The National Oceanic and Atmospheric Administration's Space Weather Prediction Center (SWPC) has upgraded its geomagnetic storm watch for today and tomorrow (September 6 and 7) to G3 (Strong).
“The G3 Watch is in anticipation of the expected arrival of a coronal mass ejection (CME) that took place in association with an M5 flare,” the SWPC said. The Center said its current analysis and forecasts indicate that the CME will arrive late on September 6, with CME effects continuing into the next day. The primary area of impact is “large portions of the sunlit side of Earth,” and blackouts for up to an hour.
Auroral displays extending down into the Midwest and lower New England have been predicted, and these conditions augur well for VHF and UHF aurora work.
A moderate (R2) radio blackout was observed on September 4 at 2033 UTC, and a strong (R3) radio blackout occurred on September 6 at 1202 UTC in the wake of a strong X9.3-class solar flare. The September 6 flare followed an X2.2 flare, also R3, at 0910 UTC.
The source region for both flares was Region 2673 of the Sun. “Radio emissions suggest a coronal mass ejection (CME) may be associated with the X9.3 flare, but we await SOHO/LASCO coronagraph imagery for confirmation,” the SWPC said today at 1350 UTC.
On Labour Day, the solar flux took a huge leap, from 120 to 183 from a day earlier.
Hurricane Watch Net Manager Bobby Graves, KB5HAV, said the blackout has affected the net’s ability to function. “Mother Nature is not being very kind today,” he allowed. “There is basically a near total communications blackout occurring on 20 meters and higher; 40 metres is not doing so well either.” he reported at 1250 UTC. “We are diligently listening with all hands on deck to those in the path of Irma.”