A-Index – Daily Average of Magnetic Activity

I’ve often wondered what the A-Index was all about. In fact, I especially wonder about its value when I’m trying to make contacts on 40-meters and the conditions are really bad i.e., static, static crashes, QSP, etc.

Is a high A-Index reading indicative of poor radio conditions?

Below is the A-Index from July 11th. A little unsettled.