As with last night, good luck continued with the clouds despite a low-pressure
system centered nearly overhead. At sunset, there was a small-ish thunderstorm 10-15 miles west of Kitt Peak.
The storm fortunately moved away to the west and dissipated quickly.
The night was mostly clear although some thin, small clouds formed and dissipated on a few occasions in the vicinity of the mountain.
At about 0300 local time, major bands of clouds formed and operations ceased for nearly an hour until the sky cleared just before the start of morning twilight.
The seeing started out at about 1.8 arcsec and improved to 1 arcsec by the middle of the night. After the sky cleared near the end of the night, the seeing was in the vicinity of 2 arcsec.