We're told if a force 10 on way – by this? (7,8)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

Homophone (we’re told) of WHETHER (if), then an anagram (10 = reference to 10a ABOUT) of A FORCE , then ST (short for street = way). Extended definition. if there’s a Force 10 storm on the way, you’d hope the weather forecast would tell you so.