What is a snow accumulation warning? Prepare for power outages due to broken power lines, etc.

2026/11/07 07:23

Due to the influence of cold air, the number of regions experiencing snowfall-particularly in northern Japan-is on the rise. Today, Saturday the 7th, snow is falling in various areas, including Hokkaido, the Tohoku region, and the mountainous parts of the Hokuriku region. The Japan Meteorological Agency (JMA) has also issued "snow accretion advisories" for certain areas.



Do you know when a "snow accretion advisory" is issued, or what kind of hazards it warns against? Here, we explain what these advisories entail.

# What is a snow accretion advisory?
A snow accretion advisory is issued by the Japan Meteorological Agency when significant snow accumulation (adhering to structures) is expected to potentially cause disasters. Specifically, it is issued when there is a risk of damage such as the snapping of power lines or the collapse of electricity transmission towers due to the weight of accumulated snow.
This type of hazard is most likely to occur when snow falls while the air temperature is near 0C.



# Hazards caused by snow accretion
When snow accumulation causes power lines to snap, it can lead to widespread power outages. Furthermore, the weight of the snow can cause electricity transmission towers to collapse, or lead to broken tree branches and fallen trees-all of which are extremely dangerous.
Additionally, fallen trees can sever power lines or obstruct transportation.
In agricultural settings, there is also a risk that structures like plastic greenhouses may collapse, or that the branches of fruit trees may break.

# Why does snow accretion occur near 0C?
Unlike snow that falls when temperatures are well below freezing, snow that falls when the temperature is near 0C tends to be "wet snow." This type of wet snow has the characteristic of being heavy and prone to adhering to objects such as power lines, utility towers, and trees. Consequently, the accumulation of snow can lead to power line breakage, the collapse of utility towers, and the breaking or falling of trees.

# Important Precautions
If you encounter a downed power line, do not approach it-it is extremely dangerous. Instead, contact the relevant authorities or the utility provider. In preparation for potential power outages, ensure you have items such as flashlights, charged mobile batteries, and spare batteries on hand. Additionally, keep warm clothing or gear ready in case your heating system becomes unusable.
Never approach utility towers or trees that appear to be leaning.

Furthermore, when wet snow accumulates on roads, it turns into a slushy, "sherbet-like" consistency. Please exercise extreme caution, as this creates slippery conditions for both pedestrians and drivers.
When a warning for snow accumulation (on structures or trees) is issued, prioritize your personal safety and take proactive steps to prepare in advance.

[One-Month Forecast] Temperatures will be low nationwide at the start of the period; subsequently, they will be higher across eastern and western Japan, with significant fluctuations.

2026/11/06 21:22

On Thursday the 5th, the Japan Meteorological Agency (JMA) released its one-month forecast covering the period from November 7 to December 6.

Over the coming month, the period will begin with temperatures dropping across northern and western Japan due to the influence of cold air; in particular, the Sea of Japan side of Hokkaido may see significantly higher-than-average snowfall.
Subsequently, eastern and western Japan are likely to be covered by warmer air, leading to higher temperatures and greater variability.
Additionally, the Pacific side of western Japan is expected to be susceptible to the influence of low-pressure systems and fronts, with precipitation likely to be near or above average.



The one-month average sea-level pressure (left chart) is expected to be higher than normal near the Primorsky Krai (Maritime Province) and south of Okinawa. Conversely, with relatively lower pressure stretching from central China to western Japan, moist air from the south is likely to flow into the region. Consequently, areas including the Pacific side of western Japan are expected to be prone to the effects of low-pressure systems and fronts.

Temperatures at an altitude of approximately 1,500 meters (right chart) are expected to be higher than average, particularly across eastern and western Japan; these regions-extending toward Okinawa and the Amami Islands-are likely to be covered by warmer air. Meanwhile, a slight negative anomaly is indicated for the Sea of ??Okhotsk, suggesting that northern Japan, in particular, may experience periods influenced by cold air.


This forecast covers the expected average temperatures, precipitation, and sunshine duration for the next month, along with weekly average temperature projections (including the probability of occurrence).

In Northern Japan, temperatures are expected to be significantly lower at the start of the period due to the influence of cold air. In particular, areas along the Sea of Japan in Hokkaido may see snowfall totals well above the seasonal average.

In Eastern and Western Japan, temperatures will be low initially, but the region will subsequently come under the influence of warmer air. By the second week, temperatures could shift to become significantly higher, indicating a period of substantial temperature fluctuation.

