In this case, there probably will be an ebook in the US when hardback comes out. Amazon US has the UK paper version available from 3rd parties, and you can probably buy it directly from Amazon UK and have it shipped to the US. As has been discussed repeatedly here, this isn't allowed for the ebook.
Series by UK authors is one reason I have a UK Kobo account. For example The Order of the Scales by Stephen Deas is the 3rd in a series and I bought the ebook back in May from WHSmith (I now go directly to Kobo). It comes out in the US next month. I do this using an Entropay virtual credit card, but it is a hassle to get from the US and they charge a fee up front. Others have had success using gift cards. For the saga of what happened last time I mentioned this, see
Top Ten Books Missing as eBooks and continue reading for what happened next.