Atmospheric instability: Beware of lightning strikes, gusts of wind, hail, and sudden heavy rain.

2025/04/26 06:51

Today, the 26th, strong cold air is expected to flow into the air at about 5,500m above northern Japan, at a time of below 33 degrees Celsius. Due to sunny weather during the day and temperatures rise, the air condition is expected to be extremely unstable between northern and eastern Japan.



Please be careful of severe gusts of winds such as lightning and tornadoes, hail and sudden heavy rain in northern and eastern Japan along the night of the 26th.
When working outdoors, please be aware of the surrounding situation, such as sudden changes in the weather.
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.

[10th Golden Week forecast] Beware of "sudden thunderstorms" in the first half of Golden Week! The second half also includes a "high temperature once every 10 years."

2025/04/25 13:10

This year's Golden Week will be a long-term stepping stone holiday, but I think many people will be starting the long-term holiday tomorrow.

Weather during the holidays is less rain than expected until yesterday, but
There are some hidden rain and lightning marks among the sunny marks.

Please check the weather forecast frequently even during the holidays.

Weather points during Golden Week
- Beware of sudden thunderstorms in the first half of Golden Week
- Summer days in a row in the second half of Golden Week! Midsummer days too
- Take full care of heat stroke and UV rays





Let's take a look at the key points for each day while looking at the latest 10-day forecast.

#Tomorrow, Saturday the 26th - Sunday the 27th #

It seems that there will be many sunny spots in the west to eastern Japan and many good places to go out.
Weather from Tokai is expected to be in summer days with temperatures above 25 C.
We are not used to the heat yet, so stay hydrated frequently.


On the other hand, in northern Japan, the air condition of the air instability is caused by the effects of the cold air above. Be careful of sudden rain and thunderstorms.

#Monday, the 28th - Tuesday, the 29th (Tues, Showa Day)#

A cold-filled low pressure will approach northern Japan again, and
It is expected that rain and thunderstorms will continue to occur more easily.
On Showa Day on the 29th, there are likely some areas along the mountains of Hokkaido where rain and snow will mix.

The cherry blossom front is currently heading north to Hokkaido, but
Please be careful of sudden changes in the weather when you go to cherry blossom viewing.

If you hear thunder, instead of taking shelter under the cherry blossom trees, evacuate to a sturdy building.

The weather will be downhill in the west to eastern Japan at the end of the week, and rain will likely be in Kyushu, Shikoku, and Okinawa, with some areas facing increasing rain.

#Wednesday, the 30th#
It will be sunny in west to eastern Japan, and sunny days will return to northern Japan and Hokuriku.
However, in eastern Japan, such as Kanto, the weather may change suddenly in the afternoon due to the effects of cold air above.


Even when the sun is marked, you should be careful of sudden rain and thunderstorms.

#May 1st (Thursday) - May 2nd (Friday)#

As May enters, the heat will likely increase even further.


With the rear of the high pressure, warm air will flow from the south, and
With the moist air that will become the source of the clouds will easily flow into.
There are sunny days, but clouds are likely to spread throughout the world.

#3rd (Saturday, Constitutional Anniversary) - 5th (Monday, Children's Day)#

There is a high pressure system in the south of Japan and a low pressure system in the north of Hokkaido
/BThis pressure system is expected to rise easily, with a high temperature of "South High North and Low".
It is expected that the northern Japan will be sunny from the 3rd to 4th, and the temperature will rise to 17 to 18 C in Sapporo.

In western and eastern Japan, there are many summer days of 25 C or higher, and inland areas the temperature can rise to around 30 C.


Even on the last day of the holiday on the 6th (Monday, replacement holiday),
Clean weather is still sunny and the temperature continues to rise.



According to the "Early Weather Information on High Temperatures" released by the Japan Meteorological Agency yesterday
The temperatures can be once every 10 years from around May 3rd to northern Kyushu to Kanto and Hokuriku
This year's Golden Week will need to be careful of heat stroke, such as heat, towards the end of the second half of the year.

Also, when it's sunny in May, UV rays become as strong as midsummer, so
Don't forget to take measures against UV rays when going out.

