NOAA’s Space Weather Prediction Center (SWPC) has issued a strong (G3) geomagnetic storm watch for September 7 through September 9. The SWPC said the watch for September 7 remains in effect due to the arrival of a coronal mass ejection (CME) and the effects of a CME on September 4.
“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),” the SWPC said early on September 7. “Analysis indicates likely CME arrival late on 8 September into early 9 September.” The September 6 flare is being called the strongest in more than a decade.
Its effect on HF radio propagation has adversely affected the Hurricane Watch Net (HWN), currently operating on 20 and 40 meters as Hurricane Irma sweeps through the Caribbean.