The second practice session for the United States Grand Prix was cancelled on Friday afternoon amid thunderstorms.
With torrential rain battering the circuit, FP2 was delayed "indefinitely" at the Circuit of the Americas, with "marshals unable to work due to the proximity of lightning". After almost an hour of further heavy rain, high winds and lightning, the session was cancelled for the day due to the lack of medical helicopter operations before 5pm local time.
The bad weather is forecast to continue throughout Saturday and in to Sunday morning due to the presence of Hurricane Patricia which is set to make landfall in Mexico. As a result, the rest of the race weekend schedule could change in an attempt to fit in qualifying ahead of the race.
Limited running took place during FP1 on Friday morning in wet conditions before the worst of the rain hit. Nico Rosberg was quickest ahead of the Red Bull pair of Daniil Kvyat and Daniel Ricciardo, with Lewis Hamilton fourth and Sebastian Vettel fifth.
With FP2 cancelled the session will not be rescheduled, leaving teams with a best case scenario of one hour of practice on Saturday before qualifying.
Technical analysis: Exclusive pictures of the 2015 Honda power unit
Click here for the F1 drivers' girlfriends gallery
Keep up to date with all the F1 news via Facebook and Twitter
