Tohoku region: Be on high alert for heavy rain through Tuesday, the 30th; total rainfall may exceed 300mm

2024/07/27 17:06

Today, the 27th (Sat), the rainy season front is stretching from North China through the Sea of Japan to the Tohoku region. Warm and humid air is flowing toward the front, making the atmospheric conditions in the Tohoku region very unstable.

Rain clouds associated with the rainy season front have been hanging over the Tohoku region since the morning, and in the afternoon, heavy rain of 25.5 mm was observed in Kinugawa, Oshu City, Iwate Prefecture, and 25.0 mm in Komanoyu, Kurihara City, Miyagi Prefecture. Heavy rain of 40 mm per hour is expected to fall locally by tomorrow.



The record-breaking heavy rain has caused flooding in the Koyoshi River, which flows through Akita Prefecture, and other rivers are also flooding. In the Tohoku region, heavy rain will fall in some areas around the 30th (Tuesday) due to the influence of the rainy season front and warm, humid air.



#Rain forecast (heavy areas)
Expected 1-hour precipitation on the 27th
Tohoku Sea of Japan side: 40mm
Tohoku Pacific side: 40mm
Expected 1-hour precipitation on the 28th
Tohoku Sea of Japan side: 40mm
Tohoku Pacific side: 40mm
Expected 24-hour precipitation from 18:00 on the 27th to 18:00 on the 28th
Tohoku Sea of Japan side: 150mm
Tohoku Pacific side: 120mm
After that, expected 24-hour precipitation from 18:00 on the 28th to 18:00 on the 29th
Tohoku Sea of Japan side: 200mm
Tohoku Pacific side: 150mm
After that, rain is expected to fall intermittently until around the 30th, with some areas experiencing heavy rain.

Some areas in the Tohoku region are already experiencing heavy rainfall that warrants warnings, but on the Sea of Japan side of Tohoku, heavy rainfall that far exceeds the warning standards is expected to continue until around the 30th (Tuesday). Please be on high alert for rising and overflowing rivers, landslides, and flooding of low-lying areas.

New tropical disturbances expected to occur; keep an eye on trends in the Southern Ocean

2024/07/27 12:22

Looking at the forecast weather chart for tomorrow night, Sunday the 28th, Typhoon No. 3, which made landfall on the Chinese mainland, is expected to weaken and turn into a tropical depression. Meanwhile, a new tropical depression is expected to form in the sea east of the Philippines.

We can see that the sea surface temperature is 30 C in the East China Sea, south of Japan, and off the coast of the Philippines.



Throughout the year, August and September are the months with the highest number of typhoons, and we are entering typhoon season.
Due to the high sea surface temperatures, it is possible that a typhoon could occur at any time.
We need to continue to keep a close eye on the southern seas.

Rain intensifies again in Tohoku region, with very heavy rain in the afternoon; be on high alert for rising river levels and flooding

2024/07/27 07:09

The rainy season front is stretching from North China through the Sea of Japan to the Tohoku region, and will move north through the Tohoku region by tomorrow, the 28th. Warm and humid air is flowing toward the front, and the Tohoku region is expected to remain in a very unstable state until late tonight, the 27th.

As of 6:30, developed rain clouds are covering northern Tohoku, and moderately heavy rain of 14.5 mm/h has been observed in Hiratsuchi, Kitaakita City, Akita Prefecture, and 14.0 mm/h in Tazawako, Senboku City, Akita Prefecture.

In the Tohoku region, the rain will gradually get stronger late tonight, the 27th, and some areas will experience very heavy rain accompanied by thunder.



