There are delays of up to 30 minutes on First Great Western services between Taunton and Bristol Temple Meads due to cows having been on the line at Nailsea and Backwell.
Lines are now open but delays are expected until around 9am.
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It should be a reasonably dry night with some light winds.
It will stay dry overnight with some cloud in parts.
Four people have died in Bristol Harbour this year.