Along the Pacific coast of Western Japan, the influence of low-pressure systems and fronts is expected to result in precipitation levels that are near or above average, while sunshine duration will likely be near or below average.

In the Okinawa and Amami regions, temperatures over the next month are expected to be higher than average, as the area will frequently be covered by warm air-with the potential for particularly high temperatures during the second week.

At the beginning of this period, much of the country will be affected by cold air, leading to lower temperatures. Please complete your winter preparations now and ensure you have warm outerwear or coats ready.
Additionally, heavy snowfall is expected, especially along the Sea of Japan side of Hokkaido; please equip your vehicle with winter tires and prepare for snowy road conditions. A strengthening "winter-type" pressure pattern could lead to heavy snow or blizzards, potentially disrupting transportation-please stay updated with the latest information.
In Eastern and Western Japan, temperatures may rise significantly later in the period. Keep an eye on daily weather and temperature forecasts, and adjust your clothing accordingly to stay healthy.

[Temperatures to hover around 15C at night] A rock festival will be held in Makuhari, Chiba Prefecture, tomorrow, Saturday the 7th—be prepared for cooler temperatures in the evening.

2026/11/06 16:59

A major rock festival is taking place this Saturday, the 7th, at an outdoor stadium in Makuhari, Chiba Prefecture. Hosted by a popular punk-rock band, the event is generating significant buzz, with a lineup that includes major superstars and international acts.

In preparation for the festival, we have compiled the local weather forecast for this weekend, along with some tips to help you stay comfortable at the venue.



Weather for Saturday, the 7th
The forecast for Saturday, the 7th, calls for a mix of sun and clouds, with a high of 21C and a low of 13C-conditions that may feel a bit chilly for an outdoor festival.

Tomorrow, the 7th, a "west-high, east-low" pressure pattern will develop over Japan, bringing clear skies and dry air to the Kanto region. Additionally, an influx of cold air from above, combined with northerly winds, will cause temperatures to drop significantly compared to today, Friday the 6th. While the daytime high in Makuhari, Chiba, will be a comfortable 21C, temperatures are expected to fall to around 15C as the evening approaches, leading to a noticeable chill.



Tips for Attendees
During the day, temperatures will hover around 20C, making for a comfortable environment. While short sleeves might feel a bit chilly, wearing a long-sleeved shirt or thermal base layers (such as Heattech) should be sufficient.
However, by the time the final acts take the stage in the evening, the temperature will drop to around 15C; it will be difficult to stay comfortable if you are underdressed. It's a good idea to bring an extra layer to wear, just in case. Please take care to ensure that temperature fluctuations don't affect your health.



Keep a close eye on the latest weather updates, and make sure you're in great shape to enjoy the best possible live concert experience!

Weekly Weather: Risk of severe weather in Northern Japan through around the 8th; cold rain expected from the Tohoku region to Kyushu early next week.

2026/11/06 16:55

Through around the 8th, the Sea of ??Japan side of Northern Japan can expect rough weather. Even in regions from Kanto westward, where skies will be clearer, there will be significant day-to-day fluctuations in temperature.



Tomorrow, Saturday the 7th, a "west-high, east-low" pressure pattern?characterized by high pressure to the west and low pressure to the east?will intensify across Honshu. A strong cold air mass, comparable to what is typically seen in early December, is expected to move southward over Northern Japan. Consequently, Hokkaido and the northern part of the Tohoku region?particularly along the Sea of ??Japan coast?will experience snow or rain, accompanied by strengthening winds and rough weather. In Hokkaido, in particular, snowfall is expected to intensify, potentially leading to blizzard conditions. Please be cautious of poor visibility and deteriorating road conditions, and be sure to check the latest information regarding road and traffic conditions.
In the mountainous and inland areas of northern Tohoku, snowfall may also intensify locally, leading to an increase in snow accumulation.
In Northern Japan, strong winds are expected to persist through around the 8th, with coastal areas potentially experiencing severe sea conditions, including waves exceeding 6 meters. Please remain on high alert for violent winds and high waves through around the 8th.
Following this, as the cold air mass remains over Northern Japan, frequent snowfall is expected, particularly in Hokkaido.



Meanwhile, while many areas along the Pacific coast?from the Kanto region westward?are expected to see clear skies, northerly winds will make the air feel cold as a mass of cold air moves southward from the upper atmosphere. From tomorrow, the 7th, through the 8th, morning low temperatures will drop below 10C in many places, leading to a significant morning chill.

