G3 Watch: 7 through 9 September, 2017 due to CME Effects
The G3 (Strong) geomagnetic storm watch for the 7 September UTC-day remains in effect due to coronal mass ejection (CME) arrival and effects from the 4 September CME. Additionally, a G3 Watch is now in effect for the 8 and 9 September UTC-days in anticipation of the arrival of another CME associated with the X9.3 flare (R3-Strong radio blackout) on 6 September at 1202 UTC (0802 ET). Analysis indicates likely CME arrival late on 8 September into early 9 September. Keep checking our SWPC website for updates to the forecast.