The latest forecast has changed to shift the timing of the rain chances a little earlier, into Friday. All the models are in good agreement that a low pressure system will pass to the north of England on Friday and Friday night, and it could bring some light rain to Silverstone on Friday. However, I have kept the chance of rain low because much of the precipitation with this system will be across Scotland and Northern England. If some rain does fall at Silverstone, I expect that it will be light - only a few hundredths of an inch, or a couple millimeters.
The system will be departing and moving into Scandinavia on Saturday, but a few scattered showers will still be possible due to colder air aloft creating some weak instability. Most of the day will be cloudy, but I expect that there will be a few periods when the sunshine breaks through the clouds. It will be quite breezy on Saturday as well as the low pressure system exits and high pressure builds in from the west. Race day looks good, with a mix of clouds and sun, and no rain expected. At least there won't be any snow or sleet like last year!