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The cycle time for update is 5 minutes.To view the latest data, click the key "Refresh“ on the tool bar. The update may halt temporally due to radar maintenance or other inspection.
●Legend
The expression of the rainfall intensity in legend is indicated on ground-based situation.
On the one hand, rain precipitation indicated by radar differs from the actual rainfall on the ground, because it shows the rainfall intensity in the air before raindrops fall on the ground.
For reference, the image of rainfall display shown in the legend is shown below.
Hourly Precipitation
(mm)
Forecast Terms Image that people receive Influence on people Indoor
(in the case of wooden house)
Outdoor When riding a car
10 or more -
less than 20
Slightly Heavy rain Amid
driving rain
(The rain
sounds like “Zah Zah”)
The feet get wet by rain splashing from the ground Being unable to hear one’s voice well due to rain There are puddles on the whole ground  
20 or more -
less than 30
Heavy rain Dousing rain Getting wet even with an umbrella Taking approximately half of sleeping people notice the rain Visibility is poor even with a faster wiper
30 or more -
less than 50
Intense rain Rain as if a bucket of water is being emptied Roads become like a river When driving at high speed, a water film is formed between the wheel and the road surface and the brake does not work. (hydroplaning phenomenon)
50 or more -
less than 80
Very intense rain Rain in torrents (constant rain with rasping sound like “Goh Goh”) Umbrella is useless at all Splashing makes the surroundings whitish and poor visibility Driving a car is dangerous
80 or more - Torrential rain Feeling of pressure that makes feel stuffy. Feeling of fear.

Source: Created with reference to Japan Meteorological Agency website (Prepared in August 2000, partially amended in January 2002, in March 2017 and in September 2017)

(Note 1)
When there is a possibility of a disaster due to heavy rain, Heavy Rain Advisory or Flood advisory is announced, when a serious disaster is likely to occur, Heavy Rain Warning or Flood Warning is announced, and if there is a significant risk of a serious disaster, Heavy Rain Emergency Warning.
(Note 2)
When short-term heavy rain that occurs only once every few years is observed and analyzed, information of record-breaking heavy rain in short-time is announced. When this information is announced, it means that there is heavy rain in your inhabited area that can lead to landslides, inundation, and flooding of small-and-medium-sized rivers. Information standards vary by region.
JR Lines displays JR Lines in the map. companiesLine displays other companies’ line, subway is not included.
stationMark means the place of each station.
●Weather Warnings and Advisories
Japan Meteorological Agency issues heavy rain emergency warnings/warnings/advisories to call attention or precaution expecting damage possible.
The 1 hour rainfall amount, the 3 hours rainfall amount, the 48 hours rainfall amount and the tanked rain amount in soil are used to judge them.
All types of information written below will be shown in this site when announced by JMA.


Emergency
Warning
Heavy rain、Storm、Snow-storm、Heavy snow、High waves、Storm surge
Warning Heavy rain、Flood、Storm、Snow-storm、Heavy snow、High waves、Storm surge
Advisory Heavy rain、Flood、Gale、Gale and snow、Heavy snow、High waves、Storm surge、Thunderstorm、Snow melting、Dense fog、 Dry air、Avalanche、Low temperature、Frost、Ice accretion、Snow accretion
The standard of warnings/advisories for Tokyo Metropolitan Area, only japanese
Examples of municipal and resident responses to weather Warnings/Advisories

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