japan side of western and eastern Japan, and at or below normal on the Sea of Japan side of northern Japan.
However, there may be a temporary winter-like atmospheric pressure distribution, which may lead to increased snowfall, so please be prepared for snow.
Also, low pressure systems are passing through the Pacific Ocean one after another, and the Pacific side of eastern and northern Japan is likely to experience a lot of precipitation over the next month.
In normal years, there is little precipitation on the Pacific side, and the air has been dry for the past month, so it looks like it will be a blessing.
Depending on the low pressure moving along the southern coast of Honshu and the way cold air moves in, rain may change to snow in some places.
In the Sea of Japan side of eastern and northern Japan, precipitation over the next month is expected to be at or below normal.



#East and Northern Japan Sea of Japan side Air drying Be careful when handling fire and avoid infectious diseases
The amount of sunshine over the next month will likely be at or above normal as winter-like atmospheric pressure patterns will not last long on the Sea of Japan side of western and northern Japan.
In addition, the Pacific side of eastern and northern Japan is susceptible to the effects of low pressure at times, so it is expected to be at or below normal.
The Pacific side of western Japan and Okinawa/Amami are prone to periods of high pressure, and the amount of sunshine this month will be at or above normal.
In the Sea of Japan side of eastern and northern Japan, the amount of sunshine will be at or above normal, and the amount of precipitation will be at or below normal, so the air will likely be dry.
Please be careful when handling fire and preventing infections.

Winter-like atmospheric pressure patterns strengthened in early December, causing barges to appear in the seas around Japan [Marine Summary 2025/11/30-12/6]

2025/12/11 14:06

This is a summary of the ocean from 2025/11/30 to 12/6.



#Pressure distribution and waves
On the 30th, a low pressure system accompanied by a front passed near Hokkaido.
Wave height of 2 to 3 m in the northern and central parts of the Sea of Japan.
On the 1st, another low pressure system developed and passed near Hokkaido.
Wave height was 3m in the Japanese waters in the morning, and 5m in the Sea of Okhotsk at night.

On the 2nd, a low pressure system in the Sea of Japan was developing and moving northeast.
From the 3rd to the 4th, a winter-like pressure pattern strengthened near Japan.
On the 4th, wave heights widely exceeded 4 meters in the Japanese waters and the Pacific Ocean.

On the 5th, an anticyclone emerged from the west, and the high waves gradually subsided from the west.
On the 6th, the area around Honshu was covered by a belt-shaped high pressure system.
In the morning, high waves continued off the coast of Sanriku on the edge of the high pressure system and from west of Hokkaido to off the coast of Akita, but subsided by night.



#Sea surface temperature
Sea surface temperatures in the Japanese waters continue to be lower than normal along the coast of Hokkaido.
In the central and western regions, sea levels continued to be higher than normal or significantly higher.

In the East China Sea, the sea area is expanding at normal levels.
South of Japan, sea areas continue to be at normal levels.
The Izu Islands have returned to normal levels, but waters off the coast of the Tokai region continue to be below normal levels.

In the eastern part of Japan, temperatures were significantly higher than normal, with temperatures up to 4 C higher.
The waters off the coast of Sanriku continue to be at normal levels. The sea off the southeast coast of Hokkaido was lower than normal, and the Sea of Okhotsk remained at normal levels.

Tomorrow (Friday) intense cold; heavy snow and blizzard on the Japan Sea side; widespread stormy weather from the weekend to the beginning of the week, affecting transportation [Weekly weather]

2025/12/11 12:38

Weekly weather points
#The coldest air of the season will arrive tomorrow
#Friday the 12th (Friday) to 13th (Saturday) will be the coldest of winter
#From the 14th (Sunday) to the 15th (Monday) there will be stormy weather and severe storms in northern and eastern Japan



Tonight, a low pressure system near Hokkaido is expected to develop and move towards the waters near the Chishima Islands.
Tomorrow, the 12th (Friday), a winter-like pressure pattern will strengthen, and cold air similar to midwinter will flow into the
sky.

Looking at the forecast for the cold air in the air at noon tomorrow,
more than the cold air expected to bring heavy snow,
an even stronger cold air of minus 42 degrees Celsius is expected to flow over Hokkaido.

The lowest temperature so far this season was -39.4c, which was observed at around 5000m above Sapporo on December 4th (Thursday), and the cold air that will arrive tomorrow is likely to be the strongest this season.

Due to the effects of this strong cold air, there will be widespread snow on the Sea of Japan side,
There will likely be heavy snowfall in some places, especially in Tohoku and Hokkaido.
Also, there will be heavy snow along the mountains on the Sea of Japan side, and there is a possibility that
heavy snow warnings will be announced in Hokkaido, Aomori prefectures, northern Nagano prefectures, etc. until
12th (Friday).



In addition, the temperature will not rise due to the cold air,
tomorrow, the 12th (Friday), the maximum temperature in Tokyo, Osaka, and Nagoya will be 10c,
It will be bitterly cold even on the Pacific side.

Furthermore, on Saturday the 13th, the maximum temperature in Tokyo will be 8c, which is likely to be the coldest of the season.

Wear warm winter clothing such as down coats, gloves, and scarves when you go out.



