Northern Japan to be careful of rough weather

2025/11/16 18:07

The area around Honshu is covered by a high pressure system moving eastward, but in Primorye there is a low pressure system with a front that is moving northwest.
The low pressure system is rapidly developing as it passes north of Hokkaido, and tomorrow, the 17th (Monday), it will advance to the Sea of Okhotsk, and the front will pass through Honshu.
We will see a winter-like atmospheric pressure pattern of high in the west and low in the east, with strong cold air moving south, creating a large gradient in atmospheric pressure and making the atmosphere extremely unstable.

In Hokkaido and Tohoku, please be careful of strong winds, especially on the Sea of Japan side.
If the atmospheric pressure gradient becomes larger than expected, there is a possibility of warning-level winds.

Also, cumulonimbus clouds are expected to develop and there are some places where thunderstorms will occur.
Please be careful of flooding of low-lying areas due to heavy rain, landslides, rising river waters, strong gusts of wind caused by tornadoes, lightning strikes, and hail.

In Hokkaido and along the high mountains of Tohoku, rain is expected to gradually change to snow.



###Wind forecast
Maximum wind speed (maximum instantaneous wind speed) expected on the 17th
Hokkaido Northern land on the Sea of Japan side 20 meters (35 meters).
Hokkaido Northern Sea of Japan Sea side 23 meters (35 meters).
Hokkaido Southern land on the Japan Sea side 18 meters (30 meters).
Hokkaido Southern Sea of Japan Sea side 20 meters (30 meters).
Hokkaido Pacific Ocean side land area 18 meters (30 meters).
Hokkaido, Pacific Ocean, Western Sea, 20 meters (30 meters).
Hokkaido Pacific Ocean side eastern land 18 meters (30 meters).
Hokkaido Pacific Ocean Eastern Sea 20 meters (30 meters).
Hokkaido Northern land on the Sea of Okhotsk side 15 meters (30 meters).
Hokkaido, Northern Sea of Okhotsk side, 18 meters (30 meters).
Hokkaido Southern land on the Sea of Okhotsk side, 18 meters (30 meters).
Hokkaido Sea of Okhotsk side, southern sea, 20 meters (30 meters).
Tohoku Sea of Japan side 18 meters (30 meters).
Tohoku Sea of Japan side land 15 meters (30 meters).





###Rain forecast
On the 17th, rain is expected to gradually turn to snow in Hokkaido and along the high altitude mountains of Tohoku.

The predicted hourly precipitation on the 17th is 30 mm in the northern part of Hokkaido on the Sea of Japan coast.
Hokkaido Southern Sea of Japan side 30mm.
Hokkaido Northern Sea of Okhotsk side 30mm.

The predicted precipitation for the 24-hour period from 18:00 on the 16th to 18:00 on the 17th is expected to be 80 mm in the northern part of Hokkaido's Sea of Japan coast.
Hokkaido Southern Sea of Japan side 50mm.
Hokkaido Northern Sea of Okhotsk side 80mm.

###Disaster Prevention Matters
The Hokkaido region is expected to experience extremely stormy weather on the 17th, with extremely strong winds and localized heavy rain accompanied by thunder.
In the northern part of the Japan Sea side, please be on guard for strong winds from early morning until dawn on the 17th.
In addition, in the Hokkaido region, please be careful of flooding of low-lying areas, landslides, and rising river waters due to strong winds from early on the 17th until late at night, and heavy rain from early on on the 17th to before noon.
Depending on the path and degree of development of the low pressure system, the area and duration of the storm may expand, and there is a risk of warning-level heavy rain.

In addition, in the Hokkaido region, there is a risk of tornadoes, strong gusts of wind, lightning, and hail from early morning until early afternoon on the 17th.
Please be careful when doing outdoor activities and managing crops.
If there are signs that a cumulonimbus cloud is approaching, please take precautions such as moving to a sturdy building.

