Curious WSPR propagation results

It seems odd to me that I would only be hearing from one rather small geographic region on 40 meters WSPR. You can see on the screen shot of the WSPRnet map that I have only picked up stns from SF area of CA (several stns repeatedly over about 1.5 hours so far). I am running a mag loop antenna from indoors... in the kitchen which has a due south facing wall.

Why only that one little region is my question? Can propagation together with mag loop antennas aim to one region that narrowly? Unless the only WSPR stns transmitting on 40 meters just happen to all be around San Fran/Sacramento.

My signal has not been spotted though. Yesterday it was the opposite. I was getting spotted but heard very little.