#Expected amount of rain (heavy areas)
+Expected 1-hour precipitation today, the 27th
Tohoku Sea of Japan side: 50 mm
Tohoku Pacific side: 50 mm
+Expected 1-hour precipitation tomorrow, the 28th
Tohoku Sea of Japan side: 40 mm
Tohoku Pacific side: 40 mm
+Expected 24-hour precipitation from 6:00 today, the 27th, to 6:00 tomorrow, the 28th
Tohoku Sea of Japan side: 180 mm
Tohoku Pacific side: 120 mm
+Expected 24-hour precipitation from 6:00 tomorrow, the 28th, to 6:00 the day after tomorrow, the 29th
Tohoku Sea of Japan side: 200 mm
Tohoku Pacific side: 120 mm

#Disaster prevention matters
On the Sea of Japan side of Tohoku, there are rivers that are flooding and rivers that are rising. Please continue to be on high alert for rising and flooding rivers. In addition, in the Tohoku region, please be on high alert for landslides and flooding in low-lying areas through tomorrow, the 28th. Be on the lookout for strong gusts of wind such as tornadoes, lightning, and hail late tonight, the 27th. If there are signs of a developed cumulonimbus cloud approaching, please take steps to ensure your safety, such as by moving inside a sturdy building.



From now on, due to the influence of warm, humid air and a low-pressure trough, intermittent rain is expected to fall around the 30th, with some areas experiencing heavy rain.
Check the latest weather information frequently and avoid dangerous areas such as steep slopes.

Weather and temperature summary (July 14th to July 20th) Linear precipitation band occurs in Nagasaki, record rainfall occurs, end of rainy season announced in various areas

2024/07/26 20:21

#Characteristics of pressure distribution
On the 14th, the rainy season front moved north from the Pacific side of Western Japan to Eastern Japan. High pressure slowly moved from the Sea of Japan side of Hokkaido to the southeast coast of Hokkaido. On the 15th, the rainy season front stretched east of Japan through the Tsushima Strait and Eastern Japan. Low pressure on the front moved east east of Japan. On the 16th, the rainy season front stretched over the Yellow Sea and Sea of Japan, and over the sea east of Japan. High pressure with its center east of the Kuril Islands moved east. On the 17th, the rainy season front stretched over the Korean Peninsula, Sea of Japan, Eastern Japan, and east of Japan, and moved north to the southern Tohoku area by night. On the 18th, the front passed through North China and the Korean Peninsula, and stagnated in the Sea of Japan and Tohoku. Low pressure on the front moved northeast from the Yellow Sea to the Korean Peninsula. On the 19th, the rainy season front stretched from the Korean Peninsula to the Sea of Japan, forming a kink on the front in the western Sea of Japan. It extended to the sea southeast of Hokkaido. The Pacific high pressure system covered the Nansei Islands and western to eastern Japan. On the 20th, the rainy season front passed through the Korean Peninsula and the Sea of Japan, and extended to Hokkaido. At 15:00, a large typhoon No. 3 formed east of the Philippines. It moved northwest east of the Philippines.

#Precipitation
On the 14th, rain fell from southern Tohoku to Kyushu. The rain intensified especially in Kyushu and the Chugoku region, and a linear precipitation band occurred in Nagasaki Prefecture. Heavy rain of 85.5 mm/h was observed. On the 15th, rain intensified in northern Kyushu toward the morning, and very heavy rain was observed in Kagoshima and Fukuoka. Heavy rain warnings were issued over a wide area of Kyushu. On the 16th, rain intensified mainly in the morning due to the influence of moist air heading toward the front, and very heavy rain of 77 mm/h was observed in Iwata, Iwata City, Shizuoka Prefecture. On the 17th, the atmospheric conditions were unstable in the afternoon in northern Kinki, Hokuriku, northern Kanto, and Tohoku. Very heavy rain fell late at night in Hokuriku. The end of the rainy season was announced in southern Kyushu. On the 18th, rain fell mainly in Tohoku, where the front was stationary. In addition, rain fell in some areas of Western Japan, mainly on the Pacific side. The end of the rainy season was announced in the Kanto, Koshin, and Tokai regions. On the 19th, warm and humid air flowed toward the front, causing rain mainly on the Sea of Japan side. The end of the rainy season was announced in Shikoku. On the 20th, warm and humid air flowed toward the rainy season front, causing very heavy rain to be observed in Hokuriku.