On the Sea of Japan side of Tohoku, from the morning of the 17th until noon, please be careful of traffic disruptions and damage to buildings caused by strong winds from the west.
Also, in the Tohoku region, please be careful of strong gusts such as tornadoes, lightning, hail, and sudden heavy rain from dawn to dusk on the 17th.
If there are signs that a cumulonimbus cloud is approaching, please take precautions such as moving to a sturdy building.

Strong cold air will move south at the beginning of the week, with the possibility of snowfall even along Mt. Honshu

2025/11/16 07:00

Today, the 16th (Sunday), the weather will be mild and sunny with sunshine reaching many places, but by the end of the week, tomorrow, the 17th (Monday), a rapidly developing low pressure system is expected to move from the northern Sea of Japan to the Sea of Okhotsk. Therefore, around the 19th (Wednesday), the area around Japan will shift to a strong winter-type atmospheric pressure pattern, and strong cold air will flow into the upper atmosphere.




Looking at the forecast for the cold air around 1,500m above the sky on the 18th (Tuesday), it is predicted that -6c cold air, which is the standard for snow in flat areas, will move south from Hokuriku to the southern part of Tohoku. Snow will fall in Tohoku and along the mountains of eastern and western Japan, and there will be places where it will snow. If you are planning to drive on mountain passes, please make preparations such as changing to winter tires on a calm day.

Also, Hokkaido is expected to experience a strong cold air of -12c for this time of year. There is a risk of increased snowfall not only along the mountains but also on the flatlands. The weather will be stormy with strong winds and blizzards in places. Please pay attention to the latest weather and traffic information as transportation may be affected in the first half of next week.

Today's weather on the 16th (Sunday): It's a good day for tourists in many places. In Hokkaido, it's raining from night onwards.

2025/11/16 06:14

Today, the 16th (Sunday), the area around Japan will continue to be covered in high pressure. It looks like it will be a good day for tourists as the sun shines in many places.



Hokkaido will receive sunlight mainly in the morning. However, due to the influence of a low pressure system and front approaching from the west, clouds will gradually spread in the afternoon, and there will be some places on the Sea of Japan side of the area where it will start to rain at night. If you will be returning late, please prepare rain gear.

On the other hand, the sun will reach a wide area from Tohoku to Kyushu and Okinawa and it will be mild and sunny. It's a good day to go out in various places, so it might be a good time to go see the autumn leaves. During the day, you can feel the warmth of the sunlight in many places, making the weather pleasant and sunny, but the mornings and evenings get colder, resulting in a larger difference in temperature throughout the day. It would be a good idea to go out in clothes that are easy to adjust.

Will the JPCZ (Japan Sea Polar Air Mass Convergence Zone) occur for the first time this season Snow will increase in northern Japan at the beginning of the week, and snow will also accumulate in the mountains of eastern and western Japan [Weekly Weather]

2025/11/15 12:01

This Saturday and Sunday will be sunny and warm and cheerful in many places during the day, but from the beginning of next week, strong cold air will move in and the cold of winter will arrive.

Especially from around the 17th (Monday) to the 19th (Wednesday), there will be heavy snowfall in northern Japan, and there will likely be some places in the mountains of eastern and western Japan as well.

Please take advantage of this mild weekend weather and prepare for snow by changing to winter tires if you are driving over the
mountain pass,
or checking the operation of your snowplow in areas where heavy snowfall is expected.




This Saturday and Sunday will be covered in high pressure and will be sunny in many places.
During the day, temperatures will rise to around 20 degrees Celsius in eastern and western Japan, and
the sun will feel warm.

However, the front will approach from the night of tomorrow, the 16th (Sunday), and
it will begin to rain in some places in Hokkaido.



#It's the first snow rush in Tohoku, with snow falling in the mountains of eastern and western Japan#

Looking at the forecast weather map and cold air forecast for the 17th (Monday) to the 19th (Wednesday),
A strong winter-type pressure pattern will occur on the 17th (Monday),
strong cold air that will bring snow on the flatlands will flow into northern Japan.

In Tohoku, many places are experiencing their first snowfall, and in Hokuriku and other areas, there may be some places where the rain will be mixed with snow.
The first snowfall may be observed in some places.

