On that "Today's space weather" site, you can click on the Kp index chart which will bring up a blown up version of the same chart. At the bottom of this page it lists the locations of the magnetometers being used.

The signals that I get in do occur in other locations such as Whittier, Calif., Irvine, Calif., and over in Arizona. What I haven't been able to verify yet is the timing of the signals between these different locations.