#Temperature
On the 14th, it became particularly hot in Okinawa and Amami, where summer skies spread, and in Naha, a scorching hot day of 35.0c was observed, following the previous day. On the 15th, temperatures rose in Okinawa, where summer skies spread. In Naha, it was scorching hot for three consecutive days. On the 16th, Kyushu, Kinki, and Tokai experienced periods of sunshine, with Maeda, Kimotsuki Town, Kagoshima Prefecture experiencing a scorching hot day of 35.2c. On the 17th, high pressure brought sunshine to Western Japan and Hokkaido, causing temperatures to rise. Many areas experienced midsummer temperatures from the morning, bringing the number of locations with scorching hot days to 17. On the 18th, many inland areas from Kanto to Kinki exceeded 35c, and Nagoya experienced its first scorching hot day in 10 days since the 8th. On the 19th, hot air flowed toward the front of the Sea of Japan, causing extreme heat. Naha City recorded a temperature of 36.0c, breaking the record set in 2001 and becoming the highest ever recorded. The number of locations with scorching hot days increased from the previous day, reaching 100 for the first time in 11 days. On the 20th, high pressure covered eastern and western Japan, causing temperatures to rise. The highest temperature in the country was recorded in Shizuoka, at 38.9c.



#Summary of the weather for this period (July 14th to July 20th)
The average temperature was high due to the inflow of warm air, as many days were covered by a mobile high pressure system in northern Japan. In Hokkaido, many places were 4 C higher than average, and even Sapporo experienced midsummer days, and the severe heat continued. In Naha, the highest temperature ever recorded was observed, and it was higher than average.
The amount of precipitation was easily affected by the rainy season front, and was high mainly on the Sea of Japan side. In particular, on the 14th, there were places where heavy rain occurred, such as a linear precipitation band in Nagasaki, and in Nagasaki, it rained more than five times the average.
The hours of sunshine were higher than average in northern Japan, covered by a mobile high pressure system, and were quite high mainly in eastern Hokkaido. On the other hand, many areas in eastern and western Japan experienced rainy season skies, with snowfall being less than average, especially on the Sea of Japan side.

The Kuroshio Current meanders for the longest time in recorded history, with sea surface temperatures off the coast of Sanriku and southeast of Hokkaido rising by up to 4-6 C (Marine summary for July 14-20, 2024)

2024/07/26 16:57

The Kuroshio Current continues to meander.
The Kuroshio Current, which began in August 2017, has now been meandering for 6 years and 11 months, making it the longest in recorded history.
The Kuroshio Current is predicted to continue meandering.
If the Kuroshio Current continues meandering as predicted, it will last for more than 7 years. (From the JAMSTEC website)

Summary of the state of the ocean around Japan (July 14-20, 2024).



#Pressure distribution and waves
From the 14th to the 16th, the rainy season front passed through Honshu from near the Tsushima Strait and stagnated to the east of Japan.
On the 14th, waves in the East China Sea reached a height of around 1.5m, while waves around Honshu remained relatively calm.
From the 17th to the 18th, the rainy season front moved north from the west, and a low pressure system on the front moved eastward across the Yellow Sea.
On the 18th, waves reached over 2m in the Yellow Sea.
From the 19th to the 20th, the rainy season front stagnated from the Sea of Japan to northern Japan.
On the morning of the 19th, waves in the Sea of Japan reached a height of 3m, but subsided by the 20th.



#Sea surface temperature
Towards the end of this season, the area of the Sea of Japan where sea surface temperatures are significantly higher than average will expand in the northern part of the country.
Temperatures in the East China Sea to the Nansei Islands were at or slightly above normal. Due to the large meandering of the Kuroshio Current, temperatures remained at normal levels off the coast of Shikoku to Cape Shionomisaki, where temperatures had remained below normal.
Temperatures off the coast of Sanriku, where the Kuroshio Current flows northward, continued to be higher than normal, up to 4 C higher.
Temperatures off the southeast coast of Hokkaido, where the Oyashio Current retreats, also continued to be significantly higher than normal, up to 6 C higher.
Temperatures off the coast of Abashiri also expanded to include areas significantly higher than normal.

