

The stated intent for this first patch is “to add polish, increase stability, tweak AI behaviour, address some known gameplay issues and redress balance in a number of areas.”

That’ll be 6am Pacific (US), 9am Eastern (US). Here’s confirmation from Creative Assembly that the release time will be 2pm BST. The first update for Total War: Warhammer is due for release tomorrow (30 June) at 2pm BST, adding beta DirectX 12 support, a gigantic list of changes, and some free Blood Knights for the Vampire Counts.