On the 18th (Tuesday), cold air will flow into the shadows of the mountains, and there is a possibility that snow will accumulate even in the high mountains of western Japan.

On the 19th (Wednesday), the area will be covered by high pressure moving from the continent, and strong cold air is expected to leave from the west.



#This season's first "JPCZ" forecast also#

Furthermore, looking at the rain and snow forecast for the 18th (Tuesday) to 19th (Wednesday),
a long band of rain clouds stretches over the Sea of Japan. On the morning of the 18th (Tuesday), it will head from the Sea of Japan to the Noto Peninsula and Niigata, but in the evening it is expected to gradually move southward from Wakasa Bay to the northern Kinki area and into the San'in area on the morning of the 19th (Wednesday).

This is called JPCZ (Japan Sea Polar Air Mass Convergence Zone),
a convergence zone created when cold air currents (northern winds) are divided into two by high mountains in the northern part of the Korean Peninsula,
and then merge again over the Sea of Japan.

An active precipitation band will occur near this convergence zone, and
there is a possibility that snowfall will increase along the mountains where this precipitation area falls.

From around the 18th (Tuesday) to the 19th (Wednesday), watch out for the sudden increase in rain and snow in Hokuriku and San'in regions.

In addition, small cyclones and disturbances occur over the JPCZ,
cumulonimbus clouds may develop, causing hail, lightning, and gusts of wind.
You must pay close attention to changes in the weather.



The cold weather of winter will arrive at the beginning of next week, and
winter clothing such as coats and mufflers and gloves will come in handy.

The temperature difference between morning and evening and during the day, as well as the temperature difference from day to day, is quite large, so
Please be careful not to get sick.

Strong cold air will move south from the beginning of the week. There is a risk of heavy snow on the Sea of ??Japan side!

2025/11/15 09:19

East of Kamchatka and the sea east of Japan, there is a developed low pressure system with a front that is moving eastward.
On the other hand, there is a high-pressure system over Primorye and China that is moving eastward.

Currently, there are a lot of clouds on the Sea of Japan coast from Hokkaido to the San'in region and the Kanto region, and there are some places where it is raining or snowing.



Today, the 15th (Sat), high pressure will spread from the west.
There will be snow and rain in Hokkaido until the morning, but the weather is expected to gradually recover.
From Tohoku to Kyushu and Okinawa, clouds tend to appear on the Sea of Japan side, and although some places may experience rain in the morning, it will be sunny in most places.
The maximum temperature is at or above normal in many places, making the weather pleasant and sunny for this time of year.
However, there is a large temperature difference between morning and evening, so please take care of yourself by wearing clothes that are easy to adjust.

Tomorrow, the 16th (Sunday), it will be sunny over a wide area from Tohoku to Okinawa, but in Hokkaido, due to the influence of a pressure trough approaching from the west, it will start to rain or snow in many places from the evening onwards.

Then, at the beginning of the week on the 17th (Monday), a low pressure system developed in the Sea of Okhotsk. A cold front extending from a low pressure system will pass through northern Japan, and there is a risk of severe weather such as heavy rain and strong winds for a short period of time, mainly in northern Japan and Hokuriku.



After that, the strongest cold air of the season is expected to peak on the 18th (Tuesday) and move southward, and by the 19th (Wednesday), the winter-like pressure pattern with high west and low east is expected to strengthen.
The cold winds are increasing across the country, and in Hokkaido, there is poor visibility and increased snowfall due to blizzards, and even on the Sea of Japan side of the Tohoku and Hokuriku regions, there are places where snow accumulates on flat areas, so you need to be careful of snowfall, frozen roads, and traffic problems caused by heavy snow.
Also, there is a risk of snowfall in the high altitude mountains of eastern and western Japan.





Please pay attention to future weather information.

The strongest cold air of the season will move south next week, a winter storm in northern Japan. Snow falls along Hokuriku and Mt. San'in, and it will be cold in December.