On Monday the 9th?the start of the new week?a low-pressure system will bring cold rain to many areas, stretching from the Tohoku region down to Kyushu. In some places, the rain may intensify and be accompanied by localized thunderstorms. Daytime highs, even in central Tokyo, are expected to be around 15C; early in the week, some areas may experience temperatures more typical of December. As we move into the latter half of next week, the cold is expected to gradually ease across a wide area, spanning from western to eastern Japan.
Please take care of your health, as significant day-to-day temperature fluctuations are likely.

Tomorrow, Saturday the 7th, marks "Rittō" (the start of winter). As a strong cold air mass moves southward, conditions are expected to turn rough—with intensifying snow and winds—across the Sea of ​​Japan side of Northern Japan.

2026/11/06 15:11

Tomorrow, Saturday the 7th, marks "Ritt?" (the Beginning of Winter) in the traditional 24-solar-term calendar?signifying the start of winter in earnest.



From tonight through tomorrow, Saturday the 7th, a "winter-type" pressure pattern?characterized by high pressure to the west and low pressure to the east?will intensify across the vicinity of Honshu. Additionally, a strong cold air mass, comparable to what is typically seen in early December, is expected to move over northern Japan.



Tomorrow, snow is expected to fall across a wide area of ??Hokkaido. Particularly along the Sea of ??Japan coast, strengthening winds may lead to blizzard conditions in some places. By noon tomorrow, the 7th, 24-hour snowfall totals are forecast to reach up to 30 cm in the northern part of the Sea of ??Japan coastal region, and up to 20 cm in the southern and western parts of the Sea of ??Japan coast, as well as the northern part of the Sea of ??Okhotsk coast.
Furthermore, very strong westerly winds are expected; in some coastal areas, these could reach warning-level, storm-force intensity. Peak instantaneous wind speeds tomorrow, the 7th, could reach as high as 35 m/s (approx. 78 mph) both on land and at sea.

Along the Sea of ??Japan coast in the Tohoku region, very strong westerly winds are also expected. Waves will build, leading to rough sea conditions with wave heights potentially exceeding 6 meters. Additionally, in the inland and mountainous areas of northern Tohoku, snowfall may intensify in some locations, leading to an increase in snow accumulation.

In Hokkaido tomorrow, please be cautious of poor visibility and deteriorating road conditions caused by blizzards; be sure to check the latest traffic information. Also, be aware of the potential for power outages resulting from snow accumulating on power lines and similar infrastructure. In coastal areas, please remain on alert for strong winds and high waves.



Across regions from Kanto westward, the weather is expected to be largely sunny; however, with morning lows generally ranging from 10C to 12C, it will be quite chilly. During the day, temperatures in many areas will be lower than they were today (the 6th), and with cold, northerly winds blowing, it will feel even colder. Please dress warmly.

[Tohoku] Strong Winds Expected on Saturday, November 7; Transportation Disruptions Possible (Commentary by Meteorologist Junuko Miyake)

2026/11/06 14:53

The Tohoku region is expected to experience a winter storm this weekend, with rain and snow accompanied by strong winds.
Transportation services may be affected, so please stay updated on the latest weather and traffic information.







These are the forecast weather charts for tonight and tomorrow night.
A low-pressure system is expected to rapidly intensify near Hokkaido through tonight.
This pattern is forecast to persist through Saturday, maintaining a strong winter pressure pattern across northern Japan.
The tightly packed isobars are expected to remain in place through Saturday, bringing strong westerly winds to the Tohoku region.



Cold air will flow into the area on these strong westerly winds.



Air temperatures at around 1,500 meters above sea level are expected to fall below -6C, which is generally cold enough to bring snow to lowland areas.
This cold air mass is forecast to cover much of northern Tohoku.



Akita and Morioka have not yet recorded their first snowfall of the season, but both cities may see their first snow as early as tomorrow.







Now let's take a look at the forecast for precipitation and wind.
Today, periods of rain are expected across the Tohoku region.
At the same time, westerly winds will gradually strengthen, and colder air will begin moving in tonight.
As temperatures fall, rain is expected to gradually change over to snow.



By early Saturday morning, not only the mountainous areas of northern Tohoku but also some lowland areas may see snow or sleet.



Winds are expected to peak across the Tohoku region on Saturday.
Wind gusts of up to 30 meters per second are forecast on both the Pacific and Sea of Japan sides of the region, strong enough to make it difficult to remain standing.



Transportation services, including railways, may be disrupted, so please monitor the latest transportation updates.







Here is a closer look at the weather across the region.



