"Guerrilla rainstorms" often hit Tokyo at short notice and scientists are hoping to use technology to come up with an earlier forecasting system ©Getty Images

Japanese researchers are hoping to develop a new system in time for the 2020 Olympic and Paralympic Games in Tokyo to accurately forecast torrential downpours.

Scientists have created a high-tech radar capable of producing a three-dimensional map of a rain cloud in 30 to 60 seconds, a significant improvement on existing systems that measure only parts of a cloud in up to five minutes.

The hope is that by the time of Tokyo 2020, the system will be able to identify the downpours - nicknamed "guerrilla rainstorms" in Japan - half-an-hour before they start. 

The radar, installed last year at Saitama University, just north of Tokyo, works in conjunction with estimating the amount of water vapour in the air to produce better forecasts. 

Katsuhiro Nakagawa, director of the Remote Sensing Laboratory at the National Institute of Information and Communications Technology, believes the new system will prove a valuable aid to Tokyo 2020 organisers. 

Japanese researchers at the Remote Sensing Laboratory at the National Institute of Information and Communications Technology are hoping new systems will help warn Tokyo 2020 of severe weather earlier ©NICT
Japanese researchers at the Remote Sensing Laboratory at the National Institute of Information and Communications Technology are hoping new systems will help warn Tokyo 2020 of severe weather earlier ©NICT

"The summer Olympic/Paralympic Games are coming up," Nakagawa told Agence France-Presse. 

"Particularly during summer, we see lots of 'guerilla downpours'.

"We believe our technology will be able to provide useful data so that people hosting outdoor events can hold them safely."

The weather is expected to be one of the biggest challenges faced by Tokyo 2020 next year.

Concerns over heat rose last summer when Japan suffered a record heatwave.

Temperatures reached 41.1 degrees Celsius with at least 96 people dying of heatstroke across Tokyo's 23 wards in July.

Typhoons are another fear and Tokyo 2020 have also reduced the maximum crowd size for sailing events to make an evacuation easier in case of a tsunami.