Alcohol and INR

I'd like to learn more about the effect of alcohol drinking on the INR of somebody who is on Cumadin (or Warfarin).

does the effect consist in raising or lowering the INR?

what is the alcohol effect trend and duration?
I mean: let's suppose one takes his Coumadin pill every day at 6pm, drinks no alcohol and his INR stays generally in the 2.3 - 2.7 range.
One day he drinks let's say a couple of wine glasses at 8pm: how could his INR react in the following hours?
Same question if he drinks that wine at noon (only at noon).

Thank you in advance