![ACE SWEPAM plot showing interplanetary shock arrival.](https://www.swpc.noaa.gov/sites/default/files/styles/pad_sides_large/public/top_news/Shock_20141221_1824.png?itok=dwDHMB3e)
Interplanetary Shock Arrived at ACE - Geomagnetic Disturbance in Progress
An interplanetary shock was detected at the ACE spacecraft December 21st at approximately 1824 UTC (1:24 p.m. EST). This shock is believed to be associated with the coronal mass ejection from December 18th. Active to minor storm (G1 - Minor) conditions followed and are expected to persist through the end of December 22nd. You'll find the latest aurora predictions at http://www.swpc.noaa.gov/products/30-minute-aurora-forecast