In 1994 I posted the following to a thread on
sci.geo.meteorology :

"A whistler mode wave is radiation that propagates in
the magnetosphere at ELF 0.3--3 Hz and VLF 3-30 kHz
frequencies. Interactions in the magnetosphere between
whistler mode waves and electrons are a form of coupling
between atmospheric regions that is well documented but
still not completely understood. The whistler mode
wave can lower the mirror height of some electrons
and cause them to precipitate into the atmosphere.
-paraphrased from Journal of Geophysical Research 97,
number A1, 65--75, Jan. 1, 1992. A Case Study of
Lightning, Whistlers, and Associated Ionospheric
Effects During a Substorm Particle Injection Event."

From that paper I take it that effects of a solar
flare on the ionosphere can cause clear sky
lightning not related to clouds over the horizon.
Am I correct there?

I remember one instance in 1990 when I was in a
downtown bar in St. John's and there were no
clouds in the sky and there was a bolt of
lightning that caused a power outage, whereupon
the bars broke out the candles.

Then at the end of August 1991, the middle of
June 1993, and near the end of August 1994 I
three times experienced clear sky lightning
about two days after an M-class solar flare.
In each case the clear sky lightning came
at the onset of one of my waning crescent highs
(mania or hypomania). I describe this in more
detail on my Salmon on the Thorns web page
http://www.nfld.com/~dalton/dtales.html .
However I need to update the science section
of that web page.

--
David Dalton http://www.nfld.com/~dalton (home page)
http://www.nfld.com/~dalton/nf.html Newfoundland&Labrador Music & Travel
"And the cart is on a wheel; And the wheel is on a hill
And the hill is shifting sand; And inside these laws we stand." (Ferron)