2025/11/14 13:02

From the 17th (Monday) to the 18th (Tuesday) at the beginning of the week, a low pressure system will develop as it moves towards the Sea of Okhotsk, and the pressure around Japan will be high in the west and low in the east.
The weather will be rough mainly in northern Japan, and it looks like it will be a winter storm.
Also, from around the 17th (Monday) to the 19th (Wednesday), the strongest cold air of the season will flow in, causing heavy snowfall mainly in northern Japan.
There is a risk of snow falling along the mountains of western and eastern Japan, and it is expected to be the coldest of December nationwide.



#Weekend It's a perfect day for fall foliage viewing around Honshu, and it's raining in Hokkaido.From tomorrow the 15th (Sat) to the 16th (Sun), the Honshu area will be covered in high pressure, and many places will have a refreshing autumn day.
It looks like it will be a good day for viewing autumn leaves.
However, the day after tomorrow, the 16th (Sunday), a low pressure system with a front will form in the Sea of Japan and will move east-northeast.
On the Sea of Japan side of Hokkaido, it is expected to start raining in some places in the afternoon.

#Low pressure develops as winter storm develops in northern Japan
Then, from the 17th (Monday) to the 18th (Tuesday) at the beginning of the week, a low pressure system will develop as it moves northeast through the Sea of Okhotsk.
The continental high pressure system is expected to protrude near Japan, resulting in a high pressure system in the west and low pressure in the east.
On the 17th (Monday), strong winds will blow in Hokkaido, which is close to a low-pressure area, and there is a risk of snow falling mainly on the Sea of Japan side, resulting in a blizzard.
Transportation may be affected, so please check the latest information.

#The coldest air of the season. Increased snowfall in northern Japan. Snowfall will cover areas from Hokuriku to Mt. San'in.
Also, from around the 17th (Monday) to the 19th (Wednesday), the strongest cold air of the season will flow into the sky.
Cold air of -36c or lower, which is a guide for heavy snow, will pass around 5,500m above Hokkaido, and cold air of -12c or lower is expected to move south to northern Hokkaido at around 1,500m.
The cold air will peak on the 18th (Tuesday), with temperatures below -6c at around 1,500 meters above the ground, which is the standard for snow on the plains, and will flow from southern Tohoku to Hokuriku and near the Sea of Japan side of western Japan.



Snow is expected to increase locally in Hokkaido and northern Tohoku.
There is a possibility of the first snow in Akita, Yamagata, etc.
Also, there are places where snow will accumulate on the flatlands on the Sea of Japan side of Tohoku, and there is a risk of heavy snow especially along the mountains.
Snow will also accumulate along the mountains on the Pacific side of Tohoku.
Even on the Sea of Japan side between Hokuriku and San'in, there are many places along the mountains that are covered in snow, and there is a risk of snow accumulation.
Please prepare winter tires and chains for your car during the weekend.

#Temperature plummets on the 18th (Tuesday); December 19th (Wednesday) will see widespread cold





On the 17th (Monday), before the cold air moves in, the expected maximum temperature will be 11c in Sapporo, 18c in Sendai, and around 20c in many places west of Kanto.
However, the temperature will plummet on the 18th (Tuesday).
The predicted maximum temperature is 2c in Sapporo, 10c in Sendai, 11c in Fukui, and around 13c west of the Tokai region, which will be cold in some places.
Although the Kanto region is relatively unaffected by the cold, the temperature in central Tokyo will be 15c, which is lower than normal.
Also, there is a strong cold monsoon wind from the northwest, and the perceived temperature will drop significantly, making it likely that you will need a winter coat.

2nd autumn foliage forecast for 2025 The best time to see autumn leaves is expected to be later than normal nationwide

2025/11/14 07:44

Today, the 14th (Friday), our company Sunny Spot announced its second forecast for the best time to see autumn leaves in 2025. Please use this as a reference for your future autumn foliage viewing plans.

The best time to see autumn leaves is from September to November, when the temperature is low, it is earlier, and when it is higher, it is later. The average temperature in September of this year was higher than normal, and in October it remained near normal. In November, there will be times when we will be affected by strong cold air, but the monthly average is expected to remain higher than normal.
In particular, eastern and western Japan are expected to be less affected by cold air, so the best time to see autumn leaves will likely be later than normal.



