SpaceWeather updates

https://spaceweather.com/ - May 23, 2021

SOLAR FLARE FRENZY AND CME: Yesterday, May 22nd, sunspot AR2824 unleashed a sequence of solar flares unlike anything we've seen in years. In only 24 hours, NASA's Solar Dynamics Observatory recorded 10 C-flares and 2 M-flares: movie. The rapidfire explosions hurled multiple overlapping CMEs into space. According to NOAA models, at least one of them will graze Earth's magnetic field on May 26th. The impact of the CME's dense flank could spark G1-class geomagnetic storms and auroras.




The radio burst coincided with an M1.4-class solar flare at 21:30 UT. "This was a very hot and dynamic flare for sure," says Ashcraft. "I was recording audio at 22 MHz and 21 MHz, and my radio spectrograph was operating from 30 MHz down to 15 MHz. Strong solar radio emissions were present at all frequencies."

This event was so intense, radio operators in the Arctic heard it at midnight. Rob Stammes chart-recorded the outburst from the Polarlightcenter in Lofoten, Norway:



"This wasn't even a particularly strong flare," says Cukas. "It was a C2-class eruption at approximately 15:34 UT." Cukas recorded the event using a homemade solar telescope and a Solar Spectrum brand H-alpha filter.

"Normally, solar radio bursts can only be received during daylight hours," says Stammes. "Here in the Lofoten islands, the sun is only just below the horizon in May around midnight. So I was able to detect the event even though the sun was not up."

Astronomers classify solar radio bursts into 5 types. Ashcraft's radio spectrograph is able to determine which ones were present in the May 22nd outburst. "It was a mixture of Type II and Type V," he says. These are caused, respectively, by shock waves and electron beams moving through the sun's atmosphere in the aftermath of strong flares.

The flaring of sunspot AR2824 continues apace on May 23rd, so more radio bursts may be in the offing.

HUGE SOLAR RADIO BURST: During yesterday's frenzy, the sun emitted a shortwave radio burst so loud that "it drowned out lightning static from a severe local thunderstorm," reports Thomas Ashcraft, who recorded the noisy signal using a radio telescope in rural New Mexico. Click to listen to a 100 second sample of the sounds emerging from his loudspeaker.

JUST IN - AN OFF-TARGET CME MIGHT SIDESWIPE EARTH: Minor G1-class geomagnetic storms are possible on June 1st when a CME is expected to sideswipe Earth's magnetic field. The storm cloud was hurled into space on May 28th by departing sunspot AR2824, shown here in a movie from the Solar and Heliospheric Observatory:

This is one of the brightest and fastest CMEs of new Solar Cycle 25. If it were heading directly toward Earth the forecast might be different, calling for major instead of minor geomagnetic storms. However, sunspot AR2824 was almost all the way out of the Earth strike zone when it erupted on May 28th. Only the trailing periphery of the plasma cloud is likely to reach us.

That said, even glancing blows from CMEs can produce a good light show. High-latitude sky watchers should be alert for auroras on June 1st.