Due to the developing low pressure system from the 13th (Sat) to the 14th (Sun),
the weather will be rough with rain, snow, and strong winds across the country.

Especially on the 14th (Sunday), there is a risk of warning-level storms, heavy rain,
heavy snow in eastern and northern Japan, and the weather is likely to be very stormy in northern Japan.

Please be aware that transportation such as aircraft, Shinkansen trains, and expressways may be affected.




#Stormy weather continues into the 15th (Monday) of the week#

Even into the 15th (Monday), there will be strong snow and wind in northern Japan, with
warning-level storms and heavy snow in some places.

Also, the cold air will remain until the middle of next week, so the December-like cold will continue even on the sunny Pacific side.

The air on the Pacific side is dry, so
Please be careful about your physical condition, especially if you catch a cold.

Weather for the week: Heavy snow and stormy weather on the Sea of ??Japan side on the weekend; cold rain also on the Pacific side of western and eastern Japan

2025/12/11 09:03

The weather will be severe over a wide area this weekend and into the beginning of next week. Snow will become heavier on the Japan Sea side, and there is a risk that snowfall will increase rapidly, especially in Hokkaido and Tohoku.



Tomorrow, the 12th (Friday), extremely cold air with temperatures below -12c at an altitude of approximately 1500 meters is expected to move southward to the Hokuriku region near Honshu.
Deep snow clouds will flow into the Hokuriku region from the Sea of Japan side of northern Japan, and even flat areas will become snowy. Locally, the snow may become heavier in a short period of time, leading to a sudden increase in snowfall. In addition, northerly winds will become stronger, causing snowstorms in some places, especially along the coast. Please be careful of poor visibility due to blizzard and traffic obstruction due to snow.




From Saturday the 13th to Sunday the 14th, two low pressure systems will pass over the Sea of Japan and the southern coast of Honshu, respectively, and the weather will deteriorate from the west. The two low pressure systems will merge into one from the 14th to the 15th, and the area around Honshu will have a winter-like pressure pattern of high in the west and low in the east.
For this reason, from the 13th to the 14th, there will be widespread rain and snow from northern Japan to eastern Japan and western Japan on the Sea of Japan side, and there will also be widespread cold rain on the Pacific side of eastern and western Japan. It looks like the wind will be strong and the weather will be rough.
The weather is expected to improve on the Pacific side from the 15th (Monday) onwards, but from the Sea of Japan side of northern Japan to the Hokuriku region, rain and snow days are expected to continue due to the effects of cold air and low pressure in the upper atmosphere.

As the cold air moves south, the temperature will change significantly. Tomorrow, the 12th (Friday), temperatures will be below 5c in many places from the Sea of Japan side of northern Japan to Hokuriku, and the predicted maximum temperature in Sapporo is -4c. Temperatures are expected to reach 9c in Tokyo on Saturday the 13th, and there will be places on the Pacific side where the temperature will not reach 10c during the day, a midwinter cold. It is expected that the weather will continue to be cold, especially in the mornings and evenings, and the winter-like cold will continue after the end of the week. Please take all possible measures to protect yourself from the cold and stay in good physical condition.

El Nino monitoring bulletin: La Nina-like conditions will rapidly resolve at the end of winter

2025/12/10 21:12

On the 10th (Wednesday), the Japan Meteorological Agency announced the latest El Nino monitoring bulletin.

Currently, the situation appears to be normal, with neither El Nino nor La Nina occurring, but conditions are close to La Nina. This situation is expected to continue until the beginning of winter, but is expected to quickly resolve after that.

The difference in sea surface temperature in the El Nino monitoring area in November from the standard value was -0.5c, which was lower than the standard value. Additionally, the five-month moving average used to determine the occurrence of El Nino and La Nina phenomena in September was -0.4 C, a value close to the standard value.
Sea surface temperatures in the equatorial Pacific Ocean remained higher than normal in the western region and lower than normal in the central and eastern regions. The easterly winds (trade winds) in the lower atmosphere of the equatorial Pacific region were stronger than normal throughout the region, and convective activity became inactive near the international date line in the equatorial Pacific region.

From the above, although it is a normal state where neither El Nino nor La Nina phenomena have occurred, the situation is close to that of La Nina.



According to the Japan Meteorological Agency's coupled atmosphere-ocean model, sea surface temperatures in the El Nino monitoring area are expected to remain lower than standard values at the beginning of winter due to continued strong trade winds in the equatorial Pacific.
However, after that, the atmosphere-ocean coupling is expected to weaken and the low sea surface temperature will rapidly disappear. Sea surface temperatures are expected to rise from late winter to spring and remain close to standard values.

From the above, the La Nina-like conditions are expected to rapidly resolve towards the end of winter, and normal conditions will continue into spring.


#What is the El Nino/La Nina phenomenon
The El Nino phenomenon is a phenomenon in which sea surface temperatures are higher than normal from the equatorial Pacific Ocean near the international date line to the coast of South America, and this condition continues for about a year.
On the other hand, a phenomenon in which sea surface temperatures continue to be lower than normal in the same area is called a La Nina phenomenon.

Once an El Nino or La Nina phenomenon occurs, it is thought that abnormal weather will occur all over the world, including Japan.