The Sao Paulo region of Brazil has received a code orange weather warning for Friday, the first day of on-track action for the Sao Paulo Grand Prix.
Earlier this week, WeerOnline in collaboration with RacingNews365.com indicated that Friday may be hit with rain and thunderstorms.
With the on-track action just hours away, the situation has not improved and the weekend is set to be disrupted by wet weather.
The Instituto Nacional de Meteorologia issued code orange for the region in which Sao Paulo and the Interlagos Circuit are located.
The warning will remain in place until 21:00 local time on Friday, long after the end of qualifying for Sunday's Grand Prix.
Should Friday's on-track action be hit with rain, it could add another challenge on top of the F1 Sprint weekend in Brazil.
Teams have just one practice session to tune their cars for qualifying and the two races that take place during the weekend.
However, the forecast for Saturday and Sunday is projected to be dry, meaning the 10 outfits may have no dry-weather data heading into the sprint race and the Grand Prix on Sunday.