[Summary of the Ocean] Sea surface temperatures that are far higher than normal continue to rise off the southeastern Hokkaido; April 13th - 19th, 2025

2025/04/25 12:04

Over the last month, sea surface temperatures continued to be significantly higher than normal off the coast of Sanriku, but are beginning to fall below normal.
There is a high sea surface temperature, much higher than normal offshore off the southeastern Hokkaido.
Latest Ocean Summary (April 13th to 19th, 2025)



#Pressure arrangement and waves
On the 13th, a low pressure system moved north across the Korean Peninsula.
The front has risen from the south of Okinawa to the south of Japan.
Waves have risen in the low pressure system, the Sea of Japan, the Yellow Sea, and the waters near Okinawa, and in the south of Japan, and in the East China Sea.
On the 14th, a low pressure system moved northeasterly through the north Kanto region, and the pressure slope became larger between the pressure and the high pressure system east of the Kuril Island.
Waves rose widely in the east of Japan, and they hit the coast off Sanriku.
On the 15th, the pressure slope increased between the low pressure in the Sea of Japan and the Sea of Okhotsk and the high pressure in the south of Japan, causing it to slump in the waters south of Japan to the Kuril Islands.
From the 16th to the 17th, a low pressure system moved northeasterly through the waters near the Kuril Islands.
The slope of the atmospheric pressure increased between the high pressure in the south of Japan, and the wave height was 5m in the east of Japan.



#Sea surface temperature
The sea surface temperature in the Japanese Sea was slightly higher than normal on the northern and central continental sides, while the western part was as low as normal or slightly lower.
The waters near the East China Sea and the Southwestern Islands have been shrinking in lower than normal waters, and the waters that are normally larger.
On the Pacific side, the situation continued to be lower than normal off Shikoku and Shiosaki, where the Kuroshio Current is ripped.
In the east of Kanto, which is a continuous trend in the Kuroshio Current, sea surface temperatures continue to rise slightly higher than normal.
The sea surface temperature off Sanriku is lower than last month, and is 4 C lower than normal.
The area off the coast of Hokkaido southeastern Hokkaido is much higher than normal, with a maximum of 4 C higher.

Beware of the difference in temperature in Hokkaido from the previous day; Western Japan and East Japan feel comfortable

2025/04/25 06:30

Today, the 25th, the weather is expected to fall apart in Hokkaido, where a low pressure system approaches. As cold air flows in above, temperatures in Hokkaido are likely to drop compared to yesterday (24th).
The estimated maximum temperature is 13c lower than the previous day in Sapporo, and 9c lower than the previous day in Kushiro. The temperature difference will be large, so please be careful not to get sick and keep warm.


There is little sunlight in Eastern to Western Japan, and in many places the temperature is lower than the previous day. The sun will return in western Japan, but the temperature will likely be the same as this time of year. The maximum temperature is often around 22 C to 24 C, so it seems to be a relatively comfortable experience during the day.

#Expected maximum temperatures in various regions (relevant season)
+Sapporo: 13c (as in normal)
+Sendai: 23c (as in mid-June)
+Tokyo: 23c (as in mid-May)
+Nagoya: 23c (as in early May)
+Osaka: 22c (as in normal)
+Kochi: 25c (as in mid-May)
+Fukuoka: 19c (as in normal)

Weather today, Friday the 25th: Hokkaido is spreading out; beware of showers in Kanto as well

2025/04/25 06:06

Today, the 25th (Friday), a low pressure system is expected to approach Hokkaido. The front will also be stagnant from the South China to the Southwest Islands.



We are expected to see the rainy area expanding in Hokkaido due to the effects of low pressure. The rain will become locally stronger and there is a risk of thunderstorms. Be careful of lightning strikes and gusts of wind.
There are some areas in Tohoku where the sun is reaching, but the weather is likely to spread clouds. There are probably some places in the north where you will need rain gear in the afternoon.


It looks like the sky will be a cloud-dominated sky. There is a possibility of showers, so it's safe to have a folding umbrella when going out.

Clouds are spreading in Tokai, Hokuriku, and western Japan at first, but it seems that more and more places will reach the sun. There are few places where the weather is disrupted, so it seems like it will be easy to spend the day.

The cold vortex attacks start from Golden Week, and the atmosphere is unstable. The weather is disrupted on the Showa days, and the summer sun continues after that.

2025/04/24 12:43

Some people may start Golden Week this weekend, but the atmosphere conditions in northern Japan will be unstable due to the effects of the cold vortex on the weekend.
White Japan is widely sunny and a good day for sightseeing, but be careful of sudden changes in the weather around Hokuriku and Kanto.
The unseasonable warmth and heat have subsided during Golden Week, and there will be many days that are jolly, typical of this time of year.
However, there are days when it's summer days, so be careful of heat stroke.



#Tomorrow the 25th (Friday) Cold vortex approaches
Tomorrow the 25th (Friday), a cold vortex will move eastward across the continent, and the corresponding low pressure system will move towards Northeast China.
Also, another low pressure system is expected to move northeasterly through the northern Sea of Japan.
Weather in Hokkaido will be raining and halting.
The atmosphere in Northern Japan is unstable, so be careful of sudden heavy rain in Tohoku as well.
It is expected that many areas around Honshu will be able to reach the sun.
There will be fronts in Okinawa and there will be some areas where rain will fall.