Today, a typical winter weather pattern is in place.
Rain is expected mainly along the Sea of Japan coast.
Westerly winds will gradually become stronger.
Even on the Pacific side, occasional light rain showers are possible.
Temperatures will be relatively high during the daytime, but they will drop sharply after sunset.
Please take care regarding the significant temperature changes.







Saturday's forecast:
Rain and snow will continue to be likely, especially along the Sea of Japan coast.
Strong westerly winds may also carry rain and snow clouds into Pacific-side areas at times.







Looking ahead:
Unsettled weather is expected to continue across the Tohoku region into the first half of next week.
On Monday, another low-pressure system and associated front are expected to approach, bringing widespread rain even to Pacific-side areas.
By the latter half of next week, sunshine is expected to return, making for more comfortable weather conditions.

[Typhoon Information] Tropical depression near Minamitorishima may develop into Typhoon No. 32 as early as tomorrow

2026/11/06 12:28

At 9:00 a.m. today, Friday, November 6, Typhoon No. 31 transitioned into an extratropical cyclone east of Japan.
Even though it has become an extratropical cyclone, please remain cautious, as high waves may still occur along the Pacific coast of Eastern Japan.

Meanwhile, as of Friday, November 6, there is a tropical depression in the vicinity of Minamitorishima.
This tropical depression is intensifying as it moves west-northwest; according to the Japan Meteorological Agency (JMA), it is expected to develop into Typhoon No. 31 within the next 24 hours.



The JMA forecasts that the tropical depression will gradually gain strength, develop into Typhoon No. 32 on Saturday, November 7, and continue to intensify while moving slowly in a northwesterly direction.
The system is expected to travel across the waters south of Japan for several days before shifting toward the east, potentially approaching the Ogasawara Islands in the latter half of next week. Please stay alert and take precautions against high waves and strong winds.

Please note that there is a high degree of uncertainty regarding its future path, so be sure to keep an eye on the latest information.

[Hokkaido: Rain Turning to Snow] Full-Scale Winter Arrives This Weekend (Weather Forecaster: Junko Miyake)

2026/11/05 15:01

Many parts of Hokkaido will see rain through Friday, but precipitation is expected to change over to snow across much of the region from Saturday onward.

As of noon today, only a few locations in Hokkaido are reporting rain. However, rain clouds associated with low-pressure systems and frontal boundaries to the south are expected to spread northward and move into Hokkaido.

Rain will begin mainly across southern Hokkaido later today, becoming widespread from late afternoon through the evening.

Around midnight, areas near Muroran may see pockets of heavy rain, indicated by yellow and orange rainfall intensity levels.

There is also a risk of thunderstorms, so please be cautious of lightning strikes and sudden gusty winds.

Rain is expected to continue over a wide area through early Friday morning.

By around midday Friday, rain will temporarily ease in many locations. However, another band of rain clouds will approach from the west during the evening.

This next round of rain is expected to be noticeably colder.

Let's take a look at the weather pattern behind this change.

By Friday night, a winter-type pressure pattern is expected to develop, with high pressure to the west and low pressure to the east. A low-pressure system near Hokkaido is forecast to deepen rapidly.

The pressure gradient will become very tight, leading to strengthening westerly winds across Hokkaido.

These strong westerly winds will usher in the strongest cold air mass of the autumn season so far.

The forecast for Friday night shows air colder than -6C at around 1,500 meters above sea level moving into western Hokkaido. This is generally cold enough to bring snowfall even to lowland areas.

This cold air mass is expected to advance farther south through Saturday and Sunday, eventually covering all of Hokkaido.

Looking at the forecast for precipitation and wind, rain will gradually change to snow from around midnight Saturday.

Many lowland areas across Hokkaido are expected to see snow, and some locations may experience accumulating snowfall by Saturday morning.

Strong westerly winds may also produce blizzard conditions and significantly reduced visibility.

Even if you have already switched to winter tires, this is still the early part of the snow season, and many drivers have not yet become accustomed to snowy road conditions.

Please use extra caution when driving on snow-covered roads.

Blowing snow may also cause poor visibility, so be especially careful when traveling.

Now, turning to the detailed forecast for each area:

Rain will begin spreading from southern Hokkaido later today and become widespread this evening.

Through early Friday morning, some locations could experience heavy rain and thunderstorms.

From Friday evening, rain will redevelop from western Hokkaido and gradually spread eastward.

Some areas are expected to change from rain to snow during the night.

At the same time, westerly winds will strengthen, making conditions feel increasingly cold.

Looking ahead to the extended forecast, cold air is expected to remain over the region for some time.

The season of frequent snow icons in the forecast has now arrived.

