Rain is on the way to the Interlagos circuit.
After a late shower or two in Sao Paulo on Thursday, Friday's track action at the Brazilian circuit took place in warm and dry conditions.
But the rain clouds are now gathering once again and forecasts suggest the night will be a wet one.
The threat of rain will continue throughout the night and into the morning, and – reminiscent of qualifying at Interlagos a year ago – heavy showers on Saturday are possible.
Some forecasts are predicting an 80 per cent chance of rain for the qualifying session at 2pm local.
"I think it's pretty certain to be raining tomorrow," agreed Mercedes' Norbert Haug.
A better day of weather is forecast for Sunday.