16 hundred hours; 16:00. Since revised down to midday (12 UTC).
https://www.swpc.noaa.gov/sites/default/files/styles/pad_sid...
https://www.swpc.noaa.gov/sites/default/files/styles/pad_sid...
Update: tonight the sky is clear and the air is frigid. I guess this logically implies there won't be an aurora :)