#Golden Week starts There are more and more days to visit on weekends, but be careful of sudden changes to the weather



On Saturday, the 26th, a cold vortex passed through northern Japan.
Northern Japan is expected to continue to be affected by cold vortexes and low pressure, with some areas expected to rain.
While there will be many sunny spots in eastern Japan, the atmosphere will also be unstable in Hokuriku and Kanto, where the upper layer is covered in cold air.
Even if the sun is coming in, be careful of sudden changes in the weather.
When leisure activities on the mountain, you need to be careful of changes in the sky.
It's sunny in western Japan, but you need to be careful when yellow sand comes flying.
The front will stagnate in the waters near Okinawa, and frontline activity will become more active.
Beware of sudden heavy rain, lightning strikes, and gusts of wind.

On Sunday the 27th, the effects of the cold vortex are expected to gradually be resolved in northern Japan, but there will be some areas where rain will fall on the Sea of Japan side.
The area around Honshu is covered by high pressure, and it is expected to clear up.
It looks like greenery and seasonal flowers will stand out against the blue sky. There are many cheerful places that are typical of this time of year, making it a perfect day to visit.
There is a front extending in the East China Sea, and the weather is expected to continue to be prone to rain in Okinawa.





#Monday, 28th - Tuesday, 29th Showa Days, the weather was disrupted widely. Then, on the summer day, a low pressure system will travel through the Sea of Japan, and rain will fall in some places on the Sea of Japan side of the northern Japan Sea of Japan.
Also, a low pressure system accompanied by a front will travel along the southern coast of Honshu, and there are some areas where rain will fall in Kanto and Okinawa.
On Showa Day, the 29th (Tuesday) there will be times when it rains north of Kanto. There is a chance that there will be a place where the sun will return to the sun in western Japan and Okinawa.
On the 30th (Wednesday) it will be sunny in Tohoku to Okinawa, and it will be a summer day for the first time in a while.
Clouds will spread across the world on Thursday the 1st, but there will be many places where the sun will reach you. It is expected that there will be more summer days.

Summary of weather and temperature (April 13th to April 19th, 2025) Unstable weather trends due to the effects of cold vortex; summer and midsummer days are constantly occurring in the second half of the week

2025/04/24 06:49

This is a summary of the weather during this period (April 13th to April 19th).

#Summary of weather for this period (April 13th to April 19th)
The average temperature was higher than normal, mainly in northern Japan and eastern Japan, where warm air was easy to get in, and in Hokkaido, there were many places that were over 2 C higher than normal. In western Japan, the average temperatures were susceptible to cold air in the first half of the week, but the cold air above was distant in the second half of the week, making it easy for temperatures to rise, especially on the Sea of Japan side.

Pressure of precipitation was affected by cold eddy, mainly on the Sea of Japan side, resulting in unstable air conditions, and more precipitation than normal, mainly in Hokkaido and Tohoku. In Sapporo and Asahikawa, precipitation is about 4 to 5 times higher than normal. The Tokai, Shikoku, and Nansei Islands, which were affected by low pressure and fronts, also tended to have more rainfall than normal.

Sunlight hours were less common in Hokkaido and Tohoku, where it was easily affected by cold vortices, low pressure, and fronts, and in Akita and Muroran, only about 40% of the average year. In western Japan and eastern Japan, although there were cloudy and rainy days due to low pressure and front-line effects, the weather was covered by high pressure from around the middle of the week, and the sun was more likely to be in the center of the Pacific Ocean than normal.



#Characteristics of atmospheric pressure arrangement
On the 13th, a low pressure system accompanied by strong cold air (cold vortex) traveled northward around the Korean Peninsula. On the southern coast of Honshu, a low pressure system accompanied by a front moves northeasterly. On the 14th, the low pressure system near the Korean Peninsula went southeast, and the low pressure system on the southern coast of Honshu proceeded northeast to reach the coast of Sanriku. On the 15th, winds in the area around Honshu were strengthened nationwide due to the effects of a low pressure system, and the maximum instantaneous wind speed on this day was 20.7m/s in central Tokyo and 29.5m/s in Irozaki, Shizuoka Prefecture. On the 16th, the gap between isobar lines continued to be narrow in the area around Honshu, and a maximum instantaneous wind speed of 30.3m/s was observed in Onagawa, Miyagi Prefecture (updated the number one value in April). On the 17th, the low pressure system in the waters near the Kuril Island continued to move eastward, with western Japan and eastern Japan within high pressure system. Around the evening, the front began to appear near the Nansei Islands. On the 18th, a low pressure system accompanied by a front traveled northeast from near the Korean Peninsula. A cyclone occurred on the front line around 3pm on the southern seas of Japan. On the 19th, the low pressure system accompanied by a front line was moved to obscure the area around Hokkaido. Another low pressure system travels eastward from the Korean Peninsula into the Sea of Japan. A low pressure system accompanied by a front passed through the area around the Ogasawara Islands.

