I have just been made aware of this article which seems to suggest something
I had suspected: that lunar tides are linked with jet streams. The article
is entitled:

"Equatorial Ionospheric Electrodynamic Perturbations During Southern
Hemisphere Stratospheric Warming Events"

But the abstract says:

"We also compare these data with extensive recent
results that showed the fundamentally important role of lunar semidiurnal
tidal effects on low latitude electrodynamic perturbations during of arctic
SSW events."
http://onlinelibrary.wiley.com/doi/1...50B B8.d01t04

If SSWs are caused by waves in jet streams breaking, then there is some sort
of connection with lunar tides.

Cheers, Alastair.