Weekend weather: Tohoku is at risk of disaster-level heavy rains, Kanto may experience severe thunderstorms

2024/07/26 16:38

Today (26th), the rainy season front remains stationary in Tohoku, and moist air is flowing into eastern and western Japan. It has been raining in Kyushu and Shikoku since the morning, and rain and thunderclouds have formed in the Kanto and Tokai regions, mainly along the mountains, in the afternoon. Be careful of sudden changes in the weather through tonight.



Tomorrow (27th), the rainy season front will be in the east of Japan, and it will be unclear near Tohoku, but the next front will extend the day after tomorrow (28th). In Tohoku, the rain will intensify, mainly on the Sea of Japan side, and there is a risk of heavy rain again. The expected 24-hour precipitation by 6:00 p.m. tomorrow, the 27th, is 100 mm in some places. After that, the 24-hour precipitation expected by 6 p.m. on the 28th is up to 200 mm in some places.

Due to the record-breaking heavy rain so far, there are rivers that have flooded, rivers that have risen in water, and places where the ground has become loose. Heavy rain is expected to occur again over the weekend, so there is a risk of new disasters occurring. Please be on high alert.



In the Kanto region, the weather will suddenly change in the afternoon in the city center on the 27th (Sat), and there is a possibility of heavy rain and thunderstorms. Be careful of lightning strikes, strong gusts of wind such as tornadoes, and hail. Summer skies will spread west of Tokai. Many places will have a maximum temperature of over 35 C, with Nagoya and Fukuoka expected to be 38 C. Some places, especially inland, will reach close to 40 C. It will be difficult to sleep in the mornings and evenings, and dangerously hot during the day. Please be on high alert for heatstroke.

Early July: Record high temperatures since statistics began in Kanto and west

2024/07/26 13:04

Today (26th), the Japan Meteorological Agency announced weather information regarding long-term high temperatures.

Kanto-Koshin, Tokai, Kinki, Chugoku, Shikoku, and Kyushu have been covered with warm air since early July, resulting in many days of high temperatures. The average temperature difference from the normal in early July was +3.6 C in the Kanto-Koshin region, +3.4 C in the Tokai region, +3.0 C in northern Kyushu, and 3.1 C in southern Kyushu, the highest for early July since statistics began in 1946, and a record high.

Temperatures were normal in mid-July, but after the end of the rainy season in various areas, the Pacific high pressure system covered the area, making it sunny and quite hot, with some areas experiencing scorching hot days with maximum temperatures of over 35 C.

It is expected that warm air will continue to cover the area for about a month, with some areas seeing maximum temperatures of over 35 C. Please be careful to manage your crops and livestock, and take care of your health to avoid heatstroke.



Average, maximum and minimum temperatures (June 26th - July 25th) (preliminary values)
Average temperature (c) Average difference (c)
Tokyo 27.6 +2.5
Nagoya 28.2 +1.9
Osaka 28.5 +1.5
Hiroshima 27.7 +1.3
Takamatsu 28.3 +1.5
Fukuoka 28.8 +2.1
Kagoshima 28.9 +1.4
Maximum temperature (c) Average difference (c)
Tokyo 32.1 +2.9
Nagoya 32.8 +2.2
Osaka 32.3 +1.3
Hiroshima 30.9 +0.8
Takamatsu 32.4 +1.5
Fukuoka 32.4 +2.0
Kagoshima 32.5 +1.3
Minimum temperature (c) Difference from average (c)
Tokyo 24.2 +2.5
Nagoya 24.7 +1.8
Osaka 25.7 +1.8
Hiroshima 25.3 +1.9
Takamatsu 25.1 +1.6
Fukuoka 26.1 +2.2
Kagoshima 26.1 +1.3

Record heavy rainfall: 400mm of rain in 24 hours in Yamagata Prefecture, flooding Mogami River and Hyuga River

2024/07/26 11:58

The rainy season front was stationary, and extremely humid air flowed in, causing record-breaking heavy rains mainly in Yamagata Prefecture. The maximum 24-hour rainfall up to 11:00 a.m. was 389 mm in Shinjo City, Yamagata Prefecture, 384 mm in Sasakubinabe, Mamurogawa Town, and 382 mm in Semi, Mogami Town, making it the heaviest rainfall ever recorded.