#Precture
On the 13th, the atmosphere became unstable due to the effects of a cold eddy, causing heavy rain on the Pacific side. The daily precipitation in Irago, Aichi Prefecture, is 108.5mm, which is above the number one value in April. On the 14th, the atmosphere conditions became unstable, mainly in western Japan, with rain and thunderstorms over a wide area. Heavy rain was hit in Mt. Amagi (24.0mm/h) in Shizuoka Prefecture and Atami City (23.0mm/h). On the 15th, the atmosphere conditions continued to be unstable, mainly on the Sea of Japan side due to the effects of the cold vortex. In the morning, the area of rain and thunderstorms gradually expanded from northern Japan to Hokuriku. On the 16th, the effects of the cold vortex continued, with rain and thunderstorms in Hokkaido, Tohoku and Hokuriku. There were also lightning strikes and hail falls in some areas. Rain continued intermittently in Hokkaido until the 17th the following day. It rained in the Sakishima Islands on the night of the 17th due to the influence of the front line. On the 18th, a severe thunderstorm occurred in the Nansei Islands due to the influence of a front stagnant over Japan's southern seas. Heavy rains of 41.5mm/h in Minamidaito, Okinawa Prefecture. In the Tohoku region, rain and thunderstorms are caused as the front approaches. On the 19th, rain and thunderstorms occurred in Hokkaido and the Ogasawara Islands due to the effects of low pressure and fronts. Daily rainfall on Hahajima, the Ogasawara Islands, was 56.5mm.

#Temperature
On the 13th, temperatures in western Japan and eastern Japan have slowed due to rain, and the highest temperature in central Tokyo is 14.1c, similar to mid-March. On the 14th, the temperatures in western Japan, where rain fell, were often lower than normal, and in Kanto, when the weather was recovering, the temperature was similar to that of mid-May. On the 15th, the effects of the cold air above continued, with temperatures in western Japan at a level similar to mid-March, with a daytime high in Osaka in Osaka. On the 16th, cold air above in western Japan became distant, and temperatures rose significantly. In Nishitoshi, Miyazaki Prefecture, 26.2 C was observed, which was 7.9 C higher than the previous day, making it a summer day. On the 17th, the area around Honshu was covered by high pressure, with the temperature difference between morning and afternoon. In Nagoya, the highest daytime temperature was 26.3 C, and the first summer day of the year was observed, reaching about 17 C. On the 18th, the influence of the Fohn phenomenon was added to the effect of the Sea of Japan side of western Japan, and temperatures rose, while Kawamoto, Shimane Prefecture, observed a temperature of 30.5 C on the midsummer day. On the 19th, summer and midsummer days began to appear over a wide area from western Japan to eastern Japan. In Toyooka City, Hyogo Prefecture, it was a midsummer day of 31.2 C, marking the highest record in Japan this year (as of April 19th).

Somei Yoshino flowers bloom in Hakodate and Sapporo; the cherry blossoms blooming front finally reaches Hokkaido

2025/04/23 20:46

Today, the 23rd, the flowering of Somei Yoshino was announced in Hakodate and Sapporo. The flower blossomed about 5-8 days earlier than usual. On the same day, the white plum blossoms were also announced in Sapporo and Muroran.



#Cherry blossoms
Hakodate 5 days earlier than normal, 5 days later than last year

#Cherry blossoms are now in bloom, 5 days later than last year

#Ume (white plum) is now in bloom
Muroran 10 days earlier than normal, 5 days later than last year

#Sapporo 6 days earlier than normal, 6 days later than last year

#Cherry blossoms have already fallen from west to eastern Japan, and many places have fallen cherry blossoms and become leafy cherry blossoms. In the Tohoku region, the cherry blossoms were announced in full bloom in Aomori by the 22nd, and the announcement of the cherry blossoms in full bloom in all regions, from Tohoku to Kyushu except Hokkaido, has been completed. In northern Tohoku, the season is right at its peak.

The cherry blossoms' flowering front has reached Hokkaido. In Hokkaido, the cherry blossoms will soon be in full bloom around Golden Week. However, during Golden Week, the weather is expected to be cloudy and rainy in northern Japan. If you are planning to view the cherry blossoms, make sure you check the latest weather forecast carefully.

