Plenty of residual high humidity and clouds made observing a challenge after
a cold front swept through southern Arizona during the early afternoon.
Some snow fell at the observatory as the front came through.
The sky was dominated by thin cirrus early in the evening, but
specropolarimetry was possible through the cloud cover.
Heavier clouds started forming a couple of hours into the night and
forced the dome to be closed for over an hour before midnight.
After midnight, observing was very limited and fog ended the night just
before 0200 local time. In all, fewer than 10 blazars were observed for polarization
in seeing of 1.2-2 arcsec.
