The visible aurora is a flora at the E layer. This aurora can be a curtain of ions capable of refracting radio waves at frequency ranges above 20Mhz. At the same time, the D layer is absorbing the lower HF radio waves. This is the time when amazing things can happen at the VHF range. As auroras are closely related to solar activity, there is a tendency for aurora to reappear in 27-day intervals.
Auroral activity has two distinct daily peaks.
Bulletins from WWV can also be found on packet or many Internet web sites. Watch for an increase in the K and A indices. Then I'll tune to the 6 Meter band and rotate my 6 Meter beam from south to north. NW U.S.A. Garhard, VE6AQO and myself are also working together to put a 144 MHz beacon at the VE6EMU site. The most common VHF band of choice is 50 MHz.