The Meteorological Agency said Thursday that its accuracy rate for predicting tornados was less than 10 percent between 2008 and 2012.
The agency issued 1,446 tornado warnings between March 2008 and May 2012. During the four years, the best rate was a mere 9 percent in 2008, while it was only 1 percent in 2011, according to a report issued at a government meeting on tornado-induced disasters.
The agency completely failed to issue warnings for tornados in numerous cases, the report said.
Agency officials said during the meeting that tornados in Japan are generally small and it is difficult to correctly forecast them.
The science ministry said it is planning to develop a new radar system to help improve the prediction rate.