Force India driver Sergio Perez says Sunday's Japanese Grand Prix may not go ahead if Typhoon Phanfone hits Suzuka.
The typhoon has formed over the Pacific Ocean, and rain is expected for Friday practice, ahead of dry weather for qualifying on Saturday.
Mexican Perez, 24, said: "Rain will come tomorrow. The hurricane might come. If it comes, probably we won't be able to race."
Williams's Valtteri Bottas said: "There is a big chance of big rain on Sunday."
Felipe Massa, Bottas's team-mate, said: "I hope we can have the race and the weather doesn't affect us."
F1 chief meteorologist Steffen Dietz expects the race to be affected by rain.
"There are still big uncertainties for the storm track in the coming days," he said.
"The current forecast track for typhoon Phanfone keeps the eye of the storm to the southeast of Japan on Sunday, but with associated rainbands extending north towards Suzuka during the morning.
"Once it starts, the rain is likely to be prolonged and become increasingly heavy."
Winds will be mostly light initially but freshen as the days goes on. At this time, nothing too severe is expected before Monday.
The race is part of the run-in for the world championship between Mercedes drivers Lewis Hamilton and Nico Rosberg.
Hamilton leads by three points following his victory in Singapore two weeks ago, and there are 150 points available over the remaining five races.