+Northern Japan (Hokkaido/Tohoku)
In northern Japan, temperatures remained higher than normal through October, and in Hokkaido, the best time to see autumn leaves was later than normal. In some places, the best time to see them has already passed and the leaves have fallen.
In the Tohoku region, the colors will gradually change from around late October, and it is expected that more and more places will reach their peak in the future. In areas such as Aomori and Akita, the best time to see them is expected to be around this time. In the southern Tohoku region, the best time to see them will start around next week.

+Eastern Japan (Kanto-Koshin, Hokuriku, Tokai)
Color is progressing in high-altitude areas, and many places are expected to reach their peak in late November. In the plains, the average temperature is expected to remain higher than normal in November, so the best time to see the cherry blossoms will be later than normal in many places. We estimate the best viewing date in Tokyo to be around December 1st.

+Western Japan (Kinki, Chugoku, Shikoku, Kyushu)
In western Japan, the average temperature in November is expected to be higher than normal, as it will be less affected by the cold air in the upper atmosphere. Therefore, the best time to see the autumn leaves is expected to be later than normal in many places, and in many places it will be after December. We predict that the best time to see the flowers in Osaka will be around December 6th, and in Fukuoka around December 7th.

Although it may be sunny on the weekend, from around the 18th of the week, strong cold air will move south, snow will spread, and it will be as cold as December.

2025/11/14 07:35

This weekend, the 15th (Saturday) and 16th (Sunday), the area around Honshu will be covered in high pressure and many places will be sunny. It's going to be a nice day for sightseeing, and it looks like it'll be a good time to go out to see the autumn leaves. However, the weather in Hokkaido is likely to go downhill on the 16th (Sunday) as a front approaches.




At the beginning of the week, a low pressure system will develop as it moves through the Sea of Okhotsk, and the area around Honshu will gradually become winter-like, with high pressure in the west and low pressure in the east. At the same time, extremely cold air in the upper atmosphere is expected to move south toward Japan.
In Hokkaido, it will be snowing from the 17th (Monday), and on the 18th (Tuesday) there will be a strong northerly wind, resulting in a blizzard in some places. In the Tohoku, Koshin, and Hokuriku regions, rain is expected to change to snow in some places around the 18th, and there may be snowfall in some places. There will be places where it snows even in the high altitude mountains of eastern and western Japan.

From around the 18th, due to the influence of strong cold air moving south, it looks like it will suddenly become winter cold. In Hokkaido, the predicted maximum temperature on the 18th is expected to be 3c, which will be bitterly cold, and in areas from Tohoku to the San'in area on the Sea of Japan side, the predicted maximum temperature will be around 10c, which is similar to December. Western Japan is also affected by the cold air, with the predicted maximum temperature in Osaka and Fukuoka on the 18th being 12c, which is expected to be as cold as December.

The end of the week will be colder than December in many places, so be sure to take measures to protect yourself from the cold over the weekend so you don't get sick from the cold.

Winter is rushing in! However, there is a trend of "high temperature and high sunshine" through December, with sunny days in early spring [1 month forecast]

2025/11/13 14:53

Early next week, the strongest cold air of the season is expected to arrive,
to bring snow to western Japan, and the cold winter weather is expected to arrive in mid-November.

However, according to the one-month forecast (weather outlook for November 15th to December 14th) released by the Japan Meteorological Agency today, November 13th (Thursday),
it is not like we are heading into winter, and the progress of the season seems to be going up and down.



[Key points of the 1-month forecast]
#Temperature#
Northern Japan: The influence of cold air is weak, and temperatures are at or above normal.
Eastern to Western Japan: Temperatures will be lower than normal at the beginning of the period due to strong cold air.
#Precipitation#
There are many days covered by high pressure, and there is little in eastern and western Japan.
#Sunshine hours
It is abundant in eastern and western Japan, and at or above normal in northern Japan.




Looking at the monthly average sea level pressure in the chart on the left, it is predicted that the
continent (near northeastern China) will have lower atmospheric pressure than normal, as shown in light blue.