Please continue to exercise caution when driving on snowy roads.

In particular, heavy snow and blizzard conditions are possible this weekend, especially on Saturday and Sunday.

Strong winds may also disrupt transportation services, so be sure to stay updated with the latest weather information.

Today, Thursday the 5th, the peak of the rain has passed in the Kanto region; meanwhile, the area affected by rain will expand across Western and Northern Japan this afternoon.

2026/11/05 13:18

Today, Thursday the 5th, a weather front and an associated low-pressure system have brought active rain clouds to the Kanto region, particularly over the Izu Islands. On Niijima Island (part of Niijima Village, Tokyo), 60.5 mm of "very heavy" rain was recorded in the hour leading up to 3:09 a.m.

Currently, the most active rain clouds are concentrated over the ocean to the east. Meanwhile, active rain clouds have also begun to move into areas near Western Japan.



The low-pressure system along the front-currently located east of the Kanto region-is expected to move toward the waters off the Sanriku coast by tonight, suggesting that the peak of the rainfall in the Kanto region has passed. However, warm, moist air-flowing in from the periphery of a high-pressure system and circulating around Typhoon No. 31-is being drawn toward the low-pressure system and the front. Consequently, atmospheric conditions will remain highly unstable, especially around the Izu Islands. Through the early morning hours of tomorrow, Friday the 6th, please remain cautious of lightning strikes, severe gusts (such as those associated with tornadoes), and hail.



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A low-pressure system near the Tsushima Strait will move eastward, and the area of ??rain across western Japan will gradually shift toward the east this afternoon. Warm, moist air is expected to flow toward this low-pressure system, making the atmosphere highly unstable. Cumulonimbus clouds may develop locally, and in the Kyushu region in particular, some areas could experience heavy rain accompanied by thunderstorms.
In the Kinki region-including Wakayama Prefecture-areas along the Pacific coast may also see heavy rain accompanied by thunderstorms late tonight.
Rain is also expected to begin in the Hokuriku region late tonight.
There is a risk of lightning strikes and severe gusts, such as those associated with tornadoes. If you notice signs that a developed cumulonimbus cloud is approaching, please take steps to ensure your safety, such as moving indoors.





Additionally, a trough of low pressure is forming near northern Japan, and the area of ??rain will gradually expand there from this evening onward.
Today, Thursday the 5th, is likely to be a day where rain is expected across much of the country.
Please remember to bring your rain gear.

[Kanto-Koshin Region] Atmospheric instability expected through the early hours of tomorrow, the 6th; caution also advised regarding unseasonable heat.

2026/11/05 13:08

A weather front extends from south of Japan, passing near the Izu Islands and reaching east of the Kanto region. A low-pressure system has formed along this front near the Izu Islands and is moving toward the northeast. Warm, moist air-flowing in from the periphery of a high-pressure system far to the east of Japan and circulating around Typhoon No. 31-has moved toward this low-pressure system and the front.
As a result, atmospheric conditions across the Kanto-Koshin region have become highly unstable,
leading to the development of active rain clouds from last night through this morning.



Due to these conditions, Niijima (Tokyo) recorded a 6-hour rainfall total of 202.5 mm by dawn on the 5th-the highest ever recorded at that location.
Kozushima also recorded 168.0 mm, setting a new record for the month of November.



As of midday, the active rain clouds have moved away toward the ocean to the east;
however, atmospheric conditions across the Kanto-Koshin region will remain unstable until tomorrow morning.
Please continue to exercise caution regarding flooding in low-lying areas, as well as rising water levels or potential overflowing of rivers.

The projected 24-hour rainfall totals through tomorrow morning are as follows (in areas with the heaviest precipitation):
Northern Kanto region: 50 mm
Southern Kanto region: 80 mm
Izu Islands: 100 mm

Additionally, please remain cautious of lightning strikes and severe gusts-such as those associated with tornadoes-through the early morning of the 6th. If there are signs that a developed cumulonimbus cloud is approaching, please take steps to ensure your safety, such as moving indoors. There is also a risk of hail, so please take precautions to protect agricultural crops and facilities.

Tomorrow, the 6th, the weather in the Kanto-Koshin region is expected to gradually improve,
with sunshine likely throughout the day.
Temperatures will rise due to the sun; the high in Tokyo is forecast to reach 24C,
while Kofu is expected to reach 25C-a "summer day" (a day with a high of 25C or above).



With a significant temperature difference of around 10C between the day and the morning/evening hours,
please take care to ensure that these temperature fluctuations do not affect your health.