Weather recovery from the west tomorrow. Be careful of changes in the sky due to the effects of cold vortex when Golden Week starts.

2025/04/23 13:04

This year's Golden Week is a long-term stepping stone holiday, and I'm sure some people will start Golden Week this weekend.
This weekend, it will be a sunny day in the west to eastern Japan, and it will be a good day for sightseeing, but be careful of sudden changes in the weather.
The unseasonable warmth and heat have subsided during Golden Week, and it looks like it will be a welcoming atmosphere that is typical of this time of year.



#Tomorrow the 24th (Thursday) - Tomorrow the 25th (Friday) Weather recovers from the west
Tomorrow the 24th (Thursday), the low pressure system will move away from the area around Honshu and move east of Japan. The weather will recover from the west, and some areas in western Japan are expected to be sunny from the morning.
In southern Kyushu and Shikoku, there are probably some places that are summer days.
In eastern Japan, such as Kanto, it is expected that there will be some areas in the morning to rain.
In the afternoon, there will be some areas of rain remaining in the Kanto coast and Niigata Prefecture, but it will gradually stop and the sun will arrive.
In Shizuoka Prefecture, the weather is expected to continue to rain easily until the night.
Also, a cold vortex will travel through the continent, and a cyclone corresponding to the cold vortex will occur in the northern Sea of Japan by night.
Rain in northern Japan gradually stops in southern Tohoku, but from the afternoon onwards, the area of rain is expected to expand in northern Tohoku at night in Hokkaido.
Tomorrow, the 25th (Friday), there will be many areas around Honshu where sunlight will reach. The cold vortex is expected to move towards the Primcoean province, and the corresponding low pressure system is expected to move north of Hokkaido. In Hokkaido, the weather will be raining and halting.

#Golden Week starts There will be more and more places to visit on weekends, but be careful of sudden changes to the weather


It is expected that many sunny spots in the west to eastern Japan on the Saturday, the 26th.
Due to the effects of the cold vortex in Northern Japan, there will be some areas where rain will fall.
Due to the effects of cold air above and humid air towards the low pressure, the atmosphere conditions in the East to Northern Japan are expected to become unstable. Be careful of sudden heavy rain and thunderstorms not only in northern Japan, but also in eastern Japan, such as in the Kanto region, where sunlight reaches you.
On Sunday the 27th, the area around Honshu will be covered by high pressure, and it will be sunny.
Fresh greenery and seasonal flowers look great against the blue sky. There are many cheerful places that are typical of this time of year, making it a perfect day to visit.





#Monday, the 28th - Tuesday, the 29th Showa Day Clouds will spread
28th (Monday), the front will move towards Okinawa, and there will be some areas where it will rain. In addition, a low pressure system is expected to move east along the southern coast of western Japan, with some areas expected to rain in southern Kyushu.
On the Showa Day, the 29th (Tuesday) On Showa Day, a low pressure system will move eastward south of Japan, while another low pressure system will move through the continent. There are expected rain in northern Japan. The weather will be dominated by clouds from the 28th (Monday) to the 29th (Tuesday) in the west to the eastern Japan, and there will be rain showers. On Wednesday the 30th, there will be many places where the sun will return, and it is likely that there will be more places where the sun will return again.

Weather outlook for the next three months (May-July)

2025/04/22 23:54

On Tuesday, the Japan Meteorological Agency announced a three-month forecast (May-July).

[Forecast Points]
#The temperature for the next three months will likely be high nationwide as it is likely to be covered in warm air.

#The rainfall for the next three months is likely to be affected by the rainy season front, so in northern Japan, it is likely to be as common or as common.



[Monthly weather]
#May
+In northern Japan, the weather will change over a few days.

+In East and Western Japan, the weather changes over a few days, and as in normal years, there will be many sunny days.

+In Okinawa and Amami, there will be many cloudy and rainy days, just like normal years.

#June
+In the northern and eastern Japan Sea of Japan side, the weather will change over a few days in the first half of the period. The second half of the period will likely be cloudy and rainy, as in normal years.

+In the Pacific side of the East Japan, Western Japan, Okinawa and Amami, there will be many cloudy and rainy days, just like normal years.

#July
+On the northern and eastern Japan Sea side, there will be many cloudy and rainy days, just like normal years.

+On the Pacific side of East Japan and Western Japan, the first half of the period will be cloudy and rainy
days, just like normal years. The second half of the period will likely be sunny, as in normal years.

+In Okinawa and Amami, there are likely to be many sunny days, just like normal years.