RS: X windsurfers in action at the Rio 2016 Games - but they could face weather problems at this week's World Championships on the Tokyo 2020 course ©Getty Images

Concerns intensified tonight over the RS:X Windsurfing World Championships that are due to start racing in earnest tomorrow as severe tropical cyclone Talim made landfall on Japan’s main island of Honshu and was predicted to move north-west throughout the day.

The Japanese Meteorological Agency (JMA) updated its severe weather warnings at 03.25 Japanese Standard Time (JST)  September  18, predicting "high waves, heavy rain, gale, thunderstorm" for Fujisawa, just to the north of the Tokyo 2020 venue at Enoshima,  with the same forecast for the next two areas along the Sagami Bay in which racing is due to take place, Hiratsuka and Chigasaki.

Many of the 111 men and 67 women from over 30 different nations taking part in these Championships - which run officially from yesterday until next Sunday (September 23) - have been involved in the first of two days of practice racing and equipment inspection.

According to the event’s official website, the weather has so far provided "some spectacular conditions for warm up training… but with Typhoon No.18 getting close to Enoshima over the weekend, competitors could experience more of a local welcome than sushi for dinner, with winds of over 180km per hour potentially forecast".

The wind limit for windsurfers is between 25-30 knots – which corresponds to 46-55 kilometres per hour.

Japanese agency NHK World reported that Talim has been downgraded from a typhoon by the JMA, adding: "As of 1 AM on Monday (JST), the storm was about 40 kilometers south-southwest of Toyama City. 

"It increased its speed and was moving northeast at 65 kilometers per hour.

"It had a central atmospheric pressure of 980 hectopascals with winds of more than 100 kilometers per hour at its centre.

"In western Japan, Kyoto Prefecture had hourly rainfall of about 100 millimeters late Sunday evening.

"The weather agency's forecast has the storm bringing torrential rain to northern Japan through Monday.

"The Meteorological Agency has issued landside and flooding warnings to many prefectures in western Japan, including Kyoto and Tottori.

"The storm is affecting transport systems. Airlines canceled more than 800 flights on Sunday, mainly to and from Kyushu and Shikoku.

"Additional 230 flights scheduled for Monday, mostly to and from Hokkaido and Tohoku, have been suspended."