It's probably just following the operational run... but the 18Z GEFS is quite a bit more ridgy than its 12Z run later next week and the 12Z run was not really chilly either.
Source: https://www.swpc.noaa.gov/products/alerts-watches-and-warnings
And note that the 11th UTC runs from 5:00 pm Friday to 5:00 pm Satuday local time, so as @Port Angeles Foothiller said, this is Friday night and Saturday morning.