Normally, the Siberian High pressure system strengthens over the continent through December,
blowing cold air into the vicinity of Japan, but
this year, the overhang of the Siberian high pressure system is weak, so
the winter-like pressure pattern centered on northern Japan is not expected to last long.

Also, if you look at the temperature at about 1,500m above the top of the chart on the right,
the area around northern Japan is orange, indicating that the temperature is higher than normal.
This indicates that the southward movement of cold air is weak, mainly in northern Japan.
Also, the deviation from normal is predicted to be small in eastern Japan and south.



Looking at the average temperature on a weekly basis,
from November 15th to 21st, temperatures are expected to be low mainly in western and eastern Japan due to the influence of the season's strongest cold air flowing in from the west.

However, after November 22nd, temperatures are expected to be higher than normal in northern Japan,
east to western Japan are expected to be at or above normal, and
this trend is likely to continue in northern to eastern Japan after November 29th.

As a result, there will be December cold in some places next week, but
from late November to early December, it will be sunny and warm,
and there will be some days where it will be a sunny day.

Typhoon No. 26 Don't let your guard down even if it becomes a temperate cyclone. Extremely heavy rain in Okinawa and Amami. Gradually the main island of Okinawa becomes a heavy rain.

2025/11/13 12:14

#Despite becoming an extratropical cyclone, Okinawa/Amami faces landslides Okinawa is also on alert for high waves
Today, Thursday, the 13th, Typhoon No. 26 approached the Sakishima Islands, and at 9 a.m. it turned into an extratropical cyclone in the waters near Yonaguni Island.
This extratropical cyclone has merged with a front that has been stationary for a long time near the Nansei Islands.
It is expected to move eastward over the Nansei Islands until tomorrow, the 14th (Friday), with some development.
Due to the influence of the low pressure system and warm, humid air blowing into the front, atmospheric conditions will become extremely unstable in Okinawa and Amami until tomorrow, the 14th (Friday).



#In some places, the total precipitation has already exceeded 300mm
For the past few days, the Nansei Islands has been experiencing continuous rain due to the stationary front and the approach of Typhoon No. 26, and there are some places where the total precipitation since the day before yesterday and the 11th (Tuesday) has exceeded 300mm.
[Precipitation amount from yesterday 11th (Tuesday) to today 13th (Thursday) 10 am]
Okinawa Main Island region, Kumejima-cho Janado 356.0mm
Miyakojima region, Shimojishima Airport 106.0mm
Yaeyama region, Yonaguni-cho Sonai 233.0mm
Amami region Kikaijima 176.5mm
As of 9 a.m. today, the 13th (Thursday), heavy rain warnings have been announced in some parts of Okinawa's main island and Amami.

#Extremely heavy rain forecast for Okinawa main island and Amami



Today, the 13th (Thursday), it is expected that there will be extremely heavy rain in the main island of Okinawa and Amami with waterfalls of 50 mm per hour, and in some places in the Sakishima Islands there will be heavy rain of 30 mm per hour.
The ground has become loose in some places due to the rain that has fallen so far, so please be on alert for landslides in Okinawa and Amami through tomorrow, the 14th (Friday), and be careful of flooding in low-lying areas and rising river levels.
Depending on the degree of rain cloud development, heavy rain warnings may be extended to more areas or the warning period may be extended.

#Beware of increasingly severe high waves, with the risk of storms



There are swells in the coastal waters of the Okinawa region, and large waves on the Sakishima Islands.
Towards tomorrow the 14th (Friday), the gradient in atmospheric pressure will increase between the low and high pressure systems.
Even on the main island of Okinawa, the wave height is expected to gradually exceed 6 meters today, the 13th (Thursday), and it will become a major storm.
Be wary of high waves with swells.
Very strong winds are expected to blow in the Sakishima Islands and the main island of Okinawa into tomorrow, the 14th (Friday).
The maximum instantaneous wind speed is expected to be 35m/s.
Please be careful of strong winds.
Depending on the degree of atmospheric pressure gradient, there is a risk of strong winds today, the 13th (Thursday).