A typical morning might show plenty of signals logged from Europe and the East coast of the USA. But there's nearly always one or two signals from the West coast that I have heard and more often than not, I am the only one or one of a few in Europe to have heard their signal. An typical example looks like the one above from K7LG in southern California. As you can see, I am the only European station that heard him that night/morning.
Looking at the great circle path, it becomes obvious that Ireland and Britain are closer than most of the mainland Europe for propogation to the west coast of the USA. As well as 30m, I have seen the same results on 40m and I presume it is the same for 20m.
So, if you are an EI/GI/GM station and are on the air after midnight or in the early hours of the morning, have a listen for those west coast stations.