Yesterday (25th), a heavy rain special warning was issued for Sakata City and Yuza Town in Yamagata Prefecture just after 1:00 p.m., and the heavy rain special warning was then lifted at 8:10 p.m., but the rain intensified again, with linear precipitation bands and record-breaking short-term heavy rain information being announced, and at 11:40 p.m. a heavy rain special warning was issued for Sakata City, Shinjo City, Funagata Town, Sakegawa Village, Tozawa Village, and Shonai Town.





The Mogami River and Hyuga River in Yamagata Prefecture, and the Koyoshi River in Akita Prefecture, have flooded one after another, and the risk of landslides and other disasters remains high.



As of 11:00 a.m. today, the rain is starting to subside, but even after the rain subsides, delayed disasters such as landslides and flooding of rivers may occur. Please continue to stay in a safe place.

Friday, 26th: Kanto region: Very unstable atmosphere. Beware of sudden changes in the weather even if it is sunny.

2024/07/26 01:22

On Friday the 26th, the Kanto region will be covered by a high pressure system and will be sunny in many places. On the other hand, the atmospheric conditions will be very unstable due to the inflow of moist air around the edge of the Pacific high pressure system and the rise in temperature due to solar radiation.



Looking at the probability of lightning at 6 p.m., we can see that the probability is high, especially in the northern Kanto region. In particular, there are places in Ibaraki Prefecture, Tochigi Prefecture, and northern Saitama Prefecture where the probability of lightning is over 90%, and localized heavy thunderstorms are expected from late afternoon to night.
In southern Kanto, the probability of lightning is not as high as in the north, but rain clouds are likely to develop, and heavy rain with thunder is expected in some parts of Tokyo in the evening. Since it may overlap with the time people return home, we recommend that you check the latest information frequently and take action early.

If you notice signs of sudden rain cloud development, please take steps to ensure your safety, such as by taking shelter in a sturdy building. There is also a risk of hail, so please be careful when managing your crops and agricultural facilities.

Tohoku region: Linear rain band occurs in Yamagata Prefecture; maximum vigilance against heavy rain disasters required

2024/07/25 23:51

The rainy season front stretches from North China to the Sea of Japan, and a low pressure system on the front is moving eastward through the central Sea of Japan. Warm, humid air is flowing toward the front, causing intermittent very heavy or torrential rain, mainly on the Sea of Japan side of Tohoku.



Flooding information was announced at 5:00 pm today in Koyoshi River, Yurihonjo City, Akita Prefecture, and at 6:00 pm in Hinatagawa River, Sakata City, Yamagata Prefecture. Active rain clouds continued to hang over the area, and a record-breaking short-term heavy rainfall information was announced in Akita Prefecture at around 9:50 pm.



At 10:47 p.m., the Yamagata Regional Meteorological Observatory issued a "Notice of Significant Heavy Rain" warning, stating that very heavy rain caused by a linear precipitation band continues to fall. At 11:41 p.m., a special heavy rain warning (flooding and landslides) was issued again in Yamagata Prefecture.

The risk of disasters caused by landslides and floods that are life-threatening is rapidly increasing, so please be on maximum alert.

If you are in a dangerous place, such as near a cliff or a river, please follow the evacuation information issued by your local city or town and take appropriate evacuation action immediately.

Check the situation around you, and if it is dangerous to evacuate to an evacuation shelter, ensure your own safety by moving to a building as far away from cliffs or streams as possible, or to a high room that is less likely to flood.

There is a risk that the situation will rapidly worsen in the future, so if you feel even the slightest bit of danger, please make the decision to evacuate to a safe place yourself, even if evacuation information has not been issued.