At night the preference direction alternates weekly (as opposed to daytime when it's always a westerly preference). It so happened that this week it's 27R/9L at night, with westerly preference.
But that nightime alternation programme is pretty meaningless as it also states:-
"the runway to be used if weather conditions... ...preclude selection of the preferred runway".
I would reckon 90% of the time the surface wind would decide which landing direction to use - not some "political" choice.