Weather front.

English weather at it's finest. May 11th 2017, 18:15hrs. South to North weather front piles up against South Downs, almost like an invisible force field, before finally breaking over the top of whatever was holding it and racing inland.

[@roboftherock]

In all my years, I've never seen anything like that before. Thank you for showing it.

[@Sparky-Tim]

It's a giant space ship. They just got their timing wrong. Should've been night time. 😎