The tail of a low-pressure system to the north of Arizona pushed across the region during the early evening, bringing some low level clouds and very strong winds. A few gusts peaked 50 mph, very rare for the Mt. Bigelow site. By 10:30pm, the sky cleared and the wind became manageable. However, the front left poor seeing in its wake. 2-3 arcsec was typical, with occasional worse seeing bursts.