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Radar and Nowcasts (Precipitation, Thunder, Tornados): 

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Composite weather radar echoes and precipitation forecasts up to 60 minutes ahead are displayed in 1 km x 1 km resolution every 5 minutes, respectively. Any out-of-operation radars may cause radar echoes in affected areas to be weaker than they should be or not displayed at all.

Precipitation Nowcasts provide precipitation intensity forecasts of swiftly growing convections with a spatial resolution of 1 km up to an hour ahead to assist with disaster prevention activities.
Activity levels are defined as follows:
  • Activity 4: frequent lightning strikes
  • Activity 3: lightning strikes
  • Activity 2: thunder
  • Activity 1: potential for thunder
When the activity level is 2 – 4, seek shelter in a safe place such as a large building. If it will take time to evacuate to a safe place, seek shelter as soon as an Activity 1 situation develops. As lightning can occur even if no activity level or thunderstorm advisory is announced, it is important to pay attention to sudden changes in the weather.
The probability of hazardous winds such as tornados within any given hour is 7 – 14% in Level 2 areas and 1 – 7% in Level 1 areas. Although hazardous winds are rare, they can cause widespread fatalities. Accordingly, even though there is only a low risk of hazardous winds in Level 1 or 2 areas, it is advisable to seek shelter in a sturdy building when thunder or lightning occur or when dark threatening clouds gather. As hazardous winds can occur even in areas where the risk is lower than Level 1, it is important to pay attention to sudden changes in the weather.