"Dec 16, 2023 Geomagnetic storms are likely on Dec. 16th and 17th when multiple CMEs hit Earth's magnetic field. A new NOAA model shows three CMEs combining to form a single storm front striking in unison on Dec. 16th around 20:00 UT.
All of the incoming CMEs were launched into space by sunspot AR3514, which has been flaring almost constantly since Dec. 13th. The most important CME is linked to the X2.8-class flare of Dec. 14th; that one alone should be sufficient to spark a geomagnetic storm this weekend. NOAA analysts have issued a watch for G2-class (Moderate) geomagnetic storms with a chance of escalating to category G3 (Strong). Aurora sky watchers should be alert for auroral displays when it is dark outside."