The sun has done it again.
After more than a week with good strong solar activity, solar flux up to over 100, the activity jumped up to about 110, the 10m band is pretty good with openings detected, using FT8 as a monitor, to all continents.
After several days of solid solar activity, yesterday one of the sunspot groups unleashed an X-class solar flare, X1 - the highest category. This is not, by far, the strongest solar flare recorded, that happened in 2001, when the X-ray sensors on the NOAA satellites were saturated. Actually, I was watching the website when the flare started, and grew and grew in intensity, then the graph flattened at the X17, and I thought that the flare had finished, but when the graph stayed at X17 for more than 10 minutes I realized that this was much more than X17. It was later estimated to have been at the X28 level, and that is the official record. An X28 flare is 28 times stronger than X1.
Looking at the website it was clear that the sunspot group had already produced several major - M-class - when it erupted, and there is still activity in the sunspot group. When it erupted there was a short wave black-out - SID (Sudden Ionospheric Disturbance) on the day time side of Earth.
When I received the mail from Spaceweather.com I took a look at the short GIF of the flare in UV light, and there was a clearly visible darkening of the sun spreading fast from the flare site. This is something I had not noticed before, so I had to watch it a few times to be sure that it was not my imagination. But no, this was definitely visible.
The X1 flare from yesterday happened just when the sunspot group was close to the center of the sun's disk as seen from Earth, so the CME (Coronal Mass Ejection) is moving towards us. The expected impact time is likely to be around the night Saturday to Sunday, although the timing can be off.
What does the impact mean? If the direction of the magnetic field is "correct" we may get good mid-latitude aurora activity, with visible, or at least photographic aurora and a strong geomagnetic storm - the alert says up to the G3 level, if it is not, we get a lesser geomagnetic storm.
What does this mean for HF propagation? As I see it the CQWW SSB contest this week end might have very poor propagation, maybe even with periods of the bands almost closed.
Longer term, if the solar activity stays at this level, approaching winter, we could have some strong day time openings on the high HF bands 15 - 12 - 10m. I would not be surprised if we get strong F2 openings between Northern Europe and the East coast on North America - if the geomagnetic activity does not get too high. I will not be surprised if we will have good 10m opening all the way through winter and well into the spring here. It may disappoint, who knows?
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