I've just checked the latest forecast, which should be pretty accurate at this late stage ...
Sunny intervals to start, with the possibility of thundery showers about 1:00 pm. Sunny intervals again later.
If we find ourselves in Chatburn with nasty-looking black clouds hovering over the hill between us and Slaidburn, we can opt to do the sensible thing and turn left before Grindleton, and ride through West Bradford to Waddington instead, staying down in the valley. Better that, than getting zapped by lightning on Beacon Hill (Grindleton Fell)!
If we go for a plan 'B' and conditions brighten during our cafe stop, then we could climb Waddington Fell afterwards and descend the other side to our route at Newton, though both sides of the Fell
would be hard on the fixie riders' legs. Alternatively, we could do an easier ride up to Cow Ark, down the Roman Road and rejoin our original route that way.
Let's see what the weather is like when we get to the
Ribble Valley. Hopefully, it will be fine for us until at least then.