Unsettled weather settled in over Arizona tonight. Orographic clouds were
the major problem, as thunderstorms to the west
of the observatory never got closer than about 100 km. Only a handful
of brighter blazars could be observed for polarization
during short gaps in the cloud cover. No photometry was attempted.
Observations were impossible after 0100 local time when it became totally
overcast.
The seeing was 2-4 arcsec and the temperature took yet another nosedive
to near freezing by the end of the night. Pretty impressive weather
for southern Arizona in May. The forecast has more of the same for tomorrow
night.
