Late on Thursday afternoon at Interlagos, heavy rain started to fall.

The weather could be a precursor to a wet weekend at the Brazilian circuit, which a year ago hosted a famously drenched qualifying session.

The forecast for Friday is for a mainly fine day, with the chance of showers increasing later on and overnight.

Saturday could be showery and the outlook for Sunday is for better weather, but the conditions in Sao Paulo are often unpredictable — Thursday, for example, was expected to remain dry.

“It’s likely we will have some wet running this weekend,” said Renault driver Robert Kubica.

Sergio Perez has denied his major sponsor Telmex is positioning to buy control of the Sauber team.

The Mexican telcom will have significant signage on next year’s C30, and its figurehead Carlos Slim – the richest man in the world – has been seen at several grands prix recently.

But boss Peter Sauber earlier this month denied he is considering selling the Hinwil based team, and Slim said the deal is a “commercial alliance” rather than a precursor to a greater involvement.

But when told that the rumours about Telmex buying Sauber still exist, rookie driver Perez said: “No, that’s not true.

“Telmex is entering as a sponsor and nothing more,” he is quoted by the AS newspaper.

The rumours are retaining their strength because Perez will be joined at the team by another Mexican, the test driver Esteban Gutierrez.

“Esteban and I are here because Sauber decided to sign us,” Perez, 20, insisted.

He also backed Fernando Alonso to win the 2010 world championship.

“He doesn’t have as good a car as the Red Bull drivers, but he is the best driver,” said Perez.

Valentino Rossi has admitted it is unlikely he will switch to formula one in the future.

Now 31, the multiple champion of MotoGP has in the past flirted with a move to F1 after several test drives.

After badly breaking his leg earlier this season, Rossi has been beaten to the 2010 title and it had been said his move from Yamaha to the Italian marque Ducati could be a precursor to a future move to Ferrari.

But while in Malaysia last weekend for the latest MotoGP race, he told Italian media: “Now, I really don’t think it (moving to F1) will happen.”

Rossi was also scathing whilst criticising the motorcycle racing series’ governing body for deciding to delay the Sepang race to avoid a television clash with F1 in Japan.

He said the move compromised riders’ safety because the threat of rain in Malaysia is greater later in the day.

“We always bend over backwards to the formula one superpower,” said the Italian.